913 research outputs found
Solving Modal Equations of Motion with Initial Conditions Using MSC/NASTRAN DMAP
By utilizing MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) in an existing NASA Lewis Research Center coupled loads methodology, solving modal equations of motion with initial conditions is possible using either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration available within module TRD1. Both the coupled and newly developed exact mode superposition methods have been used to perform transient analyses of various space systems. However, experience has shown that in most cases, significant time savings are realized when the equations of motion are integrated using the uncoupled solver instead of the coupled solver. Through the results of a real-world engineering analysis, advantages of using the exact mode superposition methodology are illustrated
Solving modal equations of motion with initial conditions using MSC/NASTRAN DMAP. Part 1: Implementing exact mode superposition
Within the MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) module TRD1, solving physical (coupled) or modal (uncoupled) transient equations of motion is performed using the Newmark-Beta or mode superposition algorithms, respectively. For equations of motion with initial conditions, only the Newmark-Beta integration routine has been available in MSC/NASTRAN solution sequences for solving physical systems and in custom DMAP sequences or alters for solving modal systems. In some cases, one difficulty with using the Newmark-Beta method is that the process of selecting suitable integration time steps for obtaining acceptable results is lengthy. In addition, when very small step sizes are required, a large amount of time can be spent integrating the equations of motion. For certain aerospace applications, a significant time savings can be realized when the equations of motion are solved using an exact integration routine instead of the Newmark-Beta numerical algorithm. In order to solve modal equations of motion with initial conditions and take advantage of efficiencies gained when using uncoupled solution algorithms (like that within TRD1), an exact mode superposition method using MSC/NASTRAN DMAP has been developed and successfully implemented as an enhancement to an existing coupled loads methodology at the NASA Lewis Research Center
COVID-19 Crowd Detection
Object detection was introduced by researchers for face detection. Researchers explain how the detected face is divided into minor frames to be recognized by the algorithm. Due to COVID-19 and government regulations, many people face problems going to shopping centers and shop safely. It has been very hard for both the government and the people to manage social distancing. In our study, we developed a system using Raspberry Pi-4 that will detect the distance between people along with counting the number of distance and mask violations. An error message will appear on the screen in red, showing the total number of distance and mask violations, which could later be used by the customer as statistical evidence for better safety precautions
Influence of the analysis technique on estimating hepatic iron content using MRI
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134998/1/jmri25317.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134998/2/jmri25317_am.pd
Fibulin-2 is required for basement membrane integrity of mammary epithelium
Fibulin-2 (FBLN2) is a secreted extracellular matrix glycoprotein which has been associated with tissue development and remodelling. In the mouse mammary gland, FBLN2 can be detected during ductal morphogenesis in cap cells and myoepithelial cells at puberty and early pregnancy, respectively. In an attempt to assign its function, we knocked down Fbln2 in the mouse mammary epithelial cell line EpH4. FBLN2 reduction led to an increase in the size of spheroidal structures when compared to scrambled control shRNA-transduced cells plated on Matrigel matrix. This phenotype was associated with a disruption of the collagen IV sheath around the epithelial spheroids and downregulation of integrin β1, suggesting a role for FBLN2 in stabilizing the basement membrane (BM). In contrast to mice, in normal adult human breast tissue, FBLN2 was detected in ductal stroma, and in the interlobular stroma, but was not detectable within the lobular regions. In tissue sections of 65 breast cancers FBLN2 staining was lost around malignant cells with retained staining in the neighbouring histologically normal tissue margins. These results are consistent with a role of FBLN2 in mammary epithelial BM stability, and that its down-regulation in breast cancer is associated with loss of the BM and early invasion
Fibulin-2 is required for basement membrane integrity of mammary epithelium
Fibulin-2 (FBLN2) is a secreted extracellular matrix glycoprotein which has been associated with tissue development and remodelling. In the mouse mammary gland, FBLN2 can be detected during ductal morphogenesis in cap cells and myoepithelial cells at puberty and early pregnancy, respectively. In an attempt to assign its function, we knocked down Fbln2 in the mouse mammary epithelial cell line EpH4. FBLN2 reduction led to an increase in the size of spheroidal structures when compared to scrambled control shRNA-transduced cells plated on Matrigel matrix. This phenotype was associated with a disruption of the collagen IV sheath around the epithelial spheroids and downregulation of integrin β1, suggesting a role for FBLN2 in stabilizing the basement membrane (BM). In contrast to mice, in normal adult human breast tissue, FBLN2 was detected in ductal stroma, and in the interlobular stroma, but was not detectable within the lobular regions. In tissue sections of 65 breast cancers FBLN2 staining was lost around malignant cells with retained staining in the neighbouring histologically normal tissue margins. These results are consistent with a role of FBLN2 in mammary epithelial BM stability, and that its down-regulation in breast cancer is associated with loss of the BM and early invasion
Calli Essential Oils Synergize with Lawsone against Multidrug Resistant Pathogens.
