bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat Transfer Analysis in a Single Spool Gas Turbine by Using Calculated-Estimated Coefficients with the Finite Element Method
Authors: Creci Geraldo , de Mendoça Márcio Teixeira , Menezes João Carlos , Barbosa João Roberto
Published: November 2020

In this paper, a calculation procedure is presented to estimate the heat transfer coefficients of a single spool gas turbine designed to generate 5 kN of thrust. These heat transfer coefficients are the boundary conditions which govern the heat interaction between the solid parts and the working fluid in the gas turbine. However, the calculation of these heat transfer coefficients is not a trivial task, since it depends on complex fluid flow conditions. Empirical correlations and assumptions have been used to find convective heat transfer coefficients over most components, including stator vanes, rotor blades, disc faces, and disc platforms. After defining the heat transfer coefficients, the finite element method was used to determine the temperature distribution in one eighth section of the gas turbine making use of the problem cyclic symmetry. Both static and rotating assemblies have been modeled. The results allowed the prediction of the thermal expansion behavior of the whole single spool gas turbine with special attention to the safety margin of clearances. Furthermore, having the temperature distribution defined, it is possible to calculate the thermal stresses in any mechanical component. Additionally, it is possible to specify suitable metallic alloys for achieving appropriate performance in every case. The structural integrity of all components was then assured with the temperature distribution and thermal expansion behavior under knowledge. Thus, the mechanical drawings could be released to manufacturing.
Corrosion and Tribocorrosion Behaviors for TA3 in Ringer’s Solution after Implantation of Nb Ions
Authors: Xue Chenfei , Zhang Pingze , Wei Dongbo , Hu Hengmei , Li Fengkun , Yang Kai
Published: November 2020

Ti alloys are prone to corrosion and wear due to the hostile environment in bodily fluids, but the Ti-45Nb alloy is considered to be a promising titanium alloy with excellent biocompatibility and resistance to physiological corrosion. In this study, Nb ions were implanted into a TA3 alloy and the effect on the biological corrosion as well as tribocorrosion behavior of TA3 in Ringer’s solution was systematically investigated. The surface microstructure and XRD results revealed that the implanted samples showed a smoother surface due to the sputtering and radiation damages, and the Nb ions mainly existed in the alloy as the solid solution element. The electrochemical polarization tests showed that the implantation of Nb ions can increase the corrosion potential of the samples, showing a better thermodynamic stability. The tribocorrosion tests showed that the implanted samples exhibited a better thermodynamic stability in a corrosive environment accompanied by wear behavior, and the worn surface showed fewer pitting pits, indicating a better corrosion resistance. However, the abrasive wear and oxidation wear degree of the sample increased because of partial softening of the surface and brittle passivation film.
Biological Applications of Short Wavelength Microscopy Based on Compact, Laser-Produced Gas-Puff Plasma Source
Authors: Torrisi Alfio , Wachulak Przemysław W. , Bartnik Andrzej , Węgrzyński Łukasz , Fok Tomasz , Fiedorowicz Henryk
Published: November 2020

Over the last decades, remarkable efforts have been made to improve the resolution in photon-based microscopes. The employment of compact sources based on table-top laser-produced soft X-ray (SXR) in the “water window” spectral range (λ = 2.3–4.4 nm) and extreme ultraviolet (EUV) plasma allowed to overcome the limitations imposed by large facilities, such as synchrotrons and X-ray free electron lasers (XFEL), because of their high complexity, costs, and limited user access. A laser-plasma double stream gas-puff target source represents a powerful tool for microscopy operating in transmission mode, significantly improving the spatial resolution into the nanometric scale, comparing to the traditional visible light (optical) microscopes. Such an approach allows generating the plasma efficiently, without debris, providing a high flux of EUV and SXR photons. In this review, we present the development and optimization of desktop imaging systems: a EUV and an SXR full field microscope, allowing to achieve a sub-50 nm spatial resolution with short exposure time and an SXR contact microscope, capable to resolve internal structures in a thin layer of sensitive photoresist. Details about the source, as well as imaging results for biological applications, will be presented and discussed.
Finite Element Analysis of Fatigue in Offshore Pipelines with Internal and External Circumferential Cracks
Authors: Olamide Ayodeji , Bennecer Abdeldjalil , Kaczmarczyk Stefan
Published: November 2020

Fatigue lifetime of offshore pipelines with semi-elliptical circumferential surface cracks is often underestimated. An accurate prediction of the pipeline structural integrity is nevertheless important in order to prevent unnecessary and expensive downtime, failures leading to leakage or spillage of pipeline contents to the surrounding environment, and ultimately improve the reliability of the pipeline. The estimation of crack growth in pipelines under varying loads is highly dependent on the calculation of crack driving parameters, such as the stress intensity factor and the crack tip opening displacement (CTOD) using the 3D J-integral or its equivalent. This paper presents a numerical study to predict the fatigue lifetime of cracks in pipes, determining the J-integral that includes first and second derivatives of the displacement field for pipes containing a range of circumferential surface cracks. A pipe segment is structurally loaded and stress intensity factors (SIF) evaluated using the finite element method (FEM). Based on the results, a number-of-cycles to failure curve shows a longer lifetime than previously predicted by about 5% for a pipe with semi-elliptical external surface cracks. In addition, they indicate that the external short cracks are more dangerous than the internal long surface crack hereby requiring earlier assessment.
A Hot Blob Eastward of New Zealand in December 2019
Authors: Shi Jian , Chen Ziyan , Ding Saisai , Lu Yiqun
Published: November 2020

