Structure of Se–Te glasses by Raman spectroscopy and DFT modeling

For the first time, the Raman spectra of bulk Se_xTe_1‐x glasses, 0.5 ≤ x ≤ 1.0, have been measured over the entire glass‐forming range. The spectra exhibit three broad spectral features between 150 and 300 cm^?1, attributed to Te–Te, Se–Te, and Se–Se stretching modes according to DFT simulations. The observed weak chemical ordering in the glasses is discussed on the basis of heteropolar and homopolar bond fractions derived from integrated intensity of the Raman modes and DFT cross‐sections. The underlying structural model of the glasses suggests a random distribution of the Se–Se, Se–Te, and Te–Te chemical bonds with some preference for heteropolar bonding within Se–Te–Se structural units.     

Self‐assembled amphiphilic poly‐N‐vinylpyrrolidone nanoparticles as carriers for hydrophobic drugs: Stability aspects

Nanoparticles can experience numerous impacts during storage or after intravenous administration resulting in disassembly and/or drug leakage and affecting their efficiency as drug delivery systems. In this study, this crucial issue was addressed by investigating the stability of amphiphilic poly‐N‐vinylpyrrolidone derivative nanocarriers in blood serum, against destabilizing agents and during long‐term storage. All amphiphilic poly‐N‐vinylpyrrolidone derivative nanoparticles prepared in this study were found to possess sizes less than 150 nm, narrow size distribution, spherical morphology, and a slightly negative surface charge. These nanoparticles could efficiently entrap hydrophobic substances (pyrene and curcumin) while retaining excellent compatibility with red blood cells. Moreover, our studies demonstrate the stability of the nanoparticles during long‐term storage and upon dilution with body liquids enhancing their potential as stable in vivo carriers, which is critically important for intravenous drug delivery applications. All properties were found to strongly depend on the ratio between the hydrophobic and the hydrophilic moiety of the polymers under study. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45637.     

An experimental study on the influence of particles on grain boundary migration

The pinning effect of particles on grain boundary migration was studied in a Fe–20 mass% Cr alloy deoxidised with Ti and Zr. The different nitrogen contents (65, 248 and 490 ppm) were used to vary the number of precipitated inclusions. The specimens from equiaxed zones of metal samples with different particle densities were examined by in situ observations during a 60-min holding time at 1200 and 1400 °C in a Confocal Scanning Laser Microscope. The change of particles pinning effect on the grain growth was described by an average grain size, [`(D)]_textA bar{D}_{text{A}} , and the ratio between the perimeter and area of grains, P _GB/A _G. It was found that the pinning effect of particles (mostly complex Ti–Zr oxynitrides) on grain growth decreased with a decreased nitrogen content in the metal. Furthermore, the effect of particles decreased with an increased temperature of treatment, due to the reduction of the number of particles on the grain boundaries.     

Benzotriazinyl‐mediated controlled radical polymerization of styrene

The stable free radical polymerization (SFRP) process based on (1,3‐diphenyl‐1,4‐dihydro‐1,2,4‐benzotriazin‐4‐yl), the so‐called ‘Blatter radical’, and several C‐7 substituted derivatives is introduced for the first time for the polymerization of styrene. Polystyrenes characterized by polydispersity indices in the 1.05 ? 1.27 range were obtained in the presence of the Blatter radical and its derivatives containing CF₃, Ph, Fur‐2‐yl and 4‐PhC₆H₄ substituents, while polymerization proceeded either in a non‐controlled manner or in very low polymerization yields in the presence of derivatives containing halogen (Cl, Br, I) substituents. This preliminary investigation, demonstrating the potential use of the Blatter radical and its derivatives in mediated SFRP, creates new opportunities to design and develop radicals to optimize performance in such polymerization processes. © 2013 Society of Chemical Industry     

Malignant Ascites Promote Adhesion of Ovarian Cancer Cells to Peritoneal Mesothelium and Fibroblasts

Although malignant ascites (MAs) are known to contribute to various aspects of ovarian cancer progression, knowledge regarding their role in the adhesion of cancer cells to normal peritoneal cells is incomplete. Here, we compared the effect of MAs and benign ascites (BAs) on the adhesion of A2780 and OVCAR-3 cancer cells to omentum-derived peritoneal mesothelial cells (PMCs) and peritoneal fibroblasts (PFBs). The results showed that MAs stimulated the adhesion of A2780 and OVCAR-3 cells to PMCs and PFBs more efficiently than did BAs, and the strongest binding occurred when both cancer and normal cells were exposed to the fluid. Intervention studies showed that MAs-driven adhesion of A2780 cells to PMCs/PFBs depends on the presence of TGF-β1 and HGF, whereas binding of OVCAR-3 cells was mediated by TGF-β1, GRO-1, and IGF-1. Moreover, MAs upregulated α5β1 integrin expression on PFBs but not on PMCs or cancer cells, vimentin expression in all cells tested, and ICAM-1 only in cancer cells. When integrin-linked kinase was neutralized in PMCs or PFBs, cancer cell adhesion to PMCs and PFBs decreased. Collectively, our report shows that MAs may contribute to the early stages of ovarian cancer metastasis by modulating the proadhesive interplay between normal and cancer cells.     

Linseed and Complex Rosin Ester Oils Additivated with MWCNTs and Nanopearls for Gears/Wheel‐Rail Systems

An innovative biolubricant for gears/wheel‐rail systems is formulated; it is produced inexpensively using high‐viscosity vegetable oils modified with additives of unpurified carbon nanopearls (CNPs) and MWCNTs produced via carbon‐vapor deposition. Traditional lubricants made from non‐renewable sources can be replaced with such additive‐based oils. The addition of both unpurified carbon nanopearls and nanotubes containing nanoparticles of Fe, Ni, Co, or SiO₂ is a simple way to improve the tribological properties of biolubricants. Therefore, carbon nanostructures used as additives are not required to be purified or functionalized, thus reducing production costs. Tribological testing is performed with ball‐on‐disc, four‐ball, and twin‐disc machines for two high‐viscosity biolubricants. A complex rosin ester and linseed oil additivated with commercial and raw CNPs/MWCNTs are tested. Scanning electron microscope characterization is used to assess the morphology and structure of both the carbon nanopearls and the multiwalled carbon nanotube particles in addition to the worn metal surfaces. Additionally, X‐ray diffraction, FTIR spectroscopy, and inductively coupled plasma atomic emission spectroscopy are used to characterize the MWCNTs additives. Practical Applications: Biolubricant additivation with raw unpurified MWCNTs and CNPs for enhanced tribological performance. Presence of Fe, Ni, Co, and Si nanoparticles helps fine‐tune the friction coefficient and anti‐wear rates. The proposed method may prove useful in biolubricant formulation for applications in gears/wheel‐rail and metal machining systems.     

CW laser-initiated formation of nano-Si crystals in glass-metal nanostructures

Local and controllable growth of nanocrystalline silicon (nano-Si) in a commercial borosilicate glass is demonstrated. The nano-Si was formed in the subsurface region of the glass via aluminothermic reaction in the course of the irradiation of a 2D array of aluminum nanodisks fabricated on the glass surface with CW low-power 633 and 532 nm lasers. The thermoplasmonic nature of the nanodisks heating is demonstrated: at low incident intensity, the phenomenon takes place only if the plasmon resonance of the array and the laser wavelength is close enough. However, when the laser beam intensity at the sample surface exceeds 8 MW/cm² mutual position of the plasmon resonance and the laser wavelength weakly influences the phenomenon. The nano-Si formation is studied with Raman scattering technique, and the average size of the silicon nanocrystals is evaluated.