bluuebunny/crossref_metadata_2025 huggingface dataset:
Crosslinked Facilitated Transport Membranes Based on Carboxymethylated NFC and Amine-Based Fixed Carriers for Carbon Capture, Utilization, and Storage Applications
Authors: Dhuiège Benjamin , Lasseuguette Elsa , Brochier-Salon Marie-Christine , Ferrari Maria-Chiara , Missoum Karim
Published: January 2020

Herein, we report the performances of crosslinked facilitated transport membranes based on carboxymethylated nanofibrils of cellulose (cmNFC) and polyvinylamine (PVAm) with the use of 3-(2-Aminoethylamino) propyltrimethoxysilane (AEAPTMS) as second fixed carrier for CO2 selectivity and permeability. The grafting of AEAPTMS on cmNFC was optimized by following the hydrolysis/condensation kinetics by 29Si Nuclear Magnetic Resonance (NMR) analyses and two different strategies of the process of membrane production were investigated. In optimized conditions, around 25% of the -COOH functions from cmNFC have crosslinked with PVAm. The crosslinked membranes were less sensitive to liquid water and the crystallinity of PVAm was tuned by the conditions of the membrane elaboration. In both processes, CO2 selectivity and permeability were enhanced especially at high water vapor concentration by the use of PVAm and AEAPTMS suggesting the existence of a facilitation effect due to amine-CO2 interaction, while the mechanical integrity of the swollen membranes remained intact.
Development of a Building-Scale Meteorological Prediction System Including a Realistic Surface Heating
Authors: Kim Dong-Jin , Lee Doo-Il , Kim Jae-Jin , Park Moon-Soo , Lee Sang-Hyun
Published: January 2020

Microscale urban meteorological models have been widely used in interpreting atmospheric flow and thermal discomfort in urban environments, but most previous studies examined the urban flow and thermal environments for an idealized urban morphology with imposing neutral or homogeneous thermal forcing. This study has developed a new building-scale meteorological prediction system that extends the ability to predict microscale meteorological fields in real urban environments. A computational fluid dynamics (CFD) model has been developed based on the non-hydrostatic incompressible Reynolds-averaged Navier-Stokes (RANS) equations with a standard k-ε turbulence model, and the microscale urban surface energy (MUSE) model was coupled with the CFD model to provide realistic surface thermal boundary conditions in real urban environments. It is driven by the large scale wind and temperature fields predicted by the Korean operational weather prediction model. The validation results of the new building-scale meteorological prediction system were presented against wind tunnel data and field measurements, showing its ability to predict in-canyon flows and thermal environments in association with spatiotemporal variations of surface temperatures in real urban environments. The effects of realistic surface heating on pedestrian level wind and thermal environments have been investigated through sensitivity simulations of different surface heating conditions in the highly built-up urban area. The results implied that the inclusion of surface thermal forcing is important in interpreting urban flow and thermal environment of the urban area, highlighting a realistic urban surface heating that should be considered in predicting building-scale meteorology over real urban environments.
Pathological Roles of Mitochondrial Oxidative Stress and Mitochondrial Dynamics in Cardiac Microvascular Ischemia/Reperfusion Injury
Authors: Zhou Hao , Toan Sam
Published: January 2020

Mitochondria are key regulators of cell fate through controlling ATP generation and releasing pro-apoptotic factors. Cardiac ischemia/reperfusion (I/R) injury to the coronary microcirculation has manifestations ranging in severity from reversible edema to interstitial hemorrhage. A number of mechanisms have been proposed to explain the cardiac microvascular I/R injury including edema, impaired vasomotion, coronary microembolization, and capillary destruction. In contrast to their role in cell types with higher energy demands, mitochondria in endothelial cells primarily function in signaling cellular responses to environmental cues. It is clear that abnormal mitochondrial signatures, including mitochondrial oxidative stress, mitochondrial fission, mitochondrial fusion, and mitophagy, play a substantial role in endothelial cell function. While the pathogenic role of each of these mitochondrial alterations in the endothelial cells I/R injury remains complex, profiling of mitochondrial oxidative stress and mitochondrial dynamics in endothelial cell dysfunction may offer promising potential targets in the search for novel diagnostics and therapeutics in cardiac microvascular I/R injury. The objective of this review is to discuss the role of mitochondrial oxidative stress on cardiac microvascular endothelial cells dysfunction. Mitochondrial dynamics, including mitochondrial fission and fusion, are critically discussed to understand their roles in endothelial cell survival. Finally, mitophagy, as a degradative mechanism for damaged mitochondria, is summarized to figure out its contribution to the progression of microvascular I/R injury.
Structural and Biophysical Analyses of Human N-Myc Downstream-Regulated Gene 3 (NDRG3) Protein
Authors: Kim Kyung Rok , Kim Kyung A. , Park Joon Sung , Jang Jun Young , Choi Yuri , Lee Hyung Ho , Lee Dong Chul , Park Kyung Chan , Yeom Young Il , Kim Hyun-Jung , Han Byung Woo
Published: January 2020

