296 research outputs found

    Summary of investigations of engine response to distorted inlet conditions

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    A survey is presented of experimental and analytical experience of the NASA Lewis Research Center in engine response to inlet temperature and pressure distortions. This includes a description of the hardware and techniques employed, and a summary of the highlights of experimental investigations and analytical modeling. Distortion devices successfully simulated inlet distortion, and knowledge was gained about compression system response to different types of distortion. A list of NASA research references is included

    Performance and stall limits of an afterburner-equipped turbofan engine with and without inlet flow distortion

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    Performance and stall limits of afterburner-type turbofan engine with and without inlet flow distortio

    Сравнение показателей соотношений тромбоциты / лимфоциты и нейтрофилы / лимфоциты в качестве предикторов исхода COVID-19

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    Clinical presentation is an undependable prognostic indicator of COVID-19 (COronaVIrus Disease 2019). So, a more objective predictor is needed to precisely evaluate and classify the prognosis. Immune dysregulation to lymphocytes, mainly T-lymphocytes, have been noticed between COVID-19 patients. The aim. This study was planned to determine the role of platelet-to-lymphocyte count ratio and neutrophil-to-lymphocyte ratio in assessment of COVID-19 prognosis. Methods. 70 hospitalized patients with confirmed COVID-19 were included in this study. All included patients underwent a consistent clinical, radiological and blood examination. Laboratory analysis was made by means of a commercially accessible kit. Blood cells ratios were computed by dividing their absolute counts. Results. Non-significant association was found between laboratory data and COVID-19 clinical severity. A significant association between CT classification and platelet-to-lymphocyte count ratio (higher value in L type; p = 0.001) was detected. Platelet-to-lymphocyte count ratio was significantly higher among intubated cases. However, Non-significant association was found between neutrophil-to-lymphocyte ratio and need of endotracheal intubation. Conclusion. Routine blood values are abnormal in patients with COVID-19. Platelet-to-lymphocyte count ratio ratios could be used as more meaningful biomarker than other values in predicting the prognosis of COVID-19. LMR helpful in COVID-19 severity.Клиническая картина является ненадежным показателем прогноза исхода новой коронавирусной инфекции (НКИ), поэтому для точной оценки и классификации прогноза необходим более объективный прогнозирующий фактор. У пациентов, перенесших НКИ, отмечается нарушение регуляции иммунного ответа со стороны лимфоцитов, в основном Т-лимфоцитов. Целью исследования явилось определение роли показателей соотношений тромбоциты / лимфоциты и нейтрофилы / лимфоциты при оценке прогноза COVID-19. Материалы и методы. В исследование были включены госпитализированные пациенты (n = 70) с подтвержденным COVID-19 (COronaVIrus Disease 2019). У всех пациентов проводились последовательное клиническое и рентгенологическое обследование и анализ крови. Лабораторные анализы выполнялись с помощью коммерческого набора. Соотношения показателей клеток крови рассчитывались путем деления их абсолютного количества. Результаты. Обнаружена незначимая связь между лабораторными показателями и степенью тяжести COVID-19. Выявлена значимая связь между степенью поражения легких по данным компьютерной томографии и показателем соотношения тромбоциты / лимфоциты (более высокое значение для L-типа; p = 0,001). У интубированных пациентов соотношение показателя тромбоциты / лимфоциты было значимо выше. Однако обнаружена незначимая связь между показателем соотношения нейтрофилы / лимфоциты и необходимостью интубации трахеи. Заключение. У пациентов с COVID-19 наблюдаются отклонения показателей рутинных анализов крови. Показатель соотношения тромбоциты / лимфоциты может служить биомаркером при прогнозировании течения COVID-19, а показатель соотношения лимфоциты / моноциты полезен при прогнозировании степени тяжести COVID-19

