bluuebunny/crossref_metadata_2025 huggingface dataset:
Nematicidal Activity of Holigarna caustica (Dennst.) Oken Fruit Is Due to Linoleic Acid
Authors: Panda Sujogya Kumar , Das Raju , Mai Anh Hung , De Borggraeve Wim M. , Luyten Walter
Published: July 2020

Holigarna caustica (Dennst.) Oken is used by the tribes of Northeast India for the treatment of intestinal problems. Therefore, the present study was undertaken to investigate the active principles of this plant responsible for its anthelmintic activity, using bioassay-guided fractionation. An ethanol extract of H. caustica fruit was fractionated on a silica gel column, followed by HPLC, while nematicidal activity was followed throughout on Caenorhabditis (C.) elegans as a model organism. Our study constitutes the first nematicidal report for this plant. Bioassay-guided purification led to the isolation of one compound (IC50 = 0.4 µM) as the only active constituent in the most active fraction. The compound was identified as linoleic acid based on spectroscopic data (1H and 13C NMR and ESI-MS). No cytotoxicity was observed in the crude extract or in linoleic acid (up to 356 µM). The results support the use of H. caustica for the treatment of intestinal problems by traditional healers in India.
NADPH Oxidases and Their Role in Atherosclerosis
Authors: Poznyak Anastasia V. , Grechko Andrey V. , Orekhova Varvara A. , Khotina Victoria , Ivanova Ekaterina A. , Orekhov Alexander N.
Published: July 2020

The current view on atherosclerosis positions it as a multifactorial disorder that results from the interplay between lipid metabolism disturbances and inflammatory processes. Oxidative stress is proven to be one of the initiating factors in atherosclerosis development, being implicated both in the inflammatory response and in atherogenic modifications of lipoproteins that facilitate lipid accumulation in the arterial wall. The hallmark of oxidative stress is the elevated level of reactive oxygen species (ROS). Correspondingly, the activity of major ROS-generating enzymes, including nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, xanthine oxidases, and cyclooxygenases, is an important element in atherosclerosis development. In particular, the role of NADPH oxidases in atherosclerosis development has become a subject of intensive research. Aberrant activity of NADPH oxidases was shown to be associated with cardiovascular disease in humans. With regard to atherosclerosis, several important pathological components of the disease development, including endothelial dysfunction, inflammation, and vascular remodeling, involve aberrations in NADPH oxidases functioning. In humans, NADPH oxidases are represented by four isoforms expressed in vascular tissues, where they serve as the main source of ROS during atherogenesis. Moreover, recent studies have demonstrated their impact on vascular remodeling processes. Interestingly, one of the NADPH oxidase isoforms, NOX4, was shown to have an atheroprotective effect. Despite the growing evidence of the crucial involvement of NADPH oxidases in atherosclerosis pathogenesis, the available data still remains controversial. In this narrative review, we summarize the current knowledge of the role of NADPH oxidases in atherosclerosis and outline the future directions of research.
Cancer-Associated Substitutions in RNA Recognition Motifs of PUF60 and U2AF65 Reveal Residues Required for Correct Folding and 3′ Splice-Site Selection
Authors: Kralovicova Jana , Borovska Ivana , Kubickova Monika , Lukavsky Peter J. , Vorechovsky Igor
Published: July 2020

U2AF65 (U2AF2) and PUF60 (PUF60) are splicing factors important for recruitment of the U2 small nuclear ribonucleoprotein to lariat branch points and selection of 3′ splice sites (3′ss). Both proteins preferentially bind uridine-rich sequences upstream of 3′ss via their RNA recognition motifs (RRMs). Here, we examined 36 RRM substitutions reported in cancer patients to identify variants that alter 3′ss selection, RNA binding and protein properties. Employing PUF60- and U2AF65-dependent 3′ss previously identified by RNA-seq of depleted cells, we found that 43% (10/23) and 15% (2/13) of independent RRM mutations in U2AF65 and PUF60, respectively, conferred splicing defects. At least three RRM mutations increased skipping of internal U2AF2 (~9%, 2/23) or PUF60 (~8%, 1/13) exons, indicating that cancer-associated RRM mutations can have both cis- and trans-acting effects on splicing. We also report residues required for correct folding/stability of each protein and map functional RRM substitutions on to existing high-resolution structures of U2AF65 and PUF60. These results identify new RRM residues critical for 3′ss selection and provide relatively simple tools to detect clonal RRM mutations that enhance the mRNA isoform diversity.
Clinical Significance of Adverse Events for Patients with Unresectable Hepatocellular Carcinoma Treated with Lenvatinib: A Multicenter Retrospective Study
Authors: Shimose Shigeo , Iwamoto Hideki , Niizeki Takashi , Shirono Tomotake , Noda Yu , Kamachi Naoki , Okamura Shusuke , Nakano Masahito , Suga Hideya , Kuromatsu Ryoko , Yamaguchi Taizo , Kawaguchi Takumi , Tanaka Masatoshi , Noguchi Kazunori , Koga Hironori , Torimura Takuji
Published: July 2020

