Electrical distribution companies have been investing in modernizing their structures, especially operation automation. The integration of information technologies and communications makes fast power ...restoration during fault events, providing better profit to companies and a more reliable and safe distribution network for customers. A self-healing strategy can be implemented for protection and control devices to work cooperatively, achieving the global purpose of automatic distribution system restoration. Thus, this work proposes a methodology for short-circuit fault detection, isolation of the faulted section, and restoration of downstream sections using neighbor feeders. The protection devices use standardized IEC and ANSI/IEEE functions to sensitize faults in the system and to promote adequate isolation, allowing the consequent restorative process. A genetic algorithm optimizes the devices’ parameters used in the protection scheme, making fastest the isolation process and ensuring the protection system coordination and selectivity. Results obtained using Simulink® allows for verifying the proposed methodology’s behavior and efficiency.
In this work, a set of experimental electrophoretic mobility (μe) data was used to show how inappropriate selection of the electrokinetic model used to calculate the zeta potential (ζ-potential) can ...compromise the interpretation of the results for nanoparticles (NPs). The main consequences of using ζ-potential values as criteria to indicate the colloidal stability of NP dispersions are discussed based on DLVO interaction energy predictions. For this, magnetite (Fe3O4) NPs were synthesized and characterized as a model system for performing electrokinetic experiments. The results showed that the Fe3O4 NPs formed mass fractal aggregates in solution, so the ζ-potential could not be determined under ideal conditions when μe depends on the NP radius. In addition, the Dukhin number (Du) estimated from potentiometric titration results indicated that stagnant layer conduction (SLC) could not be neglected for this system. The electrokinetic models that do not consider SLC grossly underestimated the ζ-potential values for the Fe3O4 NPs. The DLVO interaction energy predictions for the colloidal stability of the Fe3O4 NP dispersions also depended on the electrokinetic model used to calculate the ζ-potential. The results obtained for the Fe3O4 NP dispersions also suggested that, contrary to many reports in the literature, high ζ-potential values do not necessarily reflect high colloidal stability for charge-stabilized NP dispersions.
The scattering of light by water droplets can produce one of the most beautiful phenomena in nature: the rainbow. This optical phenomenon has analogues in molecular, atomic, and nuclear physics. ...Recently, rainbow scattering has been shown to arise from the gravitational interaction of a scalar field with a compact horizonless object. We show that rainbow scattering can also occur in the background of a black hole with surrounding matter. We study the scattering of null geodesics and planar massless scalar waves by Schwarzschild black holes surrounded by a thin spherical shell of matter. We explore various configurations of this system, analyzing changes in mass fraction and radius of the shell. We show that the deflection function can present stationary points, which leads to rainbow scattering. We analyze the large-angle scattered amplitude as a function of the shell’s parameters, showing that it presents a nonmonotonic behavior.
Black holes are a paradigm in physics nowadays and are expected to be hosted at the centers of galaxies. Supermassive galactic black holes are not isolated, and their surroundings play crucial roles ...in many observational features. The absorption and scattering of fields by isolated black holes have been vastly studied, allowing the understanding of many phenomenological features. However, as far as we are aware, a study of the influence of the presence of matter surrounding black holes in their planar wave scattering and absorption spectrum is still lacking in the literature. This may be important in the analysis of, for instance, the accretion of dark matter by black holes. We consider planar massless scalar waves incident upon a Schwarzschild black hole surrounded by a thin spherical shell. We use the partial-wave method to determine the absorption cross section and present a selection of numerical results. In the low-frequency regime, we show that the absorption cross section is equal to the horizon area. At the high-frequency regime, we show that the absorption cross section approaches the geodesic capture cross section.
