bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulatory RNAs: A Universal Language for Inter-Domain Communication
Authors: Layton Emma , Fairhurst Anna-Marie , Griffiths-Jones Sam , Grencis Richard K. , Roberts Ian S.
Published: November 2020

In eukaryotes, microRNAs (miRNAs) have roles in development, homeostasis, disease and the immune response. Recent work has shown that plant and mammalian miRNAs also mediate cross-kingdom and cross-domain communications. However, these studies remain controversial and are lacking critical mechanistic explanations. Bacteria do not produce miRNAs themselves, and therefore it is unclear how these eukaryotic RNA molecules could function in the bacterial recipient. In this review, we compare and contrast the biogenesis and functions of regulatory RNAs in eukaryotes and bacteria. As a result, we discovered several conserved features and homologous components in these distinct pathways. These findings enabled us to propose novel mechanisms to explain how eukaryotic miRNAs could function in bacteria. Further understanding in this area is necessary to validate the findings of existing studies and could facilitate the use of miRNAs as novel tools for the directed remodelling of the human microbiota.
Impact of Erythropoietin Production by Erythroblastic Island Macrophages on Homeostatic Murine Erythropoiesis
Authors: Perron-Deshaies Genève , St-Louis Philippe , Romero Hugo , Scorza Tatiana
Published: November 2020

Erythropoietin (EPO) is an essential hormone for erythropoiesis, protecting differentiating erythroblasts against apoptosis. EPO has been largely studied in stress or pathological conditions but its regulatory role in steady state erythropoiesis has been less documented. Herein, we report production of EPO by bone marrow-derived macrophages (BMDM) in vitro, and its further enhancement in BMDM conditioned with media from apoptotic cells. Confocal microscopy confirmed EPO production in erythroblastic island (EBI)-associated macrophages, and analysis of mice depleted of EBI macrophages by clodronate liposomes revealed drops in EPO levels in bone marrow (BM) cell lysates, and decreased percentages of EPO-responsive erythroblasts in the BM. We hypothesize that EBI macrophages are an in-situ source of EPO and sustain basal erythropoiesis in part through its secretion. To study this hypothesis, mice were injected with clodronate liposomes and were supplied with exogenous EPO (1–10 IU/mouse) to evaluate potential rescue of the deficiency in erythroid cells. Our results show that at doses of 5 and 10 IU, EPO significantly rescues BM steady state erythropoiesis in mice deficient of macrophages. We propose existence of a mechanism by which EBI macrophages secrete EPO in response to apoptotic erythroblasts, which is in turn controlled by the numbers of erythroid precursors generated.
Identification and Characterization of PLATZ Transcription Factors in Wheat
Authors: Fu Yuxin , Cheng Mengping , Li Maolian , Guo Xiaojiang , Wu Yongrui , Wang Jirui
Published: November 2020

The PLATZ (plant AT-rich protein and zinc-binding protein) transcription factor family is a class of plant-specific zinc-dependent DNA-binding proteins. PLATZ has essential roles in seed endosperm development, as well as promoting cell proliferation duration in the earlier stages of the crops. In the present study, 62 TaPLATZ genes were identified from the wheat genome, and they were unequally distributed on 15 chromosomes. According to the phylogenetic analysis, 62 TaPLATZ genes were classified into six groups, including two groups that were unique in wheat. Members in the same groups shared similar exon-intron structures. The polyploidization, together with genome duplication of wheat, plays a crucial role in the expansion of the TaPLATZs family. Transcriptome data indicated a distinct divergence expression pattern of TaPLATZ genes that could be clustered into four modules. The TaPLATZs in Module b possessed a seed-specific expression pattern and displayed obvious high expression in the earlier development stage of seeds. Subcellular localization data of TaPLATZs suggesting that they likely perform a function as a conventional transcription factor. This study provides insight into understanding the structure divergence, evolutionary features, expression profiles, and potential function of PLATZ in wheat.
Yil102c-A is a Functional Homologue of the DPMII Subunit of Dolichyl Phosphate Mannose Synthase in Saccharomyces cerevisiae
Authors: Piłsyk Sebastian , Perlinska-Lenart Urszula , Janik Anna , Gryz Elżbieta , Ajchler-Adamska Marta , Kruszewska Joanna S.
Published: November 2020

In a wide range of organisms, dolichyl phosphate mannose (DPM) synthase is a complex of tree proteins Dpm1, Dpm2, and Dpm3. However, in the yeast Saccharomyces cerevisiae, it is believed to be a single Dpm1 protein. The function of Dpm3 is performed in S. cerevisiae by the C-terminal transmembrane domain of the catalytic subunit Dpm1. Until present, the regulatory Dpm2 protein has not been found in S. cerevisiae. In this study, we show that, in fact, the Yil102c-A protein interacts directly with Dpm1 in S. cerevisiae and influences its DPM synthase activity. Deletion of the YIL102c-A gene is lethal, and this phenotype is reversed by the dpm2 gene from Trichoderma reesei. Functional analysis of Yil102c-A revealed that it also interacts with glucosylphosphatidylinositol-N-acetylglucosaminyl transferase (GPI-GnT), similar to DPM2 in human cells. Taken together, these results show that Yil102c-A is a functional homolog of DPMII from T. reesei and DPM2 from humans.
Zinc in the Brain: Friend or Foe?
Authors: Choi Seunghyuk , Hong Dae Ki , Choi Bo Young , Suh Sang Won
Published: November 2020

