bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary Antioxidants and Parkinson’s Disease
Authors: Park Han-A , Ellis Amy C.
Published: July 2020

Parkinson’s disease (PD) is a neurodegenerative disorder caused by the depletion of dopaminergic neurons in the basal ganglia, the movement center of the brain. Approximately 60,000 people are diagnosed with PD in the United States each year. Although the direct cause of PD can vary, accumulation of oxidative stress-induced neuronal damage due to increased production of reactive oxygen species (ROS) or impaired intracellular antioxidant defenses invariably occurs at the cellular levels. Pharmaceuticals such as dopaminergic prodrugs and agonists can alleviate some of the symptoms of PD. Currently, however, there is no treatment to halt the progression of PD pathology. Due to the nature of PD, a long and progressive neurodegenerative process, strategies to prevent or delay PD pathology may be well suited to lifestyle changes like dietary modification with antioxidant-rich foods to improve intracellular redox homeostasis. In this review, we discuss cellular and genetic factors that increase oxidative stress in PD. We also discuss neuroprotective roles of dietary antioxidants including vitamin C, vitamin E, carotenoids, selenium, and polyphenols along with their potential mechanisms to alleviate PD pathology.
Combined Generative Adversarial Network and Fuzzy C-Means Clustering for Multi-Class Voice Disorder Detection with an Imbalanced Dataset
Authors: Chui Kwok Tai , Lytras Miltiadis D. , Vasant Pandian
Published: July 2020

The world has witnessed the success of artificial intelligence deployment for smart healthcare applications. Various studies have suggested that the prevalence of voice disorders in the general population is greater than 10%. An automatic diagnosis for voice disorders via machine learning algorithms is desired to reduce the cost and time needed for examination by doctors and speech-language pathologists. In this paper, a conditional generative adversarial network (CGAN) and improved fuzzy c-means clustering (IFCM) algorithm called CGAN-IFCM is proposed for the multi-class voice disorder detection of three common types of voice disorders. Existing benchmark datasets for voice disorders, the Saarbruecken Voice Database (SVD) and the Voice ICar fEDerico II Database (VOICED), use imbalanced classes. A generative adversarial network offers synthetic data to reduce bias in the detection model. Improved fuzzy c-means clustering considers the relationship between adjacent data points in the fuzzy membership function. To explain the necessity of CGAN and IFCM, a comparison is made between the algorithm with CGAN and that without CGAN. Moreover, the performance is compared between IFCM and traditional fuzzy c-means clustering. Lastly, the proposed CGAN-IFCM outperforms existing models in its true negative rate and true positive rate by 9.9–12.9% and 9.1–44.8%, respectively.
Controlling the Doping Depth in Silicon Micropillars
Authors: Kabalan Amal
Published: July 2020

Micropillar arrays with radial p–n junctions are attractive for photovoltaic applications, because the light absorption and carrier collection become decoupled. The main challenge in manufacturing radial p–n junctions is achieving shallow (dopant depth <200 nm) and heavy doping (>1020 cm−3) that will allow the formation of a quasi-neutral region (QNR) and space charge region (SCR) in its tiny geometry. This experimental study investigates an approach that allows shallow and heavy doping in silicon micropillars. It aims to demonstrate that silicon dioxide (SiO2) can be used to control the dopant penetration depth in silicon micropillars.
A New Flexible Method for Solving Multi-Expert Multi-Criterion Decision-Making Problems
Authors: Wen Ta-Chun , Lai Hsin-Hung , Chang Kuei-Hu
Published: July 2020

Multi-expert multi-criterion decision-making problems are complicated decision issues. Different experts have different opinions with regard to multi-criterion decision-making problems, depending on their background and experience. These experts provide information that usually contains certain, uncertain, and incomplete information simultaneously. However, traditional computing methods only fully consider certain information, and ignore uncertain or incomplete information, which causes information distortion in assessment results. In order to effectively solve the above problems, this paper proposes a new flexible method for solving multi-expert multi-criterion decision-making problem. The primary purpose of the proposed method is to fully consider all information provided by experts to avoid information distortion of assessment results. Finally, an illustrative example of computer numerical control (CNC) machine tool selection is provided to prove the practicality of the proposed method. After comparing the results generated by proposed method with the results generated using linguistic ordered weighted geometric averaging operator (LOWGA) operator and induced LOWGA operator methods, the results indicate that the proposed method integrating an induced LOWGA operator and a hesitant fuzzy linguistic term set is more flexible and is able to reflect real-world situations.
A Control-Oriented Linear Parameter-Varying Model of a Commercial Vehicle Air Brake System
Authors: Hu Dawei , Li Gangyan , Zhu Guoming , Liu Zihao , Wang Yingxu
Published: July 2020