A hot blob for near-surface water was identified eastward of New Zealand in the South Pacific in December 2019, which was the second strongest event on record in this region. Its sea surface temperature anomalies reached up to 5 °C, and the anomalous warming penetrated around 40 m deep vertically. From the atmospheric perspective, the anomalous high-pressure system from the surface up to 300 hPa lasted for about 50 days, accompanied by the blocking pattern at 500 hPa and a deep warming air column extending downward to the surface. A mixed-layer heat budget analysis revealed that the surface heat flux term was the primary factor contributing to the development of this hot blob, with more shortwave radiation due to the persistent high-pressure system and lack of clouds as well as higher temperature of the troposphere aloft denoted by sensible heat. The oceanic contribution including the horizontal advection and vertical entrainment was changeable and accounted for less than 50%. Moreover, we used the strongest hot blob event which peaked in December 2001 as another example to evaluate the robustness of results derived from the 2019 case. The results show similar circulation features and driving factors, which indicate the robustness of the above characteristics.
Analysis of Long-Term Variations of Drought Characteristics Using Standardized Precipitation Index over Zambia
Authors: Musonda Bathsheba , Jing Yuanshu , Iyakaremye Vedaste , Ojara Moses
Published: November 2020

This study examines long-term spatial and temporal trends of drought characteristics based on the Standardized Precipitation Index at three different time scales (3, 6, and 12 months) over Zambia from 1981 to 2017. Drought characteristic conditions such as duration, severity, and intensity at monthly, seasonal, and annual levels were analyzed to investigate the drought patterns over Zambia. The results show a significant increase in drought events over the southwestern regions and a decrease over the northeastern regions. It is in this regard that two stations from different locations (southwest and northeast) were analyzed. The results show increasing trends of drought over Sesheke (southwest) and decreasing trends over Kasama (northeast). More drought impacts are felt over southern compared to northern areas, which poses a serious concern to both agriculture and hydrological industries over the drought-prone areas of Southern Zambia. However, the analysis further shows that droughts were more intense, persistent, and severe over the southwest, while moderate droughts were found in some few areas of Northeast Zambia. The Mann–Kendall test trend and slope indicated that both annual and seasonal drought have increased. However, drought increment at an annual level shows a low magnitude as compared to the seasonal level. This suggested the importance of evaluating drought at an interannual and seasonal time scale over Zambia. Specifically, the drought increased determinedly before 2010 and became erratic between 2010 and 2017 with considerable regional variation. Zambia experienced moderate to severe droughts during 1991–1992, 1994–1995, 2006–2005, and 2015–2016, which resulted in serious damages to the environment and society. According to the findings of this study, it is suggested that the implications of drought can be managed by creating strategies and adaptation measures.
The Promise of Optogenetics for Bioproduction: Dynamic Control Strategies and Scale-Up Instruments
Authors: Pouzet Sylvain , Banderas Alvaro , Le Bec Matthias , Lautier Thomas , Truan Gilles , Hersen Pascal
Published: November 2020

Progress in metabolic engineering and synthetic and systems biology has made bioproduction an increasingly attractive and competitive strategy for synthesizing biomolecules, recombinant proteins and biofuels from renewable feedstocks. Yet, due to poor productivity, it remains difficult to make a bioproduction process economically viable at large scale. Achieving dynamic control of cellular processes could lead to even better yields by balancing the two characteristic phases of bioproduction, namely, growth versus production, which lie at the heart of a trade-off that substantially impacts productivity. The versatility and controllability offered by light will be a key element in attaining the level of control desired. The popularity of light-mediated control is increasing, with an expanding repertoire of optogenetic systems for novel applications, and many optogenetic devices have been designed to test optogenetic strains at various culture scales for bioproduction objectives. In this review, we aim to highlight the most important advances in this direction. We discuss how optogenetics is currently applied to control metabolism in the context of bioproduction, describe the optogenetic instruments and devices used at the laboratory scale for strain development, and explore how current industrial-scale bioproduction processes could be adapted for optogenetics or could benefit from existing photobioreactor designs. We then draw attention to the steps that must be undertaken to further optimize the control of biological systems in order to take full advantage of the potential offered by microbial factories.
A Representative GIIA Phospholipase A2 Activates Preadipocytes to Produce Inflammatory Mediators Implicated in Obesity Development
Authors: Leiguez Elbio , Motta Priscila , Maia Marques Rodrigo , Lomonte Bruno , Sampaio Suely Vilela , Teixeira Catarina
Published: November 2020