The fast development of multi-drug resistant (MDR) organisms increasingly threatens global health and well-being. Plant natural products have been known for centuries as alternative medicines that can possess pharmacological characteristics, including antimicrobial activities. The antimicrobial activities of essential oil (Calli oil) extracted from the Calligonum comosum plant by hydro-steam distillation was tested either alone or when combined with lawsone, a henna plant naphthoquinone, against MDR microbes. Lawsone showed significant antimicrobial activities against MDR pathogens in the range of 200-300 µg/mL. Furthermore, Calli oil showed significant antimicrobial activities against MDR bacteria in the range of 180-200 µg/mL, Candida at 220-240 µg/mL and spore-forming Rhizopus fungus at 250 µg/mL. Calli oil's inhibition effect on Rhizopus, the major cause of the lethal infection mucormycosis, stands for 72 h, followed by an extended irreversible white sporulation effect. The combination of Calli oil with lawsone enhanced the antimicrobial activities of each individual alone by at least three-fold, while incorporation of both natural products in a liposome reduced their toxicity by four- to eight-fold, while maintaining the augmented efficacy of the combination treatment. We map the antimicrobial activity of Calli oil to its major component, a benzaldehyde derivative. The findings from this study demonstrate that formulations containing essential oils have the potential in the future to overcome antimicrobial resistance
GREEN VORTEX-ASSISTED IONIC LIQUID-BASED DISPERSIVE LIQUID-LIQUID MICROEXTRACTION FOR ENRICHMENT AND DETERMINATION OF CADMIUM AND LEAD IN WATER, VEGETABLES AND TOBACCO SAMPLES
Objective: An eco-friendly, simple and sensitive vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction method (VA-IL-DLLµE) has been proposed to enrich and determine trace levels of cadmium (Cd2+ ) and lead (Pb2+ ) ions in water, vegetables and tobacco samples, prior to its FAAS determination.
Methods: The proposed method based on utilization of ionic liquid (IL) (1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate [HMIM][FAP]) as an extraction solvent for both ions after the complexation with 4,5-dihydroxy-3-phenylazo-2,7-naphthalenedisulfonic acid, disodium salt (Chromotrope 2R) at pH 6.5. The impact of different analytical parameters on microextraction efficiency was optimized.
Results: In the ranges of 1.0–300 and 2.0-400 μg/ml, the calibration graphs were linear. The limits of detection were 0.3 and 0.6 μg/ml for Cd2+ and Pb2+ ions, respectively. The preconcentration factor was 100. The relative standard deviation (RSD %)<3.0%, which indicates the proposed method has high precision.