This paper presents a control-oriented LPV (Linear Parameter-Varying) model for commercial vehicle air brake systems, where a pneumatic valve actuator is used to control the brake chamber pressure. To improve the brake system response time and reduce the vehicle stopping distance, the traditional treadle valves used in the air brake system are replaced by electro-pneumatic valves. Also, to develop the model-based brake control strategy, a nonlinear mathematical model is developed based on Newton’s second law, fluid dynamics of the orifice, force balance of spool, and solenoid dynamic characteristics. The brake chamber dynamics is also considered during the charging and discharging processes. The developed nonlinear model is calibrated based on both valve actuator geometry and test bench experimental results. It is proposed to model the nonlinear system in the LPV form so that gain-scheduling controllers can be developed. To obtain the LPV model, system identification is conducted using the calibrated nonlinear model to obtain a set of linearized models under different brake chamber pressure levels, and the resulting identified linear models are assembled to form the LPV model with brake chamber pressure as the varying parameters. A linear infinite-horizon continuous-time LQR (Linear Quadratic Regulator) controller was designed for the braking system based on the developed LPV model with the fixed parameter to demonstrate the effectiveness of the developed LPV model.
Cell-Adhesion Properties of β-Subunits in the Regulation of Cardiomyocyte Sodium Channels
Authors: Salvage Samantha C. , Huang Christopher L.-H. , Jackson Antony P.
Published: July 2020

Voltage-gated sodium (Nav) channels drive the rising phase of the action potential, essential for electrical signalling in nerves and muscles. The Nav channel α-subunit contains the ion-selective pore. In the cardiomyocyte, Nav1.5 is the main Nav channel α-subunit isoform, with a smaller expression of neuronal Nav channels. Four distinct regulatory β-subunits (β1–4) bind to the Nav channel α-subunits. Previous work has emphasised the β-subunits as direct Nav channel gating modulators. However, there is now increasing appreciation of additional roles played by these subunits. In this review, we focus on β-subunits as homophilic and heterophilic cell-adhesion molecules and the implications for cardiomyocyte function. Based on recent cryogenic electron microscopy (cryo-EM) data, we suggest that the β-subunits interact with Nav1.5 in a different way from their binding to other Nav channel isoforms. We believe this feature may facilitate trans-cell-adhesion between β1-associated Nav1.5 subunits on the intercalated disc and promote ephaptic conduction between cardiomyocytes.
Implication of Opioid Receptors in the Antihypertensive Effect of a Novel Chicken Foot-Derived Peptide
Authors: Mas-Capdevila Anna , Iglesias-Carres Lisard , Arola-Arnal Anna , Aragonès Gerard , Muguerza Begoña , Bravo Francisca Isabel
Published: July 2020

The peptide AVFQHNCQE demonstrated to produce nitric oxide-mediated antihypertensive effect. This study investigates the bioavailability and the opioid-like activity of this peptide after its oral administration. For this purpose, in silico and in vitro approaches were used to study the peptide susceptibility to GI digestion. In addition, AVFQHNCQE absorption was studied both in vitro by using Caco-2 cell monolayers and in vivo evaluating peptide presence in plasma from Wistar rats by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and by ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Both in vivo and in vitro experiments demonstrated that peptide AVFQHNCQE was not absorbed. Thus, the potential involvement of opioid receptors in the BP-lowering effect of AVFQHNCQE was studied in the presence of opioid receptors-antagonist Naloxone. No changes in blood pressure were recorded in rats administered Naloxone, demonstrating that AVFQHNCQE antihypertensive effect is mediated through its interaction with opioid receptors. AVFQHNCQE opioid-like activity would clarify the antihypertensive properties of AVFQHNCQE despite its lack of absorption.
Effects of NAD+ in Caenorhabditis elegans Models of Neuronal Damage
Authors: Lee Yuri , Jeong Hyeseon , Park Kyung Hwan , Kim Kyung Won
Published: July 2020

Nicotinamide adenine dinucleotide (NAD+) is an essential cofactor that mediates numerous biological processes in all living cells. Multiple NAD+ biosynthetic enzymes and NAD+-consuming enzymes are involved in neuroprotection and axon regeneration. The nematode Caenorhabditis elegans has served as a model to study the neuronal role of NAD+ because many molecular components regulating NAD+ are highly conserved. This review focuses on recent findings using C. elegans models of neuronal damage pertaining to the neuronal functions of NAD+ and its precursors, including a neuroprotective role against excitotoxicity and axon degeneration as well as an inhibitory role in axon regeneration. The regulation of NAD+ levels could be a promising therapeutic strategy to counter many neurodegenerative diseases, as well as neurotoxin-induced and traumatic neuronal damage.
Surfactant Interactions with Protein-Coated Surfaces: Comparison between Colloidal and Macroscopically Flat Surfaces
Authors: Mateos Helena , Valentini Alessandra , Lopez Francesco , Palazzo Gerardo
Published: July 2020