Adipose tissue secretes proinflammatory mediators which promote systemic and adipose tissue inflammation seen in obesity. Group IIA (GIIA)-secreted phospholipase A2 (sPLA2) enzymes are found to be elevated in plasma and adipose tissue from obese patients and are active during inflammation, generating proinflammatory mediators, including prostaglandin E2 (PGE2). PGE2 exerts anti-lipolytic actions and increases triacylglycerol levels in adipose tissue. However, the inflammatory actions of GIIA sPLA2s in adipose tissue cells and mechanisms leading to increased PGE2 levels in these cells are unclear. This study investigates the ability of a representative GIIA sPLA2, MT-III, to activate proinflammatory responses in preadipocytes, focusing on the biosynthesis of prostaglandins, adipocytokines and mechanisms involved in these effects. Our results showed that MT-III induced biosynthesis of PGE2, PGI2, MCP-1, IL-6 and gene expression of leptin and adiponectin in preadipocytes. The MT-III-induced PGE2 biosynthesis was dependent on cytosolic PLA2 (cPLA2)-α, cyclooxygenases (COX)-1 and COX-2 pathways and regulated by a positive loop via the EP4 receptor. Moreover, MT-III upregulated COX-2 and microsomal prostaglandin synthase (mPGES)-1 protein expression. MCP-1 biosynthesis induced by MT-III was dependent on the EP4 receptor, while IL-6 biosynthesis was dependent on EP3 receptor engagement by PGE2. These data highlight preadipocytes as targets for GIIA sPLA2s and provide insight into the roles played by this group of sPLA2s in obesity.
A Multichannel Microfluidic Sensing Cartridge for Bioanalytical Applications of Monolithic Quartz Crystal Microbalance
Authors: Calero María , Fernández Román , García Pablo , García José Vicente , García María , Gamero-Sandemetrio Esther , Reviakine Ilya , Arnau Antonio , Jiménez Yolanda
Published: November 2020

Integrating acoustic wave sensors into lab-on-a-chip (LoC) devices is a well-known challenge. We address this challenge by designing a microfluidic device housing a monolithic array of 24 high-fundamental frequency quartz crystal microbalance with dissipation (HFF-QCMD) sensors. The device features six 6-µL channels of four sensors each for low-volume parallel measurements, a sealing mechanism that provides appropriate pressure control while assuring liquid confinement and maintaining good stability, and provides a mechanical, electrical, and thermal interface with the characterization electronics. We validate the device by measuring the response of the HFF-QCMD sensors to the air-to-liquid transition, for which the robust Kanazawa–Gordon–Mason theory exists, and then by studying the adsorption of model bioanalytes (neutravidin and biotinylated albumin). With these experiments, we show how the effects of the protein–surface interactions propagate within adsorbed protein multilayers, offering essentially new insight into the design of affinity-based bioanalytical sensors.
Propranolol Relieves L-Dopa-Induced Dyskinesia in Parkinsonian Mice
Authors: Shi Ziqing , Bamford Ian J. , McKinley Jonathan W. , Devi Suma Priya Sudarsana , Vahedipour Annie , Bamford Nigel S.
Published: November 2020

Background: Parkinsonism is caused by dopamine (DA) insufficiency and results in a hypokinetic movement disorder. Treatment with L-Dopa can restore DA availability and improve motor function, but patients can develop L-Dopa-induced dyskinesia (LID), a secondary hyperkinetic movement disorder. The mechanism underlying LID remains unknown, and new treatments are needed. Experiments in mice have shown that DA deficiency promotes an imbalance between striatal acetylcholine (ACh) and DA that contributes to motor dysfunction. While treatment with L-Dopa improves DA availability, it promotes a paradoxical rise in striatal ACh and a further increase in the ACh to DA ratio may promote LID. Methods: We used conditional Slc6a3DTR/+ mice to model progressive DA deficiency and the β-adrenergic receptor (β-AR) antagonist propranolol to limit the activity of striatal cholinergic interneurons (ChIs). DA-deficient mice were treated with L-Dopa and the dopa decarboxylase inhibitor benserazide. LID and motor performance were assessed by rotarod, balance beam, and open field testing. Electrophysiological experiments characterized the effects of β-AR ligands on striatal ChIs. Results: LID was observed in a subset of DA-deficient mice. Treatment with propranolol relieved LID and motor hyperactivity. Electrophysiological experiments showed that β-ARs can effectively modulate ChI firing. Conclusions: The work suggests that pharmacological modulation of ChIs by β-ARs might provide a therapeutic option for managing LID.
Robustness Assessment of Redundant Structural Systems Based on Design Provisions and Probabilistic Damage Analyses
Authors: Spyridis Panagiotis , Strauss Alfred
Published: November 2020

Typically in structural design, foreseeable loads are assumed in a structural design and dimensioning exercise and design material properties may be handled in a semi-probabilistic approach. Structures can, however, be exposed to largely unforeseeable events such as intense environmental phenomena, accidents, malicious acts, and planning or execution errors, in addition to degradation with time. Recent significant collapses have highlighted the fact that robustness is an indispensable integral part of the structural design and provisions in upcoming codes are currently expanding in this respect. The paper examines the practical significance of quantitative robustness indicators included in recent research and upcoming standards and it assesses their efficiency based on case studies. Moreover, it proposes a probabilistic numerical methodology for robustness assessment under uncertainty, and it demonstrates its practical applicability based on computations with indicative structural truss systems, i.e., multi-component systems. The proposed method allows for quantifiable and comparable robustness measures, which can be integrated in reliability-based design and structural health monitoring of engineering systems. The redundancy aspect of robustness is pronounced as a plausible quantitative performance indicator for multi-component systems. In particular, the robustness index combining reliability and redundancy of the elements is proven to be the most useful one out of the examined approaches. This probabilistic elaboration does not only account for the reasonable treatment of variability and randomness, but it allows for an inverse identification of the critical failure paths and the characterization of weak links in the systems.
Enzymatic Degradation of Organophosphorus Pesticides and Nerve Agents by EC: 3.1.8.2
Authors: Matula Marek , Kucera Tomas , Soukup Ondrej , Pejchal Jaroslav
Published: November 2020

