Spin transport and spin torque in antiferromagnetic devices

Ferromagnets are key materials for sensing and memory applications. In contrast, antiferromagnets which represent the more common form of magnetically ordered materials, have found less practical application beyond their use for establishing reference magnetic orientations via exchange bias. This might change in the future due to the recent progress in materials research and discoveries of antiferromagnetic spintronic phenomena suitable for device applications. Experimental demonstration of the electrical switching and detection of the Néel order open a route towards memory devices based on antiferromagnets. Apart from the radiation and magnetic-field hardness, memory cells fabricated from antiferromagnets can be inherently multilevel, which could be used for neuromorphic computing. Switching speeds attainable in antiferromagnets far exceed those of ferromagnetic and semiconductor memory technologies. Here we review the recent progress in electronic spin-transport and spin-torque phenomena in antiferromagnets that are dominantly of the relativistic quantum mechanical origin. We discuss their utility in pure antiferromagnetic or hybrid ferromagnetic/antiferromagnetic memory devices

Human 343delT HSPB5 chaperone associated with early-onset skeletal myopathy causes defects in protein solubility.

Mutations of HSPB5 (also known as CRYAB or αB-crystallin), a bona fide heat shock protein and molecular chaperone encoded by the HSPB5 (crystallin, alpha B) gene, are linked to various multisystem disorders featuring variable combinations of cataracts, cardiomyopathy, and skeletal myopathy. This study aims at investigating the pathological mechanisms involved in an early onset myofibrillar myopathy manifesting in a child harboring a homozygous recessive mutation in HSPB5, 343delT. To study HSPB5 343delT protein dynamics, we utilize model cell culture systems including induced pluripotent stem cells (iPSCs) derived from the 343delT patient (343delT/343delT) along with isogenic, heterozygous, gene-corrected control cells (WT KI/343delT), and BHK21 cells, a cell line lacking endogenous HSPB5 expression. 343delT/343delT and WT KI/343delT iPSC-derived skeletal myotubes (iSKMs) and cardiomyocytes (iCMs) did not express detectable levels of 343delT protein, contributable to extreme insolubility of the mutant protein. Overexpression of HSPB5 343delT resulted in insoluble mutant protein aggregates and induction of a cellular stress response. Co-expression of 343delT with WT prevented visible aggregation of 343delT and improved its solubility. Additionally, in vitro refolding of 343delT in the presence of WT rescued its solubility. We demonstrate an interaction between WT and 343delT both in vitro and within cells. These data support a loss of function model for the myopathy observed in the patient, as the insoluble mutant would be unavailable to perform normal functions of HSPB5, though additional gain-of-function effects of the mutant protein cannot be excluded. Additionally, our data highlights the solubilization of 343delT by WT, concordant with the recessive inheritance of the disease and absence of symptoms in carrier individuals

Human 343delT HSPB5 chaperone associated with early-onset skeletal myopathy causes defects in protein solubility.

Mutations of HSPB5 (also known as CRYAB or αB-crystallin), a bona fide heat shock protein and molecular chaperone encoded by the HSPB5 (crystallin, alpha B) gene, are linked to various multisystem disorders featuring variable combinations of cataracts, cardiomyopathy, and skeletal myopathy. This study aims at investigating the pathological mechanisms involved in an early onset myofibrillar myopathy manifesting in a child harboring a homozygous recessive mutation in HSPB5, 343delT. To study HSPB5 343delT protein dynamics, we utilize model cell culture systems including induced pluripotent stem cells (iPSCs) derived from the 343delT patient (343delT/343delT) along with isogenic, heterozygous, gene-corrected control cells (WT KI/343delT), and BHK21 cells, a cell line lacking endogenous HSPB5 expression. 343delT/343delT and WT KI/343delT iPSC-derived skeletal myotubes (iSKMs) and cardiomyocytes (iCMs) did not express detectable levels of 343delT protein, contributable to extreme insolubility of the mutant protein. Overexpression of HSPB5 343delT resulted in insoluble mutant protein aggregates and induction of a cellular stress response. Co-expression of 343delT with WT prevented visible aggregation of 343delT and improved its solubility. Additionally, in vitro refolding of 343delT in the presence of WT rescued its solubility. We demonstrate an interaction between WT and 343delT both in vitro and within cells. These data support a loss of function model for the myopathy observed in the patient, as the insoluble mutant would be unavailable to perform normal functions of HSPB5, though additional gain-of-function effects of the mutant protein cannot be excluded. Additionally, our data highlights the solubilization of 343delT by WT, concordant with the recessive inheritance of the disease and absence of symptoms in carrier individuals

