Shape memory behavior of Ni-Fe-Ga and Ni-Mn-Sn ribbons

Magnetic Shape Memory Alloys exhibit multifunctional properties due the martensitic transformation (MT) and accompanying changes in the magnetic subsystem. In this work, melt spun ribbons of nominal composition Ni55Fe16Ga29 (R1) and Ni50Mn40Sn10 (R2) have been produced and characterized by the calorimetric, thermomechanical, mechanical, microscopic and X-ray measurements. The effect of short annealing on MT and thermo-mechanical properties is rather modest and in the case of R2 enhances its brittleness. R1 and R2 as-spun ribbons show MT at TM ~ 340 K and ~ 420 K, respectively. The strain-stress curves for Ni-Fe-Ga in austenitic phase indicate good visco-elastic properties, although the superelastic effect was not well pronounced. Ni-Fe-Ga as-cast and annealed samples, as well as the as-cast Ni-Mn-Sn ribbons, present a shape memory effect with an anomalous contraction and elongation at low external stresses in the course of the forward and reverse MT, consequence of the compressive internal stresses

Shape memory behavior of Ni-Fe-Ga and Ni-Mn-Sn ribbons

Magnetic Shape Memory Alloys exhibit multifunctional properties due the martensitic transformation (MT) and accompanying changes in the magnetic subsystem. In this work, melt spun ribbons of nominal composition Ni55Fe16Ga29 (R1) and Ni50Mn40Sn10 (R2) have been produced and characterized by the calorimetric, thermomechanical, mechanical, microscopic and X-ray measurements. The effect of short annealing on MT and thermo-mechanical properties is rather modest and in the case of R2 enhances its brittleness. R1 and R2 as-spun ribbons show MT at TM ~ 340 K and ~ 420 K, respectively. The strain-stress curves for Ni-Fe-Ga in austenitic phase indicate good visco-elastic properties, although the superelastic effect was not well pronounced. Ni-Fe-Ga as-cast and annealed samples, as well as the as-cast Ni-Mn-Sn ribbons, present a shape memory effect with an anomalous contraction and elongation at low external stresses in the course of the forward and reverse MT, consequence of the compressive internal stresses

The serine hydroxymethyltransferase-2 (SHMT2) initiates lymphoma development through epigenetic tumor suppressor silencing.

Cancer cells adapt their metabolic activities to support growth and proliferation. However, increased activity of metabolic enzymes is not usually considered an initiating event in the malignant process. Here, we investigate the possible role of the enzyme serine hydroxymethyltransferase-2 (SHMT2) in lymphoma initiation. SHMT2 localizes to the most frequent region of copy number gains at chromosome 12q14.1 in lymphoma. Elevated expression of SHMT2 cooperates with BCL2 in lymphoma development; loss or inhibition of SHMT2 impairs lymphoma cell survival. SHMT2 catalyzes the conversion of serine to glycine and produces an activated one-carbon unit that can be used to support S-adenosyl methionine synthesis. SHMT2 induces changes in DNA and histone methylation patterns leading to promoter silencing of previously uncharacterized mutational genes, such as SASH1 and PTPRM. Together, our findings reveal that amplification of SHMT2 in cooperation with BCL2 is sufficient in the initiation of lymphomagenesis through epigenetic tumor suppressor silencing