The N-Myc downstream-regulated gene (NDRG) family belongs to the α/β-hydrolase fold and is known to exert various physiologic functions in cell proliferation, differentiation, and hypoxia-induced cancer metabolism. In particular, NDRG3 is closely related to proliferation and migration of prostate cancer cells, and recent studies reported its implication in lactate-triggered hypoxia responses or tumorigenesis. However, the underlying mechanism for the functions of NDRG3 remains unclear. Here, we report the crystal structure of human NDRG3 at 2.2 Å resolution, with six molecules in an asymmetric unit. While NDRG3 adopts the α/β-hydrolase fold, complete substitution of the canonical catalytic triad residues to non-reactive residues and steric hindrance around the pseudo-active site seem to disable the α/β-hydrolase activity. While NDRG3 shares a high similarity to NDRG2 in terms of amino acid sequence and structure, NDRG3 exhibited remarkable structural differences in a flexible loop corresponding to helix α6 of NDRG2 that is responsible for tumor suppression. Thus, this flexible loop region seems to play a distinct role in oncogenic progression induced by NDRG3. Collectively, our studies could provide structural and biophysical insights into the molecular characteristics of NDRG3.
Redox Signaling from Mitochondria: Signal Propagation and Its Targets
Authors: Ježek Petr , Holendová Blanka , Plecitá-Hlavatá Lydie
Published: January 2020

Progress in mass spectroscopy of posttranslational oxidative modifications has enabled researchers to experimentally verify the concept of redox signaling. We focus here on redox signaling originating from mitochondria under physiological situations, discussing mechanisms of transient redox burst in mitochondria, as well as the possible ways to transfer such redox signals to specific extramitochondrial targets. A role of peroxiredoxins is described which enables redox relay to other targets. Examples of mitochondrial redox signaling are discussed: initiation of hypoxia-inducible factor (HIF) responses; retrograde redox signaling to PGC1α during exercise in skeletal muscle; redox signaling in innate immune cells; redox stimulation of insulin secretion, and other physiological situations.
Chemoenzymatic Synthesis of Enantiomeric, Bicyclic δ-Halo-γ-lactones with a Cyclohexane Ring, Their Biological Activity and Interaction with Biological Membranes
Authors: Mazur Marcelina , Włoch Aleksandra , Bahri Fouad , Pruchnik Hanna , Pawlak Aleksandra , Obmińska-Mrukowicz Bożena , Maciejewska Gabriela , Gładkowski Witold
Published: January 2020

Starting from 1-acetyl-1-cyclohexene, three enantiomeric pairs (ee ≥ 99%) of bicyclic δ-halo-γ-lactones with cyclohexane ring were obtained in five-step synthesis. The key stereochemical steps were lipase-catalyzed kinetic resolution of racemic 1-(cyclohex-1-en-1-yl) ethanol followed by transfer of chirality to ethyl 2-(2-ethylidenecyclohexyl) acetate in the Johnson–Claisen rearrangement. Synthesized halolactones exhibited antiproliferative activity towards canine B-cell leukemia cells (GL-1) and canine B-cell chronic leukemia cells (CLB70) and the most potent (IC50 18.43 ± 1.46 μg/mL against GL-1, IC50 11.40 ± 0.40 μg/mL against CLB70) comparable with the control etoposide, was (1R,6R,1′S)-1-(1′-chloroethyl)-9-oxabicyclo[4.3.0]nonan-8-one (8b). All halolactones did not have a toxic effect on erythrocytes and did not change the fluidity of membranes in the hydrophobic region of the lipid bilayer. Only weak changes in the hydrophilic area were observed, like the degree of lipid packing and associated hydration. The racemic halolactones were also tested for their antimicrobial properties and found to exhibit selectivity towards bacteria, in particular, towards Proteus mirabilis ATCC 35659.
Early Exposure to THC Alters M-Cell Development in Zebrafish Embryos
Authors: Amin Md Ruhul , Ahmed Kazi T. , Ali Declan W.
Published: January 2020

Cannabis is one of the most commonly used illicit recreational drugs that is often taken for medicinal purposes. The psychoactive ingredient in cannabis is Δ9-Tetrahydrocannabinol (Δ9-THC, hereafter referred to as THC), which is an agonist at the endocannabinoid receptors CB1R and CB2R. Here, we exposed zebrafish embryos to THC during the gastrulation phase to determine the long-term effects during development. We specifically focused on reticulospinal neurons known as the Mauthner cells (M-cell) that are involved in escape response movements. The M- cells are born during gastrulation, thus allowing us to examine neuronal morphology of neurons born during the time of exposure. After the exposure, embryos were allowed to develop normally and were examined at two days post-fertilization for M-cell morphology and escape responses. THC treated embryos exhibited subtle alterations in M-cell axon diameter and small changes in escape response dynamics to touch. Because escape responses were altered, we also examined muscle fiber development. The fluorescent labelling of red and white muscle fibers showed that while muscles were largely intact, the fibers were slightly disorganized with subtle but significant changes in the pattern of expression of nicotinic acetylcholine receptors. However, there were no overt changes in the expression of nicotinic receptor subunit mRNA ascertained by qPCR. Embryos were allowed to further develop until 5 dpf, when they were examined for overall levels of movement. Animals exposed to THC during gastrulation exhibited reduced activity compared with vehicle controls. Together, these findings indicate that zebrafish exposed to THC during the gastrula phase exhibit small changes in neuronal and muscle morphology that may impact behavior and locomotion.
Experiments and Agent Based Models of Zooplankton Movement within Complex Flow Environments
Authors: Ozalp Mustafa Kemal , Miller Laura A. , Dombrowski Thomas , Braye Madeleine , Dix Thomas , Pongracz Liam , Howell Reagan , Klotsa Daphne , Pasour Virginia , Strickland Christopher
Published: January 2020

