bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Mechanical Criterion of Ice Lens Formation Based on Pore Size Distribution
Authors: Liu Yuhang , Li Dongqing , Chen Lei , Ming Feng
Published: December 2020

Ice lens is the key factor which determines the frost heave in engineering construction in cold regions. At present, several theories have been proposed to describe the formation of ice lens. However, most of these theories analyzed the ice lens formation from a macroscopic view and ignored the influence of microscopic pore sizes and structures. Meanwhile, these theories lacked the support of measured data. To solve this problem, the microscopic crystallization stress was converted into the macro mean stress through the principle of statistics with the consideration of pore size distribution. The mean stress was treated as the driving force of the formation of ice lens and induced into the criterion of ice lens formation. The influence of pore structure and unfrozen water content on the mean stress was analyzed. The results indicate that the microcosmic crystallization pressure can be converted into the macro mean stress through the principle of statistics. Larger mean stress means the ice lens will be formed easier in the soil. The mean stress is positively correlated with initial water content. At the same temperature, an increase to both the initial water content and the number of pores can result in a larger mean stress. Under the same initial water content, mean stress increases with decreasing temperature. The result provides a theoretical basis for studying ice lens formation from the crystallization theory.
Sulfate Resistance in Cements Bearing Bottom Ash from Biomass-Fired Electric Power Plants
Authors: Medina José M. , Rojas María Isabel Sánchez de , Bosque Isabel F. Sáez del , Frías Moisés , Medina César
Published: December 2020

To address some of the gaps in the present understanding of the behavior of new supplementary cementitious materials such as bottom ash (BA) from biomass-fired electric power plants in cement manufacture, this study explored the effect of this promising material on the sulfate resistance of the end product. Cement paste prepared with 10% or 20% (previously characterized for mineralogy and chemical composition) BA was Köch–Steinegger tested for sulfate resistance. The hydration products, in turn, were analyzed before and after soaking the reference and experimental cements in sodium sulfate to determine whether the use of the addition hastened microstructural, mineralogical, or morphological decay in the material. The 56 days findings showed that the presence of BA raised binder resistance to sulfate attack. Köch–Steinegger corrosion indices of 1.29 and 1.27 for blended cements OPC + 10 BA and OPC + 20 BA, respectively, were higher than the 1.26 recorded for ordinary Portland cement (OPC). In addition, weight gain was 20.5% and volume expansion was 28.5% lower in the new materials compared to OPC. The products resulting from the external sulfate-cement interaction, gypsum and ettringite, were deposited primarily in the pores present in the pastes. The conclusion drawn is that binders bearing 10% or 20% BA are, a priori, apt for use in the design and construction of cement-based elements exposed to sulfate-laden environments.
Application of Smoothed Particle Hydrodynamics to Structural Cable Analysis
Authors: Dinçer A. Ersin , Demir Abdullah
Published: December 2020

In this study, a numerical model is proposed for the analysis of a simply supported structural cable. Smoothed particle hydrodynamics (SPH)—a mesh-free, Lagrangian method with advantages for analysis of highly deformable bodies—is utilized to model a cable. In the proposed numerical model, it is assumed that a cable has only longitudinal stiffness in tension. Accordingly, SPH equations derived for solid mechanics are adapted for a structural cable, for the first time. Besides, a proper damping parameter is introduced to capture the behavior of the cable more realistically. In order to validate the proposed numerical model, different experimental and numerical studies available in the literature are used. In addition, novel experiments are carried out. In the experiments, different harmonic motions are applied to a uniformly loaded cable. Results show that the SPH method is an appropriate method to simulate the structural cable.
Damping Estimation of an Eight-Story Steel Building Equipped with Oil Dampers
Authors: Yang Pengchao , Xue Songtao , Xie Liyu , Cao Miao
Published: December 2020

The damping estimation of an eight-story steel building equipped with oil dampers is examined, carried out by adopting a proposed framework, which consists of an enhanced strain-energy method and an improved direct method for model updating. The building is located at Tohoku Institute of Technology and is equipped with a structural monitoring system that measures its seismic response, including floor acceleration and displacement and force of oil dampers. The enhanced strain-energy method is first developed and employed to assess the supplemental damping and stiffness provided by oil dampers, herein quantified in the form of equivalent damping ratios and natural frequencies. Then, modal characteristics extracted from the earthquake measurements are modified accordingly and utilized for the building model updating, in which mass and stiffness matrices are corrected by the improved direct method. The updated model accurately reproduces the target modal data, especially measured mode participation factors, and is further used for the building response predictions. Through prediction validations, the precision of the modified modal parameters is verified. Finally, a large earthquake event is chosen to demonstrate the effectiveness of the proposed framework for the damping estimation of the investigated building.
A Long-Term, 1-km Resolution Daily Meteorological Dataset for Modeling and Mapping Permafrost in Canada
Authors: Zhang Yu , Qian Budong , Hong Gang
Published: December 2020