Zinc is a trace metal ion in the central nervous system that plays important biological roles, such as in catalysis, structure, and regulation. It contributes to antioxidant function and the proper functioning of the immune system. In view of these characteristics of zinc, it plays an important role in neurophysiology, which leads to cell growth and cell proliferation. However, after brain disease, excessively released and accumulated zinc ions cause neurotoxic damage to postsynaptic neurons. On the other hand, zinc deficiency induces degeneration and cognitive decline disorders, such as increased neuronal death and decreased learning and memory. Given the importance of balance in this context, zinc is a biological component that plays an important physiological role in the central nervous system, but a pathophysiological role in major neurological disorders. In this review, we focus on the multiple roles of zinc in the brain.
The Gut-Muscle Axis in Older Subjects with Low Muscle Mass and Performance: A Proof of Concept Study Exploring Fecal Microbiota Composition and Function with Shotgun Metagenomics Sequencing
Authors: Ticinesi Andrea , Mancabelli Leonardo , Tagliaferri Sara , Nouvenne Antonio , Milani Christian , Del Rio Daniele , Lauretani Fulvio , Maggio Marcello Giuseppe , Ventura Marco , Meschi Tiziana
Published: November 2020

The gut microbiota could influence the pathophysiology of age-related sarcopenia through multiple mechanisms implying modulation of chronic inflammation and anabolic resistance. The aim of this study was to compare the fecal microbiota composition and functionality, assessed by shotgun metagenomics sequencing, between two groups of elderly outpatients, differing only for the presence of primary sarcopenia. Five sarcopenic elderly subjects and twelve non-sarcopenic controls, classified according to lower limb function and bioimpedance-derived skeletal muscle index, provided a stool sample, which was analyzed with shotgun metagenomics approaches, to determine the overall microbiota composition, the representation of bacteria at the species level, and the prediction of bacterial genes involved in functional metabolic pathways. Sarcopenic subjects displayed different fecal microbiota compositions at the species level, with significant depletion of two species known for their metabolic capacity of producing short-chain fatty acids (SCFAs), Faecalibacterium prausnitzii and Roseburia inulinivorans, and of Alistipes shahii. Additionally, their fecal metagenome had different representation of genes belonging to 108 metabolic pathways, namely, depletion of genes involved in SCFA synthesis, carotenoid and isoflavone biotransformation, and amino acid interconversion. These results support the hypothesis of an association between microbiota and sarcopenia, indicating novel possible mediators, whose clinical relevance should be investigated in future studies.
Age, Diet and Epidermal Signaling Modulate Dermal Fibroblasts’ Adipogenic Potential
Authors: Walendzik Katarzyna , Bukowska Joanna , Kopcewicz Marta , Machcinska Sylwia , Gimble Jeffrey M. , Gawronska-Kozak Barbara
Published: November 2020

The recognition of a distinct fat depot, the dermal white adipose tissue (dWAT), points out the complexity of the interaction among skin resident cells: keratinocytes, dermal fibroblasts (DFs) and adipocytes in response to physiological (diet, age) and pathological (injury) stimulations. dWAT has been recognized as a significant contributor to thermoregulation, hair cycle, immune response, wound healing and scarring. In this study, we examined age- and diet-related changes in dWAT modulation and DFs’ adipogenic potential. The data showed that diet modulates dWAT expansion predominantly by hypertrophy, whereas age affects the pool of adipocyte progenitor cells in the skin indicating its role in dWAT hyperplasia. Analysis of DFs’ migratory abilities in the model of skin explants isolated from the skin of young, old, low (LFD)- or high (HFD)-fat diet C56BL/6 mice revealed that HFD, regardless of animal age has the most profound stimulatory impact of DF migration. We determined that the adipogenic potential of DFs is comparable to stromal vascular fraction (SVF) of inguinal fat depot and ear mesenchymal stem cells (EMSC). We also showed the stimulatory role of epidermally expressed transcription factor Foxn1 on adipogenic signaling: bone morphogenetic protein 2 (Bmp2) and insulin-like growth factor 2 (Igf2) in keratinocytes.
Effects of Aging, Long-Term and Lifelong Exercise on the Urinary Metabolic Footprint of Rats
Authors: Tzimou Anastasia , Nikolaidis Stefanos , Begou Olga , Siopi Aikaterina , Deda Olga , Taitzoglou Ioannis , Theodoridis Georgios , Mougios Vassilis
Published: November 2020

Life expectancy has risen in the past decades, resulting in an increase in the number of aged individuals. Exercise remains one of the most cost-effective treatments against disease and the physical consequences of aging. The purpose of this research was to investigate the effects of aging, long-term and lifelong exercise on the rat urinary metabolome. Thirty-six male Wistar rats were divided into four equal groups: exercise from 3 to 12 months of age (A), lifelong exercise from 3 to 21 months of age (B), no exercise (C), and exercise from 12 to 21 months of age (D). Exercise consisted in swimming for 20 min/day, 5 days/week. Urine samples collection was performed at 3, 12 and 21 months of life and their analysis was conducted by liquid chromatography-mass spectrometry. Multivariate analysis of the metabolite data did not show any discrimination between groups at any of the three aforementioned ages. However, multivariate analysis discriminated the three ages clearly when the groups were treated as one. Univariate analysis showed that training increased the levels of urinary amino acids and possibly protected against sarcopenia, as evidenced by the higher levels of creatine in the exercising groups. Aging was accompanied by decreased levels of urinary amino acids and signs of increased glycolysis. Concluding, both aging and, to a lesser degree, exercise affected the rat urinary metabolome, including metabolites related to energy metabolism, with exercise showing a potential to mitigate the consequences of aging.
Optimisation of Urine Sample Preparation for Headspace-Solid Phase Microextraction Gas Chromatography-Mass Spectrometry: Altering Sample pH, Sulphuric Acid Concentration and Phase Ratio
Authors: Aggarwal Prashant , Baker James , Boyd Mark T. , Coyle Séamus , Probert Chris , Chapman Elinor A.
Published: November 2020

