Multifunctional Composite Materials Based on Anion Exchangers Modified with Copper Compounds-A Review of Their Synthesis Methods, Characteristics and Applications.

As copper and its compounds are of fundamental importance for the development of innovative materials, the synthesis of composites intended for water purification was undertaken in which submicron copper containing particles were dispersed within the matrix of a strongly basic anion exchanger, with a macroporous and gel-like structure. Due to their trimethylammonium functional groups, the host materials alone exhibited an affinity to anionic water contaminants and antimicrobial properties. The introduction of such particles as CuO, Cu2O, metallic Cu, CuO/FeO(OH), Cu4O3, Cu(OH)2, Cu4(OH)6SO4, Cu2(OH)3Cl increased these properties and demonstrated new properties. The composites were obtained unconventionally, in ambient conditions, using eco-friendly reagents. Alternative synthesis methods were compared and optimized, as a result of which a new group of hybrid ion exchangers was created (HIXs) containing 3.5-12.5 wt% of Cu. As the arrangement of the inorganic phase in the resin matrix was atypical, i.e., close to the surface of the beads, the obtained HIXs exhibited excellent kinetic properties in the process of oxidation and adsorption of As(III), as well as catalytic properties for the synthesis of triazoles via click reaction, and also antimicrobial properties in relation to Gram-positive Enterococcus faecalis and Gram-negative Pseudomonas aeruginosa and Escherichia coli, preventing biofilm formation. Using thermogravimetry, the effect of the inorganic phase on decomposition of the polymeric phase was evaluated for the first time and comprehensively, confirming the relationship and finding numerous regularities. It was also found that, depending on the oxidation state (CuO, Cu2O, Cu), copper-containing particles affected the textural properties of the polymeric phase endowing a tighter structure, limiting the porosity and reducing the affinity for water.

Synthesis, Thermogravimetric Analysis, and Kinetic Study of Poly-N-Isopropylacrylamide with Varied Initiator Content.

The thermal decomposition and kinetic parameters of four polymers, PN-1, PN-05, PN-01, and PN-005, were determined by thermogravimetry (TGA/DTG) under non-isothermal conditions. N-isopropylacrylamide (NIPA)-based polymers were synthesized by the surfactant-free precipitation polymerization (SFPP) with different concentrations of the anionic initiator potassium persulphate (KPS). Thermogravimetric experiments were carried out in the temperature range of 25-700 °C at four heating rates, 5, 10, 15, and 20 °C min-1, under a nitrogen atmosphere. Poly NIPA (PNIPA) showed three stages of mass loss during the degradation process. The thermal stability of the test material was determined. Activation energy values were estimated using Ozawa, Kissinger, Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Friedman (FD) methods.

Copper Rich Composite Materials Based on Carboxylic Cation Exchangers and Their Thermal Transformation.

The effect of a cupric deposit (Cu2+, CuO) on the thermal decomposition of carboxylic cation exchangers (CCEs) is not known, and such studies may have practical significance. CCEs have a very high ion exchange capacity, so an exceptionally large amount of CuO (which is a catalyst) can be precipitated inside them. Two CCEs, macroreticular (Amberlite IRC50) and gel-like (Amberlite IRC86), served as a polymeric support to obtain copper-rich hybrid ion exchangers. Composites with CuO particles inside a polyacrylic matrix (up to 35.0 wt% Cu) were obtained. Thermal analyses under air and under N2 were performed for CCEs in the H+ and Cu2+ form with and without a CuO deposit. The results of sixteen experiments are discussed based on the TG/DTG curves and XRD patterns of the solid residues. Under air, the cupric deposit shifted the particular transformations and the ultimate polymeric matter decomposition (combustion) toward lower temperatures (even about 100-150 °C). Under N2, the reduction of the cupric deposit to metallic copper took place. Unique composite materials enriched in carbonaceous matter were obtained, as the products of polymeric matrix decomposition (free radicals and hydrogen) created an additional amount of carbon char due to the utilization of a certain amount of hydrogen to reduce Cu (II) to Cu0.

