bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetics of DNA Repair in Vicia faba Meristem Regeneration Following Replication Stress
Authors: Rybaczek Dorota , Musiałek Marcelina W. , Vrána Jan , Petrovská Beáta , Pikus Ewa G. , Doležel Jaroslav
Published: January 2021

The astonishing survival abilities of Vicia faba, one the earliest domesticated plants, are associated, among other things, to the highly effective replication stress response system which ensures smooth cell division and proper preservation of genomic information. The most crucial pathway here seems to be the ataxia telangiectasia-mutated kinase (ATM)/ataxia telangiectasia and Rad3-related kinase (ATR)-dependent replication stress response mechanism, also present in humans. In this article, we attempted to take an in-depth look at the dynamics of regeneration from the effects of replication inhibition and cell cycle checkpoint overriding causing premature chromosome condensation (PCC) in terms of DNA damage repair and changes in replication dynamics. We were able to distinguish a unique behavior of replication factors at the very start of the regeneration process in the PCC-induced cells. We extended the experiment and decided to profile the changes in replication on the level of a single replication cluster of heterochromatin (both alone and with regard to its position in the nucleus), including the mathematical profiling of the size, activity and shape. The results obtained during these experiments led us to the conclusion that even “chaotic” events are dealt with in a proper degree of order.
Acute D-Serine Co-Agonism of β-Cell NMDA Receptors Potentiates Glucose-Stimulated Insulin Secretion and Excitatory β-Cell Membrane Activity
Authors: Lockridge Amber , Gustafson Eric , Wong Alicia , Miller Robert F. , Alejandro Emilyn U.
Published: January 2021

Insulin-secreting pancreatic β-cells express proteins characteristic of D-serine regulated synapses, but the acute effect of D-serine co-agonism on its presumptive β-cell target, N-methyl D-aspartate receptors (NMDARs), is unclear. We used multiple models to evaluate glucose homeostasis and insulin secretion in mice with a systemic increase in D-serine (intraperitoneal injection or DAAO mutants without D-serine catabolism) or tissue-specific loss of Grin1-encoded GluN1, the D-serine binding NMDAR subunit. We also investigated the effects of D-serine ± NMDA on glucose-stimulated insulin secretion (GSIS) and β-cell depolarizing membrane oscillations, using perforated patch electrophysiology, in β-cell-containing primary isolated mouse islets. In vivo models of elevated D-serine correlated to improved blood glucose and insulin levels. In vitro, D-serine potentiated GSIS and β-cell membrane excitation, dependent on NMDAR activating conditions including GluN1 expression (co-agonist target), simultaneous NMDA (agonist), and elevated glucose (depolarization). Pancreatic GluN1-loss females were glucose intolerant and GSIS was depressed in islets from younger, but not older, βGrin1 KO mice. Thus, D-serine is capable of acute antidiabetic effects in mice and potentiates insulin secretion through excitatory β-cell NMDAR co-agonism but strain-dependent shifts in potency and age/sex-specific Grin1-loss phenotypes suggest that context is critical to the interpretation of data on the role of D-serine and NMDARs in β-cell function.
Context Matters: NOTCH Signatures and Pathway in Cancer Progression and Metastasis
Authors: Misiorek Julia O. , Przybyszewska-Podstawka Alicja , Kałafut Joanna , Paziewska Beata , Rolle Katarzyna , Rivero-Müller Adolfo , Nees Matthias
Published: January 2021

The Notch signaling pathway is a critical player in embryogenesis but also plays various roles in tumorigenesis, with both tumor suppressor and oncogenic activities. Mutations, deletions, amplifications, or over-expression of Notch receptors, ligands, and a growing list of downstream Notch-activated genes have by now been described for most human cancer types. Yet, it often remains unclear what may be the functional impact of these changes for tumor biology, initiation, and progression, for cancer therapy, and for personalized medicine. Emerging data indicate that Notch signaling can also contribute to increased aggressive properties such as invasion, tumor heterogeneity, angiogenesis, or tumor cell dormancy within solid cancer tissues; especially in epithelial cancers, which are in the center of this review. Notch further supports the “stemness” of cancer cells and helps define the stem cell niche for their long-term survival, by integrating the interaction between cancer cells and the cells of the tumor microenvironment (TME). The complexity of Notch crosstalk with other signaling pathways and its roles in cell fate and trans-differentiation processes such as epithelial-to-mesenchymal transition (EMT) point to this pathway as a decisive player that may tip the balance between tumor suppression and promotion, differentiation and invasion. Here we not only review the literature, but also explore genomic databases with a specific focus on Notch signatures, and how they relate to different stages in tumor development. Altered Notch signaling hereby plays a key role for tumor cell survival and coping with a broad spectrum of vital issues, contributing to failed therapies, poor patient outcome, and loss of lives.
Impact of Gold Nanoparticles on the Functions of Macrophages and Dendritic Cells
Authors: Dey Arindam K. , Gonon Alexis , Pécheur Eve-Isabelle , Pezet Mylène , Villiers Christian , Marche Patrice N.
Published: January 2021