The organophosphorus substances, including pesticides and nerve agents (NAs), represent highly toxic compounds. Standard decontamination procedures place a heavy burden on the environment. Given their continued utilization or existence, considerable efforts are being made to develop environmentally friendly methods of decontamination and medical countermeasures against their intoxication. Enzymes can offer both environmental and medical applications. One of the most promising enzymes cleaving organophosphorus compounds is the enzyme with enzyme commission number (EC): 3.1.8.2, called diisopropyl fluorophosphatase (DFPase) or organophosphorus acid anhydrolase from Loligo Vulgaris or Alteromonas sp. JD6.5, respectively. Structure, mechanisms of action and substrate profiles are described for both enzymes. Wild-type (WT) enzymes have a catalytic activity against organophosphorus compounds, including G-type nerve agents. Their stereochemical preference aims their activity towards less toxic enantiomers of the chiral phosphorus center found in most chemical warfare agents. Site-direct mutagenesis has systematically improved the active site of the enzyme. These efforts have resulted in the improvement of catalytic activity and have led to the identification of variants that are more effective at detoxifying both G-type and V-type nerve agents. Some of these variants have become part of commercially available decontamination mixtures.
Smart Nanofibers with Natural Extracts Prevent Senescence Patterning in a Dynamic Cell Culture Model of Human Skin
Authors: Bellu Emanuela , Garroni Giuseppe , Cruciani Sara , Balzano Francesca , Serra Diletta , Satta Rosanna , Montesu Maria , Fadda Angela , Mulas Maurizio , Sarais Giorgia , Bandiera Pasquale , Torreggiani Elena , Martini Fernanda , Tognon Mauro , Ventura Carlo , Beznoska Jiří , Amler Evzen , Maioli Margherita
Published: November 2020

Natural cosmetic products have recently re-emerged as a novel tool able to counteract skin aging and skin related damages. In addition, recently achieved progress in nanomedicine opens a novel approach yielding from combination of modern nanotechnology with traditional treatment for innovative pharmacotherapeutics. In the present study, we investigated the antiaging effect of a pretreatment with Myrtus communis natural extract combined with a polycaprolactone nanofibrous scaffold (NanoPCL-M) on skin cell populations exposed to UV. We set up a novel model of skin on a bioreactor mimicking a crosstalk between keratinocytes, stem cells and fibroblasts, as in skin. Beta-galactosidase assay, indicating the amount of senescent cells, and viability assay, revealed that fibroblasts and stem cells pretreated with NanoPCL-M and then exposed to UV are superimposable to control cells, untreated and unexposed to UV damage. On the other hand, cells only exposed to UV stress, without NanoPCL-M pretreatment, exhibited a significantly higher yield of senescent elements. Keratinocyte-based 3D structures appeared disjointed after UV-stress, as compared to NanoPCL-M pretreated samples. Gene expression analysis performed on different senescence associated genes, revealed the activation of a molecular program of rejuvenation in stem cells pretreated with NanoPCL-M and then exposed to UV. Altogether, our results highlight a future translational application of NanoPCL-M to prevent skin aging.
New Pieces in the Puzzle of uPAR Role in Cell Migration Mechanisms
Authors: Gorrasi Anna , Petrone Anna Maria , Li Santi Anna , Alfieri Mariaevelina , Montuori Nunzia , Ragno Pia
Published: November 2020

The urokinase (uPA) receptor (uPAR) plays a key role in cell migration. We previously showed that uPAR-negative HEK-293 cells efficiently migrate toward serum but, after uPAR ectopic expression, migrate only in a uPAR-dependent manner. In fact, migration of uPAR-transfected HEK-293 (uPAR-293) cells is impaired by anti-uPAR antibodies, without recovery of the uPAR-independent migration mechanisms formerly active. Prostate carcinoma PC3 cells, which express high endogenous uPAR levels, migrated only through a uPAR-dependent mechanism; in fact, the silencing of uPAR expression inhibited their migration. We hypothesize a crucial role of the uPAR glycosyl-phosphatidyl-inositol (GPI) tail, which promotes uPAR partitioning to lipid rafts, in uPAR-controlled cell migration. Here, we show that removal of the uPAR GPI-tail, or lipid rafts disruption by methyl-beta-cyclodextrin impairs migration of PC3 cells, incapable of uPAR-independent migration, whereas it restores uPAR-independent migration in uPAR-293 cells. We then show that, in PC3 cells, both uPAR signaling partners, β1 integrins and receptors for formylated peptides (FPRs), partly associate with lipid rafts. Inhibition of their interaction with uPAR impairs this association and impairs cell migration. Interestingly, blocking uPAR association with FPRs also impairs β1 integrin partitioning to lipid rafts, whereas blocking its association with β1 integrins has no effect on FPRs partitioning. On these bases, we propose that uPAR controls cell migration by connecting β1 integrins and FPRs and, through its GPI tail, by driving them into lipid rafts, thus promoting pro-migratory signals. uPAR-mediated partitioning of integrins to lipid rafts is strictly dependent on uPAR association with FPRs.
Nutraceuticals and Exercise against Muscle Wasting during Cancer Cachexia
Authors: Aquila Giorgio , Re Cecconi Andrea David , Brault Jeffrey J. , Corli Oscar , Piccirillo Rosanna
Published: November 2020