Hydrogen-fueled internal combustion engines (H2ICEs) represent a promising technology for decarbonizing the transport sector. In pursuit of this goal, research is needed on lean hydrogen–air ...combustion under engine conditions aiming to mitigate NOx emissions. However, there is a limited amount of experimental data focusing on flame development at high pressure and temperature, especially in ultra-lean mixtures, which are recently considered to play an important role for future H2ICEs. This study investigates the behavior of very-lean to ultra-lean hydrogen–air flames (0.20 <ϕ< 0.55) in an optical spark-ignition engine, focusing on the early flame development phase. Fuel–air equivalence ratio and engine speed (900 <N< 1500 rpm) effects on hydrogen combustion are addressed with pressure-based heat release analysis and chemiluminescence flame imaging techniques. The findings revealed an intrinsic association between these two approaches. Hydrogen flames development measured before 2% of Mass Fraction Burned (MFB) strongly correlates with pressure-based quantities up to 50% MFB, underscoring the critical role of understanding the early flame phase for predicting total combustion duration and in-cylinder pressure traces. A model for hydrogen turbulent flames in the initial combustion stages is formulated based on the Zimont equation and the experimental data. An equation for 0D/1D combustion duration prediction up to 10% MFB is proposed, demonstrating its validity from the wrinkled flame to the well-stirred reactor premixed combustion regimes. Additionally, flame chemiluminescence images for each zone within the Peters–Borghi diagram are presented, offering valuable insights into the diverse characteristics of these flames.
Ankle injuries caused by the Anterior Talofibular Ligament (ATFL) are the most common type of injury. Thus, finding new ways to analyze these injuries through novel technologies is critical for ...assisting medical diagnosis and, as a result, reducing the subjectivity of this process. As a result, the purpose of this study is to compare the ability of specialists to diagnose lateral tibial tuberosity advancement (LTTA) injury using computer vision analysis on magnetic resonance imaging (MRI). The experiments were carried out on a database obtained from the Vue PACS-Carestream software, which contained 132 images of ATFL and normal (healthy) ankles. Because there were only a few images, image augmentation techniques was used to increase the number of images in the database. Following that, various feature extraction algorithms (GLCM, LBP, and HU invariant moments) and classifiers such as Multi-Layer Perceptron (MLP), Support Vector Machine (SVM), k-Nearest Neighbors (kNN), and Random Forest (RF) were used. Based on the results from this analysis, for cases that lack clear morphologies, the method delivers a hit rate of 85.03% with an increase of 22% over the human expert-based analysis.
Wnt/β-catenin signaling, a highly conserved pathway through evolution, regulates key cellular functions including proliferation, differentiation, migration, genetic stability, apoptosis, and stem ...cell renewal. The Wnt pathway mediates biological processes by a canonical or noncanonical pathway, depending on the involvement of β-catenin in signal transduction. β-catenin is a core component of the cadherin protein complex, whose stabilization is essential for the activation of Wnt/β-catenin signaling. As multiple aberrations in this pathway occur in numerous cancers, WNT-directed therapy represents an area of significant developmental therapeutics focus. The recently described role of Wnt/β-catenin pathway in regulating immune cell infiltration of the tumor microenvironment renewed the interest, given its potential impact on responses to immunotherapy treatments. This article summarizes the role of Wnt/β-catenin pathway in cancer and ongoing therapeutic strategies involving this pathway.
Propolis is a complex mixture of phytochemicals, with antibacterial, anti‐inflammatory, and healing properties. All‐trans retinoic acid is implicated in wound healing by stimulating angiogenesis, ...cell recruitment, extracellular matrix deposition, and reepithelization. The incorporation of both agents to a polymeric wound dressing composed of poly (vinyl alcohol) and sodium alginate may result in improved healing allied to controlled release, fluid uptake, and wound protection. In the present work, we have physically characterized this wound dressing and analyzed its release kinetics. The anti‐inflammatory capacity was assayed. SEM images showed a highly porous structure with a diverse morphology. FTIR spectra displayed a highly cross‐linked structure with both polymers connected by hydrogen bonds and acetal bridges. The wound dressings were able to retain great volumes of PBS. Propolis and vitamin A releasing behavior were maintained for 6 h. The concentrations of the biologically active substances were capable of promoting anti‐inflammatory action in an erythrocyte membrane stabilization model. The wound dressings obtained here showed adequate physical properties. The fabrication process did not affect the anti‐inflammatory capacity. Further tests are needed to ensure the biocompatibility and to assess other biological activities of the therapeutic agents.