Gold nanoparticles (AuNPs) have demonstrated outstanding performance in many biomedical applications. Their safety is recognised; however, their effects on the immune system remain ill defined. Antigen-presenting cells (APCs) are immune cells specialised in sensing external stimulus and in capturing exogenous materials then delivering signals for the immune responses. We used primary macrophages (Ms) and dendritic cells (DCs) of mice as an APC model. Whereas AuNPs did not alter significantly Ms and DCs functions, the exposure to AuNPs affected differently Ms and DCs in their responses to subsequent stimulations. The secretion of inflammatory molecules like cytokines (IL-6, TNF-α), chemokine (MCP-1), and reactive oxygen species (ROS) were altered differently in Ms and DCs. Furthermore, the metabolic activity of Ms was affected with the increase of mitochondrial respiration and glycolysis, while only a minor effect was seen on DCs. Antigen presentation to T cells increased when DCs were exposed to AuNPs leading to stronger Th1, Th2, and Th17 responses. In conclusion, our data provide new insights into the complexity of the effects of AuNPs on the immune system. Although AuNPs may be considered as devoid of significant effect, they may induce discrete modifications on some functions that can differ among the immune cells.
Estrogen and Glycemic Homeostasis: The Fundamental Role of Nuclear Estrogen Receptors ESR1/ESR2 in Glucose Transporter GLUT4 Regulation
Authors: Gregorio Karen Cristina Rego , Laurindo Caroline Pancera , Machado Ubiratan Fabres
Published: January 2021

Impaired circulating estrogen levels have been related to impaired glycemic homeostasis and diabetes mellitus (DM), both in females and males. However, for the last twenty years, the relationship between estrogen, glycemic homeostasis and the mechanisms involved has remained unclear. The characterization of estrogen receptors 1 and 2 (ESR1 and ESR2) and of insulin-sensitive glucose transporter type 4 (GLUT4) finally offered a great opportunity to shed some light on estrogen regulation of glycemic homeostasis. In this manuscript, we review the relationship between estrogen and DM, focusing on glycemic homeostasis, estrogen, ESR1/ESR2 and GLUT4. We review glycemic homeostasis and GLUT4 expression (muscle and adipose tissues) in Esr1−/− and Esr2−/− transgenic mice. We specifically address estradiol-induced and ESR1/ESR2-mediated regulation of the solute carrier family 2 member 4 (Slc2a4) gene, examining ESR1/ESR2-mediated genomic mechanisms that regulate Slc2a4 transcription, especially those occurring in cooperation with other transcription factors. In addition, we address the estradiol-induced translocation of ESR1 and GLUT4 to the plasma membrane. Studies make it clear that ESR1-mediated effects are beneficial, whereas ESR2-mediated effects are detrimental to glycemic homeostasis. Thus, imbalance of the ESR1/ESR2 ratio may have important consequences in metabolism, highlighting that ESR2 hyperactivity assumes a diabetogenic role.
Inflammatory Cytokines in Cancer: Comprehensive Understanding and Clinical Progress in Gene Therapy
Authors: Lan Tianxia , Chen Li , Wei Xiawei
Published: January 2021

The relationship between chronic inflammation and neoplastic diseases is not fully understood. The inflammatory microenvironment of a tumor is an intricate network that consists of numerous types of cells, cytokines, enzymes and signaling pathways. Recent evidence shows that the crucial components of cancer-related inflammation are involved in a coordinated system to influence the development of cancer, which may shed light on the development of potential anticancer therapies. Since the last century, considerable effort has been devoted to developing gene therapies for life-threatening diseases. When it comes to modulating the inflammatory microenvironment for cancer therapy, inflammatory cytokines are the most efficient targets. In this manuscript, we provide a comprehensive review of the relationship between inflammation and cancer development, especially focusing on inflammatory cytokines. We also summarize the clinical trials for gene therapy targeting inflammatory cytokines for cancer treatment. Future perspectives concerned with new gene-editing technology and novel gene delivery systems are finally provided.
Central Administration of Angiotensin-(1-7) Improves Vasopressin Impairment and Hypotensive Response in Experimental Endotoxemia
Authors: Passaglia Patrícia , de Lima Faim Felipe , Batalhão Marcelo Eduardo , Stabile Angelita Maria , Bendhack Lusiane Maria , Antunes-Rodrigues José , Lacchini Riccardo , Capellari Carnio Evelin
Published: January 2021

Angiotensin-(1-7) [Ang-(1-7)]/Mas receptor is a counter-regulatory axis that counteracts detrimental renin-angiotensin system (RAS) effects, especially regarding systemic inflammation, vasopressin (AVP) release, and hypothalamic-pituitary-adrenal (HPA) activation. However, it is not completely understood whether this system may control centrally or systemically the late phase of systemic inflammation. Thus, the aim of this study was to determine whether intracerebroventricular (i.c.v.) administration of Ang-(1-7) can modulate systemic inflammation through the activation of humoral pathways in late phase of endotoxemia. Endotoxemia was induced by systemic injection of lipopolysaccharide (LPS) (1.5 mg/kg, i.v.) in Wistar rats. Ang-(1-7) (0.3 nmol in 2 µL) promoted the release of AVP and attenuated interleukin-6 (IL-6) and nitric oxide (NO) levels but increased interleukin-10 (IL-10) in the serum of the endotoxemic rats. The central administration of Mas receptor antagonist A779 (3 nmol in 2 µL, i.c.v.) abolished these anti-inflammatory effects in endotoxemic rats. Furthermore, Ang-(1-7) applied centrally restored mean arterial blood pressure (MABP) without affecting heart rate (HR) and prevented vascular hyporesponsiveness to norepinephrine (NE) and AVP in animals that received LPS. Together, our results indicate that Ang-(1-7) applied centrally promotes a systemic anti-inflammatory effect through the central Mas receptor and activation of the humoral pathway mediated by AVP.
Targeting a Lipid Desaturation Enzyme, SCD1, Selectively Eliminates Colon Cancer Stem Cells through the Suppression of Wnt and NOTCH Signaling
Authors: Yu Yeongji , Kim Hyejin , Choi SeokGyeong , Yu JinSuh , Lee Joo Yeon , Lee Hani , Yoon Sukjoon , Kim Woo-Young
Published: January 2021