The movement of plankton is often dictated by local flow patterns, particularly during storms and in environments with strong flows. Reefs, macrophyte beds, and other immersed structures can provide shelter against washout and drastically alter the distributions of plankton as these structures redirect and slow the flows through them. Advection–diffusion and agent-based models are often used to describe the movement of plankton within marine and fresh water environments and across multiple scales. Experimental validation of such models of plankton movement within complex flow environments is challenging because of the difference in both time and spatial scales. Organisms on the scale of 1 mm or less swim by beating their appendages on the order of 1 Hz and are advected meters to kilometers over days, weeks, and months. One approach to study this challenging multiscale problem is to insert actively moving agents within a background flow field. Open source tools to implement this sort of approach are, however, limited. In this paper, we combine experiments and computational fluid dynamics with a newly developed agent-based modeling platform to quantify plankton movement at the scale of tens of centimeters. We use Artemia spp., or brine shrimp, as a model organism given their availability and ease of culturing. The distribution of brine shrimp over time was recorded in a flow tank with simplified physical models of macrophytes. These simplified macrophyte models were 3D-printed arrays of cylinders of varying heights and densities. Artemia nauplii were injected within these arrays, and their distributions over time were recorded with video. The detailed three-dimensional flow fields were quantified using computational fluid dynamics and validated experimentally with particle image velocimetry. To better quantify plankton distributions, we developed an agent-based modeling framework, Planktos, to simulate the movement of plankton immersed within such flow fields. The spatially and temporally varying Artemia distributions were compared across models of varying heights and densities for both the experiments and the agent-based models. The results show that increasing the density of the macrophyte bed drastically increases the average time it takes the plankton to be swept downstream. The height of the macrophyte bed had less of an effect. These effects were easily observed in both experimental studies and in the agent-based simulations.
Identifying Core Regions for Path Integration on Medial Entorhinal Cortex of Hippocampal Formation
Authors: Fukawa Ayako , Aizawa Takahiro , Yamakawa Hiroshi , Eguchi Yairi Ikuko
Published: January 2020

Path integration is one of the functions that support the self-localization ability of animals. Path integration outputs position information after an animal’s movement when initial-position and movement information is input. The core region responsible for this function has been identified as the medial entorhinal cortex (MEC), which is part of the hippocampal formation that constitutes the limbic system. However, a more specific core region has not yet been identified. This research aims to clarify the detailed structure at the cell-firing level in the core region responsible for path integration from fragmentarily accumulated experimental and theoretical findings by reviewing 77 papers. This research draws a novel diagram that describes the MEC, the hippocampus, and their surrounding regions by focusing on the MEC’s input/output (I/O) information. The diagram was created by summarizing the results of exhaustively scrutinizing the papers that are relative to the I/O relationship, the connection relationship, and cell position and firing pattern. From additional investigations, we show function information related to path integration, such as I/O information and the relationship between multiple functions. Furthermore, we constructed an algorithmic hypothesis on I/O information and path-integration calculation method from the diagram and the information of functions related to path integration. The algorithmic hypothesis is composed of regions related to path integration, the I/O relations between them, the calculation performed there, and the information representations (cell-firing pattern) in them. Results of examining the hypothesis confirmed that the core region responsible for path integration was either stellate cells in layer II or pyramidal cells in layer III of the MEC.
Calcitonin Gene-Related Peptide (CGRP) and Cluster Headache
Authors: Carmine Belin Andrea , Ran Caroline , Edvinsson Lars
Published: January 2020

Cluster headache (CH) is a severe primary headache with a prevalence of 1/1000 individuals, and a predominance in men. Calcitonin gene-related peptide (CGRP) is a potent vasodilator, originating in trigeminal neurons and has a central role in CH pathophysiology. CGRP and the CGRP receptor complex have recently taken center stage as therapeutic targets for primary headaches, such as migraine. Multiple CGRP and CGRP receptor monoclonal antibodies, as well as small molecule antagonists (gepants) are on their way constituting a new frontier of migraine and possibly CH medication. During a CH attack, there is an activation of the trigeminal-autonomic reflex with the release of CGRP, and inversely if CGRP is administered to a CH patient in an active disease phase, it triggers an attack. Increased levels of CGRP have been found in ipsilateral jugular vein blood during the active phase of CH. This process is hypothesized to have a key role in the intense pain perception and in the associated distinctive vasodilation. So far, clinical tests of CGRP antibodies have been inconclusive in CH patients. This review summarizes the current state of knowledge on the role of CGRP in CH pathology, and as a target for future treatments.
Measuring Biases of Visual Attention: A Comparison of Four Tasks
Authors: Sigurjónsdóttir Ólafía , Bjornsson Andri S. , Wessmann Inga D. , Kristjánsson Árni
Published: January 2020