Surface interactions with polymers or proteins are extensively studied in a range of industrial and biomedical applications to control surface modification, cleaning, or biofilm formation. In this study we compare surfactant interactions with protein-coated silica surfaces differing in the degree of curvature (macroscopically flat and colloidal nanometric spheres). The interaction with a flat surface was probed by means of surface plasmon resonance (SPR) while dynamic light scattering (DLS) was used to study the interaction with colloidal SiO2 (radius 15 nm). First, the adsorption of bovine serum albumin (BSA) with both SiO2 surfaces to create a monolayer of coating protein was studied. Subsequently, the interaction of these BSA-coated surfaces with a non-ionic surfactant (a decanol ethoxylated with an average number of eight ethoxy groups) was investigated. A fair comparison between the results obtained by these two techniques on different geometries required the correction of SPR data for bound water and DLS results for particle curvature. Thus, the treated data have excellent quantitative agreement independently of the geometry of the surface suggesting the formation of multilayers of C10PEG over the protein coating. The results also show a marked different affinity of the surfactant towards BSA when the protein is deposited on a flat surface or individually dissolved in solution.
Clinical Severity and Calcium Metabolism in Patients with Bipolar Disorder
Authors: Steardo Luca , Luciano Mario , Sampogna Gaia , Carbone Elvira Anna , Caivano Vito , Di Cerbo Arcangelo , Giallonardo Vincenzo , Palummo Carmela , Vece Alfonso , Del Vecchio Valeria , De Fazio Pasquale , Fiorillo Andrea
Published: July 2020

Parathyroid hormone (PTH), vitamin D and serum calcium play a key role in several physiological and pathological conditions. Vitamin D and PTH receptors are largely expressed in the central nervous system and are involved in the modulation of inflammatory responses. Few studies investigated the association between calcium homeostasis imbalance and psychiatric disorders. This study aims to assess calcium homeostasis imbalance in patients with bipolar disorder (BD) and its impact on clinical outcome. We recruited 199 patients with BD, who were administered with validated assessment instruments to investigate depressive, manic and anxiety symptoms, affective temperaments, childhood trauma and global functioning. Serum calcium, vitamin D and PTH levels were assessed in all patients. Levels of PTH correlated with several clinical characteristics, including the diagnosis of bipolar disorder type I (BD-I), the presence of psychotic symptoms, lithium treatment, suicidality, total number of acute episodes and of hospitalizations (p < 0.0001) and seasonality (p < 0.05). At the regression analyses, higher levels of PTH were predicted by early age at onset, number of hospitalizations, aggressive behaviors (p < 0.05), higher Childhood Trauma Questionnaire total score (CTQ) (p < 0.001) and treatment with lithium (p = 0.01). Our findings suggest that the calcium homeostasis could play a role in BD patients, and that PTH levels are correlated with the clinical severity of the disorder.
Atrial Fibrillation on Patients with Vascular Dementia: A Fundamental Target for Correct Management
Authors: Viticchi Giovanna , Falsetti Lorenzo , Burattini Marco , Zaccone Vincenzo , Buratti Laura , Bartolini Marco , Moroncini Gianluca , Silvestrini Mauro
Published: July 2020

Background: Atrial fibrillation (AF) is a risk factor for cerebrovascular diseases and vascular dementia (VAD). The aim of this study was to evaluate the effect of the adherence to anticoagulant therapy guidelines in patients with dementia and AF on the risk of stroke/TIA or major bleeding (MB). Methods: In a cohort of 1705 hospitalized patients with pre-existent AF, we observed 193 patients with vascular dementia (VAD). Non-demented AF patients were included as controls. For each subject, we calculated CHA2DS2-VASc, CHADS2, and HAS-BLED scores, and collected information regarding anticoagulant therapy, in-hospital therapeutic failure (TF) occurrence, stroke/TIA, and MB. Results: According to CHA2DS2-VASc and CHADS2 scores, 99.5% of VAD patients had the indication to anticoagulant treatment, but only 69.9% were correctly treated. During hospitalization, MB occurred in 4.66% of VAD and 8.9% of non-demented patients (p = 0.048). In-hospital stroke/TIA were observed in 24.3% of VAD and 0.8% of non-demented patients (p = 0.0001). A similar proportion of TF among patients with VAD and with normal cognition (12.9% vs. 11.2%) was observed. Conclusion: In our cohort, we observed that VAD patients with pre-existent AF were undertreated despite a higher risk of stroke/TIA with respect to non-demented patients.
Reactive Oxygen Species and Antitumor Immunity—From Surveillance to Evasion
Authors: Kotsafti Andromachi , Scarpa Marco , Castagliuolo Ignazio , Scarpa Melania
Published: July 2020

The immune system is a crucial regulator of tumor biology with the capacity to support or inhibit cancer development, growth, invasion and metastasis. Emerging evidence show that reactive oxygen species (ROS) are not only mediators of oxidative stress but also players of immune regulation in tumor development. This review intends to discuss the mechanism by which ROS can affect the anti-tumor immune response, with particular emphasis on their role on cancer antigenicity, immunogenicity and shaping of the tumor immune microenvironment. Given the complex role that ROS play in the dynamics of cancer-immune cell interaction, further investigation is needed for the development of effective strategies combining ROS manipulation and immunotherapies for cancer treatment.
Immunotherapy in Prostate Cancer
Authors: Fay Emily K. , Graff Julie N.
Published: July 2020

Immunotherapy encompasses a wide range of therapies to engage the immune system to target malignancies. In recent years, immunotherapy has made a major impact on treatment of metastatic cancer and has altered standard of care for many tumor types. However, predicting and understanding responses across tumor types has been challenging. While some metastatic cancers have shown dramatic responses to immunotherapy, such as melanoma, lung cancer, and renal cell carcinoma, prostate cancer has generally failed to show a significant response. However, small series of prostate cancer patients have shown impressive responses to cellular and immunotherapy. This review summarizes the current data for immunotherapy’s use in prostate cancer, as well as how currently available data might help predict patient responses to immunotherapy. Specifically, we will review vaccine-based therapies, immune checkpoint inhibitors, and future directions that are actively being explored.
Long-Pentraxin 3 Affects Primary Cilium in Zebrafish Embryo and Cancer Cells via the FGF System
Authors: Guerra Jessica , Chiodelli Paola , Tobia Chiara , Gerri Claudia , Presta Marco
Published: July 2020