The elimination of the cancer stem cell (CSC) population may be required to achieve better outcomes of cancer therapy. We evaluated stearoyl-CoA desaturase 1 (SCD1) as a novel target for CSC-selective elimination in colon cancer. CSCs expressed more SCD1 than bulk cultured cells (BCCs), and blocking SCD1 expression or function revealed an essential role for SCD1 in the survival of CSCs, but not BCCs. The CSC potential selectively decreased after treatment with the SCD1 inhibitor in vitro and in vivo. The CSC-selective suppression was mediated through the induction of apoptosis. The mechanism leading to selective CSC death was investigated by performing a quantitative RT-PCR analysis of 14 CSC-specific signaling and marker genes after 24 and 48 h of treatment with two concentrations of an inhibitor. The decrease in the expression of Notch1 and AXIN2 preceded changes in the expression of all other genes, at 24 h of treatment in a dose-dependent manner, followed by the downregulation of most Wnt- and NOTCH-signaling genes. Collectively, we showed that not only Wnt but also NOTCH signaling is a primary target of suppression by SCD1 inhibition in CSCs, suggesting the possibility of targeting SCD1 against colon cancer in clinical settings.
Effect of Electric Field Regulation on Laser Damage of Composite Low-Dispersion Mirrors
Authors: Zhang Yuhui , Wang Yanzhi , He Hongbo , Chen Ruiyi , Wang Zhihao , Li Dawei , Zhu Meiping , Zhao Yuanan , Jin Yunxia , Yi Kui , Shao Yuchuan , Leng Yuxin , Li Ruxin , Shao Jianda
Published: January 2021

Low dispersion mirrors are important because of their potential use in petawatt (PW) laser systems. The following two methods are known to increase the laser-induced damage threshold of low dispersion optical components: use of a wide-bandgap-material protective layer and control of electric field distribution. By controlling the electric field distribution of composite low-dispersion mirrors (CLDM), we shift the electric field peaks from the material interface into the wide-bandgap material. However, the damage threshold of modified-electric-field composite low dispersion mirror (E-CLDM) does not increase. Damage morphology shows that the initial damaged layer is Ta2O5. An immediate cause is the enhancement of the electric field in internal layers caused by surface electric field regulation. Theoretical calculations show that the damage threshold of CLDM or E-CLDM is determined by the competition results of bandgap and the electric field of layer materials. The CLDM with different materials or different protective layer periods can be optimally designed according to the electric field competition effect in the future.
Multi-Ferroic Properties on BiFeO3/BaTiO3 Multi-Layer Thin-Film Structures with the Strong Magneto-Electric Effect for the Application of Magneto-Electric Devices
Authors: Hu Cheng-Wei , Yen Ching-Min , Feng Yu-Chia , Chen Liang-Hsi , Liao Bo-Zhou , Chen Sheng-Chi , Liao Ming-Han
Published: January 2021

The characteristics of X-ray Diffraction (XRD), Current (I)-Voltage (V), and the Polarization-Electric field (P-E) on the BiFeO3 (BFO), BaTiO3 (BTO), and our proposed Multi-Layer (ML) BiFeO3/BaTiO3 (BFO/BTO) samples are studied systemically. The influence of these films with and without different external Magnetic (Mex.) inputs is also investigated. Our proposed multi-ferroic ML BFO/BTO sample has a lower tunneling current (Jg) (~5 × 103 times) and a stronger magneto-electric effect (an ~25 times higher value of the change of saturated polarization Ps with the Mex. inputs than the pure multi-ferroic BFO sample. The material properties for ML BFO/BTO samples can be optimized with the combination of the advantages of BFO and BTO thin films. The stronger magneto-electric effect in our proposed ML samples can have many applications such as magnetic sensors, magnetic electric devices, and logic Magneto-Electric Spin–Orbit (MESO) devices.
The Potential Use of Seaweed (Posidonia oceanica) as an Alternative Lignocellulosic Raw Material for Wood Composites Manufacture
Authors: Rammou Ekaterini , Mitani Andromachi , Ntalos George , Koutsianitis Dimitrios , Taghiyari Hamid R. , Papadopoulos Antonios N.
Published: January 2021

A big challenge in the composites industry is the availability of cheap raw lignocellulosic materials, potential candidates to replace slow growing trees, in order to minimize the production cost. Therefore, a variety of plants were studied and tested worldwide in composites manufacturing. The objective of this study was to investigate the technical feasibility of manufacturing particleboards from seaweed leaves (Possidonia oceanica—PO). The use of such a material may benefit both socioeconomic and environmental development since these leaves settle on seashores and decay. The results showed that an incorporation of up to 10% PO leaves did not significantly affect the mechanical properties of the board. Internal bond strength was more severely affected than the other mechanical properties. The incorporation of PO leaves up to 25% did not significantly improve the dimensional stability of the boards. Markedly, boards made from 50% wood particles and 50% PO leaves showed the best thickness swelling values. It is suggested that higher resin dosage and an alternative resin system, such as isocyanates, may improve the panel properties.
Advances in the Applications of Graphene-Based Nanocomposites in Clean Energy Materials
Authors: Xiang Yiqiu , Xin Ling , Hu Jiwei , Li Caifang , Qi Jimei , Hou Yu , Wei Xionghui
Published: January 2021