Climate warming is causing permafrost thaw and there is an urgent need to understand the spatial distribution of permafrost and its potential changes with climate. This study developed a long-term (1901–2100), 1-km resolution daily meteorological dataset (Met1km) for modeling and mapping permafrost at high spatial resolutions in Canada. Met1km includes eight climate variables (daily minimum, maximum, and mean air temperatures, precipitation, vapor pressure, wind speed, solar radiation, and downward longwave radiation) and is suitable to drive process-based permafrost and other land-surface models. Met1km was developed based on four coarser gridded meteorological datasets for the historical period. Future values were developed using the output of a new Canadian regional climate model under medium-low and high emission scenarios. These datasets were downscaled to 1-km resolution using the re-baselining method based on the WorldClim2 dataset as spatial templates. We assessed Met1km by comparing it to climate station observations across Canada and a gridded monthly anomaly time-series dataset. The accuracy of Met1km is similar to or better than the four coarser gridded datasets. The errors in long-term averages and average seasonal patterns are small. The error occurs mainly in day-to-day fluctuations, thus the error decreases significantly when averaged over 5 to 10 days. Met1km, as a data generating system, is relatively small in data volume, flexible to use, and easy to update when new or improved source datasets are available. The method can also be used to generate similar datasets for other regions, even for the entire global landmass.
New Actors Driving the Epithelial–Mesenchymal Transition in Cancer: The Role of Leptin
Authors: Olea-Flores Monserrat , Juárez-Cruz Juan C. , Zuñiga-Eulogio Miriam D. , Acosta Erika , García-Rodríguez Eduardo , Zacapala-Gomez Ana E. , Mendoza-Catalán Miguel A. , Ortiz-Ortiz Julio , Ortuño-Pineda Carlos , Navarro-Tito Napoleón
Published: December 2020

Leptin is a hormone secreted mainly by adipocytes; physiologically, it participates in the control of appetite and energy expenditure. However, it has also been linked to tumor progression in different epithelial cancers. In this review, we describe the effect of leptin on epithelial–mesenchymal transition (EMT) markers in different study models, including in vitro, in vivo, and patient studies and in various types of cancer, including breast, prostate, lung, and ovarian cancer. The different studies report that leptin promotes the expression of mesenchymal markers and a decrease in epithelial markers, in addition to promoting EMT-related processes such as cell migration and invasion and poor prognosis in patients with cancer. Finally, we report that leptin has the greatest biological relevance in EMT and tumor progression in breast, lung, prostate, esophageal, and ovarian cancer. This relationship could be due to the key role played by the enriched tumor microenvironment in adipose tissue. Together, these findings demonstrate that leptin is a key biomolecule that drives EMT and metastasis in cancer.
Peritoneal Dialysis Fluid Supplementation with Alanyl-Glutamine Attenuates Conventional Dialysis Fluid-Mediated Endothelial Cell Injury by Restoring Perturbed Cytoprotective Responses
Authors: Herzog Rebecca , Bartosova Maria , Tarantino Silvia , Wagner Anja , Unterwurzacher Markus , Sacnun Juan Manuel , Lichtenauer Anton M. , Kuster Lilian , Schaefer Betti , Alper Seth L. , Aufricht Christoph , Schmitt Claus Peter , Kratochwill Klaus
Published: December 2020

Long-term clinical outcome of peritoneal dialysis (PD) depends on adequate removal of small solutes and water. The peritoneal endothelium represents the key barrier and peritoneal transport dysfunction is associated with vascular changes. Alanyl-glutamine (AlaGln) has been shown to counteract PD-induced deteriorations but the effect on vascular changes has not yet been elucidated. Using multiplexed proteomic and bioinformatic analyses we investigated the molecular mechanisms of vascular pathology in-vitro (primary human umbilical vein endothelial cells, HUVEC) and ex-vivo (arterioles of patients undergoing PD) following exposure to PD-fluid. An overlap of 1813 proteins (40%) of over 3100 proteins was identified in both sample types. PD-fluid treatment significantly altered 378 in endothelial cells and 192 in arterioles. The HUVEC proteome resembles the arteriolar proteome with expected sample specific differences of mainly immune system processes only present in arterioles and extracellular region proteins primarily found in HUVEC. AlaGln-addition to PD-fluid revealed 359 differentially abundant proteins and restored the molecular process landscape altered by PD fluid. This study provides evidence on validity and inherent limitations of studying endothelial pathomechanisms in-vitro compared to vascular ex-vivo findings. AlaGln could reduce PD-associated vasculopathy by reducing endothelial cellular damage, restoring perturbed abundances of pathologically important proteins and enriching protective processes.
DNA Repair Biosensor-Identified DNA Damage Activities of Endophyte Extracts from Garcinia cowa
Authors: Lerksuthirat Tassanee , Wikiniyadhanee Rakkreat , Chitphuk Sermsiri , Stitchantrakul Wasana , Sampattavanich Somponnat , Jirawatnotai Siwanon , Jumpathong Juangjun , Dejsuphong Donniphat
Published: December 2020