Attention biases to stimuli with emotional content may play a role in the development and maintenance of anxiety disorders. The most commonly used tasks in measuring and treating such biases, the dot-probe and spatial cueing tasks, have yielded mixed results, however. We assessed the sensitivity of four visual attention tasks (dot-probe, spatial cueing, visual search with irrelevant distractor and attentional blink tasks) to differences in attentional processing between threatening and neutral faces in 33 outpatients with a primary diagnosis of social anxiety disorder (SAD) and 26 healthy controls. The dot-probe and cueing tasks revealed no differential processing of neutral and threatening faces between the SAD and control groups. The irrelevant distractor task showed some sensitivity to differential processing for the SAD group, but the attentional blink task was uniquely sensitive to such differences in both groups, and revealed processing differences between the SAD and control groups. The attentional blink task also revealed interesting temporal dynamics of attentional processing of emotional stimuli and may provide a uniquely nuanced picture of attentional response to emotional stimuli. Our results therefore suggest that the attentional blink task is more suitable for measuring preferential attending to emotional stimuli and treating dysfunctional attention patterns than the more commonly used dot-probe and cueing tasks.
Alkali Earth Metal Molybdates as Catalysts for the Selective Oxidation of Methanol to Formaldehyde—Selectivity, Activity, and Stability
Authors: Thrane Joachim , Lundegaard Lars Fahl , Beato Pablo , Mentzel Uffe Vie , Thorhauge Max , Jensen Anker Degn , Høj Martin
Published: January 2020

Alkali earth metal molybdates (MMoO4, M = Mg, Ca, Sr, and Ba) were investigated as catalysts for the selective oxidation of methanol to formaldehyde in the search for more stable alternatives to the current industrial iron molybdate catalyst. The catalysts were prepared by either sol-gel synthesis or co-precipitation with both stoichiometric ratio (Mo:M = 1.0) and 10 mol% to 20 mol% excess Mo (Mo:M = 1.1 to 1.2). The catalysts were characterized by X-ray diffraction (XRD), nitrogen physisorption, Raman spectroscopy, temperature programmed desorption of CO2 (CO2-TPD), and inductively coupled plasma (ICP). The catalytic performance of the catalysts was measured in a lab-scale, packed bed reactor setup by continuous operation for up to 100 h on stream at 400 °C. Initial selectivities towards formaldehyde of above 97% were achieved for all samples with excess molybdenum oxide at MeOH conversions between 5% and 75%. Dimethyl ether (DME) and dimethoxymethane (DMM) were the main byproducts, but CO (0.1%–2.1%) and CO2 (0.1%–0.4%) were also detected. It was found that excess molybdenum oxide evaporated from all the catalysts under operating conditions within 10 to 100 h on stream. No molybdenum evaporation past the point of stoichiometry was detected.
Participation of Extracellular Vesicles from Zika-Virus-Infected Mosquito Cells in the Modification of Naïve Cells’ Behavior by Mediating Cell-to-Cell Transmission of Viral Elements
Authors: Martínez-Rojas Pedro Pablo , Quiroz-García Elizabeth , Monroy-Martínez Verónica , Agredano-Moreno Lourdes Teresa , Jiménez-García Luis Felipe , Ruiz-Ordaz Blanca H.
Published: January 2020

To date, no safe vaccine or antivirals for Zika virus (ZIKV) infection have been found. The pathogenesis of severe Zika, where host and viral factors participate, remains unclear. For the control of Zika, it is important to understand how ZIKV interacts with different host cells. Knowledge of the targeted cellular pathways which allow ZIKV to productively replicate and/or establish prolonged viral persistence contributes to novel vaccines and therapies. Monocytes and endothelial vascular cells are the main ZIKV targets. During the infection process, cells are capable of releasing extracellular vesicles (EVs). EVs are mediators of intercellular communication. We found that mosquito EVs released from ZIKV-infected (C6/36) cells carry viral RNA and ZIKV-E protein and are able to infect and activate naïve mosquito and mammalian cells. ZIKV C6/36 EVs promote the differentiation of naïve monocytes and induce a pro-inflammatory state with tumor necrosis factor-alpha (TNF-α) mRNA expression. ZIKV C6/36 EVs participate in endothelial vascular cell damage by inducing coagulation (TF) and inflammation (PAR-1) receptors at the endothelial surface of the cell membranes and promote a pro-inflammatory state with increased endothelial permeability. These data suggest that ZIKV C6/36 EVs may contribute to the pathogenesis of ZIKV infection in human hosts.
Cyclic AMP Regulates Key Features of Macrophages via PKA: Recruitment, Reprogramming and Efferocytosis
Authors: Negreiros-Lima Graziele L. , Lima Kátia M. , Moreira Isabella Z. , Jardim Bruna Lorrayne O. , Vago Juliana P. , Galvão Izabela , Teixeira Lívia Cristina R. , Pinho Vanessa , Teixeira Mauro M. , Sugimoto Michelle A. , Sousa Lirlândia P.
Published: January 2020