Primary cilium drives the left-right asymmetry process during embryonic development. Moreover, its dysregulation contributes to cancer progression by affecting various signaling pathways. The fibroblast growth factor (FGF)/FGF receptor (FGFR) system modulates primary cilium length and plays a pivotal role in embryogenesis and tumor growth. Here, we investigated the impact of the natural FGF trap long-pentraxin 3 (PTX3) on the determination of primary cilium extension in zebrafish embryo and cancer cells. The results demonstrate that down modulation of the PTX3 orthologue ptx3b causes the shortening of primary cilium in zebrafish embryo in a FGF-dependent manner, leading to defects in the left-right asymmetry determination. Conversely, PTX3 upregulation causes the elongation of primary cilium in FGF-dependent cancer cells. Previous observations have identified the PTX3-derived small molecule NSC12 as an orally available FGF trap with anticancer effects on FGF-dependent tumors. In keeping with the non-redundant role of the FGF/FGR system in primary cilium length determination, NSC12 induces the elongation of primary cilium in FGF-dependent tumor cells, thus acting as a ciliogenic anticancer molecule in vitro and in vivo. Together, these findings demonstrate the ability of the natural FGF trap PTX3 to exert a modulatory effect on primary cilium in embryonic development and cancer. Moreover, they set the basis for the design of novel ciliogenic drugs with potential implications for the therapy of FGF-dependent tumors.
Penicillin Acylase from Streptomyces lavendulae and Aculeacin A Acylase from Actinoplanes utahensis: Two Versatile Enzymes as Useful Tools for Quorum Quenching Processes
Authors: Velasco-Bucheli Rodrigo , Hormigo Daniel , Fernández-Lucas Jesús , Torres-Ayuso Pedro , Alfaro-Ureña Yohana , Saborido Ana I. , Serrano-Aguirre Lara , García José L. , Ramón Fernando , Acebal Carmen , Santos Antonio , Arroyo Miguel , de la Mata Isabel
Published: July 2020

Many Gram-negative bacteria produce N-acyl-homoserine lactones (AHLs), quorum sensing (QS) molecules that can be enzymatically inactivated by quorum quenching (QQ) processes; this approach is considered an emerging antimicrobial alternative. In this study, kinetic parameters of several AHLs hydrolyzed by penicillin acylase from Streptomyces lavendulae (SlPA) and aculeacin A acylase from Actinoplanes utahensis (AuAAC) have been determined. Both enzymes catalyze efficiently the amide bond hydrolysis in AHLs with different acyl chain moieties (with or without 3-oxo modification) and exhibit a clear preference for AHLs with long acyl chains (C12-HSL > C14-HSL > C10-HSL > C8-HSL for SlPA, whereas C14-HSL > C12-HSL > C10-HSL > C8-HSL for AuAAC). Involvement of SlPA and AuAAC in QQ processes was demonstrated by Chromobacterium violaceum CV026-based bioassays and inhibition of biofilm formation by Pseudomonas aeruginosa, a process controlled by QS molecules, suggesting the application of these multifunctional enzymes as quorum quenching agents, this being the first time that quorum quenching activity was shown by an aculeacin A acylase. In addition, a phylogenetic study suggests that SlPA and AuAAC could be part of a new family of actinomycete acylases, with a preference for substrates with long aliphatic acyl chains, and likely involved in QQ processes.
High Catalytic Efficiency of a Layered Coordination Polymer to Remove Simultaneous Sulfur and Nitrogen Compounds from Fuels
Authors: Mirante Fátima , Mendes Ricardo F. , Paz Filipe A. Almeida , Balula Salete S.
Published: July 2020

An ionic lamellar coordination polymer based on a flexible triphosphonic acid linker, [Gd(H4nmp)(H2O)2]Cl2 H2O (1) (H6nmp stands for nitrilo(trimethylphosphonic) acid), presents high efficiency to remove sulfur and nitrogen pollutant compounds from model diesel. Its oxidative catalytic performance was investigated using single sulfur (1-BT, DBT, 4-MDBT and 4,6-DMDBT, 2350 ppm of S) and nitrogen (indole and quinolone, 400 ppm of N) model diesels and further, using multicomponent S/N model diesel. Different methodologies of preparation followed (microwave, one-pot, hydrothermal) originated small morphological differences that did not influenced the catalytic performance of catalyst. Complete desulfurization and denitrogenation were achieved after 2 h using single model diesels, an ionic liquid as extraction solvent ([BMIM]PF6) and H2O2 as oxidant. Simultaneous desulfurization and denitrogenation processes revealed that the nitrogen compounds are more easily removed from the diesel phase to the [BMIM]PF6 phase and consequently, faster oxidized than the sulfur compounds. The lamellar catalyst showed a high recycle capacity for desulfurization. The reusability of the diesel/H2O2/[BMIM]PF6 system catalyzed by lamellar catalyst was more efficient for denitrogenation than for desulfurization process using a multicomponent model diesel. This behavior is not associated with the catalyst performance but it is mainly due to the saturation of S/N compounds in the extraction phase.
Targeted Brain Tumor Therapy by Inhibiting the MDM2 Oncogene: In Vitro and In Vivo Antitumor Activity and Mechanism of Action
Authors: Punganuru Surendra R. , Arutla Viswanath , Zhao Wei , Rajaei Mehrdad , Deokar Hemantkumar , Zhang Ruiwen , Buolamwini John K. , Srivenugopal Kalkunte S. , Wang Wei
Published: July 2020