Extensive use of fossil fuels can lead to energy depletion and serious environmental pollution. Therefore, it is necessary to solve these problems by developing clean energy. Graphene materials own the advantages of high electrocatalytic activity, high conductivity, excellent mechanical strength, strong flexibility, large specific surface area and light weight, thus giving the potential to store electric charge, ions or hydrogen. Graphene-based nanocomposites have become new research hotspots in the field of energy storage and conversion, such as in fuel cells, lithium-ion batteries, solar cells and thermoelectric conversion. Graphene as a catalyst carrier of hydrogen fuel cells has been further modified to obtain higher and more uniform metal dispersion, hence improving the electrocatalyst activity. Moreover, it can complement the network of electroactive materials to buffer the change of electrode volume and prevent the breakage and aggregation of electrode materials, and graphene oxide is also used as a cheap and sustainable proton exchange membrane. In lithium-ion batteries, substituting heteroatoms for carbon atoms in graphene composite electrodes can produce defects on the graphitized surface which have a good reversible specific capacity and increased energy and power densities. In solar cells, the performance of the interface and junction is enhanced by using a few layers of graphene-based composites and more electron-hole pairs are collected; therefore, the conversion efficiency is increased. Graphene has a high Seebeck coefficient, and therefore, it is a potential thermoelectric material. In this paper, we review the latest progress in the synthesis, characterization, evaluation and properties of graphene-based composites and their practical applications in fuel cells, lithium-ion batteries, solar cells and thermoelectric conversion.
Analyzing Neck Circumference as an Indicator of CPAP Treatment Response in Obstructive Sleep Apnea with Network Medicine
Authors: Mihaicuta Stefan , Udrescu Lucreţia , Udrescu Mihai , Toth Izabella-Anita , Topîrceanu Alexandru , Pleavă Roxana , Ardelean Carmen
Published: January 2021

We explored the relationship between obstructive sleep apnea (OSA) patients’ anthropometric measures and the CPAP treatment response. To that end, we processed three non-overlapping cohorts (D1, D2, D3) with 1046 patients from four sleep laboratories in Western Romania, including 145 subjects (D1) with one-night CPAP therapy. Using D1 data, we created a CPAP-response network of patients, and found neck circumference (NC) as the most significant qualitative indicator for apnea–hypopnea index (AHI) improvement. We also investigated a quantitative NC cutoff value for OSA screening on cohorts D2 (OSA-diagnosed) and D3 (control), using the area under the curve. As such, we confirmed the correlation between NC and AHI (ρ=0.35, p<0.001) and showed that 71% of diagnosed male subjects had bigger NC values than subjects with no OSA (area under the curve is 0.71, with 95% CI 0.63–0.79, p<0.001); the optimal NC cutoff is 41 cm, with a sensitivity of 0.8099, a specificity of 0.5185, positive predicted value (PPV) = 0.9588, negative predicted value (NPV) = 0.1647, and positive likelihood ratio (LR+) = 1.68. Our NC =41 cm threshold classified the D1 patients’ CPAP responses—measured as the difference in AHI prior to and after the one-night use of CPAP—with a sensitivity of 0.913 and a specificity of 0.859.
Systemic Mastocytosis Associated with “Smoldering” Multiple Myeloma
Authors: Zanelli Magda , Ricci Stefano , Zizzo Maurizio , Sanguedolce Francesca , De Giorgi Federica , Palicelli Andrea , Martino Giovanni , Ascani Stefano
Published: January 2021

A 79-year-old woman presented with a long history of peripheral eosinophilia. Previous right hemicolectomy for colonic polyposis was reported. Laboratory tests were notable for mild macrocitic anaemia and eosinophilia. β2 microglobulin and serum tryptase levels were elevated. Serum immunofixation revealed IgA/kappa monoclonal protein. Bence-Jones protein was positive. Bone marrow (BM) biopsy revealed the coexistence of two neoplastic components. Cohesive clusters of bland-looking, spindle-shaped mast cells, representing 20% of marrow cellularity, were close to aggregates of mature plasma cells occupying 40% of marrow cellularity. Molecular analysis on marrow aspirate demonstrated KIT D816V mutation, TET2 mutation, monoallelic deletion of TP53/17p13 and trisomy of ATM/11q23. A bone density study revealed mild osteoporosis. Full skeletal X-rays and magnetic resonance imaging (MRI) of spine and hips showed multiple, small rarefaction areas and an old L1-L2 fracture, both ascribed to osteoporosis. The association of systemic mastocytosis (SM) and multiple myeloma (MM) is very uncommon. The coexistence of SM with MM placed our patient in the SM with associated clonal haematological non-mast-cell lineage disease (SM-AHN) subtype. Midostaurin therapy was started.
Altered Expression of Circadian Clock Genes in Patients with Atrial Fibrillation Is Associated with Atrial High-Rate Episodes and Left Atrial Remodeling
Authors: Chen Yung-Lung , Chuang Jiin-Haur , Wang Hui-Ting , Chen Huang-Chung , Liu Wen-Hao , Yang Ming-Yu
Published: January 2021