Recent developments in chemotherapy focus on target-specific mechanisms, which occur only in cancer cells and minimize the effects on normal cells. DNA damage and repair pathways are a promising target in the treatment of cancer. In order to identify novel compounds targeting DNA repair pathways, two key proteins, 53BP1 and RAD54L, were tagged with fluorescent proteins as indicators for two major double strand break (DSB) repair pathways: non-homologous end-joining (NHEJ) and homologous recombination (HR). The engineered biosensor cells exhibited the same DNA repair properties as the wild type. The biosensor cells were further used to investigate the DNA repair activities of natural biological compounds. An extract from Phyllosticta sp., the endophyte isolated from the medicinal plant Garcinia cowa Roxb. ex Choisy, was tested. The results showed that the crude extract induced DSB, as demonstrated by the increase in the DNA DSB marker γH2AX. The damaged DNA appeared to be repaired through NHEJ, as the 53BP1 focus formation in the treated fraction was higher than in the control group. In conclusion, DNA repair-based biosensors are useful for the preliminary screening of crude extracts and biological compounds for the identification of potential targeted therapeutic drugs.
Beta Cell Therapies for Preventing Type 1 Diabetes: From Bench to Bedside
Authors: Brawerman Gabriel , Thompson Peter J.
Published: December 2020

Type 1 diabetes (T1D) is a chronic metabolic disease characterized by insulin deficiency, generally resulting from progressive autoimmune-mediated destruction of pancreatic beta cells. While the phenomenon of beta cell autoimmunity continues to be an active area of investigation, recent evidence suggests that beta cell stress responses are also important contributors to disease onset. Here we review the pathways driving different kinds of beta cell dysfunction and their respective therapeutic targets in the prevention of T1D. We discuss opportunities and important open questions around the effectiveness of beta cell therapies and challenges for clinical utility. We further evaluate ways in which beta cell drug therapy could be combined with immunotherapy for preventing T1D in light of our growing appreciation of disease heterogeneity and patient endotypes. Ultimately, the emergence of pharmacologic beta cell therapies for T1D have armed us with new tools and closing the knowledge gaps in T1D etiology will be essential for maximizing the potential of these approaches.
Enhancing Mechanical Properties and Biological Performances of Injectable Bioactive Glass by Gelatin and Chitosan for Bone Small Defect Repair
Authors: Sohrabi Mehri , Eftekhari Yekta Bijan , Rezaie Hamidreza , Naimi-Jamal Mohammad Reza , Kumar Ajay , Cochis Andrea , Miola Marta , Rimondini Lia
Published: December 2020

Bioactive glass (BG) represents a promising biomaterial for bone healing; here injectable BG pastes biological properties were improved by the addition of gelatin or chitosan, as well as mechanical resistance was enhanced by adding 10 or 20 wt% 3-Glycidyloxypropyl trimethoxysilane (GPTMS) cross-linker. Composite pastes exhibited bioactivity as apatite formation was observed by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) after 14 days immersion in simulated body fluid (SBF); moreover, polymers did not enhance degradability as weight loss was >10% after 30 days in physiological conditions. BG-gelatin-20 wt% GPTMS composites demonstrated the highest compressive strength (4.8 ± 0.5 MPa) in comparison with the bulk control paste made of 100% BG in water (1.9 ± 0.1 MPa). Cytocompatibility was demonstrated towards human mesenchymal stem cells (hMSC), osteoblasts progenitors, and endothelial cells. The presence of 20 wt% GPTMS conferred antibacterial properties thus inhibiting the joint pathogens Staphylococcus aureus and Staphylococcus epidermidis infection. Finally, hMSC osteogenesis was successfully supported in a 3D model as demonstrated by alkaline phosphatase release and osteogenic genes expression.
Novel Medicine for Endometriosis and Its Therapeutic Effect in a Mouse Model
Authors: Kim Young Sang , Kim Yu Jin , Kim Myung Joo , Lee Sang Jin , Kwon Hwang , Lee Jae Ho
Published: December 2020

Current therapeutic medicines for endometriosis cannot be administered during assisted reproductive technology (ART) because they have bad effects during pregnancy. In this study, we created an animal model of endometriosis and evaluated the therapeutic effect of progestin (Dienogest), dopamine agonist (Cabergoline), and their combination (Dienogest + Cabergoline). We established a mouse model mimicking human endometriosis. The mice with endometriosis were then treated with a single drug (Dienogest or Cabergoline) or both drugs (Dienogest + Cabergoline) for 14 days. An immunohistological study was then performed to analyze inflammatory lesions in the recipient mice. Real-time polymerase chain reaction (RT-PCR) and Western blotting were also performed to determine the levels of genes and proteins in inflammatory lesions to assess the recovery of endometriosis. Histologic staining showed that all medication groups showed a clear decrease in the inflammatory phenotype in the uterus, peritoneum, and intestine. Gene and protein expression analysis showed a therapeutic effect in all medication groups. In conclusion, Cabergoline had a therapeutic effect similar to that of Dienogest and could be used as an alternative to Dienogest during ART for patients with infertility; compared to the individual drugs, the combination treatment has a synergistic effect on endometriosis.
Advances in the Detection of Toxic Algae Using Electrochemical Biosensors
Authors: Medlin Linda K. , Gamella Maria , Mengs Gerardo , Serafín Verónica , Campuzano Susana , M. Pingarrón José M.
Published: December 2020