We sought to investigate the clinical profile(s) associated with the discontinuation of lenvatinib (LEN) due to severe adverse events (DLSAE) in patients with unresectable hepatocellular carcinoma (HCC). This retrospective study enrolled 177 patients with HCC treated with LEN. Independent factors associated with DLSAE were advanced age, albumin-bilirubin (ALBI) grade 2, fatigue grade ≥ 3, and appetite loss ≥ 2. The overall survival (OS) in the group that did not require DLSAE was significantly longer compared to the group that did require DLSAE (median survival time (MST): not reached vs. 12.8 months, p < 0.001). Moreover, advanced age was the most important variable for DLSAE in a decision tree analysis. Hypertension and hand-foot-skin-reaction (HFSR) were also significantly associated with longer survival, and the occurrence of hypertension was the earliest predictor for improved prognosis, while appetite loss and development of grade ≥ 3 fatigue were predictive of a poor prognosis. We concluded that the appearance of hypertension has potential as an early surrogate marker to predict improved prognosis. Moreover, careful management to avoid discontinuation of treatment leads to longer survival in patients receiving LEN.
New Insights into Diffuse Large B-Cell Lymphoma Pathobiology
Authors: Solimando Antonio Giovanni , Annese Tiziana , Tamma Roberto , Ingravallo Giuseppe , Maiorano Eugenio , Vacca Angelo , Specchia Giorgina , Ribatti Domenico
Published: July 2020

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma (NHL), accounting for about 40% of all cases of NHL. Analysis of the tumor microenvironment is an important aspect of the assessment of the progression of DLBCL. In this review article, we analyzed the role of different cellular components of the tumor microenvironment, including mast cells, macrophages, and lymphocytes, in the tumor progression of DLBCL. We examined several approaches to confront the available pieces of evidence, whereby three key points emerged. DLBCL is a disease of malignant B cells spreading and accumulating both at nodal and at extranodal sites. In patients with both nodal and extranodal lesions, the subsequent induction of a cancer-friendly environment appears pivotal. The DLBCL cell interaction with mature stromal cells and vessels confers tumor protection and inhibition of immune response while delivering nutrients and oxygen supply. Single cells may also reside and survive in protected niches in the nodal and extranodal sites as a source for residual disease and relapse. This review aims to molecularly and functionally recapitulate the DLBCL–milieu crosstalk, to relate niche and pathological angiogenic constitution and interaction factors to DLBCL progression.
MiR-216b/Smad3/BCL-2 Axis Is Involved in Smoking-Mediated Drug Resistance in Non-Small Cell Lung Cancer
Authors: Vu Trung , Yang Shanzhong , Datta Pran K.
Published: July 2020

Epidemiologic studies have shown that vast majority of lung cancers (85–90%) are causally linked to tobacco smoking. Although much information has been gained about the effects of smoking on various signaling pathways, little is known about how deregulation of miRNAs leads to activation of oncogenes and inhibition of tumor suppressor genes in non-small cell lung cancer (NSCLC). Our previous study showed that smoking inhibits TGF-β-induced tumor suppressor functions through downregulation of Smad3 in lung cancer cells. In order to understand the upstream mechanism of downregulation of Smad3 by smoking, we performed miRNA microarray analyses after treating human lung adenocarcinoma A549 and immortalized peripheral lung epithelial HPL1A cells with cigarette smoke condensate (CSC). We identified miR-216b as being upregulated in CSC treated cells. MiR-216b overexpression decreases Smad3 protein expression by binding to its 3′-UTR, and attenuates transforming growth factor beta (TGF-β) signaling and target gene expression. MiR-216b increases B-cell lymphoma 2 (BCL-2) expression and promotes chemoresistance of NSCLC cells by decreasing apoptosis. Increased acetylation of histones H3 and H4 in miR-216b gene promoter plays a role in CSC induced miR-216b expression. Taken together, these results suggest that smoking-mediated upregulation of miR-216b increases NSCLC cell growth by downregulating Smad3 and inhibiting TGF-β-induced tumor suppressor function, and induces resistance to platinum-based therapy.
Leucine-Rich Diet Modulates the Metabolomic and Proteomic Profile of Skeletal Muscle during Cancer Cachexia
Authors: Cruz Bread , Oliveira André , Viana Lais Rosa , Lopes-Aguiar Leisa , Canevarolo Rafael , Colombera Maiara Caroline , Valentim Rafael Rossi , Garcia-Fóssa Fernanda , de Sousa Lizandra Maia , Castelucci Bianca Gazieri , Consonni Sílvio Roberto , Martins-de-Souza Daniel , de Jesus Marcelo Bispo , Russell Steven Thomas , Gomes-Mardondes Maria Cristina Cintra
Published: July 2020

Background: Cancer-cachexia induces a variety of metabolic disorders, including skeletal muscle imbalance. Alternative therapy, as nutritional supplementation with leucine, shows a modulatory effect over tumour damage in vivo and in vitro. Method: Adult rats distributed into Control (C), Walker tumour-bearing (W), control fed a leucine-rich diet (L), and tumour-bearing fed a leucine-rich diet (WL) groups had the gastrocnemius muscle metabolomic and proteomic assays performed in parallel to in vitro assays. Results: W group presented an affected muscle metabolomic and proteomic profile mainly related to energy generation and carbohydrates catabolic processes, but leucine-supplemented group (WL) recovered the energy production. In vitro assay showed that cell proliferation, mitochondria number and oxygen consumption were higher under leucine effect than the tumour influence. Muscle proteomics results showed that the main affected cell component was mitochondria, leading to an impacted energy generation, including impairment in proteins of the tricarboxylic cycle and carbohydrates catabolic processes, which were modulated and improved by leucine treatment. Conclusion: In summary, we showed a beneficial effect of leucine upon mitochondria, providing information about the muscle glycolytic pathways used by this amino acid, where it can be associated with the preservation of morphometric parameters and consequent protection against the effects of cachexia.
CCR2 of Tumor Microenvironmental Cells Is a Relevant Modulator of Glioma Biology
Authors: Felsenstein Matthäus , Blank Anne , Bungert Alexander D. , Mueller Annett , Ghori Adnan , Kremenetskaia Irina , Rung Olga , Broggini Thomas , Turkowski Kati , Scherschinski Lea , Raggatz Jonas , Vajkoczy Peter , Brandenburg Susan
Published: July 2020

