Reza Sharghi-Moshtaghin

Distinct iron architecture in SF3B1 -mutant myelodysplastic syndrome patients is linked to an SLC25A37 splice variant with a retained intron

Perturbation in iron homeostasis is a hallmark of some hematologic diseases. Abnormal sideroblasts with accumulation of iron in the mitochondria are named ring sideroblasts (RS). RS is a cardinal feature of refractory anemia with RS (RARS) and RARS with marked thrombocytosis (RARS/-T). Mutations in SF3B1, a member of the RNA splicing machinery are frequent in RARS/-T and defects of this gene were linked to RS formation. Here we showcase the differences in iron architecture of SF3B1-mutant and wild-type (WT) RARS/-T and provide new mechanistic insights by which SF3B1 mutations lead to differences in iron. We found higher iron levels in SF3B1 mutant vs WT RARS/-T by transmission electron microscopy/spectroscopy/flow cytometry. SF3B1 mutations led to increased iron without changing the valence as shown by the presence of Fe2+ in mutant and WT. Reactive oxygen species and DNA damage were not increased in SF3B1-mutant patients. RNA-sequencing and Reverse transcriptase PCR showed higher expression of a specific isoform of SLC25A37 in SF3B1-mutant patients, a crucial importer of Fe2+ into the mitochondria. Our studies suggest that SF3B1 mutations contribute to cellular iron overload in RARS/-T by deregulating SLC25A37.

Interstitial hardening of duplex 2205 stainless steel by low temperature carburisation: enhanced mechanical and electrochemical performance

Abstract The mechanical properties and corrosion resistance of duplex (ferrite–austenite) grade 2205 stainless steel have been substantially improved by interstitial hardening using low temperature carburisation. The austenite phase of the duplex stainless steel responds to low temperature carburisation in a similar manner as single phase austenitic stainless steels, forming ‘expanded’ austenite (also called S phase). The surface layer that forms on the ferritic portion of 2205 steel consists of a paraequilibrium carbide, a carbide with the same metal composition as the underlying ferrite. This two-phase case has about three times the Vickers hardness of non-treated material, an improved ultimate tensile strength and increased fatigue resistance, and much improved crevice corrosion resistance.

Synthetic nanopores for molecular spectroscopy

A new technique to sequence single strand DNA by translocation through a synthetic graphene nanopore is discussed. An amplifier connecting the two sides of the nanopore produces a feedback signal sufficient for dielectrophoresis of ssDNA through the nanopore. The feedback signal also amplifies the size and electrical differences in the DNA bases as they translocate through the nanopore. Focused electron beam, focused ion beam and scanning tunneling current microscope probe were used to produce the graphene nanopore with only scanning tunneling probe reproducibly resulting in 1 nm pores.

On phase transformations in a Ni-based superalloy

In this study, a particular nickel-based superalloy has been studied by transmission electron microscopy and the results are discussed in terms of phase transformations that may have taken place. The alloy has been found to consist of three major phases; a FCC γ phase containing a random distribution of nearly spherical γ′ – Ni3Al(Ti) – precipitates and elongated thin Ni3Ti(Ta) platelets with a hexagonal structure. The orientation relationships between the different phases have been determined; loss of coherency and possible occurrence of misfit-relieving interfacial dislocations are discussed and compared with experimental observations, and possible mechanisms of phase transformations are also addressed.

Colossal Carbon Supersaturation of Delta Ferrite in 17-7 PH Stainless Steel

Low processing temperatures allow an interstitially-hardened case to be formed on the alloy with no carbide formation [1]; a “colossal” carbon supersaturation can be achieved in austenitic stainless steels such as the 316L grade [1, 2]. In addition to the notable mechanical property improvements [3, 4], such interstitially-hardened stainless steels show surprising improvements in corrosion resistance in marine environment [5].