Harmful algal blooms (HABs) are more frequent as climate changes and tropical toxic species move northward, especially along the Iberian Peninsula, a rich aquaculture area. Monitoring programs, detecting the presence of toxic algae before they bloom, are of paramount importance to protect ecosystems, aquaculture, human health and local economies. Rapid, reliable species identification methods using molecular barcodes coupled to biosensor detection tools have received increasing attention as an alternative to the legally required but impractical microscopic counting-based techniques. Our electrochemical detection system has improved, moving from conventional sandwich hybridization protocols using different redox mediators and signal probes with different labels to a novel strategy involving the recognition of RNA heteroduplexes by antibodies further labelled with bacterial antibody binding proteins conjugated with multiple enzyme molecules. Each change has increased sensitivity. A 150-fold signal increase has been produced with our newest protocol using magnetic microbeads (MBs) and amperometric detection at screen-printed carbon electrodes (SPCEs) to detect the target RNA of toxic species. We can detect as few as 10 cells L−1 for some species by using a fast (~2 h), simple (PCR-free) and cheap methodology (~2 EUR/determination) that will allow this methodology to be integrated into easy-to-use portable systems.
When, How, and to What Extent Are Individuals with Unresponsive Wakefulness Syndrome Able to Progress? Functional Independence
Authors: Olaya José , Noé Enrique , Navarro María Dolores , O’Valle Myrtha , Colomer Carolina , Moliner Belén , Ippoliti Camilla , Ferri Joan , Maza Anny , Llorens Roberto
Published: December 2020

Accurate estimation of the functional independence of patients with unresponsive wakefulness syndrome (UWS) is essential to adjust family and clinical expectations and plan long-term necessary resources. Although different studies have described the clinical course of these patients, they have methodological limitations that could restrict generalization of the results. This study investigates the neurobehavioral progress of 100 patients with UWS consecutively admitted to a neurorehabilitation center using systematic weekly assessments based on standardized measures, and the functional independence staging of those patients who emerged from a minimally conscious state (MCS) during the first year post-emergence. Our results showed that one year after emergence, most patients were severely dependent, although some of them showed extreme or moderate severity. Clinically meaningful functional improvement was less likely to occur in cognitively-demanding activities, such as activities of daily living and executive function. Consequently, the use of specific and staging functional independence measures, with domain-specific evaluations, are recommended to detect the functional changes that might be expected in these patients. The information provided by these instruments, together with that obtained from repeated assessments of the preserved consciousness with standardized instruments, could help clinicians to adjust expectations and plan necessary resources for this population.
Predictive Values of Location and Volumetric MRI Injury Patterns for Neurodevelopmental Outcomes in Hypoxic-Ischemic Encephalopathy Neonates
Authors: Chang Peter D. , Chow Daniel S. , Alber Anna , Lin Yen-Kuang , Youn Young Ah
Published: December 2020

Hypoxic-ischemic encephalopathy (HIE) is a severe neonatal complication with up to 40–60% long-term morbidity. This study evaluates the distribution and burden of MRI changes as a prognostic indicator of neurodevelopmental (ND) outcomes at 18–24 months in HIE infants who were treated with therapeutic hypothermia (TH). Term or late preterm infants who were treated with TH for HIE were analyzed between June 2012 and March 2016. Brain MRI scans were obtained from 107 TH treated infants. For each infant, diffusion weighted brain image (DWI) sequences from a 3T Siemens scanner were obtained for analysis. Of the 107 infants, 36 of the 107 infants (33.6%) had normal brain MR images, and 71 of the 107 infants (66.4%) had abnormal MRI findings. The number of clinical seizures was significantly higher in the abnormal MRI group (p < 0.001) than in the normal MRI group. At 18–24 months, 76 of the 107 infants (70.0%) showed normal ND stages, and 31 of the 107 infants (29.0%) exhibited abnormal ND stages. A lesion size count >500 was significantly associated with abnormal ND. Similarly, the total lesion count was larger in the abnormal ND group (14.16 vs. 5.29). More lesions in the basal ganglia (BG) and thalamus areas and a trend towards more abnormal MRI scans were significantly associated with abnormal ND at 18–24 months. In addition to clinical seizure, a larger total lesion count and lesion size as well as lesion involvement of the basal ganglia and thalamus were significantly associated with abnormal neurodevelopment at 18–24 months.
The Mediation Role of Dynamic Multisensory Processing Using Molecular Genetic Data in Dyslexia
Authors: Mascheretti Sara , Riva Valentina , Feng Bei , Trezzi Vittoria , Andreola Chiara , Giorda Roberto , Villa Marco , Dionne Ginette , Gori Simone , Marino Cecilia , Facoetti Andrea
Published: December 2020

