Microstructure-Corrosion Property Correlation: Elucidating the influence of microstructure on the active corrosion behavior of Pure Iron

Microstructure-corrosion property correlation is an open question in the field of materials science. The microstructure of metals and alloys consists of several features with different individual corrosion response. The corrosion behavior of the macroscopic system is an outcome of the complex interaction of the components of microstructure. Hence, a definitive understanding of the corrosion response of the microstructural features is needed for improving the material durability and design.In the present work, the effect of grain size  on the active corrosion behavior of pure iron is investigated. Samples with different grain sizes are obtained by annealing heat-treatment. The microstructure of samples is characterized by optical microscopy, electron backscatter diffraction and X-ray diffraction. Electrochemical characterization using potentiodynamic polarization and electrochemical impedance spectroscopy are performed on the samples in deaerated 0.1 M and 0.01 M H2SO4 solutions. The surface topography of the corroded sample surface is characterized by atomic force microscopy. Following the experiments, a numerical corrosion model is attempted to replicate the observations. The results reveal an aggregate effect of grain size and crystallographic orientation of grains on the corrosion behavior of the samples.Materials Science and Engineerin

Data publication: Integration of Multifunctional Epitaxial (Magnetic) Shape Memory Films in Silicon Microtechnology

Measured raw data (XRD, texture, SEM, PPMS and EDX

Constrained incipient phase transformation in Ni-Mn-Ga films: A small-scale design challenge

Ni-Mn-Ga shape-memory alloys are promising candidates for large strain actuation and magnetocaloric cooling devices. In view of potential small-scale applications, we probe here nanomechanically the stress-induced austenite–martensite transition in single crystalline austenitic thin films as a function of temperature. In 0.5 µm thin films, a marked incipient phase transformation to martensite is observed during nanoindentation, leaving behind pockets of residual martensite after unloading. These nanomechanical instabilities occur irrespective of deformation rate and temperature, are Weibull distributed, and reveal large spatial variations in transformation stress. In contrast, at a larger film thickness of 2 μm fully reversible transformations occur, and mechanical loading remains entirely smooth. Ab-initio simulations demonstrate how an in-plane constraint can considerably increase the martensitic transformation stress, explaining the thickness-dependent nanomechanical behavior. These findings for a shape-memory Heusler alloy give insights into how reduced dimensions and constraints can lead to unexpectedly large transformation stresses that need to be considered in small-scale actuation design

Inhibition of Thioredoxin Reductase by Targeted Selenopolymeric Nanocarriers Synergizes the Therapeutic Efficacy of Doxorubicin in MCF7 Human Breast Cancer Cells

Increasing evidence suggests selenium nanoparticles (Se NPs) as potential cancer therapeutic agents and emerging drug delivery carriers, yet, the molecular mechanism of their anticancer activity still remains unclear. Recent studies indicate thioredoxin reductase (TrxR), a selenoenzyme, as a promising target for anticancer therapy. The present study explored the TrxR inhibition efficacy of Se NPs as a plausible factor impeding tumor growth. Hyaluronic acid (HA)-functionalized selenopolymeric nanocarriers (Se@CMHA NPs) were designed wielding chemotherapeutic potential for target specific Doxorubicin (DOX) delivery. Se@CMHA nanocarriers are thoroughly characterized asserting their chemical and physical integrity and possess prolonged stability. DOX-loaded selenopolymeric nanocarriers (Se@CMHA-DOX NPs) exhibited enhanced cytotoxic potential toward human cancer cells compared to free DOX in an equivalent concentration eliciting its selectivity. In first-of-its-kind findings, selenium as Se NPs in these polymeric carriers progressively inhibit TrxR activity, further augmenting the anticancer efficacy of DOX through a synergistic interplay between DOX and Se NPs. Detailed molecular studies on MCF7 cells also established that upon exposure to Se@CMHA-DOX NPs, MCF7 cells endure G2/M cell cycle arrest and p53-mediated caspase-independent apoptosis. To gauge the relevance of the developed nanosystem in in vivo settings, three-dimensional tumor sphere model mimicking the overall tumor environment was also performed, and the results clearly depict the effectiveness of our nanocarriers in reducing tumor activity. These findings are reminiscent of the fact that our Se@CMHA-DOX NPs could be a viable modality for effective cancer chemotherapy