Glioblastoma multiforme (GBM) shows a high influx of tumor-associated macrophages (TAMs). The CCR2/CCL2 pathway is considered a relevant signal for the recruitment of TAMs and has been suggested as a therapeutic target in malignant gliomas. We found that TAMs of human GBM specimens and of a syngeneic glioma model express CCR2 to varying extents. Using a Ccr2-deficient strain for glioma inoculation revealed a 30% reduction of TAMs intratumorally. This diminished immune cell infiltration occurred with augmented tumor volumes likely based on increased cell proliferation. Remaining TAMs in Ccr2-/- mice showed comparable surface marker expression patterns in comparison to wildtype mice, but expression levels of inflammatory transcription factors (Stat3, Irf7, Cox2) and cytokines (Ifnβ, Il1β, Il12α) were considerably affected. Furthermore, we demonstrated an impact on blood vessel integrity, while vascularization of tumors appeared similar between mouse strains. The higher stability and attenuated leakiness of the tumor vasculature imply improved sustenance of glioma tissue in Ccr2-/- mice. Additionally, despite TAMs residing in the perivascular niche in Ccr2-/- mice, their pro-angiogenic activity was reduced by the downregulation of Vegf. In conclusion, lacking CCR2 solely on tumor microenvironmental cells leads to enhanced tumor progression, whereby high numbers of TAMs infiltrate gliomas independently of the CCR2/CCL2 signal.
Relevance of Regulatory T Cells during Colorectal Cancer Development
Authors: Olguín Jonadab E. , Medina-Andrade Itzel , Rodríguez Tonathiu , Rodríguez-Sosa Miriam , Terrazas Luis I.
Published: July 2020

In recent years, there has been a significant increase in the study of own and foreign human factors favoring the development of different types of cancer, including genetic and environmental ones. However, the fact that the immune response plays a fundamental role in the development of immunity and susceptibility to colorectal cancer (CRC) is much stronger. Among the many cell populations of the immune system that participate in restricting or favoring CRC development, regulatory T cells (Treg) play a major role in orchestrating immunomodulation during CRC. In this review, we established concrete evidence supporting the fact that Treg cells have an important role in the promotion of tumor development during CRC, mediating an increasing suppressive capacity which controls the effector immune response, and generating protection for tumors. Furthermore, Treg cells go through a process called “phenotypic plasticity”, where they co-express transcription factors that promote an inflammatory profile. We reunited evidence that describes the interaction between the different effector populations of the immune response and its modulation by Treg cells adapted to the tumor microenvironment, including the mechanisms used by Treg cells to suppress the protective immune response, as well as the different subpopulations of Treg cells participating in tumor progression, generating susceptibility during CRC development. Finally, we discussed whether Treg cells might or might not be a therapeutic target for an effective reduction in the morbidity and mortality caused by CRC.
Recent Progress with Pincer Transition Metal Catalysts for Sustainability
Authors: Piccirilli Luca , Lobo Justo Pinheiro Danielle , Nielsen Martin
Published: July 2020

Our planet urgently needs sustainable solutions to alleviate the anthropogenic global warming and climate change. Homogeneous catalysis has the potential to play a fundamental role in this process, providing novel, efficient, and at the same time eco-friendly routes for both chemicals and energy production. In particular, pincer-type ligation shows promising properties in terms of long-term stability and selectivity, as well as allowing for mild reaction conditions and low catalyst loading. Indeed, pincer complexes have been applied to a plethora of sustainable chemical processes, such as hydrogen release, CO2 capture and conversion, N2 fixation, and biomass valorization for the synthesis of high-value chemicals and fuels. In this work, we show the main advances of the last five years in the use of pincer transition metal complexes in key catalytic processes aiming for a more sustainable chemical and energy production.
In Situ TEM Studies of Catalysts Using Windowed Gas Cells
Authors: Ye Fan , Xu Mingjie , Dai Sheng , Tieu Peter , Ren Xiaobing , Pan Xiaoqing
Published: July 2020

For decades, differentially pumped environmental transmission electron microscopy has been a powerful tool to study dynamic structural evolution of catalysts under a gaseous environment. With the advancement of micro-electromechanical system-based technologies, windowed gas cell became increasingly popular due to its ability to achieve high pressure and its compatibility to a wide range of microscopes with minimal modification. This enables a series of imaging and analytical technologies such as atomic resolution imaging, spectroscopy, and operando, revealing details that were unprecedented before. By reviewing some of the recent work, we demonstrate that the windowed gas cell has the unique ability to solve complicated catalysis problems. We also discuss what technical difficulties need to be addressed and provide an outlook for the future of in situ environmental transmission electron microscopy (TEM) technologies and their application to the field of catalysis development.
Improved SO2 Tolerance of Cu-SAPO-18 by Ce-Doping in the Selective Catalytic Reduction of NO with NH3
Authors: Han Shuai , Ye Qing , Gao Qi , Dai Hongxing
Published: July 2020