Although substantial heritability has been reported and candidate genes have been identified, we are far from understanding the etiopathogenetic pathways underlying developmental dyslexia (DD). Reading-related endophenotypes (EPs) have been established. Until now it was unknown whether they mediated the pathway from gene to reading (dis)ability. Thus, in a sample of 223 siblings from nuclear families with DD and 79 unrelated typical readers, we tested four EPs (i.e., rapid auditory processing, rapid automatized naming, multisensory nonspatial attention and visual motion processing) and 20 markers spanning five DD-candidate genes (i.e., DYX1C1, DCDC2, KIAA0319, ROBO1 and GRIN2B) using a multiple-predictor/multiple-mediator framework. Our results show that rapid auditory and visual motion processing are mediators in the pathway from ROBO1-rs9853895 to reading. Specifically, the T/T genotype group predicts impairments in rapid auditory and visual motion processing which, in turn, predict poorer reading skills. Our results suggest that ROBO1 is related to reading via multisensory temporal processing. These findings support the use of EPs as an effective approach to disentangling the complex pathways between candidate genes and behavior.
Psychometric Properties of NASA-TLX and Index of Cognitive Activity as Measures of Cognitive Workload in Older Adults
Authors: Devos Hannes , Gustafson Kathleen , Ahmadnezhad Pedram , Liao Ke , Mahnken Jonathan D. , Brooks William M. , Burns Jeffrey M.
Published: December 2020

Cognitive workload is increasingly recognized as an important determinant of performance in cognitive tests and daily life activities. Cognitive workload is a measure of physical and mental effort allocation to a task, which can be determined through self-report or physiological measures. However, the reliability and validity of these measures have not been established in older adults with a wide range of cognitive ability. The aim of this study was to establish the test–retest reliability of the National Aeronautics and Space Administration Task Load Index (NASA-TLX) and Index of Cognitive Activity (ICA), extracted from pupillary size. The convergent validity of these measures against event-related potentials (ERPs) was also investigated. A total of 38 individuals with scores on the Montreal Cognitive Assessment ranging between 17 and 30 completed a working memory test (n-back) with three levels of difficulty at baseline and at a two-week follow-up. The intraclass correlation coefficients (ICC) values of the NASA-TLX ranged between 0.71 and 0.81, demonstrating good to excellent reliability. The mean ICA scores showed fair to good reliability, with ICCs ranging between 0.56 and 0.73. The mean ICA and NASA-TLX scores showed significant and moderate correlations (Pearson’s r ranging between 0.30 and 0.33) with the third positive peak of the ERP at the midline channels. We conclude that ICA and NASA-TLX are reliable measures of cognitive workload in older adults. Further research is needed in dissecting the subjective and objective constructs of cognitive workload.
Highlights of the Most Cited Papers in the Section “Catalysis in Organic and Polymer Chemistry”
Authors: Cadierno Victorio
Published: December 2020

The aim of this editorial is to highlight the most cited papers published during 2018–2019 in the section “Catalysis in Organic and Polymer Chemistry” of the journal Catalysts [...]
Human Tissue-Resident Memory T Cells in the Maternal–Fetal Interface. Lost Soldiers or Special Forces?
Authors: DeJong Caitlin S. , Maurice Nicholas J. , McCartney Stephen A. , Prlic Martin
Published: December 2020

The immune system plays a critical role during pregnancy, but the specific mechanisms and immune cell function needed to support pregnancy remain incompletely understood. Despite decades of research efforts, it is still unclear how the immune system maintains tolerance of fetal-derived tissues, which include most cells of the placenta and of course the fetus itself, without forfeiting the ability to protect against harmful infections. T cells recognize antigen in the context of major histocompatibility complex (MHC) encoded proteins, but classical MHC class I and II expression are diminished in fetal-derived cells. Can T cells present at the maternal–fetal interface (MFI) protect these cells from infection? Here we review what is known in regard to tissue-resident memory T (Trm) cells at the MFI. We mainly focus on how Trm cells can contribute to protection in the context of the unique features of the MFI, such as limited MHC expression as well as the temporary nature of the MFI, that are not found in other tissues.
Special Issue: Current Research in Thin Film Deposition: Applications, Theory, Processing, and Characterisation
Authors: Birney Imogen
Published: December 2020

Today, thin films are near-ubiquitous and are utilised in a very wide range of industrially and scientifically important areas [...]
Zinc Complex Derived from ZnCl2-Urea Ionic Liquid for Improving Mildew Property of Bamboo
Authors: Gao Jie , Lin Huiping , Wen Aishi , Chen Jingbing , Yang Wenbin , Li Ran
Published: December 2020

The nanometer zinc complex, formed in chloride-urea ionic liquid (IL), was studied with the objective of enhancing the mildew resistance of bamboo. The nano-Zinc complex layer was coated on the bamboo surface by a simple and mild heating process. The SEM analysis revealed that the morphology of the nanometer Zinc complex layer on the bamboo surface varied with the reaction time of bamboo in zinc chloride (ZnCl2)/urea ionic liquid. The result of EDS and FTIR analysis showed that zinc and chlorine were successfully coated on the surface of bamboo. In this study, it was found that the optimum condition was 2 h of reaction with 1:2 molar ratio of zinc chloride to urea, where the nano-Zinc complex layer on the bamboo surface was the most uniform and dense to present the bamboo with the strongest mildew resistance. The infection value of Trichoderma viride, Aspergillus niger V. Tiegh, and Penicillium citrinum Thom after 28 day was 0.
Aging Effect on Functionalized Silver-Based Nanocoating Braided Coronary Stents
Authors: Rebelo Rita , Padrão Jorge , Fernandes Margarida M. , Carvalho Sandra , Henriques Mariana , Zille Andrea , Fangueiro Raul
Published: December 2020