Macrophages are central to inflammation resolution, an active process aimed at restoring tissue homeostasis following an inflammatory response. Here, the effects of db-cAMP on macrophage phenotype and function were investigated. Injection of db-cAMP into the pleural cavity of mice induced monocytes recruitment in a manner dependent on PKA and CCR2/CCL2 pathways. Furthermore, db-cAMP promoted reprogramming of bone-marrow-derived macrophages to a M2 phenotype as seen by increased Arg-1/CD206/Ym-1 expression and IL-10 levels (M2 markers). Db-cAMP also showed a synergistic effect with IL-4 in inducing STAT-3 phosphorylation and Arg-1 expression. Importantly, db-cAMP prevented IFN-γ/LPS-induced macrophage polarization to M1-like as shown by increased Arg-1 associated to lower levels of M1 cytokines (TNF-α/IL-6) and p-STAT1. In vivo, db-cAMP reduced the number of M1 macrophages induced by LPS injection without changes in M2 and Mres numbers. Moreover, db-cAMP enhanced efferocytosis of apoptotic neutrophils in a PKA-dependent manner and increased the expression of Annexin A1 and CD36, two molecules associated with efferocytosis. Finally, inhibition of endogenous PKA during LPS-induced pleurisy impaired the physiological resolution of inflammation. Taken together, the results suggest that cAMP is involved in the major functions of macrophages, such as nonphlogistic recruitment, reprogramming and efferocytosis, all key processes for inflammation resolution.
SUN1/2 Are Essential for RhoA/ROCK-Regulated Actomyosin Activity in Isolated Vascular Smooth Muscle Cells
Authors: Porter Lauren , Minaisah Rose-Marie , Ahmed Sultan , Ali Seema , Norton Rosemary , Zhang Qiuping , Ferraro Elisa , Molenaar Chris , Holt Mark , Cox Susan , Fountain Samuel , Shanahan Catherine , Warren Derek
Published: January 2020

Vascular smooth muscle cells (VSMCs) are the predominant cell type in the blood vessel wall. Changes in VSMC actomyosin activity and morphology are prevalent in cardiovascular disease. The actin cytoskeleton actively defines cellular shape and the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex, comprised of nesprin and the Sad1p, UNC-84 (SUN)-domain family members SUN1/2, has emerged as a key regulator of actin cytoskeletal organisation. Although SUN1 and SUN2 function is partially redundant, they possess specific functions and LINC complex composition is tailored for cell-type-specific functions. We investigated the importance of SUN1 and SUN2 in regulating actomyosin activity and cell morphology in VSMCs. We demonstrate that siRNA-mediated depletion of either SUN1 or SUN2 altered VSMC spreading and impaired actomyosin activity and RhoA activity. Importantly, these findings were recapitulated using aortic VSMCs isolated from wild-type and SUN2 knockout (SUN2 KO) mice. Inhibition of actomyosin activity, using the rho-associated, coiled-coil-containing protein kinase1/2 (ROCK1/2) inhibitor Y27632 or blebbistatin, reduced SUN2 mobility in the nuclear envelope and decreased the association between SUN2 and lamin A, confirming that SUN2 dynamics and interactions are influenced by actomyosin activity. We propose that the LINC complex exists in a mechanical feedback circuit with RhoA to regulate VSMC actomyosin activity and morphology.
TCTP is Essential for Cell Proliferation and Survival during CNS Development
Authors: Chen Sung-Ho , Lu Chin-Hung , Tsai Ming-Jen
Published: January 2020

Translationally controlled tumor-associated protein (TCTP) has been implicated in cell growth, proliferation, and apoptosis through interacting proteins. Although TCTP is expressed abundantly in the mouse brain, little is known regarding its role in the neurogenesis of the nervous system. We used Nestin-cre-driven gene-mutated mice to investigate the function of TCTP in the nervous system. The mice carrying disrupted TCTP in neuronal and glial progenitor cells died at the perinatal stage. The NestinCre/+; TCTPf/f pups displayed reduced body size at postnatal day 0.5 (P0.5) and a lack of milk in the stomach compared with littermate controls. In addition to decreased cell proliferation, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) and caspase assay revealed that apoptosis was increased in newly committed TCTP-disrupted cells as they migrated away from the ventricular zone. The mechanism may be that the phenotype from specific deletion of TCTP in neural progenitor cells is correlated with the decreased expression of cyclins D2, E2, Mcl-1, Bcl-xL, hax-1, and Octamer-binding transcription factor 4 (Oct4) in conditional knockout mice. Our results demonstrate that TCTP is a critical protein for cell survival during early neuronal and glial differentiation. Thus, enhanced neuronal loss and functional defect in Tuj1 and doublecortin-positive neurons mediated through increased apoptosis and decreased proliferation during central nervous system (CNS) development may contribute to the perinatal death of TCTP mutant mice.
A Weather-Pattern-Based Evaluation of the Performance of CMIP5 Models over Mexico
Authors: Díaz-Esteban Yanet , Raga Graciela B. , Díaz Rodríguez Oscar Onoe
Published: January 2020

The fifth phase of the Coupled Model Inter-Comparison Project (CMIP5) is frequently used to force regional climate models for dynamic downscaling and projections, which decision makers in turn use for future plans in different sectors. It is, therefore, highly important to assess their performance in order to use them as reliable tools. A weather-type approach for the evaluation of the performance of CMIP5 models is employed in this study, with the objective of providing insight into model errors under a set of distinct synoptic conditions and circulation types associated with the rainy season over Mexico and Central America. The Self-Organizing Maps algorithm is used to identify the main weather regimes (constructed from sea level pressure, specific humidity, and low-level winds at a daily time-scale), which are then evaluated against reanalysis. The results show that model performance depends on the weather type in all of the variables except for sea level pressure, which confirms the usefulness of this approach. The models simulate better the humidity patterns that show weak deviations from the climatological norm. In addition, the wind pattern representing the Caribbean Low Level Jet is well reproduced by all the models. The results show the capacity of this methodology for determining the extent to which climate models represent the main circulation patterns that characterize the climate and local weather in Mexico.
Effects of Heat Treatment and Tea Polyphenols on the Structure and Properties of Polyvinyl Alcohol Nanofiber Films for Food Packaging
Authors: Luo Jinjie , Zuo Duquan , Deng Zhenghua , Ji Anping , Xia Guofeng
Published: January 2020

