Stability of elastic-plastic sandwich conical shells with a change in the thickness of face-layers

The paper presents an analysis of elastic-plastic stability of sandwich conical shells with a change in the thickness of face-layers. The shells under consideration consist of two load-carrying face-layers and a lightweight core layer. The thickness of those faces may vary, just as their material properties. The load carrying faces are made of isotropic, compressible, work-hardening materials. The core layer is assumed to be elastic, incompressible in the normal z direction and it resists transverse shear only. External load is assumed to be in the form of longitudinal force and lateral pressure. Deformation of the shells within the plastic range is possible before buckling. With respect to the presented research, constitutive relations of the Nadai-Hencky deformation theory, alongside the H-M-H (Huber-Mises-Hencky) yield condition constitutive relations, are accepted in the analysis. To derive the stability equations a variation, strain energy method is accepted and the Ritz method has been used to solve the stability equations

The use of mathematical model of hardness spread in the research on the property of cast-iron molds

The paper determines the range and form of a surface layer of a spheroid cast iron founding. It presents proofs of the possibility to form an operative surface of a product in the range of an intermediate surface layer of the cast. Based on research and experience, one has stated that the hardness spread and structures in cross sections of the wall of a cast are the most representative parameters determining the range of the surface layer of the iron cast

Performance comparison of conventional and composite leaf spring

The automobile industry has shown increased interest in the use of composite leaf spring due to its high strength to weight ratio. The introduction of composite materials has made it possible to reduce the weight of the leaf spring without any reduction in load carrying capacity and stiffness. In this paper, results of research on vibration suppression in steel and composite (Glass Fibre Reinforced plastic – GFRP) leaf springs are presented. Polymeric composite leaf springs and steel springs are studied. Composite springs were designed in such a way that they could replace steel springs in a van. The amplitude of vibrations and the reaction of props were measured and recorded. These parameters rendered it possible to calculate the coefficient of vibration suppression for steel and composite leaf springs. It is concluded that composite leaf springs in comparison to steel springs about three times better suppress vibrations, they are about five times lighter and generate smaller dynamic burdens to vehicle bodies

Performance comparison of conventional and composite leaf spring

The automobile industry has shown increased interest in the use of composite leaf spring due to its high strength to weight ratio. The introduction of composite materials has made it possible to reduce the weight of the leaf spring without any reduction in load carrying capacity and stiffness. In this paper, results of research on vibration suppression in steel and composite (Glass Fibre Reinforced plastic – GFRP) leaf springs are presented. Polymeric composite leaf springs and steel springs are studied. Composite springs were designed in such a way that they could replace steel springs in a van. The amplitude of vibrations and the reaction of props were measured and recorded. These parameters rendered it possible to calculate the coefficient of vibration suppression for steel and composite leaf springs. It is concluded that composite leaf springs in comparison to steel springs about three times better suppress vibrations, they are about five times lighter and generate smaller dynamic burdens to vehicle bodies

Characterizing the secretome of licensed hiPSC-derived MSCs

Although mesenchymal stromal cells (MSCs) from primary tissues have been successfully applied in the clinic, their expansion capabilities are limited and results are variable. MSCs derived from human-induced pluripotent stem cells (hiMSCs) are expected to overcome these limitations and serve as a reproducible and sustainable cell source. We have explored characteristics and therapeutic potential of hiMSCs in comparison to hBMSCs. RNA sequencing confirmed high resemblance, with average Pearson correlation of 0.88 and Jaccard similarity index of 0.99, and similar to hBMSCs the hiMSCs released extracellular vesicles with in vitro immunomodulatory properties. Potency assay with TNF alpha and IFN gamma demonstrated an increase in well-known immunomodulatory genes such as IDO1, CXCL8/IL8, and HLA-DRA which was also highlighted by enhanced secretion in the media. Notably, expression of 125 genes increased more than 1000-fold. These genes were predicted to be regulated by NFKB signaling, known to play a central role in immune response. Altogether, our data qualify hiMSCs as a promising source for cell therapy and/or cell-based therapeutic products. Additionally, the herewith generated database will add to our understanding of the mode of action of regenerative cell-based therapies and could be used to identify relevant potency markers.Molecular Epidemiolog

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

Overlapping frontoparietal networks for tactile and visual parametric working memory representations

Previous working memory (WM) research based on non-human primate electrophysiology and human EEG has shown that frontal brain regions maintain frequencies of flutter stimulation across different sensory modalities by means of a supramodal parametric WM code. These findings imply that frontal regions encode the memorized frequencies in a sensory-unspecific, quantitative format. Here, we explored which brain regions maintain information about frequencies provided by different sensory modalities at the level of activity pattern across fMRI voxel populations. Moreover, we sought evidence for a supramodal multivariate WM representation. Participants maintained the same set of frequencies of tactile vibration and visual flicker for a 6 s WM delay in a frequency discrimination task. A support vector regression model for multivariate pattern analysis was applied. We observed that sensory cortices were only selective for memoranda of their corresponding modalities, while frontoparietal regions exhibited distinguishable activity patterns to memorized frequencies regardless of sensory modality. A common multivariate code was not evident in our data. Collectively, we show that mnemonic representations for stimulus frequencies are maintained throughout the cortical hierarchy, in line with the suggested transformation of information across different representational formats. Although evidence for a supramodal multivariate code is absent, our findings underpin the generalized role of the frontoparietal cortex for maintaining quantitative information across sensory modalities

Characterizing the secretome of licensed hiPSC-derived MSCs

Although mesenchymal stromal cells (MSCs) from primary tissues have been successfully applied in the clinic, their expansion capabilities are limited and results are variable. MSCs derived from human-induced pluripotent stem cells (hiMSCs) are expected to overcome these limitations and serve as a reproducible and sustainable cell source. We have explored characteristics and therapeutic potential of hiMSCs in comparison to hBMSCs. RNA sequencing confirmed high resemblance, with average Pearson correlation of 0.88 and Jaccard similarity index of 0.99, and similar to hBMSCs the hiMSCs released extracellular vesicles with in vitro immunomodulatory properties. Potency assay with TNF alpha and IFN gamma demonstrated an increase in well-known immunomodulatory genes such as IDO1, CXCL8/IL8, and HLA-DRA which was also highlighted by enhanced secretion in the media. Notably, expression of 125 genes increased more than 1000-fold. These genes were predicted to be regulated by NFKB signaling, known to play a central role in immune response. Altogether, our data qualify hiMSCs as a promising source for cell therapy and/or cell-based therapeutic products. Additionally, the herewith generated database will add to our understanding of the mode of action of regenerative cell-based therapies and could be used to identify relevant potency markers.Molecular Epidemiolog

Small extracellular vesicles obtained from hypoxic mesenchymal stromal cells have unique characteristics that promote cerebral angiogenesis, brain remodeling and neurological recovery after focal cerebral ischemia in mice

Obtained from the right cell-type, mesenchymal stromal cell (MSC)-derived small extracellular vesicles (sEVs) promote stroke recovery. Within this process, microvascular remodeling plays a central role. Herein, we evaluated the effects of MSC-sEVs on the proliferation, migration, and tube formation of human cerebral microvascular endothelial cells (hCMEC/D3) in vitro and on post-ischemic angiogenesis, brain remodeling and neurological recovery after middle cerebral artery occlusion (MCAO) in mice. In vitro, sEVs obtained from hypoxic (1%