Piezoelectric Phononic Plates: Retrieving the Frequency Band Structure via All-electric Experiments

We propose an experimental technique based on all-electric measurements to retrieve the frequency response of a one-dimensional piezoelectric phononic crystal plate, structured periodically with millimeter-scaled metallic strips on its two surfaces. The metallic electrodes, used for the excitation of Lamb-like guided modes in the plate, ensure at the same time control of their dispersion by means of externally loaded electric circuits that offer non-destructive tunability in the frequency response of these structures. Our results, in very good agreement with finite-element numerical predictions, reveal interesting symmetry aspects that are employed to analyze the frequency band structure of such crystals. More importantly, Lamb-like guided modes interact with electric-resonant bands induced by inductance loads on the plate, whose form and symmetry are discussed and analyzed in depth, showing unprecedented dispersion characteristics.Comment: This is the version of the article before peer review or editing, as submitted by an author to Smart Materials and Structures. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-665X/ab4aa

Neuropilin-1 Controls Endothelial Homeostasis by Regulating Mitochondrial Function and Iron-Dependent Oxidative Stress.

The transmembrane protein neuropilin-1 (NRP1) promotes vascular endothelial growth factor (VEGF) and extracellular matrix signaling in endothelial cells (ECs). Although it is established that NRP1 is essential for angiogenesis, little is known about its role in EC homeostasis. Here, we report that NRP1 promotes mitochondrial function in ECs by preventing iron accumulation and iron-induced oxidative stress through a VEGF-independent mechanism in non-angiogenic ECs. Furthermore, NRP1-deficient ECs have reduced growth and show the hallmarks of cellular senescence. We show that a subcellular pool of NRP1 localizes in mitochondria and interacts with the mitochondrial transporter ATP-binding cassette B8 (ABCB8). NRP1 loss reduces ABCB8 levels, resulting in iron accumulation, iron-induced mitochondrial superoxide production, and iron-dependent EC senescence. Treatment of NRP1-deficient ECs with the mitochondria-targeted antioxidant compound mitoTEMPO or with the iron chelator deferoxamine restores mitochondrial activity, inhibits superoxide production, and protects from cellular senescence. This finding identifies an unexpected role of NRP1 in EC homeostasis

Understanding the key parameters for the rational design of layered oxide materials by composite sol-gel procedures

Previous works have well demonstrated that particle size of the filler used in layered oxide formulation is the first important parameter and must be decreased below 5 μm (Agrafiotis, 1999-2000 [10]). But once the particle size is set what are the next formulation parameters to highlight as critical? How do we improve cohesion and adhesion of the coatings? To highlight the key parameters driving the quality of coating, a model layered oxide material was prepared inside a pan granulator. The model composite sol gel formulation is based on boehmite nanoparticles (binder) and amonomodal two micrometer grain size gamma alumina (filler) which is applied onto alpha alumina beads substrate. The influences of the wetting method and relative amount of filler and binderwere investigated. Extensive characterization and imaging of the layered materials (SEM, Cryo-SEM, EPMA, Washburn test, mechanical tests, Hg-porosimetry) were used in order to follow the microstructure evolution of coating during and at the end of drying. Several crack propagation schemes were observed and explained qualitatively. Overall quality of coating is mainly related to the sol-gel transition of the binder. It defines if prior to shaping, the binder primer will be able to improve the coating adhesion and it defines also the nature and extent of damages that the coating undergoes during drying. The mechanical properties of layered oxide materials obtained using composite sol-gel formulation are definitely correlated with the binder gel shrinkage during drying

Environment and female entrepreneurship in Southeast Asia: investigation of the environmental Kuznets curve hypothesis

This paper examines the relationship between female entrepreneurship and environmental implications in ASEAN economies. While economic growth and affluence benefit society, they come at the cost of environmental degradation, particularly rising carbon dioxide levels and ecosystem concerns. Women entrepreneurs in Southeast Asia can potentially support their families and contribute to societal development by starting their own businesses. Their ventures provide fresh perspectives on societal challenges and enable active participation and contribution to creative endeavors, leading to economic and social empowerment with ripple effects on families and communities. To assess the environmental consequences of women’s entrepreneurial activities, the study applies the bias-corrected method of moments and tests the Environmental Kuznets Curve hypothesis across ten ASEAN nations from 1980 to 2021. Results show cross-sectional dependence in all variables and confirm a long-term relationship within the EKC model. The fixed-effects estimator with bias correction is deemed the most suitable model. Findings indicate that GDPpc leads to decreased emissions, while the square of GDPpc contributes to increased emissions; however, the cubic term of GDPpc leads to decreased CO2 emissions, supporting the “inverted N” curve distribution of emissions across ASEAN nations proposed by the EKC theory. Additionally, the study reveals that higher percentages of female entrepreneurs are associated with increased carbon dioxide emissions, potentially due to increased efforts to support and develop female entrepreneurs. Conversely, a reduction in the gender gap in marriage, divorce, remarriage, and domestic violence leads to a shift away from entrepreneurial activities among women, positively impacting the environment

