Uniaxial pulling and nano-scratching of a newly synthesised high entropy

Multi component alloys possessing nanocrystalline structure, often alluded to be as Cantor alloys or high entropy alloys (HEAs), continues to attract great attention of the research community. It has been suggested that about 64 elements in the periodic table can be mixed in various compositions to synthesize as many as ~108 different types of HEA alloys. Most HEA's possess a face centered cubic or a body centered cubic crystal structure. The nanomechanical studies on any types of HEA combining experimental and atomic simulations are rather scarce in literature, which was a major motivation behind this work. In this spirit, a novel high entropy alloy (Ni25Cu18.75Fe25Co25Al6.25) was synthesized using arc melting method which followed a joint simulation and experimental effort to investigate dislocation mediated plastic mechanisms in HEA. The investigation takes advantage of an Embedded atomic method (EAM) type potential energy function corroborating the material composition to perform the nanoscale tensile and scratch MD simulation studies followed by experimental nano-scratching to investigate plasticity and material removal mechanisms, aspects related to nanofriction and nanotribology, side flow, pileup and crystal defects formed in the sub-surface as an elasto-plastic material response of the HEA during and after the scratch process. The major types of crystal defects associated with the plastic deformation of the crystalline face centred cubic structure of HEA were 2,3,4-hcp layered like defect coordination structure, coherent ∑3 twin boundary and ∑11 fault or tilt boundary, in combination with Stair rods, Hirth locks, Frank partials and Lomer–Cottrell (LC) locks. They formed much of the damage in the sub-surface and side-flow mechanisms. Moreover, 1/6 Shockley with exceptionally larger dislocation loops were seen to be the transporters of stacking faults deeper into the substrate than the location of the applied cutting load. The (100) orientation showed the highest value for the coefficient of kinetic friction but least amount of cutting stress and cutting temperature during HEA deformation suggesting this orientation to be better than the other orientations for its improved manufacturing

Binary temporal upconversion codes of Mn2+-activated nanoparticles for multilevel anti-counterfeiting

Luminescent materials that are capable of binary temporal coding are desirable for multilevel anti-counterfeiting. Here, the authors engineer nanoparticles that produce binary color codes on different timescales by combining the long-lived luminescence of Mn2+ with the relatively short-lived emission of lanthanides

Cardiomyocyte viability upon tunicamycin treatment.

<p>Cardiomyocytes were treated with 100/ml tunicamycin (Tm) for indicated time (0, 24 h, 48 h, 72 h, 96 h) and cell viability was measured by the MTT-assay (A) and cell injury tested by the LDH-assay (B). For cell viability, the viable cell number was compared with Control group. For the LDH release assay, all the values were compared with Control group. *P<0.05 vs Ctrl, n = 5.</p

Chemical Structure of baicalin (BC).

<p>Chemical Structure of baicalin (BC).</p

CHOP-eNOS pathway in baicalin mediated protective role.

<p>Cardiomyocytes were transfected with or without siRNA for 24(BC, 25 µM) and L-NAME (10 µM) pretreatment. Viability was measured by the MTT-assay in cardiomyocytes (A, D, G). Apoptosis was tested by TUNEL analysis (B, E, H). Quantitative analysis of TUNEL-positive cardiomyocytes (C, F, I). A, B, C: *P<0.05 vs Tm+si NC, n = 5; D, E, F: *P<0.05 vs Ctrl+Tm, **P<0.05 vs Ctrl+Tm+BC, n = 5; G, H, I: *P<0.05 vs Tm+si CHOP, **P<0.05 vs Tm+BC+si CHOP, n = 5.</p

CHOP dependent induction of endothelial nitric oxide synthase (eNOS) in BC treated cardiomyocytes.

<p>(A) Cardiomyocytes were treated with Tm (100 ng/ml) in the presence or absence of baicalin (BC) for 24 h at indicated concentrations (12.5, 25, 50 µM). The expressions of eNOS and phospho eNOS at protein levels were examined by western blot. (B) BC treatment increased NO production in cultured cardiomyocytes. Cardiomyocytes were treated with Tm (100 ng/ml) in the presence or absence of baicalin (BC) for 24 h and incubated with 10 µM of DAF-FM and fluorescence intensity was assayed. (C) CHOP knockdown efficiency was tested by western blot. Cells transfected with either control siRNA or siRNA targeting CHOP were further treated with Tm (100 ng/ml) in the presence or absence of baicalin (BC, 25 µM) for 24 h. (D) The expression of eNOS mRNA levels was examined by real-time quantitative PCR. Cells were treated as C. (E) The expressions of eNOS and phospho eNOS protein levels were examined by western blot. Cells were treated as C. (F) NO production was measured by DAF-FM and fluorescence intensity was assayed. Cells were treated as C. A, B: *P<0.05 vs Ctrl, **P<0.05 vs Tm, n = 5; C, D, E, F: *P<0.05 vs Control+si NC, **P<0.05 vs Tm+si NC, n = 5.</p