There is a desperate need for novel and efficacious chemotherapeutic strategies for human brain cancers. There are abundant molecular alterations along the p53 and MDM2 pathways in human glioma, which play critical roles in drug resistance. The present study was designed to evaluate the in vitro and in vivo antitumor activity of a novel brain-penetrating small molecule MDM2 degrader, termed SP-141. In a panel of nine human glioblastoma and medulloblastoma cell lines, SP-141, as a single agent, potently killed the brain tumor-derived cell lines with IC50 values ranging from 35.8 to 688.8 nM. Treatment with SP-141 resulted in diminished MDM2 and increased p53 and p21cip1 levels, G2/M cell cycle arrest, and marked apoptosis. In intracranial xenograft models of U87MG glioblastoma (wt p53) and DAOY medulloblastoma (mutant p53) expressing luciferase, treatment with SP-141 caused a significant 4- to 9-fold decrease in tumor growth in the absence of discernible toxicity. Further, combination treatment with a low dose of SP-141 (IC20) and temozolomide, a standard anti-glioma drug, led to synergistic cell killing (1.3- to 31-fold) in glioma cell lines, suggesting a novel means for overcoming temozolomide resistance. Considering that SP-141 can be taken up by the brain without the need for any special delivery, our results suggest that SP-141 should be further explored for the treatment of tumors of the central nervous system, regardless of the p53 status of the tumor.
Diversely Responsive Turn-On Fluorescent Cyclodextrin Chemosensors: Guest Selectivities and Mechanism Insights
Authors: Ikeda Hiroshi
Published: July 2020

Chemosensors have attracted considerable attention among the numerous strategies for detecting organic molecules in water. A turn-off mechanism was previously employed for the construction of a cyclodextrin (CD) chemosensor. This mechanism is greatly effective but has several shortcomings. In order to overcome these shortcomings, new fluorescent chemosensors NC0αCD, NC0βCD, and NC0γCD, which were (7-nitrobenz-2-oxa-1,3-diazol-4-yl)amine-modified α-CD, β-CD, and γ-CD, respectively, were prepared. Their guest selectivities were different from those of previously reported CD chemosensors. Here, the mechanism of new CD chemosensors was investigated using nuclear magnetic resonance (NMR) spectroscopy and molecular mechanics calculations. The fluorescence intensity of NC0βCD and NC0γCD slightly decreased and largely increased, respectively, upon the addition of ursodeoxycholic acid as a guest. This is due to the fact that the fluorophore of NC0βCD moved away to the hydrophilic bulk water to form hydrogen bonds between the host and the guest, while the fluorophore of NC0γCD remained located at the primary hydroxy side of the γ-CD unit to form a stable inclusion complex with hydrogen bonds between the fluorophore and the guest. NC0αCD also acted as a turn-on chemosensor for small guests, which could not be detected by the previous CD chemosensors. The motion restriction of the fluorophore through the generation of inclusion complexes could also contribute to increase in fluorescence intensity.
The Crucial Things in Science Often Happen Quite Unexpectedly—Das Entscheidende in der Wissenschaft geschieht oft ganz unerwartet (K. Alex Müller)
Authors: Kremer Reinhard K. , Bussmann-Holder Annette , Keller Hugo , Haunschild Robin
Published: July 2020

We analyzed the publication output of one of the 1987 Nobel Prize awardees, K. Alex Müller, using bibliometric methods. The time-dependent number of publications and citations and the network with respect to the coauthors and their affiliations was studied. Specifically, the citation history of the Nobel Prize awarded 1986 article on “Possible high-temperature superconductivity in the Ba-La-Cu-O system” has been evaluated in terms of the overall number of articles on superconductivity and the corresponding citations of other most frequently referenced articles. Thereby, a publication with “delayed recognition” was identified.
Planning the Future Electricity Mix for Countries in the Global South: Renewable Energy Potentials and Designing the Use of Artificial Neural Networks to Investigate Their Use Cases
Authors: Allison Michael , Pillai Gobind
Published: July 2020