The Ce-Cu-SAPO-18 catalysts were prepared using the ion exchange method. The impact of sulfur dioxide on catalytic performance of Ce-Cu-SAPO-18 for the selective catalytic reduction (SCR) of NO with NH3 was examined. Detailed characterization of the fresh and sulfur-poisoning Cu-SAPO-18 and Ce-Cu-SAPO-18 samples was conducted. XRD and BET results show that SO2 treatment of the Ce-doped Cu-SAPO-18 (Ce-Cu-SAPO-18-S) sample did not induce a remarkable change in structure, as compared with that of the fresh counterpart. According to in situ DRIFT, H2-TPR, SEM, and EDS results, it is found that the sulfation species attached preferentially to the cerium species, rather than the isolated Cu2+ species. In particular, the TG/DSC results confirm that the sulfate species on the Ce-Cu-SAPO-18-S sample was easier to decompose than that on the Cu-SAPO-18-S sample. The catalytic active sites of Ce-Cu-SAPO-18 were less influenced after SO2 treatment, as demonstrated by the TPR and XPS results. All of the above results show that the Ce-Cu-SAPO-18 sample exhibited better sulfur-resistant performance than the Cu-SAPO-18 sample.
Are FDA-Approved Sunscreen Components Effective in Preventing Solar UV-Induced Skin Cancer?
Authors: Bode Ann M. , Roh Eunmiri
Published: July 2020

Solar ultraviolet (SUV) exposure is a major risk factor in the etiology of cutaneous squamous cell carcinoma (cSCC). People commonly use sunscreens to prevent SUV-induced skin damage and cancer. Nonetheless, the prevalence of cSCC continues to increase every year, suggesting that commercially available sunscreens might not be used appropriately or are not completely effective. In the current study, a solar simulated light (SSL)-induced cSCC mouse model was used to investigate the efficacy of eight commonly used FDA-approved sunscreen components against skin carcinogenesis. First, we tested FDA-approved sunscreen components for their ability to block UVA or UVB irradiation by using VITRO-SKIN (a model that mimics human skin properties), and then the efficacy of FDA-approved sunscreen components was investigated in an SSL-induced cSCC mouse model. Our results identified which FDA-approved sunscreen components or combinations are effective in preventing cSCC development. Not surprisingly, the results indicated that sunscreen combinations that block both UVA and UVB significantly suppressed the formation of cutaneous papillomas and cSCC development and decreased the activation of oncoproteins and the expression of COX-2, keratin 17, and EGFR in SSL-exposed SKH-1 (Crl:SKH1-Hrhr) hairless mouse skin. Notably, several sunscreen components that were individually purported to block both UVA and UVB were ineffective alone. At least one component had toxic effects that led to a high mortality rate in mice exposed to SSL. Our findings provide new insights into the development of the best sunscreen to prevent chronic SUV-induced cSCC development.
Slc38a1 Conveys Astroglia-Derived Glutamine into GABAergic Interneurons for Neurotransmitter GABA Synthesis
Authors: Qureshi Tayyaba , Bjørkmo Mona , Nordengen Kaja , Gundersen Vidar , Utheim Tor Paaske , Watne Leiv Otto , Storm-Mathisen Jon , Hassel Bjørnar , Chaudhry Farrukh Abbas
Published: July 2020

GABA signaling is involved in a wide range of neuronal functions, such as synchronization of action potential firing, synaptic plasticity and neuronal development. Sustained GABA signaling requires efficient mechanisms for the replenishment of the neurotransmitter pool of GABA. The prevailing theory is that exocytotically released GABA may be transported into perisynaptic astroglia and converted to glutamine, which is then shuttled back to the neurons for resynthesis of GABA—i.e., the glutamate/GABA-glutamine (GGG) cycle. However, an unequivocal demonstration of astroglia-to-nerve terminal transport of glutamine and the contribution of astroglia-derived glutamine to neurotransmitter GABA synthesis is lacking. By genetic inactivation of the amino acid transporter Solute carrier 38 member a1 (Slc38a1)—which is enriched on parvalbumin+ GABAergic neurons—and by intraperitoneal injection of radiolabeled acetate (which is metabolized to glutamine in astroglial cells), we show that Slc38a1 mediates import of astroglia-derived glutamine into GABAergic neurons for synthesis of GABA. In brain slices, we demonstrate the role of Slc38a1 for the uptake of glutamine specifically into GABAergic nerve terminals for the synthesis of GABA depending on demand and glutamine supply. Thus, while leaving room for other pathways, our study demonstrates a key role of Slc38a1 for newly formed GABA, in harmony with the existence of a GGG cycle.
Effect of the Porosity, Roughness, Wettability, and Charge of Micro-Arc Coatings on the Efficiency of Doxorubicin Delivery and Suppression of Cancer Cells
Authors: Sedelnikova Mariya Borisovna , Komarova Ekaterina G. , Sharkeev Yurii P. , Chebodaeva Valentina V. , Tolkacheva Tatiana V. , Kondranova Anastasia M. , Zakharenko Alexander M. , Bakina Olga V.
Published: July 2020

