11 research outputs found
Regression theory in linear and logistic model With an illustrated example in programming language R
No full textThe validity of the model in linear theory regression, was determined through theoptimal estimation of the line variation through the analysis of sediments on OLS, but if study was concerned on logistic model, a number of different statistics will have to be resorted to, such asHoms -limcho 'statistics to examining the quality of conformity ,such classification tables where there is on other statistics that's give a partial indication. and significance of the variables Interpretation. Where the study aimed to meet the regression theory between the two models while supporting the idea with an applied example in the programming language R
Analyticity of solutions to thermo‐elastic‐plastic flow problem with microtemperatures
No full textIn this paper, we study some qualitative and numerical properties of new equations including the coupled effects of thermal elastic-plastic theory with microtemperatures. We establish the necessary and sufficient conditions to guarantee that the model dissipates energy. The one-dimensional case, which corresponds to isotropic hardening problem, is chosen in order to present some qualitative and numerical properties. With the help of the semigroup theory of linear operators, we prove the well-posedness of the one-dimensional problem corresponding to plastic flow. Then, we show that the associated C0−semigroup is not analytical in general, except for a special case. The exponential stability of the solutions is kept in all cases. Finally, a numerical tool, based on the finite element method, is developed to validate the proposed model and to show its capability. Particular attention is paid to the consideration of the elastoplastic behavior in the development of this tool.Part of this work was done when the first author visited the laboratory LEM3 of ENSAM of Metz as invited Professor
Decay and numerical results in nonsimple viscoelasticity
No full textIn this paper, we give some mathematical and numerical results on the behavior of a nonsimple viscoelastic plate corresponding to anti-plane shear deformations. First, we derive briefly the equations of the considered plate, and then, we study the well-posedness problem. Second, we prove that the solutions decay exponentially at a rate proportional to the total mass of the second order. Finally, we give some numerical experiments based on the spectral method developed for multi-dimensional problems with implementation in MATLAB for one and two-dimensional spaces. © 2021 Author(s)
In-Situ Techniques to Understand Changes in Surface Chemistry During Ablation
No full textAblation is an effective and reliable method largely used in aerospace structures to protect the payload from damaging effects of external high temperatures. Substantial research is required to develop basic knowledge that is required to characterize the response of a high temperature thermal protection system to extreme hypersonic environment. This presentation will provide an overview of experimental techniques that are currently being used to understand the degradation behavior of composite materials used for thermal protection. Advantages and disadvantages of each method will be discussed. In addition, novel in situ quantitative methods of material degradation during high temperature ablation events will be identified. Specific techniques developed by the authors for hypersonic applications will be discussed. For example, in situ Raman spectroscopy during high temperature wear testing of chameleon coatings was employed by the lead author to correlate surface chemistry to measured changes in friction coefficients simultaneously. Chameleon coatings are adaptive coatings that reduce friction coefficient from 25 to 1000 °C for moving assemblies for next-generation hypersonic aircraft and missiles
Identification of Map4k4 as a novel suppressor of skeletal muscle differentiation
No full textCo-author Mengxi Wang is a student in the Interdisciplinary Graduate Program in the Graduate School of Biomedical Sciences (GSBS) at UMass Medical School.Myoblast differentiation into mature myotubes is a critical step in the development and repair of human skeletal muscle. Here we show that small interfering RNA (siRNA)-based silencing of the Ste20-like mitogen-activated protein 4 kinase 4 (Map4k4) in C2C12 myoblasts markedly enhances expression of myogenic differentiation genes, myoblast fusion, and myotube diameter. In contrast, adenovirus-mediated expression of native Map4k4 in C2C12 cells attenuates each of these processes, indicating that Map4k4 is a negative regulator of myogenic differentiation and hypertrophy. Expression of a Map4k4 kinase-inactive mutant enhances myotube formation, suggesting that the kinase activity of Map4k4 is essential for its inhibition of muscle differentiation. Map4k4 regulation of myogenesis is unlikely to be mediated by classic mitogen-activated protein kinase (MAPK) signaling pathways, because no significant difference in phosphorylation of extracellular signal-regulated kinase (ERK), p38, or c-Jun N-terminal kinase (JNK) is observed in Map4k4-silenced cells. Furthermore, silencing of these other MAPKs does not result in a hypertrophic myotube phenotype like that seen with Map4k4 depletion. Uniquely, Map4k4 silencing upregulates the expression of the myogenic regulatory factor Myf5, whose depletion inhibits myogenesis. Furthermore, Myf5 is required for enhancement of myotube formation in Map4k4-silenced cells, while Myf5 overexpression rescues Map4k4-mediated inhibition of myogenic differentiation. These results demonstrate that Map4k4 is a novel suppressor of skeletal muscle differentiation, acting through a Myf5-dependent mechanism
GaN-on-Porous Silicon for RF Applications
No full textThis research has been supported by the Win4Company funding of the Walloon Region (GaNGSTER project) and the Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA), FNRS, Belgium
Author Correction: Liver macrophages regulate systemic metabolism through non-inflammatory factors
No full textIn the version of this article initially published, in Fig. 4c, the y-axis units read ‘mg/dl’ but should have read ‘percent baseline’. The error has been corrected in the HTML and PDF versions of the article.</p
NLRP3- and AIM2-autonomy in a mouse model of MSU crystal-induced acute inflammation in vivo highlights imiquimod-dependent targeting of Il-1E expression as relevant therapy for gout patients.