Due to a symbiotic relationship, economic growth leads to greater energy consumption in transportation, manufacturing, and domestic sectors. Electricity consumption in the global south is rising as nations in the region strive for economic development. Due to the high costs of fossil fuels and environmental issues, these countries are planning exploitation of their renewable energy potential for meeting their energy needs. In this paper, we take Myanmar as a case study for which photovoltaic (PV) is seen as the preferred technology owing to its modular nature and Myanmar’s tremendous PV potential. To create sustainable systems, the impact of diurnal PV profiles on electricity demand profiles needs investigating. Accurate load forecasts lead to significant savings in operation and planning and maintenance. Artificial neural networks (ANNs) can easily be used for load profile forecasting. This work proposes a three-stage systematic approach which could be employed by global south countries for designing ANN load forecasting models with the aim of simplifying the design process. While the results of this work demonstrate that PV is a suitable energy source for countries like Myanmar, they also point to the importance of including annual load increase rate and PV output degradation rate in system planning.
Systematic Review on the Role of Lasers in Endodontic Therapy: Valuable Adjunct Treatment?
Authors: Anagnostaki Eugenia , Mylona Valina , Parker Steven , Lynch Edward , Grootveld Martin
Published: July 2020

(1) Background: Adjunctive instruments, such as lasers have been investigated to address the risk of failure of endodontic therapy due to the complexity of the root canal system. Lasers have been used therapeutically, in direct irradiation of the root canals or adjunct to irrigants placed into the canals, in combination with a photosensitizer (antimicrobial photodynamic therapy) and in pain management (photobiomodulation). The purpose of this systematic review was to evaluate the evidence in clinical use within these three areas of therapy. (2) Methods: PubMed, Cochrane and Scopus search engines were used to identify human clinical trials regarding the use of lasers in endodontic therapy. (3) Results: After applying the keywords and additional filters, inclusion and exclusion criteria, the initial number of 1486 articles was reduced to 17. It was revealed that almost all studies (14/17) presented a statistically significant improved outcome in laser-assisted endodontic therapy, with the remaining three not showing any adverse effects. (4) Conclusions: The use of laser photonic energy of appropriate delivered parameters can be proposed as useful adjunctive when considering optimal treatment modalities in orthograde endodontics. Additionally, a tendency of research towards pain modulation in this field is developing.
Correlating the Plant Height of Wheat with Above-Ground Biomass and Crop Yield Using Drone Imagery and Crop Surface Model, A Case Study from Nepal
Authors: Panday Uma Shankar , Shrestha Nawaraj , Maharjan Shashish , Pratihast Arun Kumar , Shahnawaz  , Shrestha Kundan Lal , Aryal Jagannath
Published: July 2020

Food security is one of the burning issues in the 21st century, as a tremendous population growth over recent decades has increased demand for food production systems. However, agricultural production is constrained by the limited availability of arable land resources, whereas a significant part of these is already degraded due to overexploitation. In order to get optimum output from the available land resources, it is of prime importance that crops are monitored, analyzed, and mapped at various stages of growth so that the areas having underdeveloped/unhealthy plants can be treated appropriately as and when required. This type of monitoring can be performed using ultra-high-resolution earth observation data like the images captured through unmanned aerial vehicles (UAVs)/drones. The objective of this research is to estimate and analyze the above-ground biomass (AGB) of the wheat crop using a consumer-grade red-green-blue (RGB) camera mounted on a drone. AGB and yield of wheat were estimated from linear regression models involving plant height obtained from crop surface models (CSMs) derived from the images captured by the drone-mounted camera. This study estimated plant height in an integrated setting of UAV-derived images with a Mid-Western Terai topographic setting (67 to 300 m amsl) of Nepal. Plant height estimated from the drone images had an error of 5% to 11.9% with respect to direct field measurement. While R2 of 0.66 was found for AGB, that of 0.73 and 0.70 were found for spike and grain weights respectively. This statistical quality assurance contributes to crop yield estimation, and hence to develop efficient food security strategies using earth observation and geo-information.
Confidence Distributions for FIC Scores
Authors: Cunen Céline , Hjort Nils Lid
Published: July 2020

When using the Focused Information Criterion (FIC) for assessing and ranking candidate models with respect to how well they do for a given estimation task, it is customary to produce a so-called FIC plot. This plot has the different point estimates along the y-axis and the root-FIC scores on the x-axis, these being the estimated root-mean-square scores. In this paper we address the estimation uncertainty involved in each of the points of such a FIC plot. This needs careful assessment of each of the estimators from the candidate models, taking also modelling bias into account, along with the relative precision of the associated estimated mean squared error quantities. We use confidence distributions for these tasks. This leads to fruitful CD–FIC plots, helping the statistician to judge to what extent the seemingly best models really are better than other models, etc. These efforts also lead to two further developments. The first is a new tool for model selection, which we call the quantile-FIC, which helps overcome certain difficulties associated with the usual FIC procedures, related to somewhat arbitrary schemes for handling estimated squared biases. A particular case is the median-FIC. The second development is to form model averaged estimators with weights determined by the relative sizes of the median- and quantile-FIC scores.
Resonant Cavity Antennas for 5G Communication Systems: A Review
Authors: Goudarzi Azita , Honari Mohammad Mahdi , Mirzavand Rashid
Published: July 2020