Porous calcium phosphate coatings were formed by the micro-arc oxidation method on the surface of titanium for the loading and controlled release of the anticancer drug doxorubicin. The coatings’ morphology and microstructure were examined by scanning electron microscopy. The phase composition was determined with the help of X-ray diffraction analysis. Studies of the hydrophilic properties of the coatings and their zeta potential were carried out. Data on the kinetics of doxorubicin adsorption-desorption were obtained. In addition, the effect of calcium phosphate coatings impregnated with doxorubicin on the viability of the Neuro-2a cell line was revealed. The coating formed at low voltages of 200–250 V contained a greater number of branched communicating pores, and therefore they were able to adsorb a greater amount of doxorubicin. The surface charge also contributes to the process of the adsorption-desorption of doxorubicin, but this effect is not fully understood and further studies are required to identify it.
Obtaining and Corrosion Performance of Composite Zinc Coatings with Incorporated Carbon Spheres
Authors: Boshkova Nelly , Kamburova Kamelia , Koprinarov Nikola , Konstantinova Mariana , Boshkov Nikolai , Radeva Tsetska
Published: July 2020

The present work describes one possible way to prepare a stable aqueous suspension of carbon sphere particles with a positive charge that is suitable for simultaneous electrodeposition with zinc on steel substrate. In order to stabilize the suspension against aggregation, tri-block amphiphilic copolymer Pluronic F127, which is commercially available, was adsorbed on the surface of carbon sphere particles. This polymer contained poly (ethylene oxide) blocks as hydrophilic segments and poly (propylene oxide) blocks as the hydrophobic part. Scanning electron microscopy and visual observations confirmed the stability of the obtained suspension. The carbon sphere particles were embedded into the zinc coating by the co-electrodeposition process. The surface morphology of the composite coating was investigated using scanning electron microscopy. The influence of the carbon spheres on the cathodic and anodic processes was evaluated with cyclic voltammetry studies. The electrochemical investigations were realized in a model corrosion medium (5% NaCl solution with pH 6.7) by application of selected methods such as polarization resistance, potentiodynamic polarization, and electrochemical impedance spectroscopy, which revealed higher protective ability of the composite coating against corrosion in an aggressive environment.
Mesoporous Metal Oxide Films
Authors: Topoglidis Emmanuel
Published: July 2020

Great progress has been made in the preparation and application of mesoporous metal oxide films and materials during the last three decades. Numerous preparation methods and applications of these novel and interesting materials have been reported, and it was demonstrated that mesoporosity has a direct impact on the properties and potential applications of such materials. This Special Issue of Coatings contains a series of ten research articles demonstrating emphatically that various metal oxide materials could be prepared using a number of different methods, and focuses on many areas where these mesoporous materials could be used, such as sensors, solar cells, supercapacitors, photoelectrodes, anti-corrosion agents and bioceramics. Our aim is to present important developments in this fast-moving field, from various groups around the world.
Amplitude Dependent Internal Friction in Strained Magnesium Alloys of AZ Series
Authors: Uhríčik Milan , Dresslerová Zuzana , Palček Peter , Chalupová Mária , Trojanová Zuzanka , Hanusová Patrícia
Published: July 2020

Amplitude dependent internal friction (ADIF) was measured in three AZ magnesium alloys. Two types of experiments were performed: ADIF was measured step by step with the increasing strain amplitude and ADIF was measured after predeformation of samples in torsion. All experiments were done at room temperature. The quality factor was used as a measure of internal friction (IF). The quality factor decreased in the region of smaller amplitudes, and approaching some critical amplitude, εcr, rapidly increased. This critical amplitude increased with increasing maximum strain amplitude and predeformation of samples up to ~6%. Such behavior can be explained by considering mobile solute atoms, which may migrate along the dislocation line in the region of smaller amplitudes and perpendicular to the dislocation line in the region of higher amplitudes. A competition between dragging and depinning of solute atoms with dislocation lines may very well explain the measured dependencies.
Microwave Irradiation to Produce High Performance Thermoelectric Material Based on Al Doped ZnO Nanostructures
Authors: Baghdadi Neazar , Salah Numan , Alshahrie Ahmed , Koumoto Kunihito
Published: July 2020

Microwave irradiation is found to be effective to provide highly crystalline nanostructured materials. In this work, this technique has been used to produce highly improved thermoelectric (TE) material based on aluminum (Al) doped zinc oxide (ZnO) nanostructures (NSs). The effect of Al dopant at the concentration range 0.5–3 mol % on the structural and TE properties has been investigated in more details. The optimum concentration of Al for better TE performance is found to be 2 mol %, which could significantly increase the electrical conductivity and reduce the thermal conductivity of ZnO NSs and thus enhance the TE performance. This concentration showed almost metallic conductivity behavior for ZnO NSs at low temperatures, e.g., below 500 K. The electrical conductivity reached 400 S/m at room temperature, which is around 200 times greater than the value recorded for the pure ZnO NSs. Remarkably, the measured room temperature thermal conductivity of the microwave synthesized ZnO NSs was very low, which is around 4 W/m·K. This value was further reduced to 0.5 W/m·K by increasing the Al doping to 3 mol %. The figure of merit recorded 0.028 at 675 K, which is 15 times higher than that of the pure ZnO NSs. The output power of a single leg module made of 2 mol % Al doped ZnO NSs was 3.7 µW at 485 K, which is higher by 8 times than that of the pure sample. These results demonstrated the advantage of the microwave irradiation rout as a superior synthetic technique for producing and doping promising TE nanomaterials like ZnO NSs.
Morphology, Thermal Stability, and Flammability Properties of Polymer-Layered Double Hydroxide (LDH) Nanocomposites: A Review
Authors: Mochane Mokgaotsa Jonas , Magagula Sifiso Innocent , Sefadi Jeremia Shale , Sadiku Emmanuel Rotimi , Mokhena Teboho Clement
Published: July 2020

