Particle size influence on crystallization behavior of Ge2Sb2Se5 glass

Differential scanning calorimetry was used to study crystallization in the Ge₂Sb₂Se₅ glass under non-isothermal conditions. The crystallization kinetics was described in terms of autocatalytic ?esták–Berggren model. An extensive discussion of all aspects of a full-scale kinetic study for a crystallization process was performed. Number of suggestions regarding the experimental part and importance of the particle size influence study was introduced in order to maximize precision, reproducibility and predicative potential of the experimental data. Complexity of the crystallization process was identified to be represented by closely overlapping consecutive competing surface and bulk mechanisms. Mutual interactions of both mechanisms as well as all other observed effects were discussed in relation to the ability of nowadays theoretical models to accurately and correctly describe the experimental data. Advanced error analysis was performed for each step of the kinetic study.     

Antibacterial Optimization of Highly Deformed Titanium Alloys for Spinal Implants

The goal of the work was to develop materials dedicated to spine surgery that minimized the potential for infection originating from the transfer of bacteria during long surgeries. The bacteria form biofilms, causing implant loosening, pain and finally, a risk of paralysis for patients. Our strategy focused both on improvement of antibacterial properties against bacteria adhesion and on wear and corrosion resistance of tools for spine surgery. Further, a ~35% decrease in implant and tool dimensions was expected by introducing ultrahigh-strength titanium alloys for less-invasive surgeries. The tested materials, in the form of thin, multi-layered coatings, showed nanocrystalline microstructures. Performed direct-cytotoxicity studies (including lactate dehydrogenase activity measurement) showed that there was a low probability of adverse effects on surrounding SAOS-2 (Homo sapiens bone osteosarcoma) cells. The microbiological studies (e.g., ISO 22196 contact tests) showed that implanting Ag nanoparticles into Ti/Ti_xN coatings inhibited the growth of E. coli and S. aureus cells and reduced their adhesion to the material surface. These findings suggest that Ag-nanoparticles present in implant coatings may potentially minimize infection risk and lower inherent stress.     

Enhanced Cytotoxic Effect of Doxorubicin Conjugated to Glutathione-Stabilized Gold Nanoparticles in Canine Osteosarcoma—In Vitro Studies

Osteosarcoma (OSA) is the most common malignant bone neoplasia in humans and dogs. In dogs, treatment consists of surgery in combination with chemotherapy (mostly carboplatin and/or doxorubicin (Dox)). Chemotherapy is often rendered ineffective by multidrug resistance. Previous studies have revealed that Dox conjugated with 4 nm glutathione-stabilized gold nanoparticles (Au-GSH-Dox) enhanced the anti-tumor activity and cytotoxicity of Dox in Dox-resistant feline fibrosarcoma cell lines exhibiting high P-glycoprotein (P-gp) activity. The present study investigated the influence of Au-GSH-Dox on the canine OSA cell line D17 and its relationship with P-gp activity. A human Dox-sensitive OSA cell line, U2OS, served as the negative control. Au-GSH-Dox, compared to free Dox, presented a greater cytotoxic effect on D17 (IC₅₀ values for Au-GSH-Dox and Dox were 7.9 μg/mL and 15.2 μg/mL, respectively) but not on the U2OS cell line. All concentrations of Au-GSH (ranging from 10 to 1000 μg/mL) were non-toxic in both cell lines. Inhibition of the D17 cell line with 100 μM verapamil resulted in an increase in free Dox but not in intracellular Au-GSH-Dox. The results indicate that Au-GSH-Dox may act as an effective drug in canine OSA by bypassing P-gp.     

Multicriteria decision support using rules that represent rough-graded preference relations

The approach described in this paper aims to support multicriteria choice and ranking of actions when the input preference information acquired from the decision maker is a graded comprehensive pairwise comparison (or ranking) of reference actions. It is based on decision-rule preference model induced from a rough approximation of the graded comprehensive preference relation among the reference actions. The set of decision rules applied to a new set of actions provides a graded fuzzy preference relation, which can be exploited by weighted-fuzzy net flow score or lexicographic-fuzzy net flow score procedure to obtain a final recommendation in terms of the best choice or of the ranking.     

Some properties of milled vanadium phosphates

Mechanochemical modification of vanadium phosphates doped with Bi, Zr, Mo has been studied. Milled samples have been investigated by means of XRD, DTA-TG, FTIR, nitrogen adsorption, electrokinetic measurements. It was found that phase composition of the phosphates does not change upon the mechanochemical modification process. Milling in water causes formation of porous materials. Modification of surface results in changes of the electrokinetic and adsorption properties of the milled samples.     

Invariants of contact structures from open books

In this note we define three invariants of contact structures in terms of open books supporting the contact structures. These invariants are the support genus (which is the minimal genus of a page of a supporting open book for the contact structure), the binding number (which is the minimal number of binding components of a supporting open book for the contact structure with minimal genus pages) and the norm (which is minus the maximal Euler characteristic of a page of a supporting open book).

     

Small angle scattering andX-ray transform in classical mechanics

We consider the Newton equation

Analytic and asymptotic properties of non-symmetric Linnik's probability densities

The function

Critical Region for Droplet Formation in the Two-Dimensional Ising Model

We study the formation/dissolution of equilibrium droplets in finite systems at parameters corresponding to phase coexistence. Specifically, we consider the 2D Ising model in volumes of size L ² , inverse temperature > _c and overall magnetization conditioned to take the value m L ² –2m v _L , where _c ^–1 is the critical temperature, m =m () is the spontaneous magnetization and v _L is a sequence of positive numbers. We find that the critical scaling for droplet formation/dissolution is when v _L ^3/2 L ^–2 tends to a definite limit. Specifically, we identify a dimensionless parameter , proportional to this limit, a non-trivial critical value _c and a function such that the following holds: For < _c , there are no droplets beyond log L scale, while for > _c , there is a single, Wulff-shaped droplet containing a fraction _c =2/3 of the magnetization deficit and there are no other droplets beyond the scale of log L. Moreover, and are related via a universal equation that apparently is independent of the details of the system.