Headspace-solid phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) can be used to measure volatile organic compounds (VOCs) in human urine. However, there is no widely adopted standardised protocol for the preparation of urine samples for analysis resulting in an inability to compare studies reliably between laboratories. This paper investigated the effect of altering urine sample pH, volume, and vial size for optimising detection of VOCs when using HS-SPME-GC-MS. This is the first, direct comparison of H2SO4, HCl, and NaOH as treatment techniques prior to HS-SPME-GC-MS analysis. Altering urine sample pH indicates that H2SO4 is more effective at optimising detection of VOCs than HCl or NaOH. H2SO4 resulted in a significantly larger mean number of VOCs being identified per sample (on average, 33.5 VOCs to 24.3 in HCl or 12.2 in NaOH treated urine) and more unique VOCs, produced a more diverse range of classes of VOCs, and led to less HS-SPME-GC-MS degradation. We propose that adding 0.2 mL of 2.5 M H2SO4 to 1 mL of urine within a 10 mL headspace vial is the optimal sample preparation prior to HS-SPME-GC-MS analysis. We hope the use of our optimised method for urinary HS-SPME-GC-MS analysis will enhance our understanding of human disease and bolster metabolic biomarker identification.
Self-Aligned Top-Gate Metal-Oxide Thin-Film Transistors Using a Solution-Processed Polymer Gate Dielectric
Authors: Choi Seungbeom , Song Seungho , Kim Taegyu , Shin Jae Cheol , Jo Jeong-Wan , Park Sung Kyu , Kim Yong-Hoon
Published: November 2020

For high-speed and large-area active-matrix displays, metal-oxide thin-film transistors (TFTs) with high field-effect mobility, stability, and good uniformity are essential. Moreover, reducing the RC delay is also important to achieve high-speed operation, which is induced by the parasitic capacitance formed between the source/drain (S/D) and the gate electrodes. From this perspective, self-aligned top-gate oxide TFTs can provide advantages such as a low parasitic capacitance for high-speed displays due to minimized overlap between the S/D and the gate electrodes. Here, we demonstrate self-aligned top-gate oxide TFTs using a solution-processed indium-gallium-zinc-oxide (IGZO) channel and crosslinked poly(4-vinylphenol) (PVP) gate dielectric layers. By applying a selective Ar plasma treatment on the IGZO channel, low-resistance IGZO regions could be formed, having a sheet resistance value of ~20.6 kΩ/sq., which can act as the homojunction S/D contacts in the top-gate IGZO TFTs. The fabricated self-aligned top-gate IGZO TFTs exhibited a field-effect mobility of 3.93 cm2/Vs and on/off ratio of ~106, which are comparable to those fabricated using a bottom-gate structure. Furthermore, we also demonstrated self-aligned top-gate TFTs using electrospun indium-gallium-oxide (IGO) nanowires (NWs) as a channel layer. The IGO NW TFTs exhibited a field-effect mobility of 0.03 cm2/Vs and an on/off ratio of >105. The results demonstrate that the Ar plasma treatment for S/D contact formation and the solution-processed PVP gate dielectric can be implemented in realizing self-aligned top-gate oxide TFTs.
Biominerals Fossilisation: Fish Bone Diagenesis in Plio–Pleistocene African Hominid Sites of Malawi
Authors: Denys Christiane , Otero Olga , Kullmer Ottmar , Sandrock Oliver , Bromage Timothy G. , Schrenk Friedemann , Dauphin Yannicke
Published: November 2020

Fish fossilisation is relatively poorly known, and skeletal element modifications resulting from predation, burial and diagenesis need to be better investigated. In this article, we aim to provide new results about surface, structural and chemical changes in modern and fossil fish bone. Fossil samples come from two distinct localities of roughly the same age in the Pliocene–Pleistocene Chiwondo Beds adjacent to Lake Malawi. Optical and scanning electron microscope (SEM) observations, energy dispersive spectroscopy (EDS) analyses and Fourier transform infrared (FTIR) spectrometry were carried out on three categories of fish bones: (i) fresh modern samples collected in the lake, (ii) extracted from modern fish eagle regurgitation pellets, and (iii) fossils from Malema and Mwenirondo localities. A comparison of these data allowed us to detect various modifications of bone surfaces and structure as well as composition changes. Some differences are observed between fresh bones and modern pellets, and between pellets and fossils. Moreover, fossil fish bone surface modifications, crystallinity, and chemical composition from Malema and Mwenirondo differ despite their chronological and spatial proximities (2.5–2.4 Ma, 500 m). In both sites, the post-predation modifications are strong and may hide alterations due to the predation by bird of prey such as the fish eagle. The combination of the used methods is relevant to analyses of diagenetic alterations in fish bones.
Melatonin Rescues the Dendrite Collapse Induced by the Pro-Oxidant Toxin Okadaic Acid in Organotypic Cultures of Rat Hilar Hippocampus
Authors: Solís-Chagoyán Héctor , Domínguez-Alonso Aline , Valdés-Tovar Marcela , Argueta Jesús , Sánchez-Florentino Zuly A. , Calixto Eduardo , Benítez-King Gloria
Published: November 2020