A prominent circadian variation is present in atrial fibrillation (AF) attacks that may be related to the expression of circadian clock genes. Little is known about the expression of circadian clock genes in AF. We prospectively enrolled 73 patients who had received pacemaker implantation, in order to define the burden of atrial high-rate episodes (AHREs) accurately. AF was diagnosed clinically in 43 (59%) patients (15 with persistent AF and 28 with paroxysmal AF). The expression levels of circadian clock genes of peripheral blood leukocytes were checked. There were more males and patients with a larger left atrial (LA) size and lower expression levels of BMAL1, CRY2, NR1D1, NR1D2, PER2, RORA, RORC, and TIM genes in persistent AF group than in other groups. There was a significant correlation between higher AHRE burden and larger LA size and between higher AHRE burden and decreased expression of circadian clock genes in patients with AF. LA volume and the expression of CRY1, NR1D1, and RORA are significantly associated with AHRE burden. However, the underlying mechanism needs to be elucidated in further studies.
Minimization of Entropy Generation Rate in Hydrogen Iodide Decomposition Reactor Heated by High-Temperature Helium
Authors: Kong Rui , Chen Lingen , Xia Shaojun , Li Penglei , Ge Yanlin
Published: January 2021

The thermochemical sulfur-iodine cycle is a potential method for hydrogen production, and the hydrogen iodide (HI) decomposition is the key step to determine the efficiency of hydrogen production in the cycle. To further reduce the irreversibility of various transmission processes in the HI decomposition reaction, a one-dimensional plug flow model of HI decomposition tubular reactor is established, and performance optimization with entropy generate rate minimization (EGRM) in the decomposition reaction system as an optimization goal based on finite-time thermodynamics is carried out. The reference reactor is heated counter-currently by high-temperature helium gas, the optimal reactor and the modified reactor are designed based on the reference reactor design parameters. With the EGRM as the optimization goal, the optimal control method is used to solve the optimal configuration of the reactor under the condition that both the reactant inlet state and hydrogen production rate are fixed, and the optimal value of total EGR in the reactor is reduced by 13.3% compared with the reference value. The reference reactor is improved on the basis of the total EGR in the optimal reactor, two modified reactors with increased length are designed under the condition of changing the helium inlet state. The total EGR of the two modified reactors are the same as that of the optimal reactor, which are realized by decreasing the helium inlet temperature and helium inlet flow rate, respectively. The results show that the EGR of heat transfer accounts for a large proportion, and the decrease of total EGR is mainly caused by reducing heat transfer irreversibility. The local total EGR of the optimal reactor distribution is more uniform, which approximately confirms the principle of equipartition of entropy production. The EGR distributions of the modified reactors are similar to that of the reference reactor, but the reactor length increases significantly, bringing a relatively large pressure drop. The research results have certain guiding significance to the optimum design of HI decomposition reactors.
Computational Thermal Analysis of the Photothermal Effect of Thermoplasmonic Optical Fiber for Localized Neural Stimulation In Vivo
Authors: Hong Woongki , Lee Junhee , Kim Duhee , Hwang Yujin , Kwon Hyuk-Jun , Jang Jae Eun , Kang Hongki
Published: January 2021

Optical neuromodulation is a versatile neural stimulation technology that enables highly localized excitatory or inhibitory stimulation of neuronal activities. Photothermal neural stimulation using thermoplasmonic metallic nanoparticles for light to heat conversion has been suggested as an optical neural stimulation technology without genetic modification. Optical fibers implementing the thermoplasmonic effect were recently developed for localized neural stimulation, and the successful demonstration of localized neural stimulation in vitro was reported. However, before photothermal neural stimulation is further applied in the brains of live animals and ultimately in human trials, a safety analysis must carefully be performed for the thermal effect of stimulation in vivo. With the complexity of the physical structure and different thermal properties of the brain and surrounding body, the resulting thermal effect could vary despite the same power of light delivered to the optical fiber. In addition, dynamic thermal properties of the brain such as the daily blood perfusion rate change or metabolic heat generation must also be carefully considered for the precise implementation of photothermal neural stimulation. In this work, an in-depth computational analysis was conducted of the photothermal effects using a thermoplasmonic optical fiber for in vivo neural stimulation. The effects of the experimental design and stimulation protocols on the thermal effect in the brain were analyzed. We believe that the results provide a good experimental guideline for safely conducting photothermal neural stimulation using the thermoplasmonic optical fiber technology.
Stabilization of the J-V Characteristic of a Perovskite Solar Cell Using an Intelligent Control Loop
Authors: Bheesayagari Chenna Reddy , Martínez-Denegri Guillermo , Orpella Albert , Pons-Nin Joan , Bermejo Sandra , Alcubilla Ramon , Martorell Jordi , Domínguez-Pumar Manuel
Published: January 2021

The phenomena related to charge trapping are among the most relevant open issues that affect the long-term stability of perovskite-based devices. According to this, the objective of this paper is to report experimental results in which a charge control strategy is used for the first time in a solar cell structure that has a high trap density perovskite absorber. This device has also noticeable J-V hysteresis, produced by non-capacitive effects. The control strategy proposed, based on sigma-delta modulation, applies to the device an appropriate sequence of voltage waveforms determined after periodical current measurements made at a constant voltage. The experimental results obtained and the fittings made with a phenomenological model indicate that this approach allows controlling several charge-related effects. As a consequence, the J-V characteristic of the device is successfully shifted and stabilized to predetermined positions.
A Novel Algorithm for Fast DC Electric Arc Detection
Authors: Dołęgowski Michał , Szmajda Mirosław
Published: January 2021