A previously developed fiber-based polyester (PES) stent, with mechanical properties comparable to commercial nitinol stents, was coated with metallic silver (Ag0) and silver oxides (AgxO) thin films through direct current (DC) magnetron sputtering. Ag0 and AgxO coatings provide antimicrobial properties to the stents to minimize the occurrence of coronary stent infections. Nevertheless, the stent interacts with the atmosphere and then with the biological fluids and may lead to the generation of silver species with diminished antimicrobial efficiency and/or prone to induce cytotoxicity. Therefore, stent coating nanostructures aged 3 months were thoroughly analyzed by X-ray photoelectron spectroscopy (XPS) and their antimicrobial and cytotoxicity properties were assessed. Aging led to the presence of silver carbonate and bicarbonate as well as chemisorbed oxygen species in Ag0 and AgxO coatings. Bactericidal efficacy was tested against an important nosocomial bacterium, particularly associated to indwelling devices: Staphylococcus epidermidis. Aged Ag0 and AgxO coating presented a Log reduction of 1 and 2 at their surface; respectively. However, aged stents were able to induce a Log reduction of 2 (Ag0) and 4 (AgxO) on the surrounding medium. Only aged AgxO stent was able to provide a mild reduction of the bacterium at its surface and a clear antimicrobial effect (Log reduction >3) within its vicinity. More importantly, both aged Ag0 and AgxO stents were shown to be compatible with fibroblasts cells indicating that they can be safely used as indwelling devices, despite the aging effect.
Synergistic Effect of MWCNT and Carbon Fiber Hybrid Fillers on Electrical and Mechanical Properties of Alkali-Activated Slag Composites
Authors: Park Hyeong Min , Park Chanho , Bang Jinho , Lee Minwook , Yang Beomjoo
Published: December 2020

Herein, we investigated the synergistic effect of multi-walled carbon nanotube (MWCNT) and carbon fiber (CF) hybrid fillers on electrical and mechanical characteristics of alkali-activated slag (AAS) composites. Many studies on AAS composites have been conducted in the past; however, not much progress has been made regarding characteristics of AAS composites with hybrid conductive fillers. The specimens with different mix proportions were fabricated in the present study, and numerous material characteristics, including flowability, electrical resistivity, and compressive strength of AAS composites were measured. In addition, the synergistic effects were investigated through scanning electron microscopy and thermogravimetric analysis. It was found that the 0.5 wt.% of MWCNTs and CFs lead the effects of the bridging and reducing crack propagation, thereby improving its electrical and mechanical performances. The filler exceeding a percolation point improved the electrical performance of the AAS composites; however, it interfered with the hydration process during the curing period, and caused a decrease in compressive strength of AAS composites.
Dynamics of Quasiperiodic Beams
Authors: Gupta Mohit , Ruzzene Massimo
Published: December 2020

Quasiperiodic metastrucures are characterized by edge localized modes of topological nature, which can be of significant technological interest. We here investigate such topological modes for stiffened and sandwich beams, which can be employed as structural members with inherent vibration localization capabilities. Quasiperiodicity is achieved by altering the geometric properties and material properties of the beams. Specifically, in the stiffened beams, the geometric location of stiffeners is modulated to quasiperiodic patterns, while, in the sandwich beams, the core’s material properties are varied in a step-wise manner to generate such patterns. The families of periodic and quasiperiodic beams for both stiffened and sandwich-type are obtained by varying a projection parameter that governs the location of the center of the stiffener or the alternating core, respectively. The dynamics of stiffened quasiperiodic beams is investigated through 3-D finite element simulations, which leads to the observation of the fractal nature of the bulk spectrum and the illustration of topological edge modes that populate bulk spectral bandgaps. The frequency spectrum is further elucidated by employing polarization factors that distinguish multiple contributing modes. The frequency response of the finite stiffened cantilever beams confirms the presence of modes in the non-trivial bandgaps and further demonstrates that those modes are localized at the free edge. A similar analysis is conducted for the analysis of sandwich composite beams, for which computations rely on a dynamic stiffness matrix approach. This work motivates the use of quasiperiodic beams in the design of stiffened and sandwich structures as structural members in applications where vibration isolation is combined with load-carrying functions.
Nuclear Expression Loss of SSBP2 Is Associated with Poor Prognostic Factors in Colorectal Adenocarcinoma
Authors: Chung Yumin , Kim Hyunsung , Bang Seongsik , Jang Kiseok , Paik Seung Sam , Shin Su-Jin
Published: December 2020