The utilization of layered nanofillers in polymer matrix, as reinforcement, has attracted great interest in the 21st century. This can be attributed to the high aspect ratios of the nanofillers and the attendant substantial improvement in different properties (i.e., increased flammability resistance, improved modulus and impact strength, as well as improved barrier properties) of the resultant nanocomposite when compared to the neat polymer matrix. Amongst the well-known layered nanofillers, layered inorganic materials, in the form of LDHs, have been given the most attention. LDH nanofillers have been employed in different polymers due to their flexibility in chemical composition as well as an adjustable charge density, which permits numerous interactions with the host polymer matrices. One of the most important features of LDHs is their ability to act as flame-retardant materials because of their endothermic decomposition. This review paper gives detailed information on the: preparation methods, morphology, flammability, and barrier properties as well as thermal stability of LDH/polymer nanocomposites.
Evaluation of Commercial qPCR Kits for Detection of SARS-CoV-2 in Pooled Samples
Authors: Petrovan Vlad , Vrajmasu Virgil , Bucur Ana Cristina , Soare Dan Sebastian , Radu Eugen , Dimon Paula , Zaulet Mihaela
Published: July 2020

Due to the current pandemic, a global shortage of reagents has drawn interest in developing alternatives to increase the number of coronavirus tests. One such alternative is sample pooling. We compared commercial kits that are used in COVID-19 diagnostics in terms of their sensitivity and feasibility for use in pooling. In this preliminary study, we showed that pooling of up to 80 samples did not affect the efficacy of the kits. Additionally, the RNA-dependent RNA polymerase (RdRp) gene is a more suitable target in pooled samples than the envelope (E) gene. This approach could provide an easy method of screening a large number of samples and help adjust different governmental regulations.
Network Analysis of Multivariate Transfer Entropy of Cryptocurrencies in Times of Turbulence
Authors: García-Medina Andrés , C. José B. Hernández
Published: July 2020

We investigate the effects of the recent financial turbulence of 2020 on the market of cryptocurrencies taking into account the hourly price and volume of transactions from December 2019 to April 2020. The data were subdivided into time frames and analyzed the directed network generated by the estimation of the multivariate transfer entropy. The approach followed here is based on a greedy algorithm and multiple hypothesis testing. Then, we explored the clustering coefficient and the degree distributions of nodes for each subperiod. It is found the clustering coefficient increases dramatically in March and coincides with the most severe fall of the recent worldwide stock markets crash. Further, the log-likelihood in all cases bent over a power law distribution, with a higher estimated power during the period of major financial contraction. Our results suggest the financial turbulence induce a higher flow of information on the cryptocurrency market in the sense of a higher clustering coefficient and complexity of the network. Hence, the complex properties of the multivariate transfer entropy network may provide early warning signals of increasing systematic risk in turbulence times of the cryptocurrency markets.
Intelligent Sea States Identification Based on Maximum Likelihood Evidential Reasoning Rule
Authors: Zhang Xuelin , Xu Xiaojian , Xu Xiaobin , Gao Diju , Gao Haibo , Wang Guodong , Grosu Radu
Published: July 2020

It is necessary to switch the control strategies for propulsion system frequently according to the changes of sea states in order to ensure the stability and safety of the navigation. Therefore, identifying the current sea state timely and effectively is of great significance to ensure ship safety. To this end, a reasoning model that is based on maximum likelihood evidential reasoning (MAKER) rule is developed to identify the propeller ventilation type, and the result is used as the basis for the sea states identification. Firstly, a data-driven MAKER model is constructed, which fully considers the interdependence between the input features. Secondly, the genetic algorithm (GA) is used to optimize the parameters of the MAKER model in order to improve the evaluation accuracy. Finally, a simulation is built to obtain experimental data to train the MAKER model, and the validity of the model is verified. The results show that the intelligent sea state identification model that is based on the MAKER rule can identify the propeller ventilation type more accurately, and finally realize intelligent identification of sea states.
Discrete-Time Fractional, Variable-Order PID Controller for a Plant with Delay
Authors: Oziablo Piotr , Mozyrska Dorota , Wyrwas Małgorzata
Published: July 2020

In this paper, we discuss the implementation and tuning algorithms of a variable-, fractional-order Proportional–Integral–Derivative (PID) controller based on Grünwald–Letnikov difference definition. All simulations are executed for the third-order plant with a delay. The results of a unit step response for all described implementations are presented in a graphical and tabular form. As the qualitative criteria, we use three different error values, which are the following: a summation of squared error (SSE), a summation of squared time weighted error (SSTE) and a summation of squared time-squared weighted error (SST2E). Besides three types of error values, obtained results are additionally evaluated on the basis of an overshoot and a rise time of the output signals achieved by systems with the designed controllers.
Two-Stage Monitoring of Patients in Intensive Care Unit for Sepsis Prediction Using Non-Overfitted Machine Learning Models
Authors: Abromavičius Vytautas , Plonis Darius , Tarasevičius Deividas , Serackis Artūras
Published: July 2020