Electric arcing is a common problem in DC power systems. To overcome this problem, the electric arc detection algorithm has been developed as a faster alternative to existing algorithms. The following issues are addressed in this paper: The calculation of the proposed algorithm of incremental decomposition of the signal over time; the computational complexity of Fast Fourier Transform (FFT) and the incremental decomposition; the test bench used to measure electric arcs at given parameters; the analysis of measurements using FFT; and the analysis of measurements using incremental decomposition. The parameters are the DC voltage, electric load, and width of the gap between electrodes. The results showed that the proposed algorithm allows for a faster calculation—about seven times faster than FFT—and cheaper implementation in electric arc detection devices than FFT.
Risk Assessment in Energy Infrastructure Installations by Horizontal Directional Drilling Using Machine Learning
Authors: Krechowicz Maria , Krechowicz Adam
Published: January 2021

Nowadays we can observe a growing demand for installations of new gas pipelines in Europe. A large number of them are installed using trenchless Horizontal Directional Drilling (HDD) technology. The aim of this work was to develop and compare new machine learning models dedicated for risk assessment in HDD projects. The data from 133 HDD projects from eight countries of the world were gathered, profiled, and preprocessed. Three machine learning models, logistic regression, random forests, and Artificial Neural Network (ANN), were developed to predict the overall HDD project outcome (failure free installation or installation likely to fail), and the occurrence of identified unwanted events. The best performance in terms of recall and accuracy was achieved for the developed ANN model, which proved to be efficient, fast and robust in predicting risks in HDD projects. Machine learning applications in the proposed models enabled eliminating the involvement of a group of experts in the risk assessment process and therefore significantly lower the costs associated with the risk assessment process. Future research may be oriented towards developing a comprehensive risk management system, which will enable dynamic risk assessment taking into account various combinations of risk mitigation actions.
Analysis of the Electricity Supply Contracts for Medium-Voltage Apartments in the Republic of Korea
Authors: Kim Dong Sik , Jung Wookyung , Chung Beom Jin
Published: January 2021

For apartment complexes receiving medium-voltage electrical energies, the apartments can choose an electricity charging method between the single and general contracts in the Republic of Korea. In the single contract, a residential high-voltage rate is applied to the total electrical energy consumptions of households and common areas. On the other hand, in the general contract, different rate plans are applied to the electrical energy consumptions of households and their common areas, where a generic high-voltage rate plan is applied to the common consumption. Hence, depending on the amounts and composition of the consumptions, both contracts have their own strengths and weaknesses in terms of the total electricity charge. The management office of an apartment complex can select its preferred contract considering the amount and composition of the power consumptions on an annual basis. In this paper, we first formulate a model for the contracts and analyze their properties based on Monte-Carlo simulations. We then observe the contract properties through actual metering data from 30 apartment complexes in Korea. From the analysis of this paper, we can select appropriate contract for a given apartment complex and have guidelines for saving electricity charges. The greater the consumption of the electrical energy and the common area portion, the more advantageous the general contract is in terms of reducing electricity charges.
Modeling and Optimization of Microwave-Based Bio-Jet Fuel from Coconut Oil: Investigation of Response Surface Methodology (RSM) and Artificial Neural Network Methodology (ANN)
Authors: Ong Mei Yin , Nomanbhay Saifuddin , Kusumo Fitranto , Raja Shahruzzaman Raja Mohamad Hafriz , Shamsuddin Abd Halim
Published: January 2021

In this study, coconut oils have been transesterified with ethanol using microwave technology. The product obtained (biodiesel and FAEE) was then fractional distillated under vacuum to collect bio-kerosene or bio-jet fuel, which is a renewable fuel to operate a gas turbine engine. This process was modeled using RSM and ANN for optimization purposes. The developed models were proved to be reliable and accurate through different statistical tests and the results showed that ANN modeling was better than RSM. Based on the study, the optimum bio-jet fuel production yield of 74.45 wt% could be achieved with an ethanol–oil molar ratio of 9.25:1 under microwave irradiation with a power of 163.69 W for 12.66 min. This predicted value was obtained from the ANN model that has been optimized with ACO. Besides that, the sensitivity analysis indicated that microwave power offers a dominant impact on the results, followed by the reaction time and lastly ethanol–oil molar ratio. The properties of the bio-jet fuel obtained in this work was also measured and compared with American Society for Testing and Materials (ASTM) D1655 standard.
Research on Non-Pillar Coal Mining for Thick and Hard Conglomerate Roof
Authors: Liu Xiaoyu , He Manchao , Wang Jiong , Ma Zimin
Published: January 2021

This article introduces a new non-pillar coal mining technology (i.e., Gob-side Entry Retaining by Roof Cutting (GERRC)) under the condition of thick and hard roofs. First, we theoretically analyzed the solution to the large suspension span of the thick and hard roof in coal mining. Three-Zone pre-split blasting design in non-pillar coal mining for thick and hard roofs was proposed, based on the principles of rock mechanics. After field experiments, the technology was successfully applied to the non-pillar coal mining of a huge thick conglomerate roof. This research supplements the non-pillar mining technology system. The proposed technologies and methods have strong applicability and have certain guiding significance for the safe and efficient mining of related coal mines.
Storage Placement and Sizing in a Distribution Grid with High PV Generation
Authors: Matthiss Benjamin , Momenifarahani Arghavan , Binder Jann
Published: January 2021