Single-stranded DNA binding protein 2 (SSBP2) is involved in DNA damage response and may induce growth arrest in cancer cells, having a potent tumor suppressor role. SSBP2 is ubiquitously expressed and the loss of its expression has been reported in various tumor types. However, the correlation between SSBP2 expression and colorectal cancer (CRC) prognosis remains unclear. SSBP2 nuclear expression was evaluated immunohistochemically in 48 normal colonic mucosae, 47 adenomas, 391 primary adenocarcinomas, and 131 metastatic carcinoma tissue samples. The clinicopathological factors, overall survival (OS), and recurrence-free survival were evaluated, and associations with the clinicopathological parameters were analyzed in 391 colorectal adenocarcinoma patients. A diffuse nuclear SSBP2 expression was detected in all normal colonic mucosa and adenoma samples. SSBP2 expression loss was observed in 131 (34.3%) primary adenocarcinoma and 100 (76.3%) metastatic carcinoma samples. SSBP2 expression was significantly associated with poor prognostic factors, such as vascular invasion (p = 0.005), high pT category (p = 0.045), and shorter OS (p = 0.038), using univariate survival analysis. Nuclear SSBP2 expression loss was significantly observed in colorectal carcinoma and metastatic carcinoma tissues, being associated with poor prognostic factors. SSBP2 acts as a tumor suppressor and may be used as a CRC prognostic biomarker.
On Yaglom’s Law for the Interplanetary Proton Density and Temperature Fluctuations in Solar Wind Turbulence
Authors: Consolini Giuseppe , Alberti Tommaso , Carbone Vincenzo
Published: December 2020

In the past decades, there has been an increasing literature on the presence of an inertial energy cascade in interplanetary space plasma, being interpreted as the signature of Magnetohydrodynamic turbulence (MHD) for both fields and passive scalars. Here, we investigate the passive scalar nature of the solar wind proton density and temperature by looking for scaling features in the mixed-scalar third-order structure functions using measurements on-board the Ulysses spacecraft during two different periods, i.e., an equatorial slow solar wind and a high-latitude fast solar wind, respectively. We find a linear scaling of the mixed third-order structure function as predicted by Yaglom’s law for passive scalars in the case of slow solar wind, while the results for fast solar wind suggest that the mixed fourth-order structure function displays a linear scaling. A simple empirical explanation of the observed difference is proposed and discussed.
Time Delay Complex Chen Chaotic System and Secure Communication Scheme for Wireless Body Area Networks
Authors: Zhang Fangfang , Leng Sen , Li Zhengfeng , Jiang Cuimei
Published: December 2020

Although many chaotic systems with time delays have been studied in recent years, most studies have only focused on the theoretical level, without special applications. Therefore, we present a basic introduction of a time delay complex Chen chaotic system, including the influence of parameter changes and time delay factors on the time delay system. On the basis of complex modified projection synchronization (CMPS), we detail the design of a new controller and communication scheme and apply this communication scheme to a wireless body area network (WBAN), in order to encrypt and decrypt body data collected by sensors. Finally, we perform a numerical simulation, demonstrating the effectiveness of the proposed communication scheme.
PV Module Fault Detection Using Combined Artificial Neural Network and Sugeno Fuzzy Logic
Authors: Vieira Romênia G. , Dhimish Mahmoud , de Araújo Fábio M. U. , Guerra Maria I. S.
Published: December 2020

This work introduces a new fault detection method for photovoltaic systems. The method identifies short-circuited modules and disconnected strings on photovoltaic systems combining two machine learning techniques. The first algorithm is a multilayer feedforward neural network, which uses irradiance, ambient temperature, and power at the maximum power point as input variables. The neural network output enters a Sugeno type fuzzy logic system that precisely determines how many faulty modules are occurring on the power plant. The proposed method was trained using a simulated dataset and validated using experimental data. The obtained results showed 99.28% accuracy on detecting short-circuited photovoltaic modules and 99.43% on detecting disconnected strings.
Fault Diagnosis Reasoning Algorithm for Electromechanical Actuator Based on an Improved Hybrid TFPG Model
Authors: Cao Yuyan , Lyu Yongxi , Wang Xinmin
Published: December 2020

As a new generation of power-by-wire actuators, electromechanical actuators are finding increasingly more applications in the aviation field. Aiming at the application problem of the fault diagnosis of the electromechanical actuator, an improved diagnosis reasoning algorithm based on a hybrid timed failure propagation graph (TFPG) model is proposed. On the basis of this hybrid TFPG model, the activation conditions of OR and causality among nodes are given. The relationship discrepancy node is transformed into a relationship node and discrepancy node, which unifies the model storage process. The backward and forward extension operations of hypothesis generation and updating are improved. In the backward expansion operation, the specific process of backward update from non-alarm nodes is given, and the judging logic of the branch of relationship nodes is added, which guarantees the unity of the algorithm framework and the accuracy of the time update. In the forward expansion operation, the update order is adjusted to ensure the accuracy of the node update for the case of multiple parents. A hybrid TFPG model of the electromechanical actuator is established in the general modeling environment (GME), and a systematic verification scheme with two simulation types is tested with the application of the P2020 reference design board (RDB) and VxWorks 653 system. The results show that the proposed algorithm can realize the fault diagnosis of the electromechanical actuator as well as fault propagation prediction.
Event-Focused Digital Control to Keep High Efficiency in a Wide Power Range in a SiC-Based Synchronous DC/DC Boost Converter
Authors: Rogina María R. , Rodríguez Alberto , Vázquez Aitor , Lamar Diego G. , Hernando Marta M.
Published: December 2020