The pro-oxidant compound okadaic acid (OKA) mimics alterations found in Alzheimer’s disease (AD) as oxidative stress and tau hyperphosphorylation, leading to neurodegeneration and cognitive decline. Although loss of dendrite complexity occurs in AD, the study of this post-synaptic domain in chemical-induced models remains unexplored. Moreover, there is a growing expectation for therapeutic adjuvants to counteract these brain dysfunctions. Melatonin, a free-radical scavenger, inhibits tau hyperphosphorylation, modulates phosphatases, and strengthens dendritic arbors. Thus, we determined if OKA alters the dendritic arbors of hilar hippocampal neurons and whether melatonin prevents, counteracts, or reverses these damages. Rat organotypic cultures were incubated with vehicle, OKA, melatonin, and combined treatments with melatonin either before, simultaneously, or after OKA. DNA breaks were assessed by TUNEL assay and nuclei were counterstained with DAPI. Additionally, MAP2 was immunostained to assess the dendritic arbor properties by the Sholl method. In hippocampal hilus, OKA increased DNA fragmentation and reduced the number of MAP2(+) cells, whereas melatonin protected against oxidation and apoptosis. Additionally, OKA decreased the dendritic arbor complexity and melatonin not only counteracted, but also prevented and reversed the dendritic arbor retraction, highlighting its role in post-synaptic domain integrity preservation against neurodegenerative events in hippocampal neurons.
Co2+ Substituted Spinel MgCuZn Ferrimagnetic Oxide: A Highly Versatile Electromagnetic Material via a Facile Molten Salt Route
Authors: Thorat Lankeshwar M. , Nadargi Digambar Y. , Tamboli Mohaseen S. , Al-Enizi Abdullah M. , Kambale Rahul C. , Shaikh Shoyebmohamad F. , Suryavanshi Shard S. , Ubaidullah Mohd , Nafady Ayman , Al-Abdrabalnabia Mohammed A.
Published: November 2020

We report on the electromagnetic properties of Co2+ substituted spinel MgCuZn ferrites developed via a facile molten salt synthesis (MSS) route. The choice of synthesis route in combination with cobalt substitution led to strong electromagnetic properties such as high saturation magnetization (i.e., 63 emu/g), high coercivity (17.86 gauss), and high initial permeability (2730), which are beneficial for the multilayer chip inductor (MLCI) application. In a typical process, the planned ferrites were synthesized at 800 °C using sodium chloride as a growth inhibitor, with dense morphology and irregularity in the monolithicity of the grains. The compositional analysis of as-prepared ferrite confirms the presence of desired elements with their proportion. The crystallite size (using X-ray diffraction (XRD) analysis) for different samples varies in the range of 49–51 nm. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showcases the compact morphology of the developed samples, which is typical in the ferrite system. The dielectric properties (dielectric-loss and dielectric-constant) in the frequency range of 100Hz–1MHz suggest normal dielectric distribution according to interfacial polarization from Maxwell–Wagner. From the developed ferrites, upon comparison with a low dielectric loss with high permeability value, Mg-Cu-Zn ferrite with Co = 0.05 substitution proved to be a stronger material for MLCIs with high-performance applications.
SnS2 Nanocrystalline-Anchored Three-Dimensional Graphene for Sodium Batteries with Improved Rate Performance
Authors: Zeng Li , Zhang Liping , Liu Xingang , Zhang Chuhong
Published: November 2020

Tin disulfide (SnS2) is regarded as one of the most suitable candidates as the electrode material for sodium-ion batteries (SIBs). However, the easy restacking and volume expansion properties of SnS2 during the charge/discharge process lead to the destruction of the electrode structure and a decrease in capacity. We successfully synthesized a SnS2 nanocrystalline-anchored three-dimensional porous graphene composite (SnS2/3DG) by combining hydrothermal and high-temperature reduction methods. The SnS2 nanocrystalline was uniformly dispersed within the connected reduced graphene oxide matrix. The SnS2/3DG battery showed a high reversible capacity of 430 mAh/g after 50 cycles at 100 mA/g. The SnS2/3DG composite showed an excellent rate capability with the current density increasing from 100 mA/g to 2 A/g. The excellent performance of the novel SnS2/3DG composite is attributed to the porous structure, which not only promoted the infiltration of electrolytes and hindered volume expansion for the porous structure, but also improved the conductivity of the whole electrode, demonstrating that the SnS2/3DG composite is a prospective anode for the next generation of sodium-ion batteries.
High Glycemic Load Is Associated with Cognitive Decline in Apolipoprotein E ε4 Allele Carriers
Authors: Gentreau Mélissa , Raymond Michel , Chuy Virginie , Samieri Cécilia , Féart Catherine , Berticat Claire , Artero Sylvaine
Published: November 2020