STABILITE ELASTOPLASTIQUE DES BARRES COMPRIME-FLECHIES A IMPERFECTIONS INITIALES

La sédimentation des barrages dans les pays de l’Afrique du nord est très élevée et même spectaculaire. Elle est due directement aux forts taux d’érosion des bassins versants, dont les particules solides sont drainées directement par les cours d’eau et provoqueront à l’entrée des retenues des courants de densité. Cette sédimentation pose d’énormes problèmes à savoir ; la réduction de la capacité, l’obturation des organes de vidange, la sécurité de l’ouvrage, la sédimentation des canaux d’irrigation et elle a même un impact sur la qualité de l’eau

Improved control strategy of DFIG-based wind turbines using direct torque and direct power control techniques

This paper presents different control strategies for a variable-speed wind energy conversion system (WECS), based on a doubly fed induction generator. Direct Torque Control (DTC) with Space-Vector Modulation is used on the rotor side converter. This control method is known to reduce the fluctuations of the torque and flux at low speeds in contrast to the classical DTC, where the frequency of switching is uncontrollable. The reference for torque is obtained from the maximum power point tracking technique of the wind turbine. For the grid-side converter, a fuzzy direct power control is proposed for the control of the instantaneous active and reactive power. Simulation results of the WECS are presented to compare the performance of the proposed and classical control approaches.Peer reviewedFinal Accepted Versio

p63 is an alternative p53 repressor in melanoma that confers chemoresistance and a poor prognosis.

The role of apoptosis in melanoma pathogenesis and chemoresistance is poorly characterized. Mutations in TP53 occur infrequently, yet the TP53 apoptotic pathway is often abrogated. This may result from alterations in TP53 family members, including the TP53 homologue TP63. Here we demonstrate that TP63 has an antiapoptotic role in melanoma and is responsible for mediating chemoresistance. Although p63 was not expressed in primary melanocytes, up-regulation of p63 mRNA and protein was observed in melanoma cell lines and clinical samples, providing the first evidence of significant p63 expression in this lineage. Upon genotoxic stress, endogenous p63 isoforms were stabilized in both nuclear and mitochondrial subcellular compartments. Our data provide evidence of a physiological interaction between p63 with p53 whereby translocation of p63 to the mitochondria occurred through a codependent process with p53, whereas accumulation of p53 in the nucleus was prevented by p63. Using RNA interference technology, both isoforms of p63 (TA and ΔNp63) were demonstrated to confer chemoresistance, revealing a novel oncogenic role for p63 in melanoma cells. Furthermore, expression of p63 in both primary and metastatic melanoma clinical samples significantly correlated with melanoma-specific deaths in these patients. Ultimately, these observations provide a possible explanation for abrogation of the p53-mediated apoptotic pathway in melanoma, implicating novel approaches aimed at sensitizing melanoma to therapeutic agents

Loss of Niemann-Pick C1 or C2 Protein Results in Similar Biochemical Changes Suggesting That These Proteins Function in a Common Lysosomal Pathway

Niemann-Pick Type C (NPC) disease is a lysosomal storage disorder characterized by accumulation of unesterified cholesterol and other lipids in the endolysosomal system. NPC disease results from a defect in either of two distinct cholesterol-binding proteins: a transmembrane protein, NPC1, and a small soluble protein, NPC2. NPC1 and NPC2 are thought to function closely in the export of lysosomal cholesterol with both proteins binding cholesterol in vitro but they may have unrelated lysosomal roles. To investigate this possibility, we compared biochemical consequences of the loss of either protein. Analyses of lysosome-enriched subcellular fractions from brain and liver revealed similar decreases in buoyant densities of lysosomes from NPC1 or NPC2 deficient mice compared to controls. The subcellular distribution of both proteins was similar and paralleled a lysosomal marker. In liver, absence of either NPC1 or NPC2 resulted in similar alterations in the carbohydrate processing of the lysosomal protease, tripeptidyl peptidase I. These results highlight biochemical alterations in the lysosomal system of the NPC-mutant mice that appear secondary to lipid storage. In addition, the similarity in biochemical phenotypes resulting from either NPC1 or NPC2 deficiency supports models in which the function of these two proteins within lysosomes are linked closely

Vaccine delivery by penetratin: mechanism of antigen presentation by dendritic cells

Cell-penetrating peptides (CPP) or membrane-translocating peptides such as penetratin from Antennapedia homeodomain or TAT from human immunodeficiency virus are useful vectors for the delivery of protein antigens or their cytotoxic (Tc) or helper (Th) T cell epitopes to antigen-presenting cells. Mice immunized with CPP containing immunogens elicit antigen-specific Tc and/or Th responses and could be protected from tumor challenges. In the present paper, we investigate the mechanism of class I and class II antigen presentation of ovalbumin covalently linked to penetratin (AntpOVA) by bone marrow-derived dendritic cells with the use of biochemical inhibitors of various pathways of antigen processing and presentation. Results from our study suggested that uptake of AntpOVA is via a combination of energy-independent (membrane fusion) and energy-dependent pathways (endocytosis). Once internalized by either mechanism, multiple tap-dependent or independent antigen presentation pathways are accessed while not completely dependent on proteasomal processing but involving proteolytic trimming in the ER and Golgi compartments. Our study provides an understanding on the mechanism of antigen presentation mediated by CPP and leads to greater insights into future development of vaccine formulations