With the increasing penetration of renewable resources into the low-voltage distribution grid, the demand for alternatives to grid reinforcement measures has risen. One possible solution is the use of battery systems to balance the power flow at crucial locations in the grid. Hereby, the optimal location and size of the system have to be determined in regard to investment and its effect on grid stability. In this paper, the optimal placement and sizing of battery storage systems for grid stabilization in a small low-voltage distribution grid in southern Germany with high PV penetration are investigated and compared to a grid heuristic reinforcement strategy.
Citizen Participation in Low-Carbon Energy Systems: Energy Communities and Its Impact on the Electricity Demand on Neighborhood and National Level
Authors: Zwickl-Bernhard Sebastian , Auer Hans
Published: January 2021

In this work, the main research question is how a high penetration of energy communities (ECs) affects the national electricity demand in the residential sector. Thus, the existing building stock of three European regions/countries, namely, the Iberian Peninsula, Norway, and Austria, is analyzed and represented by four different model energy communities based on characteristic settlement patterns. A tailor-made, open-source model optimizes the utilization of the local energy technology portfolio, especially small-scale batteries and photovoltaic systems within the ECs. Finally, the results on the national level are achieved by upscaling from the neighborhood level. The findings of different 2030 scenarios (building upon narrative storylines), which consider various socio-economic and techno-economic determinants of possible future energy system development, identify a variety of modification potentials of the electricity demand as a result of EC penetration. The insights achieved in this work highlight the important contributions of ECs to low-carbon energy systems. Future work may focus on the provision of future local energy services, such as increasing cooling demand and/or high shares of electric vehicles, further enhancement of the upscaling to the national level (i.e., considering the distribution network capacities), and further diversification of EC composition beyond the residential sector.
State-of-Charge Estimation of Lithium-Ion Batteries in the Battery Degradation Process Based on Recurrent Neural Network
Authors: Li Shuqing , Ju Chuankun , Li Jianliang , Fang Ri , Tao Zhifei , Li Bo , Zhang Tingting
Published: January 2021

Due to the rapidly increasing energy demand and the more serious environmental pollution problems, lithium-ion battery is more and more widely used as high-efficiency clean energy. State of Charge (SOC) representing the physical quantity of battery remaining energy is the most critical factor to ensure the stability and safety of lithium-ion battery. The novelty SOC estimation model, which is two recurrent neural networks with gated recurrent units combined with Coulomb counting method is proposed in this paper. The estimation model not only takes voltage, current, and temperature as input feature but also takes into account the influence of battery degradation process, including charging and discharging times, as well as the last discharge charge. The SOC of the battery is estimated by the network under three different working conditions, and the results show that the average error of the proposed neural network is less than 3%. Compared with other neural network structures, the proposed network estimation results are more stable and accurate.
Heat Transfer in Flow Past Two Cylinders in Tandem and Enhancement with a Slit
Authors: Hsu Li-Chieh , Liang Che-Wei
Published: January 2021

This study aimed to determine the flow structures and heat transfer for flow past a tandem cylinder array and the effect of a slit on the enhancement of heat transfer. Different distances between cylinders and inclination angles of the slit were simulated to determine the effects on the flow pattern and heat transfer. Overall, the Nusselt number of the array is increased by 6–15% with applying a slit on a cylinder. However, in some special conditions, the slit induces two kinds of flow pattern transforms which are Suppression and Revival. The suppression mode inhibits the vortex shedding and reduces the heat transfer. In contrast, the revival mode triggers the vortex shedding and increases heat transfer.
Multivariable Deadbeat Control of Power Electronics Converters with Fast Dynamic Response and Fixed Switching Frequency
Authors: Rohten Jaime A. , Dewar David N. , Zanchetta Pericle , Formentini Andrea , Muñoz Javier A. , Baier Carlos R. , Silva José J.
Published: January 2021

Power converters have turned into a critical and every-day solution for electric power systems. In fact, the incorporation of renewable energies has led towards the constant improvement of power converter topologies and their controls. In this context, over the last 10 years, model predictive control (MPC) is positioned as one the most studied and promising alternatives for power converter control. In voltage source inverters (VSI), MPC has only been applied in the inner current control loop, accelerating and improving its dynamic response, but as mentioned, has been limited only to the current control loop. The fastest of the MPC techniques is the Deadbeat (DB) control, and in this paper, it is proposed to employ DB control on the entire system, therefore accelerating the time response not only for the current loops, but also for voltage loops. At the same time, this avoids overshoots and overpower in order to protect the power converter, leading to the fastest dynamic response according to VSI capabilities. For renewable energies, fast-dynamics entails fast maximum power tracking and therefore, maximizes energy harvesting, or in other words, reduces the losses due to the control dynamics. Thus, this paper gives a clear procedure and key points for designing a DB control for all the variables based on a mathematical model, which is corroborated by simulations and the experimental results.
Research on the Non-Magnetic Conductor of a PMSM Based on the Principle of Variable Exciting Magnetic Reluctance
Authors: Li Chunyan , Guo Fei , Kou Baoquan , Meng Tao
Published: January 2021

