SI-ATRP Decoration of Magnetic Nanoparticles with PHEMA and Post-Polymerization Modification with Folic Acid for Tumor Cells’ Specific Targeting

Targeted nanocarriers could reach new levels of drug delivery, bringing new tools for personalized medicine. It is known that cancer cells overexpress folate receptors on the cell surface compared to healthy cells, which could be used to create new nanocarriers with specific targeting moiety. In addition, magnetic nanoparticles can be guided under the influence of an external magnetic field in different areas of the body, allowing their precise localization. The main purpose of this paper was to decorate the surface of magnetic nanoparticles with poly(2-hydroxyethyl methacrylate) (PHEMA) by surface-initiated atomic transfer radical polymerization (SI-ATRP) followed by covalent bonding of folic acid to side groups of the polymer to create a high specificity magnetic nanocarrier with increased internalization capacity in tumor cells. The biocompatibility of the nanocarriers was demonstrated by testing them on the NHDF cell line and folate-dependent internalization capacity was tested on three tumor cell lines: MCF-7, HeLa and HepG2. It has also been shown that a higher concentration of folic acid covalently bound to the polymer leads to a higher internalization in tumor cells compared to healthy cells. Last but not least, magnetic resonance imaging was used to highlight the magnetic properties of the functionalized nanoparticles obtained.     

Alkaline treatment of cotton in different reagent mixtures with reduced water content. II. Influence of finishing procedure

Changes in cotton fabrics brought about by different swelling agents and different types of finishing procedures have been studied in this work, using a single‐step swelling of cotton in the reagent. Cotton fabrics were treated with different alkalis and mixtures of alkalis and other additives and finished with a modified type of 1,3‐dimethylol‐4,5‐dihydroxyethylene urea, using wet‐on‐wet and wet‐on‐dry technique. Properties generally used to characterize mercerized cotton were selected that are technologically important, such as water retention, shrinkage, stiffness, and crease recovery angle. Water retention method has been used to compare the degree of swelling for different samples. Differences in properties among these samples were observed and some practically important conclusions were arrived at. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1194–1201, 2006     

Reversed and Anomalous Doppler Effects in Photonic Crystals and other Time-dependent Periodic Media

We predict that reversed and anomalous non-relativistic Doppler shifts can be observed under some circumstances when light reflects from a shock wave front propagating through a photonic crystal, or material with a periodic modulation of the dielectric. This theoretical prediction is generalizable and applies to wave-like excitations in a variety of periodic media. An experimental observation of this effect has recently been made (Seddon, N. and Bearpark, T. Science, 302 (2003) 1537) and we provide a brief discussion of this experiment.     

Cationic Heterogeneous Copolymerization of Octamethylcyclotetrasiloxane with 1,3,5,7-Tetramethyl-1,3,5,7-tetravinylcyclotetra-Siloxane: Optimization of Reaction Conditions

Copolymerization of octamethylcyclotetrasiloxane (D₄) with 1,3,5,7-tetrametyl-1,3,5,7-tetravinylcyclotetrasiloxane (V₄) by heterogeneous acid catalysis has been carried out. In order to find the optimal conditions of the reaction, a second-order experimental design was performed with reaction time, reaction temperature, amount of catalyst, and the initial molar fraction of the monomers as independent parameters. By data processing, response surfaces of monomer conversion and copolymer composition were obtained, which were studied by eigenvalues analysis and by plotting in 2-D fields. It was found that the most important factors of influence were reaction temperature for the monomer conversion and the initial monomer molar fraction for the copolymer final composition.     

Achieving centimetre-scale supercollimation in a large-area two-dimensional photonic crystal

Diffraction, a fundamental process in wave physics, leads to spreading of the optical beams as they propagate. However, new photonic crystal (PhC) meta-materials can be nano-engineered to generate extreme anisotropy, resulting in apparent propagation of light without diffraction. This surprising phenomenon, called supercollimation, effectively freezes the spatial width of a light beam inside a PhC, observed over a few isotropic diffraction-lengths. However, using such experiments to predict the behaviour for longer propagation lengths is difficult, as a tiny error in a measured width can extrapolate to order unity uncertainty in the width at distances over hundreds of diffraction-lengths. Here, supercollimation is demonstrated in a macroscopic PhC system over centimetre-scale distances, retaining spatial width confinement without the need for waveguides or nonlinearities. Through quantitative studies of the beam evolution in a two-dimensional PhC, we find that supercollimation possesses unexpected but inherent robustness with respect to short-scale disorder such as fabrication roughness, enabling supercollimation over 600 isotropic diffraction-lengths. The effects of disorder are identified through experiments and understood through rigorous simulations. In addition, a supercollimation steering capability is proposed.     