Conclusion: The proposed VA-IL-DLLµE method was developed and applied for the estimation of Cd2+ and Pb2+ ion content in various water, vegetables and tobacco samples, and satisfactory results were obtained. The obtained recovery values showed good agreement with the certified values
BADANIE WPŁYWU UŁAMKOWEJ LICZBY SZCZELIN BIEGUNÓW NA GENERACJĘ TURBINY WIATROWEJ PRZY UŻYCIU ULEPSZONEGO ALGORYTMU OPTYMALIZACJI CĘTKOWANEJ HIENY
The design of machines with permanent magnets is actively developing day by day and is often used in wind energy. The main advantages of such variable speed drives are high efficiency, high power density and torque density. When designing a wind generator with two rotors and permanent magnets, it is necessary to solve such a problem as the correct choice of the number of poles and slots to increase efficiency and minimize the cost of the machine. In this work, an improved spotted hyena optimization algorithm is used to obtain the optimal combination of slots and poles. This optimization algorithm makes it possible to obtain the number of fractional slots per pole and evaluate the operating efficiency of a wind generator with a double rotor and ferrite magnets. At the first stage of machine design, various combinations of slots are installed. Next, the optimal combination is selected from various slot-pole combinations, taking into account the Enhanced Spotted Hyena Optimization (ESHO) algorithm, in which a multi-objective function is configured. Accordingly, the multi-objectives are the integration of reverse electromotive force, output torque, gear torque, flux linkage, torque ripple along with losses. Analysis of the results obtained shows that the proposed algorithm for determining the optimal slot combination is more efficient than other slot combinations. It has also been found that the choice of slot and pole combination is critical to the efficient operation of permanent magnet machines.Projektowanie maszyn z magnesami trwałymi aktywnie rozwija się z dnia na dzień i jest często wykorzystywane w energetyce wiatrowej. Głównymi zaletami takich napędów o zmiennej prędkości są wysoka sprawność, wysoka gęstość mocy i gęstość momentu obrotowego. Podczas projektowania generatora wiatrowego z dwoma wirnikami i magnesami trwałymi konieczne jest rozwiązanie takiego problemu, jak prawidłowy dobór liczby biegunów i szczelin w celu zwiększenia wydajności i zminimalizowania kosztów maszyny. W niniejszej pracy zastosowano ulepszony algorytm optymalizacji hieny plamistej w celu uzyskania optymalnej kombinacji szczelin i biegunów. Ten algorytm optymalizacji umożliwia uzyskanie liczby ułamkowych szczelin na biegun i ocenę wydajności operacyjnej generatora wiatrowego z podwójnym wirnikiem i magnesami ferrytowymi. Na pierwszym etapie projektowania maszyny instalowane są różne kombinacje szczelin. Następnie wybierana jest optymalna kombinacja spośród różnych kombinacji szczelin i biegunów, biorąc pod uwagę algorytm Enhanced Spotted Hyena Optimization (ESHO) (ulepszony algorytm optymalizacjihieny cętkowanej hieny), w którym skonfigurowana jest funkcja wielocelowa. W związku z tym, celami wielozadaniowymi są integracja odwrotnej siły elektromotorycznej, wyjściowego momentu obrotowego, momentu obrotowego przekładni, połączenia strumienia, tętnienia momentu obrotowego wraz ze stratami. Analiza uzyskanych wyników pokazuje, że proponowany algorytm określania optymalnej kombinacji szczelin jest bardziej wydajny niż inne kombinacje szczelin. Stwierdzono również, że wybór kombinacji szczelin i biegunów ma kluczowe znaczenie dla wydajnej pracy maszyn z magnesami trwałymi
Antioxidant and cardioprotective activity of Stachys schimperi Vatke against doxorubicin-induced cardiotoxicity
AbstractCardiotoxicity is one of the major side effects of anthracycline antibiotics. Most studies implicated increased oxidative stress as the major determinant of doxorubicin (DOX) cardiotoxicity. The aim of the current investigation was to study the possible cardioprotective effect of Stachys schimperi Vatke (family Lamiaceae) on DOX-induced cardiotoxicity in rats based on biochemical and histopathological parameters. The phenolic profile of the methanol extract was determined qualitatively by HPLC. Isoscutellarein 7-O-[2″-O-(6″′-acetyl)-β-d-allopyranosyl]-β-d-glucopyranoside (compound 1) was isolated and identified from EB fraction as a major constituent for the first time from this Stachys species. The methanolic extract and the combined EtOAc and n-butanol fractions (EB) as well as compound 1 showed prominent free radical scavenging activity when assessed by the DPPH method. The methanolic extract showed moderate protection against DOX-induced alteration in cardiac oxidative stress markers; GSH and MDA, and cardiac serum markers; CK-MB and LDH activities. Additionally, histopathological study denoted mild protection against DOX-induced cardiotoxicity.It was concluded that Stachys schimperi Vatke methanolic extract protected against DOX-induced cardiotoxicity, at least in part, by virtue of its antioxidant activity
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