A permanent magnet synchronous motor (PMSM) based on the principle of variable exciting magnetic reluctance (VMRPMSM) is presented. The motor is equipped with symmetrical non-magnetic conductors on both sides of the tangential magnetized permanent magnets (PMs). By placing the non-magnetic conductor (NMC), the magnetic reluctance in the exciting circuit is adjusted, and the flux weakening (FW) of the motor is realized. Hence, the NMC is studied comprehensively. On the basis of introducing the motor structure, the FW principle of this PMSM is described. The shape of the NMC is determined by analyzing and calculating the electromagnetic force (EF) acting on the PMs. We calculate the magnetic reluctance of the NMC and research on the effects of the NMC on electromagnetic force, d-axis and q-axis inductance and FW performance. The critical speeds from the test of the no-load back electromotive force (EMF) verify the correctness of the NMC design. The analysis is corresponding to the test result which lays the foundation of design for this kind of new PMSM.
New Equation for Optimal Insulation Dependency on the Climate for Office Buildings
Authors: Ahmed Kaiser , Kurnitski Jarek
Published: January 2021

The comparison of building energy efficiency in different climates is a growing issue. Unique structural solutions will not ensure the same energy use, but the differences also remain if cost-optimal solutions are applied. This study developed a new equation for the assessment of building envelope optimal insulation in different climates for office buildings. The developed method suggests determining actual degree days from simulated heating energy need and the thermal conductance of a building, avoiding in such a way the use of a base temperature. The method was tested in four climates and validated against cost-optimal solutions solved with optimization. The accuracy of the method was assessed with sensitivity analyses of key parameters such as window-to-wall ratios (WWRs), window g-values, costs of heating, and electricity. These results showed that the existing square root equation overestimated the climate difference effect so that the calculation from the cold climate U-value resulted in less insulation than cost-optimal in warmer climates. Parametric analyses revealed that the power value of 0.2 remarkably improved the accuracy as well as performance worked well in all cases and can be recommended as a default value. Sensitivity analyses with a broad range of energy costs and window parameters revealed that the developed equation resulted in maximum 5% underestimation and maximum 7% overestimation of an average area-weighted optimal U-value of building envelope in another climate. The developed method allows objectively to compare optimal insulation of the building envelope in different climates. The method is easy to apply for energy performance comparison of similar buildings in different climates and also for energy performance requirements comparison.
Penetration of Different Liquids in Wood-Based Composites: The Effect of Adsorption Energy
Authors: Taghiyari Hamid R. , Majidi Roya , Arsalan Mahnaz Ghezel , Moradiyan Asaad , Militz Holger , Ntalos George , Papadopoulos Antonios N.
Published: January 2021

The penetration properties of three different liquids on the surface of medium-density fiberboard (MDF) and particleboard panels were studied. Water, as a polar liquid, was compared to two other less polar liquids (namely, ethanol and kerosene) with significantly larger molecules. Measurement of penetration time and wetted area demonstrated significantly higher values for water in comparison with the other two liquids, in both composite types. Calculation of adsorption energies, as well as adsorption distances, of the three liquid molecules on hemicellulose showed higher potentiality of water molecules in forming bonds on hemicellulose. However, comparison of the adsorption energies of cellulose with hemicellulose indicated a higher impact of the formation of bonds between hydroxyl groups in water and cellulose in hindering the penetration of water molecules into the composite textures. It was concluded that the formation of strong and stable bonds between the hydroxyl groups in water and cellulose resulted in a significant increase in penetration time and wetted area.
Antimicrobial, Shelf-Life Stability, and Effect of Maltodextrin and Gum Arabic on the Encapsulation Efficiency of Sugarcane Bagasse Bioactive Compounds
Authors: Velazquez-Martinez Victor , Valles-Rosales Delia , Rodriguez-Uribe Laura , Holguin Omar , Quintero-Quiroz Julian , Reyes-Jaquez Damian , Rodriguez-Borbon Manuel Ivan , Villagrán-Villegas Luz Yazmin , Delgado Efren
Published: January 2021

This study shows the effects of maltodextrins and gum arabic as microencapsulation agents on the stability of sugarcane bagasse extracts and the potential use of the extracts as antimicrobial agents. The bioactive compounds in sugarcane bagasse (SCB) were extracted using 90% methanol and an orbital shaker at a fixed temperature of 50 °C, thereby obtaining a yield of the total phenolic content of 5.91 mg GAE/g. The bioactive compounds identified in the by-product were flavonoids, alkaloids, and lignan (-) Podophyllotoxin. The total phenolic content (TPC), antioxidant activity, and shelf-life stability of fresh and microencapsulated TPC were analyzed. This experiment’s optimal microencapsulation can be obtained with a ratio of 0.6% maltodextrin (MD)/9.423% gum arabic (GA). Sugarcane bagasse showed high antioxidant activities, which remained stable after 30 days of storage and antimicrobial properties against E. coli, B. cereus, S. aureus, and the modified yeast SGS1. The TPC of the microencapsulated SCB extracts was not affected (p > 0.05) by time or storage temperature due to the combination of MD and GA as encapsulating agents. The antioxidant and antimicrobial capacities of sugarcane bagasse extracts showed their potential use as a source of bioactive compounds for further use as a food additive or nutraceutical. The results are a first step in encapsulating phenolic compounds from SCB as a promising source of antioxidant agents and ultimately a novel resource for functional foods.