Multi-component low and high entropy metallic coatings synthesized by pulsed magnetron sputtering

This paper presents the findings of the synthesis of multicomponent (Al, W, Ni, Ti, Nb) alloy coatings from mosaic targets. For the study, a pulsed magnetron sputtering method was employed under different plasma generation conditions: modulation frequency (10 Hz and 1000 Hz), and power (600 W and 1000 W). The processes achieved two types of alloy coatings, high entropy and classical alloys. After the deposition processes, scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy techniques were employed to find the morphology, thickness, and chemical and phase compositions of the coatings. Nanohardness and its related parameters, namely H3.Er2, H.E, and 1.Er2H ratios, were measured. An annealing treatment was performed to estimate the stability range for the selected coatings. The results indicated the formation of as-deposited coatings exhibiting an amorphous structure as a single-phase solid solution. The process parameters had an influence on the resulting morphology-a dense and homogenous as well as a columnar morphology, was obtained. The study compared the properties of high-entropy alloy (HEA) coatings and classical alloy coatings concerning their structure and chemical and phase composition. It was found that the change of frequency modulation and the post-annealing process contributed to the increase in the hardness of the material in the case of HEA coatings

Clusterin and Megalin in The Spinal Cord

Nerve injury induces up-regulation of the chaperone protein clusterin in affected neurons and adjacent astrocytes but the functional significance of this response is unclear. We find that motor neuron survival is significantly greater in clusterin(+/+) compared to (-/-) mice. These results suggest that endogenous expression of clusterin is neuroprotective after nerve injury. However, motor neuron survival in clusterin overexpressing mice was not different from that in wildtype mice. In contrast, treatment of neuronal cultures with clusterin-TAT recombinant protein is neuroprotective, including a positive effect on neuronal network complexity. Since extracellular clusterin complexes are endocytosed after binding to various receptors, we examined the expression of known clusterin binding receptors in the spinal cord. We find that megalin is expressed in the nuclei of two cell populations in the mouse spinal cord: i) oligodendrocytes in late postnatal and adult spinal cord white matter, and ii) transiently (E11-15) in a population of immature astrocytes in the dorsal spinal cord. We find no correlation between clusterin and megalin in the intact or injured spinal cord. However, intranuclear localization of megalin, suggesting signalling properties, is supported by the co-localization with γ-secretase, the enzyme responsible for endodomain cleavage of megalin. Megalin deficient mice display a pronounced deformation of the dorsal part of spinal cord, an almost complete absence of oligodendroglial progenitor cells, and a marked reduction in the population of mature astrocytes at later prenatal developmental stages. Taken together, our findings indicate that megalin is a novel signalling molecule for distinct populations of glial cells in the pre- and postnatal spinal cord. The functional role(s) of megalin is unknown. However, its expression patterns and cellular localization suggest that megalin regulates differentiation of oligodendrocytes and astrocytes in the prenatal spinal cord, as well as the function of myelinating oligodendrocytes in the postnatal spinal cord

Clusterin and Megalin in The Spinal Cord

Nerve injury induces up-regulation of the chaperone protein clusterin in affected neurons and adjacent astrocytes but the functional significance of this response is unclear. We find that motor neuron survival is significantly greater in clusterin(+/+) compared to (-/-) mice. These results suggest that endogenous expression of clusterin is neuroprotective after nerve injury. However, motor neuron survival in clusterin overexpressing mice was not different from that in wildtype mice. In contrast, treatment of neuronal cultures with clusterin-TAT recombinant protein is neuroprotective, including a positive effect on neuronal network complexity. Since extracellular clusterin complexes are endocytosed after binding to various receptors, we examined the expression of known clusterin binding receptors in the spinal cord. We find that megalin is expressed in the nuclei of two cell populations in the mouse spinal cord: i) oligodendrocytes in late postnatal and adult spinal cord white matter, and ii) transiently (E11-15) in a population of immature astrocytes in the dorsal spinal cord. We find no correlation between clusterin and megalin in the intact or injured spinal cord. However, intranuclear localization of megalin, suggesting signalling properties, is supported by the co-localization with γ-secretase, the enzyme responsible for endodomain cleavage of megalin. Megalin deficient mice display a pronounced deformation of the dorsal part of spinal cord, an almost complete absence of oligodendroglial progenitor cells, and a marked reduction in the population of mature astrocytes at later prenatal developmental stages. Taken together, our findings indicate that megalin is a novel signalling molecule for distinct populations of glial cells in the pre- and postnatal spinal cord. The functional role(s) of megalin is unknown. However, its expression patterns and cellular localization suggest that megalin regulates differentiation of oligodendrocytes and astrocytes in the prenatal spinal cord, as well as the function of myelinating oligodendrocytes in the postnatal spinal cord