Cancer cachexia (CC) is a debilitating multifactorial syndrome, involving progressive deterioration and functional impairment of skeletal muscles. It affects about 80% of patients with advanced cancer and causes premature death. No causal therapy is available against CC. In the last few decades, our understanding of the mechanisms contributing to muscle wasting during cancer has markedly increased. Both inflammation and oxidative stress (OS) alter anabolic and catabolic signaling pathways mostly culminating with muscle depletion. Several preclinical studies have emphasized the beneficial roles of several classes of nutraceuticals and modes of physical exercise, but their efficacy in CC patients remains scant. The route of nutraceutical administration is critical to increase its bioavailability and achieve the desired anti-cachexia effects. Accumulating evidence suggests that a single therapy may not be enough, and a bimodal intervention (nutraceuticals plus exercise) may be a more effective treatment for CC. This review focuses on the current state of the field on the role of inflammation and OS in the pathogenesis of muscle atrophy during CC, and how nutraceuticals and physical activity may act synergistically to limit muscle wasting and dysfunction.
Caffeine and TiO2 Nanoparticles Treatment of Spruce and Beech Wood for Increasing Transparent Coating Resistance against UV-Radiation and Mould Attacks
Authors: Pánek Miloš , Šimůnková Kristýna , Novák David , Dvořák Ondřej , Schönfelder Ondřej , Šedivka Přemysl , Kobetičová Klára
Published: November 2020

The effect of the initial modification of beech and spruce wood using a solution of caffeine and of a commercial product FN-NANO® FN-1 containing a water dispersion of TiO2 nanoparticles for increasing the service life of a transparent oil and acrylate coatings during 6 weeks of artificial accelerated weathering was tested. Changes in colour, gloss, and the contact angle of water were monitored. Degradation of the coating film was also evaluated visually and microscopically. The resistance of the coatings to mould growth was also subsequently tested. Based on the results, it is possible to recommend the initial treatment of spruce and beech wood with a 2% caffeine solution or 15% solution of FN-NANO® dispersion to increase the overall life of a transparent acrylic coating in exterior applications. No positive effect of the applied treatments was observed with the oil coating. In addition, lower concentrations of FN-NANO® did not have a sufficient effect, and the synergistic effect of using FN-NANO® in a mixture with a 1% caffeine solution was also not confirmed.
Digital 3D Wood Texture: UV-Curable Inkjet Printing on Board Surface
Authors: Sang Ruijuan , Manley Adam John , Wu Zhihui , Feng Xinhao
Published: November 2020

Natural wood textures are appreciated in most forest products industries for their appealing visual characteristics including grain and color, but also their fine surface tactile sensation. The following presents an ultraviolet (UV)-curable inkjet technology printing 3D wood texture on wood-based substrate by image processing and surface treatment. The UV printing was created from scanned digital images of a real wood surface and processed in graphics software. The images were converted to grayscale graphics by selecting color range and setting the parameter of fuzziness. The grayscale images were printed as 3D texture height simulation on the substrates and coated by printing the color images as texture mapping. Based on these wood texture digital images, the marquetry art is also considered in the images processing design to increase the artistry of the printed materials. The medium-density fiberboard (MDF) coated printing marquetry surface replicate realistic natural 3D wood texture surface layers on wood-based panels and imitated the effect of handcrafted wood art works. This study proves that printing 3D texture surface material is creative and valuable with ecologically friendly, low-consumption UV-curable inkjet technology and provides a feasible and scalable approach in flooring/furniture/decorative architectural panels.
Electrical Characteristics and Stability Improvement of Top-Gate In-Ga-Zn-O Thin-Film Transistors with Al2O3/TEOS Oxide Gate Dielectrics
Authors: Lee Yih-Shing , Wang Yu-Hsin , Tien Tsung-Cheng , Hsieh Tsung-Eong , Lai Chun-Hung
Published: November 2020