This paper is focused on the design of a control approach, based on the detection of events and changing between two different conduction modes, to reach high efficiency over the entire power range, especially at medium and low power levels. Although the proposed control strategy can be generalized for different topologies and specifications, in this paper, the strategy is validated in a SiC-based synchronous boost DC/DC converter rated for 400 V to 800 V and 10 kW. Evaluation of the power losses and current waveforms of the converter for different conduction modes and loads predicts suitable performance of quasi-square wave mode with zero voltage switching (QSW-ZVS) conduction mode for low and medium power and of continuous conduction Mode with hard switching (CCM-HS) for high power. Consequently, this paper proposes a control strategy, taking advantage of digital control, that allows automatic adjustment of the conduction mode to optimize the performance for different power ranges.
Monopulse Antenna Based on Singular Spoof Surface Plasmon Polariton Structure for Angle Measurement
Authors: Li Shunli , Zhang Qiuyi , Li Jinlun , Zhao Hongxin , Yin Xiaoxing , Yang Mei
Published: December 2020

Direction finding and target tracking make demanding requirements on the measurement of incoming angles of electromagnetic waves. A monopulse antenna, based on the singular symmetric spoof surface plasmon polariton (SSPP) structure, is proposed for high-accuracy angle sensing. The singular SSPP structure is composed of periodic corrugated grooves for the confinement of the electromagnetic fields. Due to the microstrip–coplanar waveguide transition, the fields along both sides of the SSPP add constructively to form the endfire beam at the sum port and destructively to form the null radiation in the endfire direction at the difference port. An optimization based on the team progress algorithm is adopted to facilitate this antenna design. A prototype is designed and fabricated to validate the design principle, and measured results agree with the simulation. The proposed antenna shows a wide bandwidth ranging from 5.0 GHz to 7.5 GHz for both the sum and difference ports with the return loss greater than 10 dB, realizing a relative bandwidth of 40%. The isolation for the sum and difference ports is higher than 21 dB, and the null depth is larger than 20 dB over the entire operating range, which is favorable for the high accuracy angle sensing and measurement. This monopulse antenna has broad prospect in angle measuring systems such as direction finding and radar tracking scenes.
Dynamic Data Envelopment Analysis Model Involving Undesirable Outputs in the Electricity Power Generation Sector: The Case of Latin America and the Caribbean Countries
Authors: Cuadros Sebastian , Rodríguez Yeny E. , Contreras Javier
Published: December 2020

Studying the evolution of the efficiency of the electricity generation sector is a relevant task for policy makers, and requires the undesirable outputs derived from the activity to be considered in the evaluation. In this work, we propose a dynamic slack-based Data Envelopment Analysis (DEA) model that incorporates the assumption of weak disposability between the generation of electricity from fossil sources and the CO2 emissions caused by the sector to measure the technical efficiency of 24 Latin American and Caribbean countries in the period 2000–2016. The results show that, of the total number of countries studied, four are efficient overall, and four groupings of countries in relation to the levels of efficiency achieved are also identified. These results are important given that less-efficient countries can, through learning, increase their efficiency in electricity generation or emulate the future strategies proposed by the most efficient countries.
Modelling the Integration of Residential Heat Demand and Demand Response in Power Systems with High Shares of Renewables
Authors: Magni Chiara , Arteconi Alessia , Kavvadias Konstantinos , Quoilin Sylvain
Published: December 2020

The EU aims to become the world’s first climate-neutral continent by 2050. In order to meet this target, the integration of high shares of Renewable Energy Sources (RESs) in the energy system is of primary importance. Nevertheless, the large deployment of variable renewable sources such as wind and photovoltaic power will pose important challenges in terms of power management. For this reason, increasing the system flexibility will be crucial to ensure the security of supply in future power systems. This work investigates the flexibility potential obtainable from the diffusion of Demand Response (DR) programmes applied to residential heating for different renewables penetration and power system configuration scenarios. To that end, a bottom-up model for residential heat demand and flexible electric heating systems (heat pumps and electric water heaters) is developed and directly integrated into Dispa-SET, an existing unit commitment optimal dispatch model of the power system. The integrated model is calibrated for the case of Belgium and different simulations are performed varying the penetration and type of residential heating technologies, installed renewables capacity and capacity mix. Results show that, at country level, operational cost could be reduced up to €35 million and curtailment up to 1 TWh per year with 1 million flexible electric heating systems installed. These benefits are significantly reduced when nuclear power plants (non-flexible) are replaced by gas-fired units (flexible) and grow when more renewable capacity is added. Moreover, when the number of flexible heating systems increases, a saturation effect of the flexibility is observed.
Conformance Checking of a Longwall Shearer Operation Based on Low-Level Events
Authors: Szpyrka Marcin , Brzychczy Edyta , Napieraj Aneta , Korski Jacek , Nalepa Grzegorz J.
Published: December 2020

Conformance checking is a process mining technique that compares a process model with an event log of the same process to check whether the current execution stored in the log conforms to the model and vice versa. This paper deals with the conformance checking of a longwall shearer process. The approach uses place-transition Petri nets with inhibitor arcs for modeling purposes. We use event log files collected from a few coal mines located in Poland by Famur S.A., one of the global suppliers of coal mining machines. One of the main advantages of the approach is the possibility for both offline and online analysis of the log data. The paper presents a detailed description of the longwall process, an original formal model we developed, selected elements of the approach’s implementation and the results of experiments.