Structure and Mechanical Behaviour of Cu‐Zr‐Ni‐Al Amorphous Alloys Produced by Rapid Solidification

The amorphous ribbons of Cu50Zr40Ni5Al5 alloy were manufactured by rapid solidification. The ribbons were investigated by X‐ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM‐EDX) and differential scanning calorimetry (DSC). The activation energy of the crystallisation in amorphous alloys was determined by Kissenger technique. The mechanical properties of the ribbons were characterized using Vickers microhardness (HV) tester. According to the XRD and SEM results, the Cu50Zr40Ni5Al5 alloys have a fully amorphous structure. The EDX analysis of the ribbons showed that compositional homogeneity of the Cu50Zr40Ni5Al5 alloy was fairly high. From the DSC curves of the amorphous ribbons, it was determined that glass transition temperature (Tg) is around 440–442°C and super‐cooled liquid region (ΔTx = Tx - Tx) before crystallisation is around 61–64°C. The microhardness of the as‐quenched ribbons was measured about 550 HV. However, this microhardness value decreased with increasing annealing temperature and it was calculated about 465 HV after annealing temperature of 800°C

Phase Identification and Size Evaluation of Mechanically Alloyed Cu-Mg-Ni Powders

Ternary mixture of Cu, Mg, and Ni with the nominal composition of nanocrystalline Cu50Mg25Ni25 (in at.%) was milled for 25 hours. Analysis of an X‐ray diffraction pattern (XRD) and transmission electron microscopy (TEM) was used to characterize the chemical phases and microstructure of the final product, which is shown to consist of ternary alloy of Cu‐Mg‐Ni with FCC structure along with small amounts of FCC MgO and Mg0.85Cu0.15. The good agreement between the size values obtained by XRD and TEM is attributed to the formation of defect‐free grains with no substructure during ball milling. Dynamic recrystallization may be a possible mechanism for the emergence of such small grains (<20 nm). The particle size distribution and morphological changes of Cu–Mg–Ni powders were also analyzed by scanning electron microscopy (SEM). According to the SEM results, the particle size of the powders decreased with increasing milling time. Lattice parameter of the Cu‐Mg‐Ni ternary FCC alloy formed during mechanical alloying increased with increase in milling time from 3.61 to 3.65 Å after 20 hours milling

Reduced gene expression of bikunin as a prognostic marker for renal cell carcinoma

Aim: Experimental and clinical studies showed that bikunin, a Kunitz-type protease inhibitor, found in urine and amniotic fluid has a role in spread of tumor cells by providing a significant reduction in the levels of urokinase-type plasminogen activator (uPA) and its specific receptor urokinase-type plasminogen activator receptor (uPAR). The aim of this study was to investigate expression of bikunin at the mRNA level and screen for mutations in exon sequence in renal cell carcinoma (RCC) tissues. Materials and Methods: Total RNA and DNA were extracted from paired normal and tumor tissues of total 50 RCC (11 papillary, 8 chromophobe, 26 clear cell, and 5 other types) patients (23 females, mean age: 53.55 ± 14.17; 27 males mean age: 62.1 ± 7.92). Bikunin mRNA levels were detected using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Mutational screening was performed by using single strand conformation polymorphism (SSCP) method and nucleotide sequence analysis. Results: There was a statistically significant decrease in the 25 (50%) of tumor tissues comparing to normal tissues in terms of mRNA levels of bikunin (Wilcoxon signed rank test, p = 0.0337). According to the classification based on subtypes of RCC; clear cell RCC samples displayed a reduced gene expression (p = 0.0148). Additionally, the patients with the age above 50 had low bikunin expression. The SNP rs80057939 spanning 4th exon of bikunin was detected in 13 tumor tissues. However, it was not statistically significant (p > 0.05). Conclusion: Decreased bikunin mRNA level in renal cells might be associated with poor prognosis of renal carcinoma. Therefore, gene constructs or exogenous administration of bikunin might be a potential adjuvant therapy for RCC treatment. Key Words: Bikunin, nucleotide sequence analysis, prognostic marker, renal cell carcinoma, semi-quantitative RT-PCR

Quantitative investigation for the dielectrophoretic effect of fluorescent dyes at single-cell resolution

Most of the microscopy-based, quantitative assays rely on fluorescent dyes. In this study, we investigated the impact of fluorescent dyes on the dielectrophoretic response of the mammalian cells. The dielectrophoretic measurements were performed to quantify whether the fluorescent dyes alter the dielectrophoretic properties of the cells at single-cell resolution. Our results present that when 10 V-pp electric field is applied, the fluorescent-labeled cells experienced the crossover frequency at 8-10 kHz, whereas the label-free cells exhibited at 16-18 kHz

Cancer reversion with oocyte extracts is mediated by cell cycle arrest and induction of tumour dormancy

Inducing stable control of tumour growth by tumour reversion is an alternative approach to cancer treatment when eradication of the disease cannot be achieved. The process requires re-establishment of normal control mechanisms that are lost in cancer cells so that abnormal proliferation can be halted. Embryonic environments can reset cellular programmes and we previously showed that axolotl oocyte extracts can reprogram breast cancer cells and reverse their tumorigenicity. In this study, we analysed the gene expression profiles of oocyte extract-treated tumour xenografts to show that tumour reprogramming involves cell cycle arrest and acquisition of a quiescent state. Tumour dormancy is associated with increased P27 expression, restoration of RB function and downregulation of mitogen-activated signalling pathways. We also show that the quiescent state is associated with increased levels of H4K20me3 and decreased H4K20me1, an epigenetic profile leading to chromatin compaction. The epigenetic reprogramming induced by oocyte extracts is required for RB hypophosphorylation and induction of P27 expression, both occurring during exposure to the extracts and stably maintained in reprogrammed tumour xenografts. Therefore, this study demonstrates the value of oocyte molecules for inducing tumour reversion and for the development of new chemoquiescence-based therapies