Recent evidence suggests that a high glycemic load (GL) diet is a risk factor for dementia, especially among apolipoprotein E ε4 allele (APOE4) carriers, while its association with cognitive decline is poorly known. Here, we investigated the association of high-GL meals with cognitive decline in older adults during a 12-year follow-up, according to their APOE4 carrier status. We used random-effect models and data from 2539 elderly participants from the Three-City study who completed a food frequency questionnaire (FFQ) to longitudinally assess the association of GL with changes in different cognitive domains (verbal fluency, visual memory, attention, visual motor processing speed, episodic memory). In APOE4 carriers, afternoon snack with high GL was significantly associated with cognitive decline in visual memory, episodic memory, and global cognition compared with APOE4 non-carriers. This study suggests a detrimental association between a high-GL diet and cognitive decline. The promotion of a low GL diet as a target to prevent cognitive decline in high-risk populations deserves more research.
The Case of Medication-Related Osteonecrosis of the Jaw Addressed from a Pathogenic Point of View. Innovative Therapeutic Strategies: Focus on the Most Recent Discoveries on Oral Mesenchymal Stem Cell-Derived Exosomes
Authors: Giudice Amerigo , Antonelli Alessandro , Chiarella Emanuela , Baudi Francesco , Barni Tullio , Di Vito Anna
Published: November 2020

Bisphosphonates-related osteonecrosis of the jaw (BRONJ) was firstly reported by Marx in 2003. Since 2014, the term medication-related osteonecrosis of the jaw (MRONJ) is recommended by the American Association of Oral and Maxillofacial Surgeons (AAOMS). Development of MRONJ has been associated to the assumption of bisphosphonates but many MRONJ-promoting factors have been identified. A strong involvement of immunity components has been suggested. Therapeutic intervention includes surgical and non-surgical treatments, as well as regenerative medicine procedures for the replacement of the lost tissues. The literature confirms that the combination of mesenchymal stem cells (MSCs), biomaterials and local biomolecules can support the regeneration/repair of different structures. In this review, we report the major open topics in the pathogenesis of MRONJ. Then, we introduce the oral tissues recognized as sources of MSCs, summing up in functional terms what is known about the exosomes release in physiological and pathological conditions.
Fabrication and Characterization of Activated Carbon Fibers from Oil Palm Trunk
Authors: Lin Jian , Choowang Rattana , Zhao Guangjie
Published: November 2020

To develop more valuable application, oil palm trunk was successfully converted into activated carbon fibers (ACFs). An effective process of chemical treatment with dilute sulfuric acid was conducted to improve the thermal stability of primary fibers for further heating treatment. Carbon dioxide (CO2) was used as activator to produce much porous structure with various pore diameter. The specific surface area (SBET) and total pore volume (Vtotal) of resultant ACFs showed increasing trend as rise of activation temperature and time. The ACFs obtained under the temperature of 900 °C and time of 90 min exhibited highest SBET and Vtotal, which were more than 1800 m2/g and 0.7 mL/g, respectively. Meanwhile, more graphic carbon on the surface of ACFs were destroyed with prolonging activation time, resulting in the oxygen-containing functional groups formed during activation process with CO2. Due to the abundant pores and surface functional groups, the ACFs exhibited excellent adsorption capacity of chromium and would be an alternative material for industrial adsorption utilization.
Vortex Polymer Optical Fiber with 64 Stable OAM States
Authors: Borda-Hernández José A. , Serpa-Imbett Claudia M. , Figueroa Hugo E. Hernandez
Published: November 2020

This research introduces a numerical design of an air-core vortex polymer optical fiber in cyclic transparent optical polymer (CYTOP) that propagates 32 orbital angular momentum (OAM) modes, i.e., it may support up to 64 stable OAM-states considering left- and right-handed circular polarizations. This fiber seeks to be an alternative to increase the capacity of short-range optical communication systems multiplexed by modes, in agreement with the high demand of low-cost, insensitive-to-bending and easy-to-handle fibers similar to others optical fibers fabricated in polymers. This novel fiber possesses unique characteristics: a diameter of 50 µm that would allow a high mechanical compatibility with commercially available polymer optical fibers, a difference of effective index between neighbor OAM modes of around 10−4 over a bandwidth from 1 to 1.6 µm, propagation losses of approximately 15 × 10−3 dB/m for all OAM modes, and a very low dispersion for OAM higher order modes (±l = 16) of up to +2.5 ps/km-nm compared with OAM lower order modes at a telecom wavelength of 1.3 µm, in which the CYTOP exhibits a minimal attenuation. The spectra of mutual coupling coefficients between modes are computed considering small bends of up to 3 cm of radius and slight ellipticity in the ring of up to 5%. Results show lower-charge weights for higher order OAM modes.
CoralTemp and the Coral Reef Watch Coral Bleaching Heat Stress Product Suite Version 3.1
Authors: Skirving William , Marsh Benjamin , De La Cour Jacqueline , Liu Gang , Harris Andy , Maturi Eileen , Geiger Erick , Eakin C. Mark
Published: November 2020