Extracellular clusterin promotes neuronal network complexity in vitro

Clusterin (apolipoprotein J), a highly conserved amphiphatic glycoprotein and chaperone, has been implicated in a wide range of physiological and pathological processes. As a secreted protein, clusterin has been shown to act extracellularly where it is involved in lipid transportation and clearance of cellular debris. Intracellularly, clusterin may regulate signal transduction and is upregulated after cell stress. After neural injury, clusterin may be involved in nerve cell survival and postinjury neuroplasticity. In this study, we investigated the role of extracellular clusterin on neuronal network complexity in vitro. Quantitative analysis of clustrin-treated neuronal cultures showed significantly higher network complexity. These findings suggest that in addition to previously demonstrated neuroprotective roles, clusterin may also be involved in neuronal process formation, elongation, and plasticity

MALDI mass spectrometry based molecular phenotyping of CNS glial cells for prediction in mammalian brain tissue.

The development of powerful analytical techniques for specific molecular characterization of neural cell types is of central relevance in neuroscience research for elucidating cellular functions in the central nervous system (CNS). This study examines the use of differential protein expression profiling of mammalian neural cells using direct analysis by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). MALDI-MS analysis is rapid, sensitive, robust, and specific for large biomolecules in complex matrices. Here, we describe a newly developed and straightforward methodology for direct characterization of rodent CNS glial cells using MALDI-MS-based intact cell mass spectrometry (ICMS). This molecular phenotyping approach enables monitoring of cell growth stages, (stem) cell differentiation, as well as probing cellular responses towards different stimulations. Glial cells were separated into pure astroglial, microglial, and oligodendroglial cell cultures. The intact cell suspensions were then analyzed directly by MALDI-TOF-MS, resulting in characteristic mass spectra profiles that discriminated glial cell types using principal component analysis. Complementary proteomic experiments revealed the identity of these signature proteins that were predominantly expressed in the different glial cell types, including histone H4 for oligodendrocytes and S100-A10 for astrocytes. MALDI imaging MS was performed, and signature masses were employed as molecular tracers for prediction of oligodendroglial and astroglial localization in brain tissue. The different cell type specific protein distributions in tissue were validated using immunohistochemistry. ICMS of intact neuroglia is a simple and straightforward approach for characterization and discrimination of different cell types with molecular specificity

High-mass metal ion irradiation enables growth of high-entropy sublattice nitride thin films from elemental targets

Synthesis of high-entropy sublattice nitride (HESN) coatings by magnetron sputtering is typically done using custom-made alloyed targets with specific elemental compositions. This approach is expensive, requires long delivery times, and offers very limited flexibility to adjust the film composition. Here, we demonstrate a new method to grow HESN films, which relies on elemental targets arranged in the multicathode configuration with substrates rotating during deposition. TiVNbMoWN films are grown at a temperature of similar to 520(degrees)C using Ti, V, Nb, and Mo targets operating in the direct current magnetron sputtering mode, while the W target, operated by high power impulse magnetron sputtering (HiPIMS), provides a source of heavy ions. The energy of the metal ions EW+ is controlled in the range from 80 to 620 eV by varying the amplitude of the substrate bias pulses V-s, synchronized with the metal-ion-rich phase of HiPIMS pulses. We demonstrate that W(+ )irradiation provides dynamic recoil mixing of the film-forming components in the near-surface atomic layers. For EW+ >= 320 eV the multilayer formation phenomena, inherent for this deposition geometry, are suppressed and, hence, compositionally uniform HESN films are obtained, as confirmed by the microstructural and elemental analysis.(c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/