Resonant cavity antennas (RCAs) are suitable candidates to achieve high-directivity with a low-cost and easy fabrication process. The stable functionality of the RCAs over different frequency bands, as well as, their pattern reconfigurability make them an attractive antenna structure for the next generation wireless communication systems, i.e., fifth generation (5G). The variety of designs and analytical techniques regarding the main radiator and partially reflective surface (PRS) configurations allow dramatic progress and advances in the area of RCAs. Adding different functionalities in a single structure by using additional layers is another appealing feature of the RCA structures, which has opened the various fields of studies toward 5G applications. This paper reviews the recent advances on the RCAs along with the analytical methods, and various capabilities that make them suitable to be used in 5G communication systems. To discuss different capabilities of RCA structures, some applicable fields of studies are followed in different sections of this paper. To indicate different techniques in achieving various capabilities, some recent state-of-the-art designs are demonstrated and investigated. Since wideband high-gain antennas with different functionalities are highly required for the next generation of wireless communication, the main focus of this paper is to discuss primarily the antenna gain and bandwidth. Finally, a brief conclusion is drawn to have a quick overview of the content of this paper.
Energy Storage for 1500 V Photovoltaic Systems: A Comparative Reliability Analysis of DC- and AC-Coupling
Authors: He Jinkui , Yang Yongheng , Vinnikov Dmitri
Published: July 2020

There is an increasing demand in integrating energy storage with photovoltaic (PV) systems to provide more smoothed power and enhance the grid-friendliness of solar PV systems. To integrate battery energy storage systems (BESS) to an utility-scale 1500 V PV system, one of the key design considerations is the basic architecture selection between DC- and AC-coupling. Hence, it is necessary to assess the reliability of the power conversion units, which are not only the key system components, but also represent the most reliability-critical parts, in order to ensure an efficient and reliable 1500 V PV-battery system. Thus, this paper investigates the BESS solutions of DC- and AC-coupled configurations for 1500 V PV systems with a comparative reliability analysis. The reliability analysis is carried out through a case study on a 160 kW/1500 V PV-system integrated DC- or AC-coupled BESS for PV power smoothing and ramp-rate regulation. In the analysis, all of the DC-DC and DC-AC power interfacing converters are taken into consideration along with component-, converter-, and system-level reliability evaluation. The results reveal that the reliability of the 1500 V PV inverter can be enhanced with the DC-coupled BESS, while seen from the system-level reliability (i.e., a PV-battery system), both of the DC- and AC-coupled BESSs will affect the overall system reliability, especially for the DC-coupled case. The findings can be added into the design phase of 1500 V PV systems in a way to further lower the cost of energy.
Cogeneration Economics for Greenhouses in Europe
Authors: Tataraki Kalliopi , Giannini Eugenia , Kavvadias Konstantinos , Maroulis Zacharias
Published: July 2020

Cogeneration is a cost-effective technology, and modern greenhouses are considered one of the best applications for it due to their energy intensity. Taking into account that in such cases the production cost is significantly affected by the cost of energy, the potential of combined heat and power (CHP) has already been examined and proved in practice in some European countries, with the Netherlands being the most representative example. In this study, a comparative investigation of the greenhouse energy cost in all European countries is presented through the use of a combined cooling heat and power (CCHP) system. Using actual historical data spanning a decade, a total overview of the European level is given regarding greenhouse thermal requirements and CCHP energy costs for the cultivation of products with an accepted temperature cultivation range 20 ± 5 °C. By consulting (a) the available daily historical meteorological data for the 2008–2018 period, (b) the recorded actual electricity and natural gas prices for the 2008–2018 period, and (c) the technical characteristics of the CCHP system, the annual heating and cooling requirements of greenhouses are determined for all EU countries. Assuming a cogeneration unit with an internal combustion engine (ICE) as a prime mover, as well as a single-effect absorption chiller for the production of useful cooling, the unitary cost of energy is estimated along with the annual cost for heating and cooling per unit cultivation area. Using this methodology, the economic efficiency of cogeneration in greenhouses is assessed for the selected 10-year period, allowing the identification of the countries that benefit the most from this technology. The results indicate that the spark ratio (e.g., the electricity to natural gas price ratio) is the most crucial parameter for greenhouse costs. For countries where the ratio is larger than 3, greenhouses can even result in an extra cashflow instead of energy expenditures. The most favorable conditions for cogeneration use were found in Italy and the United Kingdom with an average spark ratio more than 4, resulting in an annual total cost of heating energy close to −7 €/m2 per year. On the other hand, cogeneration proved not to be a cost-efficient system in Sweden and Finland as a result of significantly high greenhouse energy requirements.
Optimal Frequency Support of Variable-Speed Hydropower Plants at Telemark and Vestfold, Norway: Future Scenarios of Nordic Power System
Authors: Acosta Martha N. , Pettersen Daniel , Gonzalez-Longatt Francisco , Peredo Argos Jaime , Andrade Manuel A.
Published: July 2020