Bibliometric study of family business succession between 1939 and 2017: mapping and analyzing authors’ networks

This study maps and analyzes the scientific research networks of family business succession. We examine coauthors’ activities in terms of not only productivity but also their importance to the coauthorship network. The most influential contributors and universities, as well as their research networks and theoretical underpinnings, are discussed. The review examines 661 articles published by 1105 authors in 224 academic journals indexed in the Social Science Citation Index and Scopus between 1939 and 2017. We used a bibliometric approach based on coauthorship analysis to measure cooperation. The results show that family business succession research is characterized by high fragmentation in the authors’ collaboration in general, but the leading scholars are strongly interconnected. We map and analyze the most influential networks by identifying the most important topics studied, the theoretical and methodological approaches employed, the scope of the research conducted, and where it has been published. Most of the identified networks are in North America and Europe, and most are not theoretically or methodologically specialized.     

Radiopaque acrylic bone cements with bromine‐containing monomer

One important issue for the acrylic bone cements concerns the radiopacity, which may be achieved by different ways. In this work, a new bromine‐containing acrylic monomer, the 2‐(2‐bromopropionyloxy) propyl methacrylate (BPPM), was synthesized and proposed to be used for providing radiopaque bone cements. Different acrylic bone cements were realized by partially replacing the methyl methacrylate (MMA) monomer phase with 5–20% w/w of BPPM‐comonomer. The effect of this comonomer on the curing parameters of acrylic bone cements, on their thermal and rheological properties, water absorption, density, contact angle, compression tests, and radiopacity was studied. It appears that the presence of BPPM does provide radiopacity, improves the curing parameters by decreasing the maximum curing temperature and increasing the setting time. The new BPPM‐acrylic bone cements exhibit lower glass transition temperature and better thermal stability when compared with the classical radiolucent acrylic cements. Rheological measurements have shown that 10–20% w/w of BPPM in the liquid phase of acrylic bone cement formulations increase its flexibility, and may also induce a slight crosslinking reaction during the curing phase. BPPM‐modified acrylic bone cements present lower polymerization shrinkage and higher compression strength, and similar water uptake, porosity, and water contact angle as the radiolucent PMMA‐cements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Alkaline treatment of cotton in different reagent mixtures with reduced water content. I. Influence of alkali type and additives

The purpose of this study was to examine the influence of some swelling agents with reduced water content on final properties of cotton fabrics. A single‐step swelling of cotton in the reagent was used. There were selected properties generally used to characterize mercerized cotton that are technologically important, such as water retention, shrinkage, stiffness, crease recovery angle, and hand. Water retention method and dyeing with CI Direct Red 81 have been used to compare the degree of swelling for different samples. Correlations have been established between structural changes induced by the swelling agents and final properties of cotton fabric. The mixtures of an alkali solution and an additive produced similar or better end‐use properties as compared with classical sodium hydroxide or ammonia treatments, combining the action of a diluted alkali solution (3.13 mol/L NaOH or KOH) and a nonalkali reagent. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2848–2855, 2006     

Thermo-sensitive polymers based on graft polysiloxanes

The synthesis of novel polymers obtained by grafting poly(dimethyl siloxane) with NIPAM, N,N′-dimethyl acrylamide (DMA) and copolymers of NIPAM with DMA and butyl acrylate using SET-LRP technique is presented. The polymers were characterized by ¹H NMR, fluorescence spectroscopy, and DSC. The thermo-sensitivity and the LCST as well as the aggregation phenomena during phase transition are evidenced by dynamic light scattering (DLS) and rheology coupled with small angle light scattering (SALS). Rheological and Rheo-SALS measurements proved to be useful tools to characterize the macroscopic behavior but also to evidence structural changes below and above the LCST for the analyzed systems. Good correlation was found between rheological, rheo-SALS and DLS data.