In this work, two stacked gate dielectrics of Al2O3/tetraethyl-orthosilicate (TEOS) oxide were deposited by using the equivalent capacitance with 100-nm thick TEOS oxide on the patterned InGaZnO layers to evaluate the electrical characteristics and stability improvement of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) devices, including positive bias stress (PBS) and negative bias stress (NBS) tests. Three different kinds of gate dielectrics (Al2O3, TEOS, Al2O3/TEOS) were used to fabricate four types of devices, differing by the gate dielectric, as well as its thickness. As the Al2O3 thickness of Al2O3/TEOS oxide dielectric stacks increased, both the on-current and off-current decreased, and the transfer curves shifted to larger voltages. The lowest ∆Vth of 0.68 V and ∆S.S. of −0.03 V/decade from hysteresis characteristics indicate that the increase of interface traps and charge trapping between the IGZO channel and gate dielectrics is effectively inhibited by using two stacked dielectrics with 10-nm thick Al2O3 and 96-nm thick TEOS oxide. The lowest ∆Vth and ∆S.S. values of a-IGZO TFTs with 10-nm thick Al2O3 and 96-nm thick TEOS oxide gate dielectrics according to the PBS and NBS tests were shown to have the best electrical stability in comparison to those with the Al2O3 or TEOS oxide single-layer dielectrics.
Usefulness of the IgA and IgG Responses to Macrophage Migration Inhibitory Factor for the Diagnosis of Tuberculosis
Authors: Lee Ji Yeon , Kim Byoung-Jun , Kim Jee-min , Kim Junghyun , Joh Joon-Sung , Jeong Ina , Kook Yoon-Hoh , Kim Bum-Joon
Published: November 2020

Serological tests offer the potential in order to improve the diagnosis of tuberculosis (TB). Macrophage migration inhibitory factor (MIF) plays a protective role in infection control in TB; however, to date, no studies on antibody responses to MIF have been reported. We measured immunoglobulin (Ig)A and IgG responses to MIF in individuals with either active tuberculosis (ATB; n = 65), latent tuberculosis (LTBI; n = 53), or in non-infected individuals (NI; n = 62). The QuantiFERON-TB Gold In-Tube (QFT-GIT) assay was used in order to screen for LTBI. The level of IgA against MIF was significantly lower in LTBI and ATB patients than in NI individuals, was significantly related to LTBI and ATB diagnosis, and it could discriminate between LTBI and ATB. In contrast, the level of IgG against MIF was significantly lower in LTBI patients than in NI individuals and was significantly related to LTBI diagnosis. Anti-MIF IgG levels were significantly lower in AFB-negative TB, minimal TB, and new ATB patients, than in the NI group. IgA and IgG levels against MIF both showed significant negative correlations with IFN-γ levels, as assessed using the QFT-GIT test. Although none of the antibodies could achieve high diagnostic predictive power individually, our results suggest the possibility of using IgA antibody responses to MIF in the diagnosis of LTBI and ATB.
Multi-Gene Next-Generation Sequencing for Molecular Diagnosis of Autosomal Recessive Congenital Ichthyosis: A Genotype-Phenotype Study of Four Italian Patients
Authors: Fioretti Tiziana , Auricchio Luigi , Piccirillo Angelo , Vitiello Giuseppina , Ambrosio Adelaide , Cattaneo Fabio , Ammendola Rosario , Esposito Gabriella
Published: November 2020

Autosomal recessive congenital ichthyoses (ARCI) are rare genodermatosis disorders characterized by phenotypic and genetic heterogeneity. At least fourteen genes so far have been related to ARCI; however, despite genetic heterogeneity, phenotypes associated with mutation of different ARCI genes may overlap, thereby making difficult their clinical and molecular classification. In addition, molecular tests for diagnosis of such an extremely rare heterogeneous inherited disease are not easily available in clinical settings. In the attempt of identifying the genetic cause of the disease in four Italian patients with ARCI, we performed next-generation sequencing (NGS) analysis targeting 4811 genes that have been previously linked to human genetic diseases; we focused our analysis on the 13 known ARCI genes comprised in the panel. Nine different variants including three novel small nucleotide changes and two novel large deletions have been identified and validated in the ABCA12, ALOX12B, CYP4F22, and SULT2B1 genes. Notably, two patients had variants in more than one gene. The identification and validation of new pathogenic ABCA12, ALOX12B, CYP4F22, and SULT2B1 variants through multi-gene NGS in four cases of ARCI further highlight the importance of these genes in proper skin function and development.
Clinical Applications of Mesenchymal Stem/Stromal Cell Derived Extracellular Vesicles: Therapeutic Potential of an Acellular Product
Authors: Massa Margherita , Croce Stefania , Campanelli Rita , Abbà Carlotta , Lenta Elisa , Valsecchi Chiara , Avanzini Maria Antonietta
Published: November 2020

In the last decade, the secreting activity of mesenchymal stem/stromal cells (MSCs) has been widely investigated, due to its possible therapeutic role. In fact, MSCs release extracellular vesicles (EVs) containing relevant biomolecules such as mRNAs, microRNAs, bioactive lipids, and signaling receptors, able to restore physiological conditions where regenerative or anti-inflammatory actions are needed. An actual advantage would come from the therapeutic use of EVs with respect to MSCs, avoiding the possible immune rejection, the lung entrapment, improving the safety, and allowing the crossing of biological barriers. A number of concerns still have to be solved regarding the mechanisms determining the beneficial effect of MSC-EVs, the possible alteration of their properties as a consequence of the isolation/purification methods, and/or the best approach for a large-scale production for clinical use. Most of the preclinical studies have been successful, reporting for MSC-EVs a protecting role in acute kidney injury following ischemia reperfusion, a potent anti-inflammatory and anti-fibrotic effects by reducing disease associated inflammation and fibrosis in lung and liver, and the modulation of both innate and adaptive immune responses in graft versus host disease (GVHD) as well as autoimmune diseases. However, the translation of MSC-EVs to the clinical stage is still at the initial phase. Herein, we discuss the therapeutic potential of an acellular product such as MSC derived EVs (MSC-EVs) in acute and chronic pathologies.
Radiation-Thermodynamic Modelling and Simulating the Core of a Thermophotovoltaic System
Authors: Ogbonnaya Chukwuma , Abeykoon Chamil , Nasser Adel , Turan Ali
Published: November 2020