In this study, biodegradable polyvinyl alcohol (PVA) was blended with natural antioxidant tea polyphenols (TPs) to produce PVA/TP nanofiber films by electrospinning. The effects of heat treatment and TP incorporation on the structural and physical properties of the films were then evaluated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) revealed that the PVA/TP nanofiber film has a more compact structure and better morphology than PVA alone. In addition, the water resistance was enhanced, and the formation of hydrogen bonds between the TP and PVA molecules increased via the heat treatment. Furthermore, the mechanical, antioxygenic, and antibacterial properties of the nanofiber films were significantly improved (P < 0.05) owing to the incorporation of TP. In particular, when the mass ratio of the PVA/TP was 7:3, the elongation at break (EAB) of the film increased to 105.24% ± 2.87%, and the antioxidant value reached a maximum at 64.83% ± 5.21%. In addition, the antibacterial activity of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) increased to the maximum levels of 82.48% ± 2.12% and 86.25% ± 2.32%, respectively. In summary, our study produced a functional food packaging material that includes preservation with an acceptable bioactivity, ability to keep food fresh, and biodegradability.
Development of Novel Lightweight Dual-Phase Al-Ti-Cr-Mn-V Medium-Entropy Alloys with High Strength and Ductility
Authors: Liao Yu-Chin , Chen Po-Sung , Li Chao-Hsiu , Tsai Pei-Hua , Jang Jason , Hsieh Ker-Chang , Chen Chih-Yen , Lin Ping-Hung , Huang Jacob , Wu Hsin-Jay , Lo Yu-Chieh , Huang Chang-Wei , Tsao I-Yu
Published: January 2020

A novel lightweight Al-Ti-Cr-Mn-V medium-entropy alloy (MEA) system was developed using a nonequiatiomic approach and alloys were produced through arc melting and drop casting. These alloys comprised a body-centered cubic (BCC) and face-centered cubic (FCC) dual phase with a density of approximately 4.5 g/cm3. However, the fraction of the BCC phase and morphology of the FCC phase can be controlled by incorporating other elements. The results of compression tests indicated that these Al-Ti-Cr-Mn-V alloys exhibited a prominent compression strength (~1940 MPa) and ductility (~30%). Moreover, homogenized samples maintained a high compression strength of 1900 MPa and similar ductility (30%). Due to the high specific compressive strength (0.433 GPa·g/cm3) and excellent combination of strength and ductility, the cast lightweight Al-Ti-Cr-Mn-V MEAs are a promising alloy system for application in transportation and energy industries.
Forma Mentis Networks Reconstruct How Italian High Schoolers and International STEM Experts Perceive Teachers, Students, Scientists, and School
Authors: Stella Massimo
Published: January 2020

This study investigates how students and researchers shape their knowledge and perception of educational topics. The mindset or forma mentis of 159 Italian high school students and of 59 international researchers in science, technology, engineering and maths (STEM) are reconstructed through forma mentis networks, i.e., cognitive networks of concepts connected by free associations and enriched with sentiment labels. The layout of conceptual associations between positively/negatively/neutrally perceived concepts is informative on how people build their own mental constructs or beliefs about specific topics. Researchers displayed mixed positive/neutral mental representations of “teacher”, “student” and, “scientist”. Students’ conceptual associations of “scientist” were highly positive and largely non-stereotypical, although links about the “mad scientist” stereotype persisted. Students perceived “teacher” as a complex figure, associated with positive aspects like mentoring/knowledge transmission but also to negative sides revolving around testing and grading. “School” elicited stronger differences between the two groups. In the students’ mindset, “school” was surrounded by a negative emotional aura or set of associations, indicating an anxious perception of the school setting, mixing scholastic concepts, anxiety-eliciting words, STEM disciplines like maths and physics, and exam-related notions. Researchers’ positive stance of “school” included concepts of fun, friendship, and personal growth instead. Along the perspective of Education Research, the above results are discussed as quantitative evidence for test- and STEM anxiety co-occurring in the way Italian students perceive education places and their actors. Detecting these patterns in student populations through forma mentis networks offers new, simple to gather yet detailed knowledge for future data-informed intervention policies and action research.
Electromagnetic Soil Characterization for Undergrounded RFID System Implementation
Authors: Elboushi Ayman , Telba Ahmed , Sebak Abdelrazik , Jamil Khalid
Published: January 2020

This paper can be divided into two main parts. In the first part, an extensive experimental study for electromagnetic characteristic assessment of different soil samples is presented. In the second part of the paper, a practical verification of the obtained link budget model is performed using a buried metal-backed RFID tag antenna under a 40 cm sand layer. This antenna is designed to operate at 915 MHz with MONZA3 chip. Using Impinj Speedway system the tag antenna could be detected, and its information could be read from different distances of up to more than 2.5 m.
FPGA-Based Implementation of Finite Set-MPC for a VSI System Using XSG-Based Modeling
Authors: Singh Vijay Kumar , Tripathi Ravi Nath , Hanamoto Tsuyoshi
Published: January 2020