The presented research faces the problem of early detection of sepsis for patients in the Intensive Care Unit. The PhysioNet/Computing in Cardiology Challenge 2019 facilitated the development of automated, open-source algorithms for the early detection of sepsis from clinical data. A labeled clinical records dataset for training and verification of the algorithms was provided by the challenge organizers. However, a relatively small number of records with sepsis, supported by Sepsis-3 clinical criteria, led to highly unbalanced dataset (only 2% records with sepsis label). A high number of unbalanced data records is a great challenge for machine learning model training and is not suitable for training classical classifiers. To address these issues, a method taking into the account the amount of time the patients spent in the intensive care unit (ICU) was proposed. The proposed method uses two separate ensemble models, one trained on patient records under 56 h in the ICU, and another for patients who stayed longer than 56 h. A solution including feature selection and weighting based training on imbalanced data was proposed in this paper. In addition, several performance metrics were investigated. Results show, that for successful prediction, a particular model having few or more predictors based on the length of stay in the Intensive Care Unit should be applied.
SMS: A Secure Healthcare Model for Smart Cities
Authors: Tripathi Gautami , Abdul Ahad Mohd , Paiva Sara
Published: July 2020

Technological innovations have enabled the realization of a utopian world where all objects of everyday life, as well as humans, are interconnected to form an “Internet of Things (IoT).” These connected technologies and IoT solutions have led to the emergence of smart cities where all components are converted into a connected smart ecosystem. IoT has envisioned several areas of smart cities including the modern healthcare environment like real-time monitoring, patient information management, ambient-assisted living, ambient-intelligence, anomaly detection, and accelerated sensing. IoT has also brought a breakthrough in the medical domain by integrating stake holders, medical components, and hospitals to bring about holistic healthcare management. The healthcare domain is already witnessing promising IoT-based solutions ranging from embedded mobile applications to wearable devices and implantable gadgets. However, with all these exemplary benefits, there is a need to ensure the safety and privacy of the patient’s personal and medical data communicated to and from the connected devices and systems. For a smart city, it is pertinent to have an accessible, effective, and secure healthcare system for its inhabitants. This paper discusses the various elements of technology-enabled healthcare and presents a privacy-preserved and secure “Smart Medical System (SMS)” framework for the smart city ecosystem. For providing real-time analysis and responses, this paper proposes to use the concept of secured Mobile Edge Computing (MEC) for performing critical time-bound computations on the edge itself. In order to protect the medical and personal data of the patients and to make the data tamper-proof, the concept of blockchain has been used. Finally, this paper highlights the ways to capture and store the medical big data generated from IoT devices and sensors.
Open-Source Coprocessor for Integer Multiple Precision Arithmetic
Authors: Rudnicki Kamil , Stefański Tomasz P. , Żebrowski Wojciech
Published: July 2020

This paper presents an open-source digital circuit of the coprocessor for an integer multiple-precision arithmetic (MPA). The purpose of this coprocessor is to support a central processing unit (CPU) by offloading computations requiring integer precision higher than 32/64 bits. The coprocessor is developed using the very high speed integrated circuit hardware description language (VHDL) as an intellectual property (IP) core. Therefore, it can be implemented within field programmable gate arrays (FPGAs) at various scales, e.g., within a system on chip (SoC), combining CPU cores and FPGA within a single chip as well as FPGA acceleration cards. The coprocessor handles integer numbers with precisions in the range 64 bits–32 kbits, with the limb size set to 64 bits. In our solution, the sign-magnitude representation is used to increase the efficiency of the multiplication operation as well as to provide compatibility with existing software libraries for MPA. The coprocessor is benchmarked in factorial ( n ! ), exponentiation ( n n ) and discrete Green’s function (DGF) computations on Xilinx Zynq-7000 SoC on TySOM-1 board from Aldec. In all benchmarks, the coprocessor demonstrates better runtimes than a CPU core (ARM Cortex A9) executing the same computations using a software MPA library. For sufficiently large input parameters, our coprocessor is up to three times faster when implemented in FPGA on SoC, rising to a factor of ten in DGF computations. The open-source coprocessor code is licensed under the Mozilla Public License.
Underwater Network Management System in Internet of Underwater Things: Open Challenges, Benefits, and Feasible Solution
Authors: K. M Delphin Raj , Lee Jinyoung , Ko Eunbi , Shin Soo-Young , Namgung Jung-Il , Yum Sun-Ho , Park Soo-Hyun
Published: July 2020

As oceans cover the majority of the earth’s surface, it becomes inevitable in extending the concepts of Internet of Things (IoT) to ocean bodies, thereby tiling the way for a new drift in the digital world, the Internet of Underwater Things (IoUT). The primary objective of IoUT is the creation of a network of several smart interconnected undersea things, to digitally link water bodies by using devices such as autonomous underwater vehicles. Since the traditional ideas of IoT cannot be merely expanded to underwater, due to the difference in environmental characteristics, this puts forward a variety of challenges for scientists to work with IoUT, and one such challenge is the network management with IoUT. This paper gives an overview on (1) underwater network management systems (U-NMS) using acoustic communication in IoUT; (2) the challenges and benefits and use cases of U-NMS; (3) fault, configuration, accounting, performance, security and constrained management (FCAPSC) functionalities of U-NMS and (4) a comparison between network management system in IoT and U-NMS system in IoUT. Additionally, this paper shows the prototype design and implementation setup of U-NMS in a laboratory environment, using lightweight machine to machine (LWM2M) and acoustic communication technology for IoUT. This paper will contribute much to the profit of researchers and industry players in uncovering the critical areas of the Internet of Underwater Things.
Evaluating the Future Efficiency of Wave Energy Converters along the NW Coast of the Iberian Peninsula
Authors: Ribeiro Américo S. , deCastro Maite , Rusu Liliana , Bernardino Mariana , Dias João M. , Gomez-Gesteira Moncho
Published: July 2020