The National Oceanic and Atmospheric Administration (NOAA) Coral Reef Watch (CRW) program has been providing resource managers, scientific researchers, and other coral reef ecosystem stakeholders with coral bleaching heat stress products for more than 20 years. The development of the CoralTemp sea surface temperature (SST) dataset has allowed CRW to produce the Coral Bleaching Heat Stress product suite with climatologies and daily SST measurements from within the same SST dataset, significantly improving data quality. Previously, the Monthly Mean (MM) SST and Maximum Monthly Mean (MMM) SST climatologies were derived using a different dataset from the near real-time SST. Here we provide an up-to-date description of how each product within the Coral Reef Watch Coral Bleaching Heat Stress product suite version 3.1 is derived, including descriptions of the MM, MMM, SST Anomaly, Coral Bleaching HotSpot and Degree Heating Week (DHW) products.
An Improved Deep Keypoint Detection Network for Space Targets Pose Estimation
Authors: Xu Junjie , Song Bin , Yang Xi , Nan Xiaoting
Published: November 2020

The on-board pose estimation of uncooperative target is an essential ability for close-proximity formation flying missions, on-orbit servicing, active debris removal and space exploration. However, the main issues of this research are: first, traditional pose determination algorithms result in a semantic gap and poor generalization abilities. Second, specific pose information cannot be accurately known in a complicated space target imaging environment. Deep learning methods can effectively solve these problems; thus, we propose a pose estimation algorithm that is based on deep learning. We use keypoints detection method to estimate the pose of space targets. For complicated space target imaging environment, we combined the high-resolution network with dilated convolution and online hard keypoint mining strategy. The improved network pays more attention to the obscured keypoints, has a larger receptive field, and improves the detection accuracy. Extensive experiments have been conducted and the results demonstrate that the proposed algorithms can effectively reduce the error rate of pose estimation and, compared with the related pose estimation methods, our proposed model has a higher detection accuracy and a lower pose determination error rate in the speed dataset.
Downscaling TRMM Monthly Precipitation Using Google Earth Engine and Google Cloud Computing
Authors: Elnashar Abdelrazek , Zeng Hongwei , Wu Bingfang , Zhang Ning , Tian Fuyou , Zhang Miao , Zhu Weiwei , Yan Nana , Chen Zeqiang , Sun Zhiyu , Wu Xinghua , Li Yuan
Published: November 2020

Accurate precipitation data at high spatiotemporal resolution are critical for land and water management at the basin scale. We proposed a downscaling framework for Tropical Rainfall Measuring Mission (TRMM) precipitation products through integrating Google Earth Engine (GEE) and Google Colaboratory (Colab). Three machine learning methods, including Gradient Boosting Regressor (GBR), Support Vector Regressor (SVR), and Artificial Neural Network (ANN) were compared in the framework. Three vegetation indices (Normalized Difference Vegetation Index, NDVI; Enhanced Vegetation Index, EVI; Leaf Area Index, LAI), topography, and geolocation are selected as geospatial predictors to perform the downscaling. This framework can automatically optimize the models’ parameters, estimate features’ importance, and downscale the TRMM product to 1 km. The spatial downscaling of TRMM from 25 km to 1 km was achieved by using the relationships between annual precipitations and annually-averaged vegetation index. The monthly precipitation maps derived from the annual downscaled precipitation by disaggregation. According to validation in the Great Mekong upstream region, the ANN yielded the best performance when simulating the annual TRMM precipitation. The most sensitive vegetation index for downscaling TRMM was LAI, followed by EVI. Compared with existing downscaling methods, the proposed framework for downscaling TRMM can be performed online for any given region using a wide range of machine learning tools and environmental variables to generate a precipitation product with high spatiotemporal resolution.
Subsampling Approaches for Compressed Sensing with Ultrasound Arrays in Non-Destructive Testing
Authors: Pérez Eduardo , Kirchhof Jan , Krieg Fabian , Römer Florian
Published: November 2020

Full Matrix Capture is a multi-channel data acquisition method which enables flexible, high resolution imaging using ultrasound arrays. However, the measurement time and data volume are increased considerably. Both of these costs can be circumvented via compressed sensing, which exploits prior knowledge of the underlying model and its sparsity to reduce the amount of data needed to produce a high resolution image. In order to design compression matrices that are physically realizable without sophisticated hardware constraints, structured subsampling patterns are designed and evaluated in this work. The design is based on the analysis of the Cramér–Rao Bound of a single scatterer in a homogeneous, isotropic medium. A numerical comparison of the point spread functions obtained with different compression matrices and the Fast Iterative Shrinkage/Thresholding Algorithm shows that the best performance is achieved when each transmit event can use a different subset of receiving elements and each receiving element uses a different section of the echo signal spectrum. Such a design has the advantage of outperforming other structured patterns to the extent that suboptimal selection matrices provide a good performance and can be efficiently computed with greedy approaches.
Improving Polar-Coded SCMA System by Information Coupling and Parity Check
Authors: Wu Xi , Wang Yafeng
Published: November 2020

In this paper, the uplink information-coupled polar-coded sparse code multiple access (PC-SCMA) system is proposed. For this system, we first design the encoding method of systematic joint parity check and CRC-aided (PCCA) polar code. Using the systematic PCCA-polar code as base code, the partially information-coupled (PIC) polar code is constructed. Then, a joint iterative detection and successive cancellation list (SCL)-decoding receiver is proposed for the PC-SCMA system. For the receiver, the coupled polar decoder’s extrinsic messages are calculated by the Bayes rule and soft cancellation (SCAN) algorithm. Based on the extrinsic information transfer (EXIT) idea, the PIC PCCA-polar code is optimized. Simulation results demonstrate that the PIC PCCA-PC-SCMA system outperforms the other polar (or LDPC) coded SCMA systems at various code rates and channel configurations. Additionally, compared with an uncoupled PC-SCMA system with SCL decoder, the complexity of PIC PCCA-PC-SCMA is reduced at a high Eb/N0
Wind Turbine Gearbox Condition Monitoring Based on Class of Support Vector Regression Models and Residual Analysis
Authors: Dhiman Harsh S. , Deb Dipankar , Carroll James , Muresan Vlad , Unguresan Mihaela-Ligia
Published: November 2020