Weakly Hydrated Anion Exchangers Doped with Cu2O and Cu0 Particles-Thermogravimetric Studies.

Hybrid ion exchangers (HIXs) containing fine Cu2O and Cu0 particles were subjected to thermal analysis in order to determine their hygroscopic water content (with regard to their anomalously low porosity) and to determine the effect of the oxidation state of the copper atom in the deposit on the thermal properties of composite materials. Commercially available anion exchangers, Amberlite IRA 900Cl (macroreticular, M) and Amberlite IRA 402OH (gel-like, G), were used as supporting materials. M/Cu2O, G/Cu2O, M/Cu and G/Cu, containing 4.3-8.4 wt% Cu, were subjected to thermal analysis under respectively air and N2. TG/DTG curves revealed that dry M/Cu and G/Cu contained as little as 7.2% and 4.3% hygroscopic water, while M/Cu2O and G/Cu2O contained respectively 10.6% and 9.4% (Cu0 was a stronger water repellent than Cu2O). The oxidation state of the copper atom in the deposit was found to affect the amount of the forming char, and also Cu0 was found to contribute to the formation of more char than in the pyrolysis of the pure resin (the anion exchanger with no copper deposit). Under air the two kinds of particles transformed into CuO, while under N2 metallic copper and char (from the resin phase) made up the solid residue. This means that in the pyrolysis of the HIXs the inorganic phase participated in char formation and it also transformed itself (undergoing reduction when possible). The above findings provide a basis for in-depth research aimed at the innovative use of copper-containing HIXs and at obtaining usable composite materials with a designed (organic-inorganic) composition.

Molecular Mobility and Stability Studies of Amorphous Imatinib Mesylate.

The proposed study examined the characterization and stability of solid-state amorphous imatinib mesylate (IM) after 15 months under controlled relative humidity (60 ± 5%) and temperature (25 ± 2 °C) conditions. After 2 weeks, and 1, 3, 6, and 15 months, the samples were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray powder diffractometry (XRPD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). Additionally, the amorphous form of imatinib mesylate was obtained via supercooling of the melt in a DSC apparatus, and aged at various temperatures (3, 15, 25 and 30 °C) and time periods (1-16 h). Glass transition and enthalpy relaxation were used to calculate molecular-relaxation-time parameters. The Kohlrausch-Williams-Watts (KWW) equation was applied to fit the experimental enthalpy-relaxation data. The mean molecular-relaxation-time constant (τ) increased with decreasing ageing temperature. The results showed a high stability of amorphous imatinib mesylate adequate to enable its use in solid dosage form.

Effect of Selected Comonomers on the Transition Temperature of Thermosensitive NIPA Derivatives Synthesized with an Anionic Initiator.

The present study evaluates the effect of the cationic initiator on the hydrodynamic diameter of copolymers of N-isopropylacrylamide nanogels synthesized via a surfactant-free precipitation polymerization at 70 °C in the presence of the cationic initiator 2,2'-azobis[2- methylpropionamidine] dihydrochloride. Three types of polymeric nanoparticles were synthesized using N, N'-methylenebisacrylamide as a crosslinker. The first batch was used as a reference. The second type of particles included a poly(ethylene glycol) methyl ether-acrylate monomer, while the third type used an N-tert-butylacrylamide comonomer. The hydrodynamic diameters of the synthesized particles were between 160 and 970 nm at 18 °C. The chemical composition and morphology of the synthesized co-polymeric nanoparticles were confirmed using infrared spectroscopy, nuclear magnetic resonance and scanning electron microscopy. The zeta potentials measured via dynamic light scattering were 20.0, 17.0, -0.1 mV for the three types, respectively. The volume phase transition temperature was between 22 and 41 °C. The polydispersity index of particles synthesized with N-tert-butylacrylamide varied depending on the measurement temperature.