This paper discloses the development of a polymeric wound dressing comprised of poly (vinyl alcohol) and sodium alginate. We have developed an inexpensive and easy to manufacture wound dressing, able to carry and deliver biological agents to aid in wound healing. We provided the material characterization and supplemental data of the biological activities regarding the addition of propolis and all‐trans‐retinoic acid. The image displayed is the possible structure of the wound dressing.
Prostate cancer is the most common cancer in men, and most patients have localized disease at the time of diagnosis. However, 4% already present with metastatic disease. Epithelial-mesenchymal ...transition is a fundamental process in carcinogenesis that has been shown to be involved in prostate cancer progression. The main event in epithelial-mesenchymal transition is the repression of E-cadherin by transcription factors, but the process is also regulated by microRNAs. The aim of this study was to analyze gene and microRNA expression involved in epithelial-mesenchymal transition in localized prostate cancer and metastatic prostate cancer cell lines and correlate with clinicopathological findings. We studied 51 fresh frozen tissue samples from patients with localized prostate cancer (PCa) treated by radical prostatectomy and three metastatic prostate cancer cell lines (LNCaP, DU145, PC3). The expression of 10 genes and 18 miRNAs were assessed by real-time PCR. The patients were divided into groups according to Gleason score, pathological stage, preoperative PSA, biochemical recurrence, and risk group for correlation with clinicopathological findings. The majority of localized PCa cases showed an epithelial phenotype, with overexpression of E-cadherin and underexpression of the mesenchymal markers. MiRNA-200 family members and miRNAs 203, 205, 183, 373, and 21 were overexpressed, while miRNAs 9, 495, 29b, and 1 were underexpressed. Low-expression levels of miRNAs 200b, 30a, and 1 were significantly associated with pathological stage. Lower expression of miR-200b was also associated with a Gleason score ≥ 8 and shorter biochemical recurrence-free survival. Furthermore, low-expression levels of miR-30a and high-expression levels of Vimentin and Twist1 were observed in the high-risk group. Compared with the primary tumor, the metastatic cell lines showed significantly higher expression levels of miR-183 and Twist1. In summary, miRNAs 200b, 30a, 1, and 183 and the genes Twist1 and Vimentin might play important roles in the progression of prostate cancer and may eventually become important prognostic markers.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Purpose
Intestinal mucositis and the closely associated diarrhea are common costly side effects of irinotecan. Cytokine modulators, such as thalidomide and pentoxifylline, are found capable of ...attenuating intestinal mucositis progression. Nitric oxide (NO) seems to be a key mediator of the antineoplastic drug toxicity. The aim of this study was to investigate the role of NO on the pathogenesis of intestinal mucositis, as well as the participation of cytokines upon inducible nitric oxide synthase (iNOS) expression in irinotecan-induced intestinal mucositis.
Methods
iNOS-knockout (iNOS
−/−
) and C57BL/6 (WT, wild type) animals (
n
= 5–6) were given either saline or irinotecan (60 mg/kg i.p for 4 days), with or without pretreatment with aminoguanidine (50 mg/kg s.c.), thalidomide (60 mg/kg s.c), infliximab (5 mg/kg i.v.), or pentoxifylline (1.7 mg/kg s.c). On day 5, diarrhea was assessed, and following euthanasia, proximal intestinal samples were obtained for myeloperoxidase (MPO) and iNOS activity, morphometric analysis, western blot and immunohistochemistry to iNOS, cytokine dosage, and for in vitro evaluation of gut contractility.
Results
Irinotecan induced severe diarrhea and intestinal smooth muscle over-contractility, accompanied with histopathological changes. Additionally, increased MPO and iNOS activity and iNOS immunoexpression were found in WT animals treated with irinotecan. The rise in MPO, smooth muscle over-contractility, and diarrhea were abrogated in aminoguanidine-treated and iNOS
−/−
mice. Moreover, through western blot, we verified that infliximab and pentoxifylline significantly inhibited irinotecan-induced iNOS expression. In addition, cytokine concentration was found only partially decreased in irinotecan-treated iNOS
−/−
mice when compared with wild-type animals that were given irinotecan.
Conclusions
This study suggests a role of nitric oxide in the pathogenesis of irinotecan-induced intestinal mucositis and also provides evidence for the participation of cytokines on iNOS induction.
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