Finite set-model predictive control (FS-MPC) is used for power converters and drives having unique advantages as compared to the conventional control strategies. However, the computational burden of the FS-MPC is a primary concern for real-time implementation. Field programmable gate array (FPGA) is an alternative and exciting solution for real-time implementation because of the parallel processing capability, as well as, discrete nature of the hardware platform. Nevertheless, FPGA is capable of handling the computational requirements for the FS-MPC implementation, however, the system development involves multiple steps that lead to the time-consuming debugging process. Moreover, specific hardware coding skill makes it more complex corresponding to an increase in system complexity that leads to a tedious task for system development. This paper presents an FPGA-based experimental implementation of FS-MPC using the system modeling approach. Furthermore, a comparative analysis of FS-MPC in stationary αβ and rotating dq frame is considered for simulation as well as experimental result. The FS-MPC for a three-phase voltage source inverter (VSI) system is developed in a realistic digital simulator integrated with MATLAB-Simulink. The simulated controller model is further used for experimental system implementation and validation using Xilinx FPGA: Zedboard Zynq Evaluation and Development Kit. The digital simulator termed as Xilinx system generator (XSG) provided by Xilinx is used for modeling-based FPGA design.
Design Considerations of Series-Connected Devices Based LLC Converter
Authors: Yoon Dongkwan , Lee Sungmin , Cho Younghoon
Published: January 2020

This paper describes the design of a Series-Connected Device based on a fixed–frequency LLC resonant converter (SCDLLC). Isolation of the dc-dc converter like the LLC resonant converter is used for the stability of the high voltage system such as a solid-state-transformer (SST). The series-connected devices driving method is one of the methods applicable to a high voltage system. When driving series-connected devices, an auxiliary circuit for voltage balancing between series-connected devices is required, which can be simply implemented using a passive element. In this paper, LLC converter design with balancing circuits configured in parallel with a device is provided, and both the simulations and experiments were performed.
A Molecular Dynamics Study of the Generation of Ethanol for Insulating Paper Pyrolysis
Authors: Zhang Yiyi , Li Yi , Li Shizuo , Zheng Hanbo , Liu Jiefeng
Published: January 2020

Cellulosic insulation paper is usually used in oil-immersed transformer insulation systems. In this study, the molecular dynamics method based on reaction force field (ReaxFF) was used to simulate the pyrolysis process of a cellobiose molecular model. Through a series of ReaxFF- Molecular Dynamics (MD) simulations, the generation path of ethanol at the atomic level was studied. Because the molecular system has hydrogen bonding, force-bias Monte Carlo (fbMC) is mixed into ReaxFF to reduce the cost of calculation by reducing the sampled data. In order to ensure the reliability of the simulation, a model composed of 20 cellobioses and a model composed of 40 cellobioses were respectively established for repeated simulation in the range of 500–3000 K. The results show that insulating paper produced ethanol at extreme thermal fault, and the intermediate product of vinyl alcohol is the key to the aging process. It is also basically consistent with others’ previous experiment results. So it can provide an effective reference for the use of ethanol as an indicator to evaluate the aging condition of transformers.
A Study on the Operational Condition of a Ground Source Heat Pump in Bangkok Based on a Field Experiment and Simulation
Authors: Shimada Yutaro , Uchida Youhei , Takashima Isao , Chotpantarat Srilert , Widiatmojo Arif , Chokchai Sasimook , Charusiri Punya , Kurishima Hideaki , Tokimatsu Koji
Published: January 2020

The deployment of highly efficient cooling equipment is expected to promote energy savings and greenhouse gas emissions reductions in the tropics. A ground source heat pump (GSHP) has high energy-savings potential for use in Bangkok, Thailand. This study aimed to elucidate the operational conditions of a GSHP when used in Bangkok which was expected to achieve a higher efficiency than an air source heat pump (ASHP) over the long term. An operational experiment on a pilot facility in Bangkok and a simulation over a three-year GSHP operation were conducted. As a result of the operational experiment and simulation, the proposed operational condition was that the 90th percentile value of the hourly heat pump (HP) inlet temperature did not exceed 5 °C above that of the hourly annual ambient temperature during the third year of operation. When a GSHP designed based on this condition was utilized for a small government building, the required number of boreholes were 24, 4, and 3 for air-conditioned areas of 200, 40, and 25 m2, respectively, which achieved 40% energy savings. Thus, a small-scale GSHP in Bangkok designed based on the proposed condition can achieve high efficiency within space limitations.
Data-Driven Fault Localization in Distribution Systems with Distributed Energy Resources
Authors: Lin Zhidi , Duan Dongliang , Yang Qi , Hong Xuemin , Cheng Xiang , Yang Liuqing , Cui Shuguang
Published: January 2020

The integration of Distributed Energy Resources (DERs) introduces a non-conventional two-way power flow which cannot be captured well by traditional model-based techniques. This brings an unprecedented challenge in terms of the accurate localization of faults and proper actions of the protection system. In this paper, we propose a data-driven fault localization strategy based on multi-level system regionalization and the quantification of fault detection results in all subsystems/subregions. This strategy relies on the tree segmentation criterion to divide the entire system under study into several subregions, and then combines Support Vector Data Description (SVDD) and Kernel Density Estimation (KDE) to find the confidence level of fault detection in each subregion in terms of their corresponding p-values. By comparing the p-values, one can accurately localize the faults. Experiments demonstrate that the proposed data-driven fault localization can greatly improve the accuracy of fault localization for distribution systems with high DER penetration.
A Systematic Approach to Predict the Economic and Environmental Effects of the Cost-Optimal Energy Renovation of a Historic Building District on the District Heating System
Authors: Milić Vlatko , Amiri Shahnaz , Moshfegh Bahram
Published: January 2020