The intelligent condition monitoring of wind turbines reduces their downtime and increases reliability. In this manuscript, a feature selection-based methodology that essentially works on regression models is used for identifying faulty scenarios. Supervisory control and data acquisition (SCADA) data with 1009 samples from one year and one month before failure are considered. Gearbox oil and bearing temperatures are treated as target variables with all the other variables used for the prediction model. Neighborhood component analysis (NCA) as a feature selection technique is employed to select the best features and prediction performance for several machine learning regression models is assessed. The results reveal that twin support vector regression (99.91%) and decision trees (98.74%) yield the highest accuracy for gearbox oil and bearing temperatures respectively. It is observed that NCA increases the accuracy and thus reliability of the condition monitoring system. Furthermore, the residuals from the class of support vector regression (SVR) models are tested from a statistical point of view. Diebold–Mariano and Durbin–Watson tests are carried out to establish the robustness of the tested models.
Investigating the Potential of Radar Interferometry for Monitoring Rural Artisanal Cobalt Mines in the Democratic Republic of the Congo
Authors: Brown Chloe , Daniels Anna , Boyd Doreen S. , Sowter Andrew , Foody Giles , Kara Siddharth
Published: November 2020

Greater awareness of the serious human rights abuses associated with the extraction and trade of cobalt in the Democratic Republic of the Congo (DRC) has applied increasing pressure for businesses to move towards more responsible and sustainable mineral sourcing. Artisanal and small-scale mining (ASM) activities in rural and remote locations may provide heightened opportunities to conceal the alleged human rights violations associated with mining, such as: hazardous working conditions, health impacts, child labour, child trafficking, and debt bondage. In this study, we investigate the feasibility of the Intermittent Small Baseline Subset (ISBAS) interferometric synthetic aperture radar (InSAR) method, teamed with high temporal frequency Sentinel-1 imagery, for monitoring ASM activity in rural locations of the “Copperbelt”, the DRC. The results show that the ISBAS descriptive variables (mean, standard deviation, minimum, and maximum) were significantly different (p-value = ≤ 0.05) between mining and non-mining areas. Additionally, a significant difference was found for the ISBAS descriptive variables mean, standard deviation, and minimum between the different mine types (industrial, surface, and tunnels). As expected, a high level of subsidence (i.e., negative ISBAS pixel value) was a clear indicator of mine activity. Trial activity thresholds were set for the descriptive variables mean (-2.43 mm/yr) and minimum (-5.36 mm/yr) to explore an ISBAS approach to active mine identification. The study concluded that the ISBAS method has great potential as a monitoring tool for ASM, with the ability to separate mining and non-mining areas based on surface motion values, and further distinguish the different mine types (industrial, surface, and tunnel). Ground data collection and further development of ISBAS analysis needs to be made to fully understand the value of an ISBAS-based ASM monitoring system. In particular, surrounding the impact of seasonality relative to longer-term trends in ASM activity.
An Analytical Method for Estimating the Maximum Penetration of DFIG Considering Frequency Stability
Authors: Qing Mengqi , Tang Fei , Liu Fusuo , Liu Dichen , Du Nianchun , Hu Benxi
Published: November 2020

With the increasing wind power in power systems and the wide application of frequency regulation technology, the accurate calculation of the limit wind power capacity in systems is critical to ensure the stability of the frequency and guide the planning of wind power sources. This paper proposes an analytical method for calculating the maximum wind generation penetration under the constraints of frequency regulation control and frequency stability taking doubly fed induction generator as an example. Firstly, the frequency-domain dynamic model of the doubly fed induction generator is established considering the supplementary frequency proportion-differentiation control under small disturbance. The equivalent inertia time constant of the doubly fed induction generator is calculated. On this basis, the frequency response model of the power system with the consideration of wind power integration in frequency regulation control is constructed. Then, the frequency-domain analytical solution of the system frequency is obtained. Finally, with the constraint by the steady-state deviation and dynamic change rate of the system frequency, the maximum wind generation penetration is analytically solved. The accuracy of the proposed analytical calculation method for the limit value of the percentage of wind power is verified by MATLAB/Simulink.
Social Impact Assessment of HealthyAIR Tool for Real-Time Detection of Pollution Risk
Authors: Moreno Cano Antonia , Romón Sagredo Rafael , García-Carrión Rocío , Garcia-Zapirain Begonya
Published: November 2020