Comparison on In Vitro Characterization of Fucospheres and Chitosan Microspheres Encapsulated Plasmid DNA (pGM-CSF): Formulation Design and Release Characteristics

Granulocyte–macrophage colony-stimulating factor (GM-CSF) is a cytokine used in the treatment of serious conditions resulting from chemotherapy and bone marrow transplantation such as neutropenia and aplastic anemia. Despite these effects, GM-CSF has a very short biological half-life, and it requires frequent injection during the treatment. Therefore, the cytokine production is possible in the body with plasmid-encoded GM-CSF (pGM-CSF) coding for cytokine administered to the body. However, the selection of the proper delivery system for the plasmid is important. In this study, two different delivery systems, encapsulated plasmid such as fucoidan–chitosan (fucosphere) and chitosan microspheres, were prepared and the particle physicochemical properties evaluated. Fucospheres and chitosan microspheres size ranges are 151–401 and 376–681 nm. The zeta potential values of the microspheres were changed between 8.3–17.1 mV (fucosphere) and +21.9–28.9 mV (chitosan microspheres). The encapsulation capacity of fucospheres changed between 84.2% and 94.7% depending on the chitosan molecular weight used in the formulation. In vitro plasmid DNA release from both delivery systems exhibited slower profiles of approximately 90–140 days. Integrity of released samples was checked by agarose gel electrophoresis, and any additional band was not seen. All formulations were analyzed kinetically. The calculated regression coefficients showed a higher r2 value with zero-order kinetics. In conclusion, the characterizations of the microspheres can be modulated by changing the formulation variables, and it can be concluded that fucospheres might be a potential carrier system for the controlled delivery of GM-CSF encoding plasmid DNA

Enhancement of the protective efficacy of a ROP18 vaccine against chronic toxoplasmosis by nasal route

International audienceInfection with the parasite Toxoplasma gondii causes serious public health problems and is of great economic importance worldwide. No vaccine is currently available, so the design of efficient vaccine strategies is still a topical question. In this study, we evaluated the immunoprophylactic potential of a T. gondii virulence factor, the rhoptry kinase ROP18, in a mouse model of chronic toxoplasmosis: first using a recombinant protein produced in Schneider insect cells adjuvanted with poly I:C emulsified in Montanide SV71 by a parenteral route or adjuvanted with cholera toxin by the nasal route and second using a DNA plasmid encoding ROP18 adjuvanted with GM-CSF ± IL-12 DNA. If both intranasal and subcutaneous recombinant ROP18 immunizations induced predominantly anti-ROP18 IgG1 antibodies and generated a mixed systemic Th1-/Th2-type cellular immune response characterized by the production of IFN-γ, IL-2, Il-10 and IL-5, only intranasal vaccination induced a mucosal (IgA) humoral response in intestinal washes associated with a significant brain cyst reduction (50 %) after oral challenge with T. gondii cysts. DNA immunization induced antibodies and redirected the cellular immune response toward a Th1-type response (production of IFN-γ and IL-2) but did not confer protection. These results suggest that ROP18 could be a component of a subunit vaccine against toxoplasmosis and that strategies designed to enhance mucosal protective immune responses could lead to more encouraging results

Dual-light control of nanomachines that integrate motor and modulator subunits

International audienc