    Neurological effects of glucocerebrosidase gene mutations

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    The association between Gaucher disease (GD) and Parkinson disease (PD) has been described for almost two decades. In the biallelic state (homozygous or compound heterozygous) mutations in the glucocerebrosidase gene (GBA) may cause GD, in which glucosylceramide, the sphingolipid substrate of the glucocerebrosidase enzyme (GCase), accumulates in visceral organs leading to a number of clinical phenotypes. In the biallelic or heterozygous state, GBA mutations increase the risk for PD. Mutations of the GBA allele are the most significant genetic risk factor for idiopathic PD, found in 5%–20% of idiopathic PD cases depending on ethnicity. The neurological consequences of GBA mutations are reviewed and the proposition that GBA mutations result in a disparate but connected range of clinically and pathologically related neurological features is discussed. The literature relating to the clinical, biochemical and genetic basis of GBA PD, type 1 GD and neuronopathic GD is considered highlighting commonalities and distinctions between them. The evidence for a unifying disease mechanism is considered

    Conformal Transformations in Cosmology of Modified Gravity: the Covariant Approach Perspective

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    The 1+3 covariant approach and the covariant gauge-invariant approach to perturbations are used to analyze in depth conformal transformations in cosmology. Such techniques allow us to obtain very interesting insights on the physical content of these transformations, when applied to non-standard gravity. The results obtained lead to a number of general conclusions on the change of some key quantities describing any two conformally related cosmological models. In particular, it is shown that the physics in the Einstein frame has characteristics which are completely different from those in the Jordan frame. Even if some of the geometrical properties of the cosmology are preserved (homogeneous and isotropic Universes are mapped into homogeneous and isotropic universes), it can happen that decelerating cosmologies are mapped into accelerated ones. Differences become even more pronounced when first-order perturbations are considered: from the 1+3 equations it is seen that first-order vector and tensor perturbations are left unchanged in their structure by the conformal transformation, but this cannot be said of the scalar perturbations, which include the matter density fluctuations. Behavior in the two frames of the growth rate, as well as other evolutionary features, like the presence or absence of oscillations, etc., appear to be different too. The results obtained are then explicitly interpreted and verified with the help of some clarifying examples based on f(R)f(R)-gravity cosmologies.Comment: 26 pages, 8 figure

    The metabolomic analysis of five Mentha species: cytotoxicity, anti-Helicobacter assessment, and the development of polymeric micelles for enhancing the anti-Helicobacter activity

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    Mentha species are medicinally used worldwide and remain attractive for research due to the diversity of their phytoconstituents and large therapeutic indices for various ailments. This study used the metabolomics examination of five Mentha species (M. suaveolens, M. sylvestris, M. piperita, M. longifolia, and M. viridis) to justify their cytotoxicity and their anti-Helicobacter effects. The activities of species were correlated with their phytochemical profiles by orthogonal partial least square discriminant analysis (OPLS-DA). Tentatively characterized phytoconstituents using liquid chromatography high-resolution electrospray ionization mass spectrometry (LC-HR-ESI-MS) included 49 compounds: 14 flavonoids, 10 caffeic acid esters, 7 phenolic acids, and other constituents. M. piperita showed the highest cytotoxicity to HepG2 (human hepatoma), MCF-7 (human breast adenocarcinoma), and CACO2 (human colon adenocarcinoma) cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. OPLS-DA and dereplication studies predicted that the cytotoxic activity was related to benzyl glucopyranoside-sulfate, a lignin glycoside. Furthermore, M. viridis was effective in suppressing the growth of Helicobacter pylori at a concentration of 50 mg mL−1. OPLS-DA predicted that this activity was related to a dihydroxytrimethoxyflavone. M. viridis extract was formulated with Pluronic® F127 to develop polymeric micelles as a nanocarrier that enhanced the anti-Helicobacter activity of the extract and provided minimum inhibitory concentrations and minimum bactericidal concentrations of 6.5 and 50 mg mL−1, respectively. This activity was also correlated to tentatively identified constituents, including rosmarinic acid, catechins, carvone, and piperitone oxide