Background: HealthyAIR is a tool that detects pollution risk in real life. The target population is people with cardiorespiratory complications who are especially susceptible to the current COVID-19. The goal is to empower people by controlling air pollution everywhere to minimize the risk of having a seizure. Methods: We measured the social impact of the HealthyAIR tool using a Likert scale survey with two groups: professionals (engineers/healthcare) and end-users. We assessed the data in accordance with the indicators for social impact defined for the Key Impact Pathways introduced by the European Commission for Horizon Europe, and the criteria of the Social Impact Open Repository (SIOR). Results: Professionals highlight the fact that they “totally agree” (33.33%) and “agree” (26.67%) that HealthyAIR could help authorities improve their health prevention policies and programs. Users considered the tool to be “very useful” (38.46%) and “quite useful” (42.31%), which denotes its necessity. Conclusions: professionals and end users see HealthyAIR as a great preventative tool, with the former seeing it as a way to avoid seizures in their patients who, in this COVID-19 era, are particularly sensitive to any cardiorespiratory health problem. However, users suggest improving the user’s manual to make it more understandable.
Medical Electronic Prescription for Home Respiratory Care Services (PEM-CRD) at a Portuguese University Tertiary Care Centre (2014–2018): A Case Study
Authors: Alves Ricardo , Caneiras Cátia , Santos Ana Isabel , Barbosa Patricia , Cardoso João , Caseiro Paulo , Vitorino Maria João , Pereira João , Escoval Ana
Published: November 2020

Home respiratory care (HRC) is the provision of healthcare services at the place of residence of patients or their families, with the aim of meeting needs mainly resulting from chronic respiratory conditions, permanent disability, or terminal illness. In 2016, an innovative electronic prescription system, PEM-CRD, was fully implemented for HRC services in Portugal. To date, no study has addressed the impact of the execution of this digital innovation. For this purpose, we carried out an analysis of the prevalence and number of prescriptions for people with chronic respiratory diseases receiving HRC in the Lisbon metropolitan area, during 2014–2018, using the information obtained from the PEM-CRD database. The data analysis shows that while the number of patients receiving HRC treatment with a prescription has remained stable over the last four years, the number of prescriptions has significantly dropped since 2016 (2016–2018), with consequent paper and processes efficiency. The implementation of the digital Medical Electronic Prescription for Home Respiratory Care tool (PEM-CRD) and consequent dematerialization of these processes has increased the efficiency of prescribing in HRC. Additionally, the possibility of obtaining data through the PEM-CRD allows the monitoring of the evolving prevalence of therapies, improving the health services optimization and allowing reporting on data other than medicines.
Volatility Connectedness between Clean Energy Firms and Crude Oil in the COVID-19 Era
Authors: Foglia Matteo , Angelini Eliana
Published: November 2020

The work investigates the volatility connectedness between oil price and clean energy firms over the period 2011–2020 (including the COVID-19 outbreak). Using the volatility spillover models, and dynamic conditional correlation, we are able to identify the volatility spillover effect between these financial markets and its implications for portfolio diversification. The results indicate a significant change in both static and dynamic volatility connectedness around the COVID-19 outbreak. For instance, total connectedness index changes from 21.36% (pre-COVID-19) to 61.23% (COVID-19). This finding shows the strong effect of the COVID-19 pandemic on these financial markets. Furthermore, we show how the WTI oil from the volatility transmitter (before the outbreak of the pandemic) becomes a risk receiver after the start of the global pandemic COVID-19. Our findings indicate that recent pandemic intensified volatility spillovers, supporting the financial contagion effects. Finally, we determine the optimal hedge ratios and portfolio weights. The estimates provided suggest the need for active portfolio management, taking into account the distinct characteristics of each sector and thus, the firm. For example, the optimal weight analysis shows how the clean sector has become important in optimal diversification strategies. Our results can be used for portfolio decisions and regulatory policymaking, particularly in the current context of high uncertainty.
New Oscillation Results for Second-Order Neutral Differential Equations with Deviating Arguments
Authors: Wang Yakun , Meng Fanwei
Published: November 2020

In this paper, we focus on the second-order neutral differential equations with deviating arguments which are under the canonical condition. New oscillation criteria are established, which are based on a first-order delay differential equation and generalized Riccati transformations. The idea of symmetry is a useful tool, not only guiding us in the right way to study this function but also simplifies our proof. Our results are generalizations of some previous results and we provide an example to illustrate the main results.
Population Characteristics of the Mid-Littoral Chthamalid Barnacle C. stellatus (Poli, 1791) in Eastern Mediterranean (Central Greece)
Authors: Klaoudatos Dimitris , Kotsiri Zoi , Neofitou Nikos , Lolas Alexios , Vafidis Dimitris
Published: November 2020

Barnacles are key space-occupiers in rocky shore communities on European coasts. Barnacles of the species Chthamalus stellatus (Poli, 1791) were collected between June 2014 and May 2015 from two sites, two stations per each site with varying degree of exposure to wave action and anthropogenic pressure (trampling), in the Eastern Mediterranean (Pagasitikos Gulf, Central Greece). This study addresses a knowledge gap in population characteristics of C. stellatus populations in the Eastern Mediterranean, assessing population structure and allometric relationships. Patterns of distribution and abundance (density and percentage cover) were studied both temporally (seasonally) and spatially (water level and site). Morphometric characteristics exhibited spatiotemporal variation. Population density was significantly higher at the site with higher wave exposure. The population cover exhibited high levels of similarity among shore levels, both spatially and temporally. Spatial distribution exhibited a clumped pattern of dispersion in autumn, winter, and spring, mainly in the sheltered site. Six dominant age groups were identified, with the dominant cohort in the third-year class. Significant negative allometric relationships were exhibited between all morphometric characteristics. Differences in growth patterns among populations were indicated, with a higher rate of growth at the site of lower wave exposure.