Thermophotovoltaic (TPV) systems generate electricity without the limitations of radiation intermittency, which is the case in solar photovoltaic systems. As energy demands steadily increase, there is a need to improve the conversion dynamics of TPV systems. Consequently, this study proposes a novel radiation-thermodynamic model to gain insights into the thermodynamics of TPV systems. After validating the model, parametric studies were performed to study the dependence of power generation attributes on the radiator and PV cell temperatures. Our results indicated that a silicon-based photovoltaic (PV) module could produce a power density output, thermal losses, and maximum voltage of 115.68 W cm−2, 18.14 W cm−2, and 36 V, respectively, at a radiator and PV cell temperature of 1800 K and 300 K. Power density output increased when the radiator temperature increased; however, the open circuit voltage degraded when the temperature of the TPV cells increased. Overall, for an 80 W PV module, there was a potential for improving the power generation capacity by 45% if the TPV system operated at a radiator and PV cell temperature of 1800 K and 300 K, respectively. The thermal efficiency of the TPV system varied with the temperature of the PV cell and radiator.
Streaming Electrification of Nycodiel 1255 Synthetic Ester and Trafo EN Mineral Oil Mixtures by Using Rotating Disc Method
Authors: Zdanowski Maciej
Published: November 2020

Power transformers are the main element of an electric power system. The service life of these devices depends to a large extent on the technical condition of their insulation system. Replacing mineral oils with natural or synthetic ester (retrofilling process) may increase the efficiency and operational safety of transformers, and also limit their adverse environmental impact. It is technically unfeasible to completely remove mineral oil from a transformer. Its small residues form a mixture with fluid ester, with different physicochemical and electric properties. Streaming electrification is one of the phenomena which, under unfavorable conditions, may damage the insulation system of a forced oil cooled transformer. It is necessary to run prophylactic tests for the ECT (electrostatic charging tendency) of insulating liquid mixtures from the point of view of transformer retrofilling, which is being used more often than before. The article presents the results of studies on selected physicochemical, and electrical properties, and the ECT of mixtures of fresh and aged Trafo EN mineral oil with Nycodiel 1255 synthetic ester. In this regard, the density, the kinematic viscosity, the conductivity, and the relative dielectric constant were measured. The molecular diffusion coefficient was determined using Adamczewski’s empirical dependency. The streaming electrification was tested in a rotating disc system. The impact of the rotation time, the diameter, and the disc’s rotation speed on the amount of the electrification current generated were analyzed. In addition, the co-relation between the electrification current and the composition of the mixture was determined using fresh and aged mineral oil. On the basis of the electrification model, the volume density of the qw charge was calculated, which is a parameter defining the ECT of insulating liquids. Based on the results, it was concluded that the synthetic ester is characterized by a higher susceptibility to electrification than the mineral oil. However, combining synthetic ester with a small amount (up to 20%) of fresh or aged mineral oil significantly reduces its ECT, which is beneficial from the point of view of retrofilling power transformers.
Renewable Energy Equivalent Footprint (REEF): A Method for Envisioning a Sustainable Energy Future
Authors: Ward James , Mohr Steve , Costanza Robert , Sutton Paul , Coscieme Luca
Published: November 2020

We present an alternative approach to estimating the spatial footprint of energy consumption, as this represents a major fraction of the ecological footprint (EF). Rather than depicting the current lack of sustainability that comes from estimating a footprint based on uptake of carbon emissions (the method used in EF accounting), our proposed “Renewable Energy Equivalent Footprint” (REEF) instead depicts a hypothetical world in which the electricity and fuel demands are met entirely from renewable energy. The analysis shows that current human energy demands could theoretically be met by renewable energy and remain within the biocapacity of one planet. However, with current technology there is no margin to leave any biocapacity for nature, leading to the investigation of two additional scenarios: (1) radical electrification of the energy supply, assuming 75% of final energy demand can be met with electricity, and (2) adopting technology in which electricity is used to convert atmospheric gases into synthetic fuel. The REEF demonstrates that a sustainable and desirable future powered by renewable energy: (i) may be possible, depending on the worldwide adoption of consumption patterns typical of several key exemplar countries; (ii) is highly dependent on major future technological development, namely electrification and synthetic fuels; and (iii) is still likely to require appropriation of a substantial, albeit hopefully sustainable, fraction of the world’s forest area.
Adaptive Control of HVDC Links for Frequency Stability Enhancement in Low-Inertia Systems
Authors: Stojković Jelena , Lekić Aleksandra , Stefanov Predrag
Published: November 2020