    A Unified Approach to Variational Derivatives of Modified Gravitational Actions

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    Our main aim in this paper is to promote the coframe variational method as a unified approach to derive field equations for any given gravitational action containing the algebraic functions of the scalars constructed from the Riemann curvature tensor and its contractions. We are able to derive a master equation which expresses the variational derivatives of the generalized gravitational actions in terms of the variational derivatives of its constituent curvature scalars. Using the Lagrange multiplier method relative to an orthonormal coframe, we investigate the variational procedures for modified gravitational Lagrangian densities in spacetime dimensions n3n\geqslant 3. We study well-known gravitational actions such as those involving the Gauss-Bonnet and Ricci-squared, Kretchmann scalar, Weyl-squared terms and their algebraic generalizations similar to generic f(R)f(R) theories and the algebraic generalization of sixth order gravitational Lagrangians. We put forth a new model involving the gravitational Chern-Simons term and also give three dimensional New massive gravity equations in a new form in terms of the Cotton 2-form

    Improving localization accuracy for non-invasive automated early left ventricular origin localization approach

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    Background: We previously developed a non-invasive approach to localize the site of early left ventricular activation origin in real time using 12-lead ECG, and to project the predicted site onto a generic LV endocardial surface using the smallest angle between two vectors algorithm (SA).Objectives: To improve the localization accuracy of the non-invasive approach by utilizing the K-nearest neighbors algorithm (KNN) to reduce projection errors.Methods: Two datasets were used. Dataset #1 had 1012 LV endocardial pacing sites with known coordinates on the generic LV surface and corresponding ECGs, while dataset #2 included 25 clinically-identified VT exit sites and corresponding ECGs. The non-invasive approach used “population” regression coefficients to predict the target coordinates of a pacing site or VT exit site from the initial 120-m QRS integrals of the pacing site/VT ECG. The predicted site coordinates were then projected onto the generic LV surface using either the KNN or SA projection algorithm.Results: The non-invasive approach using the KNN had a significantly lower mean localization error than the SA in both dataset #1 (9.4 vs. 12.5 mm, p < 0.05) and dataset #2 (7.2 vs. 9.5 mm, p < 0.05). The bootstrap method with 1,000 trials confirmed that using KNN had significantly higher predictive accuracy than using the SA in the bootstrap assessment with the left-out sample (p < 0.05).Conclusion: The KNN significantly reduces the projection error and improves the localization accuracy of the non-invasive approach, which shows promise as a tool to identify the site of origin of ventricular arrhythmia in non-invasive clinical modalities

    Radiological Hazards and Natural Radionuclide Distribution in Granitic Rocks of Homrit Waggat Area, Central Eastern Desert, Egypt

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    Natural radioactivity, radiological hazard, and petrological studies of Homrit Waggat granitic rocks, Central Eastern Desert, Egypt were performed in order to assess their suitability as ornamental stone. On the basis of mineralogical and geochemical compositions, Homrit Waggat granitic rocks can be subdivided into two subclasses. The first class comprises granodiorite and tonalite (I-type) and is ascribed to volcanic arc, whereas the second one includes alkali-feldspar granite, syenogranite, and albitized granite with high-K calc alkaline character, which is related to post-orogenic granites.238 U,226 Ra,232 Th, and40 K activities of natural radionuclides occurring in the examined rocks were measured radiometrically using sodium iodide detector. Furthermore, assessment of the hazard indices—such as: annual effective dose (AED) with mean values (0.11, 0.09, 0.07, 0.05, and 0.03, standard value = 0.07); gamma radiation index (Iγ) with mean values (0.6, 0.5, 0.4, 0.3, and 0.14, standard value = 0.5); internal (Hin) with mean values (0.6, 0.5, 0.4, 0.3, and 0.2, standard value = 1.0); external (Hex) index (0.5, 0.4, 0.3, 0.24, and 0.12, standard value = 1.0); absorbed gamma dose rate (D) with mean values (86.4, 75.9, 53.5, 43.6, and 20.8, standard value = 57); and radium equivalent activity (Raeq) with mean values (180, 154, 106.6, 90.1, and 42.7, standard value = 370)—were evaluated with the knowledge of the natural radionuclides. The result of these indices falls within the acceptable worldwide limits. Therefore, we suggest that these rocks are safe to be used in industrial applications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.RF 3621/2021The researcher (Hamdy A. Awad) is funded by a scholarship under the Joint Executive Program between Egypt and Russian Federation. The work of the author A.E. and the APC were funded by the “Dunarea de Jos” University of Galati, Romania and grant no. RF 3621/2021
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