INFLUENCE OF LIPOPHILIC AND HYDROPHILIC CO-MONOMERS ON THE HYDRODYNAMIC DIAMETER OF THERMOSENSITIVE NIPA DERIVATIVES FOR THERMALLY CONTROLLED DRUG DELIVERY.

For modem drug delivery, new drug carriers sensitive to various factors and with size in the range of micro- and nanometers are required. The aim of this work was to evaluate the influence of hydrophilic and hydrophobic co-monomers on the hydrodynamic diameter of three co-polymers of N-isopropylacrylamide (NIPA) nanogels synthesized at 70*C in the presence of potassium persulfate (KPS) as the initiator and N.N'-methylene bis-acrylamide (MBA) as the cross-linker. The first batch of nanoparticles was synthesized without co-monomer, whereas poly(ethylene glycol) methyl ether acrylate (PEG-MEA), and N-teii-butylacrylamide (NTB), were implemented as co-monomers for the second and third batch. Hydrodynamic diameter of nanoparticles was in the range 550-800 rn. The compositions of the synthesized co-polymer nanoparticles were con- firmed via IR and NMR analyses. The SFPP conditions resulted in hydrodynamic diameters ranging from approximately 550 to 800 nm at temperatures lower than the volume phase transition temperature (VPTT) and diameters ranging from 250 to 600 nm at temperatures above the VPTT, where the VPTT was between 26 and 41'C. The polydispersity index (PDI) showed a maximum or a minimum value at the VPTT, which was an important indicator of the volume phase transition. According to the PDI observation during thermal cycling, the addition of NTB into the polymeric chain resulted in maximal values of the PDI at the VPIT, similar to the case of nanoparticles without any additional co-monomers. In contrast, in the case of PEG-MEA, the PDI presented a minimal value. Dynamic light scattering (DLS) volume measurements, performed simultaneously with spectral methods, may lead to a fast evaluation of nanoparticles prepared by SFPP.

Thermal stability and decompositions kinetics under non-isothermal conditions of imatinib mesylate α form.

The thermal decomposition and kinetic parameters of synthetized imatinib mesylate α form α form were determined by thermogravimetry (TGA/DTG) under non-isothermal conditions. The experiments were performed at a 25-940°C temperature range at five different heating rates: 2.5Kmin(-1), 5Kmin(-1), 10Kmin(-1), 15Kmin(-1) and 20Kmin(-1) per minute in a nitrogen atmosphere. Imatinib mesylate α form presents one-step mass loss during the degradation process. The thermal stability of the examined material, the melting temperature (Tonset=220.6°C) and ΔH fusion=-95.74Jg(-1) at a heating rate of 10°Cmin(-1) was established. The values of activation energies have been estimated using Kissinger, Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods.

Telomerase activity in head and neck cancer.

BACKGROUND: Telomerase activity is associated with many malignancies, including head and neck cancer. The use of telomerase activity as a diagnostic and prognostic marker of head and neck cancer development was examined and compared with standard histological analysis. PATIENTS AND METHODS: Telomerase activity was determined using quantitative dual-colour real-time TRAP (telomeric repeat amplification protocol). In each of 58 patients, a sample of tumour tissue, adjacent mucosa and normal muscle was collected. RESULTS: Telomerase activation was observed in 88% of tumour tissues and 34% of tumour-adjacent mucosa samples. No telomerase activity was detected in normal muscle tissues. Telomerase activity correlated with tumour grade, with an average of 4.6 telomerase units (T.U.) in well-differentiated, 8.3 T.U. in moderately-differentiated and 20 T.U. in poorly differentiated tumours. Relapse occurred in 13 patients and no telomerase activity was detected in 3 recurrent tumours. CONCLUSION: Telomerase activity may be used as an objective parameter inversely related to tumour differentiation. Prognosis in telomerase-negative tumours is worse than that of the telomerase-positive group.