The integration of renewable resources is quickly growing in the Nordic power system (NPS), and it has led to increasing challenges for the operation and control of the NPS. Nordic countries require that the first-generation power plants have a more flexible operation regime to overcomes power imbalances coming from fluctuations of the demand and supply. This paper assesses optimal frequency support of variable-speed hydropower plants installed in Telemark and Vestfold, Norway, considering future scenarios of NPS. The total kinetic energy of the NPS is expected to be significantly reduced in the future. This paper looks into the implementation of hydropower units with a variable-speed operation regime and battery energy storage systems (BESS), equipped with fast-active power controller (FAPC) technology, to provide fast frequency response after a system frequency disturbance. The frequency support was formulated as an optimization process; therefore, the parameter of the FAPC was optimally calculated for future scenarios of low inertia in NPS. Three main futures scenarios were developed for technology penetration in the Vestfold and Telemark area in Norway. The simulation results showed that the integration variable-speed hydropower units and BESS technologies improved the frequency response even in low-kinetic energy scenarios.
A Novel Economical Method of Determining the Geometric Characteristic of the Metal Foam Based on Image Analysis
Authors: Beer Martin , Taušová Marcela , Rybár Radim , Kaľavský Michal
Published: July 2020

The presented paper deals with the metal foams, which have a wide application potential ranging from power engineering, through catalysts to impact energy absorbers. The main aim of the paper is to propose an economical non-destructive method of determining the basic characteristics and dimensions using affordable devices. The basic principle of the proposed method lies in the image capture of metal foam and their subsequent analysis in image analysis software. An important element of the work is a comparison of results obtained by the proposed method with results obtained by high-resolution X-ray microtomography. The proposed method was evaluated in terms of measurement uncertainty and propagation of error in overall results. The use of the method is limited to the metal foams, characterized by an ordered structure, which are produced mainly by the electrophoretic deposition process. Based on the descriptive statistical analysis of results, it is possible to state, that the proposed method is in great agreement with accurate, but more expensive high-resolution X-ray microtomography.
Laminar Burning Velocity Model Based on Deep Neural Network for Hydrogen and Propane with Air
Authors: Malik Konrad , Żbikowski Mateusz , Teodorczyk Andrzej
Published: July 2020

The aim of the study was to develop deep neural network models for laminar burning velocity (LBV) calculations. The present study resulted in models for hydrogen–air and propane–air mixtures. An original data-preparation/data-generation algorithm was also developed in order to obtain the datasets sufficient in quality and quantity for models training. The discussion about the current analytical models highlighted issues with both experimental data and methodology of creating those analytical models. It was concluded that there is a need for models that can capture data from multiple experimental techniques with ease and automate the model design and training process. We presented a full machine learning based approach that fulfills these requirements. Not only model development, but also data preparation was described in detail as it is crucial in obtaining good results. Resulting models calculations were compared with popular analytical models and experimental data gathered from literature. The calculations comparison showed that the models developed were characterized by the smallest error with regards to the experiments and behaved equally well for variable pressure, temperature, and equivalence ratio. The source code of ready-to-use models has been provided and can be easily integrated in, for example, CFD software.
Renewable Energy Auction Prices: Near Subsidy-Free?
Authors: Martín Helena , Coronas Sergio , Alonso Àlex , de la Hoz Jordi , Matas José
Published: July 2020

The latest trend of low record bid prices in renewable energy auctions has raised concerns on the effective deployment of the winning projects. A survey of recent auction data from several countries, technologies and remuneration designs is analysed and compared with the corresponding levelised costs of energy (LCOEs) to draw first insights on their viability. A critical assessment of the ability of the LCOE for determining the adequate bid level is then performed and the preliminary unviable results of selected mature technologies are further investigated using improved profitability metrics as the project and equity net present value (NPV) and internal rate of return (IRR). As representative examples, the analysed Danish 2019 onshore wind and photovoltaics (PV) auctions require very specific scenarios to become viable, which cast doubts on their effective implementation. Under the assumptions of a realistic base case, the sensitivity analysis revealed that either 59% of decrease in the weighted average cost of capital (WACC), or 37% of discount on the investment cost or a 3.6% annual increment in the mean market price is needed for achieving the NPV break-even in the onshore wind case. Likewise, the PV case is unprofitable whatever the WACC may be, and either a 60% discount on the investment cost or a 6.8% annual increment in the mean market price is needed for the NPV to break-even. Although some projects could be relying on indirect revenues or additional sources of incomes beyond the auction support, it remains to see if they are finally materialised.
Climate Change Mitigation Policies Targeting Households and Addressing Energy Poverty in European Union
Authors: Streimikiene Dalia , Lekavičius Vidas , Baležentis Tomas , Kyriakopoulos Grigorios L. , Abrhám Josef
Published: July 2020

Climate change mitigation measures linked to households’ energy consumption have huge greenhouse gases (GHG) emission reduction potential and positive impact on energy poverty reduction. However, measures such as renovation of residential buildings or installation of micro generation technologies based on renewable energy sources have not realized their full energy saving and GHG emission reduction potentials, due to the energy efficiency paradox and other barriers. These climate change mitigation policies targeting the households’ sector can deliver extra benefits such as energy poverty reduction and implementation of the energy justice principle; therefore, they require more attention of scholars and policy makers. The aim of this paper is to analyze the energy poverty and climate change mitigation issues in EU households based on a systematic literature review, and to provide future research paths and policy recommendations. Based on the systematic literature review, this paper develops an integrated framework for addressing energy poverty, just carbon free energy transition and climate change mitigation issues in the EU. Additionally, we argue that more targeted climate change policies and measures are necessary in the light of the shortcomings of current measures to reduce energy poverty and realize climate change mitigation potential linked to energy consumption in households.