The economic and environmental performance of a district heating (DH) system is to a great extent affected by the size and dynamic behavior of the DH load. By implementing energy efficiency measures (EEMs) to increase a building’s thermal performance and by performing cost-optimal energy renovation, the operation of the DH system will be altered. This study presents a systematic approach consisting of building categorization, life cycle cost (LCC) optimization, building energy simulation and energy system optimization procedures, investigating the profitability and environmental performance of cost-optimal energy renovation of a historic building district on the DH system. The results show that the proposed approach can successfully be used to predict the economic and environmental effects of cost-optimal energy renovation of a building district on the local DH system. The results revealed that the financial gains of the district are between 186 MSEK (23%) and 218 MSEK (27%) and the financial losses for the DH system vary between 117–194 MSEK (5–8%). However, the suggested renovation measures decrease the local and global CO2 emissions by 71–75 metric ton of CO2eq./year (4%) and 3545–3727 metric ton of CO2eq./year (41–43%), respectively. Total primary energy use was decreased from 57.2 GWh/year to 52.0–52.2 GWh/year.
Heat and Mass Transfer in Hydromagnetic Second-Grade Fluid Past a Porous Inclined Cylinder under the Effects of Thermal Dissipation, Diffusion and Radiative Heat Flux
Authors: Bilal Sardar , Majeed Afraz Hussain , Mahmood Rashid , Khan Ilyas , Seikh Asiful H. , Sherif El-Sayed M.
Published: January 2020

Current disquisition is presented to excogitate heat and mass transfer features of second grade fluid flow generated by an inclined cylinder under the appliance of diffusion, radiative heat flux, convective and Joule heating effects. Mathematical modelling containing constitutive expressions by obliging fundamental conservation laws are constructed in the form of partial differential equations. Afterwards, transformations are implemented to convert the attained partial differential system into ordinary differential equations. An implicit finite difference method known as the Keller Box was chosen to extract the solution. The impact of the flow-controlling variables on velocity, temperature and concentration profiles are evaluated through graphical visualizations. Variations in skin friction, heat transfer and mass flux coefficients against primitive variables are manipulated through numerical data. It is inferred from the analysis that velocity of fluid increases for incrementing magnitude of viscoelastic parameter and curvature parameter whereas it reduces for Darcy parameter whereas skin friction coefficient decreases against curvature parameter. Assurance of present work is manifested by constructing comparison with previous published literature.
Effect of Vertical Vibration on the Mixing Time of a Passive Scalar in a Sparged Bubble Column Reactor
Authors: Mohagheghian Shahrouz , Ghajar Afshin J. , Elbing Brian R.
Published: January 2020

The present study used a sparged bubble column to study the mixing of a passive scalar under bubble-induced diffusion. The effect of gas superficial velocity (up to 69 mm/s) and external vertical vibrations (amplitudes up to 10 mm, frequency <23 Hz) on the mixing time scale were investigated. The bubble-induced mixing was characterized by tracking the distribution of a passive scalar within a sparged swarm of bubbles. Void fraction and bubble size distribution were also measured at each test condition. Without vibrations (static), the bubble column operated in the homogenous regime and the mixing time scale was insensitive to void fraction, which is consistent with the literature. In addition, the temporal evolution of the static column mixing was well approximated as an error function. With vertical vibrations at lower amplitudes tested, the bubble-induced mixing was restrained due to the suppression of the liquid velocity agitations in the bubble swarm wake, which decelerates mixing. Conversely, at higher amplitudes tested, vibration enhanced the bubble-induced mixing; this is attributed to bubble clustering and aggregation that produced void fraction gradients, which, in turn, induced a mean flow and accelerated the mixing. The vibration frequency for the range studied in the present work did not produce a significant effect on the mixing time. Analysis of the temporal evolution of the concentration of the passive scalar at a fixed point within the column revealed significant fluctuations with vibration. A dimensionally reasoned correlation is presented that scales the non-dimensional mixing time with the transient buoyancy number.
Effect of Surface Topography on Particle Deposition from Liquid Suspensions in Channel Flow
Authors: Zaw Myo Min , Zhu Liang , Ma Ronghui
Published: January 2020

A Eulerian—Lagrangian model has been developed to simulate particle attachment to surfaces with arc-shaped ribs in a two-dimensional channel flow at low Reynolds numbers. Numerical simulation has been performed to improve the quantitative understanding of how rib geometries enhance shear rates and particle-surface interact for various particle sizes and flow velocities. The enhanced shear rate is attributed to the wavy flows that develop over the ribbed surface and the weak vortices that form between adjacent ribs. Varying pitch-to-height ratio can alter the amplitude of the wavy flow and the angle of attack of the fluid on the ribs. In the presence of these two competing factors, the rib geometry with a pitch-to-height ratio of two demonstrates the greatest shear rate and the lowest fraction of particle attachment. However, the ribbed surfaces have negligible effects on small particles at low velocities. A force analysis identifies a threshold shear rate to reduce particle attachment. The simulated particle distributions over the ribbed surfaces are highly non-uniform for larger particles at higher velocities. The understanding of the effect of surface topography on particle attachment will benefit the design of surface textures for mitigating particulate fouling in a wide range of applications.