Decarbonization of power systems has put Renewable Energy Sources (RES) at the forefront when it comes to electric power generation. The increasing shares of converter-connected renewable generation cause a decrease of the rotational inertia of the Electric Power System (EPS), and consequently deteriorate the system capability to withstand large load-generation imbalances. Low-inertia systems are subjected to fast and large frequency changes in case of in-feed loss, where the traditional primary frequency control is not sufficient to preserve the frequency stability and to maintain the frequency above the critical value. One possible solution to this rising problem is seen in Fast Frequency Response (FFR) provided by the High-Voltage Direct-Current (HVDC)-based systems. This paper presents the adaptive FFR control of HVDC-based systems for frequency stability enhancement in the low-inertia system. The EPS is considered as a “black box” and the HVDC response is determined only using the locally measured frequency change. Sliding Mode Control (SMC) of the Modular Multilevel Converter (MMC) was developed and demonstrated to provide faster and more appropriate frequency response compared to the PI controller. The described adaptive HVDC control considers the size of disturbance and the inertia of the power system, and it is verified by simulations on the IEEE 39 bus test system implemented in MATLAB/Simulink for different system configurations and different sizes of disturbance.
Wave Energy Extraction by Flexible Floaters
Authors: Michele Simone , Buriani Federica , Renzi Emiliano , van Rooij Marijn , Jayawardhana Bayu , Vakis Antonis I.
Published: November 2020

We present a novel mathematical model to investigate the extraction of wave power by flexible floaters. The model is based on the method of dry modes, coupled with a matched eigenfunction expansion. Our model results compare satisfactorily with preliminary data obtained from a demonstrator device, developed at the University of Groningen. We show that the role of elasticity is to increase the number of resonant frequencies with respect to a rigid body, which has a positive effect on wave power output. The mathematical model is then extended to irregular incident waves, described by a JONSWAP spectrum. Our results show that the peak capture factors decrease in irregular waves, as compared to the monochromatic case. However, the system becomes more efficient at non-resonant frequencies. This work highlights the need to scale-up experimental investigations on flexible wave energy converters, which are still a small minority, compared to those on rigid converters.
Design and Fabrication of Solar Thermal Energy Storage System Using Potash Alum as a PCM
Authors: Malik Muhammad Suleman , Iftikhar Naveed , Wadood Abdul , Khan Muhammad Omer , Asghar Muhammad Usman , Khan Shahbaz , Khurshaid Tahir , Kim Ki-Chai , Rehman Zabdur , Rizvi S. Tauqeer ul Islam
Published: November 2020

Renewable energy resources like solar energy, wind energy, hydro energy, photovoltaic etc. are gaining much importance due to the day by day depletion of conventional resources. Owing to the lower efficiencies of renewable energy resources, much attention has been paid to improving them. The concept of utilizing phase change materials (PCMs) has attracted wide attention in recent years. This is due to their ability to extract thermal energy when used in collaboration with photovoltaic (PV), thus improving the photoelectric conversion efficiency. In this paper, the objective is to design and fabricate a novel thermal energy storage system using phase change material. An investigation on the characteristics of Potash Alum as a phase change material due to its low cost, easy availability and its usage as an energy storage for the indoor purposes are taken into account. The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantage of high-energy storage density and the isothermal nature of the storage process. In the current study, potash alum was identified as a phase change material combined with renewable energy sources, that can be efficiently and effectively used in storing thermal energy at compartively lower temperatures that can later be used in daily life heating requirements.A parabolic dish which acts of a heat collector is used to track and reflects solar radiation at a single point on a receiver tank. Heat transfer from the solar collector to the storage tank is done by using a circulating heat transfer fluid with the help of a pump. The experimental results show that this system is capable of successfully storing and utilizing thermal energy on indoor scale such as cooking, heating and those applications where temperature is below 92 °C.
Novel Non-Cerevisiae Saccharomyces Yeast Species Used in Beer and Alcoholic Beverage Fermentations
Authors: Bruner James , Fox Glen
Published: November 2020

A great deal of research in the alcoholic beverage industry was done on non-Saccharomyces yeast strains in recent years. The increase in research interest could be attributed to the changing of consumer tastes and the search for new beer sensory experiences, as well as the rise in popularity of mixed-fermentation beers. The search for unique flavors and aromas, such as the higher alcohols and esters, polyfunctional thiols, lactones and furanones, and terpenoids that produce fruity and floral notes led to the use of non-cerevisiae Saccharomyces species in the fermentation process. Additionally, a desire to invoke new technologies and techniques for making alcoholic beverages also led to the use of new and novel yeast species. Among them, one of the most widely used non-cerevisiae strains is S. pastorianus, which was used in the production of lager beer for centuries. The goal of this review is to focus on some of the more distinct species, such as those species of Saccharomyces sensu stricto yeasts: S. kudriavzevii, S. paradoxus, S. mikatae, S. uvarum, and S. bayanus. In addition, this review discusses other Saccharomyces spp. that were used in alcoholic fermentation. Most importantly, the factors professional brewers might consider when selecting a strain of yeast for fermentation, are reviewed herein. The factors include the metabolism and fermentation potential of carbon sources, attenuation, flavor profile of fermented beverage, flocculation, optimal temperature range of fermentation, and commercial availability of each species. While there is a great deal of research regarding the use of some of these species on a laboratory scale wine fermentation, much work remains for their commercial use and efficacy for the production of beer.
Introduction to a New Open Access Journal by MDPI: Geographies
Authors: Salvati Luca
Published: November 2020

With big data and advanced tools becoming available to scientific communities, geographical research is constantly addressing new issues and questions [...]