No full textL'article est publié dans la revue sous le titre définitif :"A mouse model of MSU-induced acute inflammation in vivo suggests imiquimod-dependent targeting of Il-1β as relevant therapy for gout patients"International audienceThe role of Monosodium Urate (MSU) crystals in gout pathophysiology is well described, as is the major impact of IL-1 in the inflammatory reaction that constitutes the hallmark of the disease. However, despite the discovery of the NLRP3 inflammasome and its role as a Pattern Recognition Receptor linking the detection of a danger signal (MSU) to IL-1 secretion in vitro, the precise mechanisms leading to joint inflammation in gout patients are still poorly understood. Here, we provide an extensive clinical, biological and molecular characterization of the acute uratic inflammation mouse model induced by subcutaneous injection of MSU crystals, which accurately mimics human gout. Our work reveals several key features of MSU-dependent inflammation and identifies novel therapeutic opportunities, among which the use of topical application of imiquimod to promote interferon-dependent anti-inflammatory action maybe relevant. All rights reserved. No reuse allowed without permission. (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity
NLRP3- and AIM2-autonomy in a mouse model of MSU crystal-induced acute inflammation in vivo highlights imiquimod-dependent targeting of Il-1E expression as relevant therapy for gout patients.
No full textL'article est publié dans la revue sous le titre définitif :"A mouse model of MSU-induced acute inflammation in vivo suggests imiquimod-dependent targeting of Il-1β as relevant therapy for gout patients"International audienceThe role of Monosodium Urate (MSU) crystals in gout pathophysiology is well described, as is the major impact of IL-1 in the inflammatory reaction that constitutes the hallmark of the disease. However, despite the discovery of the NLRP3 inflammasome and its role as a Pattern Recognition Receptor linking the detection of a danger signal (MSU) to IL-1 secretion in vitro, the precise mechanisms leading to joint inflammation in gout patients are still poorly understood. Here, we provide an extensive clinical, biological and molecular characterization of the acute uratic inflammation mouse model induced by subcutaneous injection of MSU crystals, which accurately mimics human gout. Our work reveals several key features of MSU-dependent inflammation and identifies novel therapeutic opportunities, among which the use of topical application of imiquimod to promote interferon-dependent anti-inflammatory action maybe relevant. All rights reserved. No reuse allowed without permission. (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity
GaN-on-Porous Silicon for RF Applications
No full textGallium nitride (GaN) is a promising semiconductor for RF and high-power applications. However, its large-scale industrialization is hindered by several challenges, primarily the lack of cost-effective, high-performance handle substrates. Sapphire and SiC present high performances, but their use in electronic applications is limited due to their high cost. GaN-on-Si substrates are more affordable but suffer from high substrate-induced RF losses. We introduce an innovative method to mitigate the substrate losses. Porous silicon is known for decades for its high RF performance, but its integration is challenging. We performed porosification of the handle silicon substrate after the fabrication of the RF devices, from the backside, preserving the high quality of the GaN layers and the low cost of GaN-on-Si, while boosting the RF performances. We achieved harmonics H2 =-140 dBm at Pout=15 dBm, RF losses under 0.1 dB/mm at 5 GHz, and an effective resistivity higher than 8 kΩ·cm at 5 GHz