The efficiency of wave energy converters (WECs) is generally evaluated in terms of historical wave conditions that do not necessarily represent the conditions that those devices will encounter when put into operation. The main objective of the study is to assess the historical and near future efficiency and energy cost of two WECs (Aqua Buoy and Pelamis). A SWAN model was used to downscale the wave parameters along the NW coast of the Iberian Peninsula both for a historical period (1979–2005) and the near future (2026–2045) under the RCP 8.5 greenhouse scenario. The past and future efficiency of both WECs were computed in terms of two parameters that capture the relationship between sea states and the WEC power matrices: the load factor and the capture width. The wave power resource and the electric power capacity of both the WECs will decrease in the near future. The load factor for Aqua Buoy will decrease in the entire area, while it will remain unchanged for Pelamis in most of the area, except north of 43.5° N. The capture width and cost of energy will increase for both devices. The methodology here applied can be easily applied to any device and coastal domain under different climate change scenarios.
Design and Performance Evaluation of Multi-Gb/s Silicon Photonics Transmitters for High Energy Physics
Authors: Cammarata Simone , Ciarpi Gabriele , Faralli Stefano , Velha Philippe , Magazzù Guido , Palla Fabrizio , Saponara Sergio
Published: July 2020

Optical links are rapidly becoming pervasive in the readout chains of particle physics detector systems. Silicon photonics (SiPh) stands as an attractive candidate to sustain the radiation levels foreseen in the next-generation experiments, while guaranteeing, at the same time, multi-Gb/s and energy-efficient data transmission. Integrated electronic drivers are needed to enable SiPh modulators’ deployment in compact on-detector front-end modules. A current-mode logic-based driver harnessing a pseudo-differential output stage is proposed in this work to drive different types of SiPh devices by means of the same circuit topology. The proposed driver, realized in a 65 nm bulk technology and already tested to behave properly up to an 8 MGy total ionizing dose, is hybridly integrated in this work with a lumped-element Mach–Zehnder modulator (MZM) and a ring modulator (RM), both fabricated in a 130 nm silicon-on-insulator (SOI) process. Bit-error-rate (BER) performances confirm the applicability of the selected architecture to either differential and single-ended loads. A 5 Gb/s data rate, in line with the current high energy physics requirements, is achieved in the RM case, while a packaging-related performance degradation is captured in the MZM-based system, confirming the importance of interconnection modeling.
Recovery of Cenospheres and Fine Fraction from Coal Fly Ash by a Novel Dry Separation Method
Authors: Wrona Jan , Żukowski Witold , Bradło Dariusz , Czupryński Piotr
Published: July 2020

Aluminosilicate microspheres are a valuable fraction of coal fly ash with diverse applications due to their low density. Currently, there is no efficient and ecologically rational method of cenosphere recovery from fly ash. A combination of dry methods for the recovery of both fine ash particles and aluminosilicate microspheres from coal fly ash is presented. It is comprised of fluidised bed separation followed by screening and pneumatic separation in a free-fall air chamber. Fluidised bed separation was assisted by a mechanical activator to prevent agglomeration. This step reduced the portion of material that required further treatment by 52–55 wt.%, with the recovery of microspheres exceeding 97%. Then, the concentrates were individually subjected to pneumatic separation. The final separation product for the fly ash containing 0.64 wt.% cenospheres was a cenosphere concentrate that constituted about 17 wt.% of the initial fly ash. The recovery of cenospheres was around 81%. Usage of a combination of dry methods allowed for maintaining almost 83 wt.% of the raw material in its dry form. Furthermore, the produced fly ash grain fractions could be used for different industrial purposes.
Water Adsorption Effect on Carbon Molecular Sieve Membranes in H2-CH4 Mixture at High Pressure
Authors: Nordio Maria L. V. , Medrano José A. , van Sint Annaland Martin , Pacheco Tanaka David Alfredo , Llosa Tanco Margot , Gallucci Fausto
Published: July 2020

Carbon molecular sieve membranes (CMSMs) are emerging as promising solution to overcome the drawbacks of Pd-based membranes for H2 separation since (i) they are relatively easy to manufacture; (ii) they have low production and raw material costs; (iii) and they can work at conditions where polymeric and palladium membranes are not stable. In this work CMSMs have been investigated in pure gas and gas mixture tests for a proper understanding of the permeation mechanism, selectivity and purity towards hydrogen. No mass transfer limitations have been observed with these membranes, which represents an important advantage compared to Pd-Ag membranes, which suffer from concentration polarization especially at high pressure and low hydrogen concentrations. H2, CH4, CO2 and N2 permeation at high pressures and different temperatures in presence of dry and humidified stream (from ambient and water vapour) have been carried out to investigate the effect of the presence of water in the feed stream. Diffusion is the main mechanism observed for hydrogen, while methane, nitrogen and especially carbon dioxide permeate through adsorption-diffusion at low temperatures and high pressures. Finally, H2 permeation from H2-CH4 mixtures in presence of water has been compared at different temperatures and pressure, which demonstrates that water adsorption is an essential parameter to improve the performance of carbon molecular sieve membranes, especially when working at high temperature. Indeed, a hydrogen purity of 98.95% from 10% H2—90% CH4 was achieved. The main aim of this work is to understand the permeation mechanisms of CMSMs in different operating conditions and find the best conditions to optimize the separation of hydrogen.