In vitro and in vivo studies on biocompatibility of carbon fibres

In the present study we focused on the in vitro and in vivo evaluation of two types of carbon fibres (CFs): hydroxyapatite modified carbon fibres and porous carbon fibres. Porous CFs used as scaffold for tissues regeneration could simultaneously serve as a support for drug delivery or biologically active agents which would stimulate the tissue growth; while addition of nanohydroxyapatite to CFs precursor can modify their biological properties (such as bioactivity) without subsequent surface modifications, making the process cost and time effective. Presented results indicated that fibre modification with HAp promoted formation of apatite on the fibre surface during incubation in simulated body fluid. The materials biocompatibility was determined by culturing human osteoblast-like cells of the line MG 63 in contact with both types of CFs. Both tested materials gave good support to adhesion and growth of bone-derived cells. Materials were implanted into the skeletal rat muscle and a comparative analysis of tissue reaction to the presence of the two types of CFs was done. Activities of marker metabolic enzymes: cytochrome c oxidase (CCO) and acid phosphatase were examined to estimate the effect of implants on the metabolic state of surrounding tissues. Presented results evidence the biocompatibility of porous CFs and activity that stimulates the growth of connective tissues. In case of CFs modified with hydroxyapatite the time of inflammatory reaction was shorter than in case of traditional CFs

Electronic Structure of Mononuclear Bis(1,2-diaryl-1,2-ethylenedithiolato)iron Complexes Containing a Fifth Cyanide or Phosphite Ligand: A Combined Experimental and Computational Study

A series of mononuclear square-based pyramidal complexes of iron containing two 1,2-diaryl-ethylene-1,2-dithiolate ligands in various oxidation levels has been synthesized. The reaction of the dinuclear species [FeIII2(1L•)2(1L)2]0, where (1L)2- is the closed shell di-(4-tert-butylphenyl)-1,2-ethylenedithiolate dianion and (1L•)1- is its one-electron-oxidized π-radical monoanion, with [N(n-Bu)4]CN in toluene yields dark green crystals of mononuclear [N(n-Bu)4][FeII(1L•)2(CN)] (1). The oxidation of 1 with ferrocenium hexafluorophosphate yields blue [FeIII(1L•)2(CN)] (1ox), and analogously, a reduction with [Cp2Co] yields [Cp2Co][N(n-Bu)4][FeII(1L•)(1L)(CN)] (1red); oxidation of the neutral dimer with iodine gives [FeIII(1L•)2I] (2). The dimer reacts with the phosphite P(OCH3)3 to yield [FeII(1L•)2{P(OCH3)3}] (3), and [FeIII2(3L•)2(3L)2] reacts with P(OC6H5)3 to give [FeII(3L•)2{P(OC6H5)3}] (4), where (3L)2- represents 1,2-diphenyl-1,2-ethylenedithiolate(2−). Both 3 and 4 were electrochemically one-electron oxidized to the monocations 3ox and 4ox and reduced to the monoanions 3red and 4red. The structures of 1 and 4 have been determined by X-ray crystallography. All compounds have been studied by magnetic susceptibility measurements, X-band EPR, UV−vis, IR, and Mössbauer spectroscopies. The following five-coordinate chromophores have been identified:  (a) [FeIII(L•)2X]n, X = CN-, I- (n = 0) (1ox, 2); X = P(OR)3 (n = 1+) )3ox, 4ox) with St = 1/2, SFe = 3/2; (b) [FeII(L•)2X]n, X = CN-, (n = 1−) (1); X = P(OR)3 (n = 0) (3, 4) with St = SFe = 0; (c) [FeII(L•)(L)X]n ↔ [FeII(L)(L•)X]n, X = CN- (n = 2−) (1red); X = P(OR)3 (n = 1−) (3red, 4red) with St = 1/2, SFe = 0 (or 1). Complex 1ox displays spin crossover behavior:  St = 1/2 ↔ St = 3/2 with intrinsic spin-state change SFe = 3/2 ↔ SFe = 5/2. The electronic structures of 1 and 1ox have been established by density functional theoretical calculations:  [FeII(1L•)2(CN)]1- (SFe = 0, St = 0) and [FeIII(1L•)2(CN)]0 (SFe = 3/2, St = 1/2)

Long-range Transport of Ambrosia Pollen to Poland

The long-range transport of Ambrosia pollen to Poland is intermittent and mainly related to the passage of air masses over the Carpathian and Sudetes mountains. These episodes are associated with hot dry weather, a deep Planetary Boundary Layer (PBL) in the source areas and winds from the south. Such episodes can transport significant amounts of Ambrosia pollen into Poland. The study investigates Ambrosia pollen episodes at eight sites in Poland during the period 7th to 10th September 2005, by examining temporal variations in Ambrosia pollen and back-trajectories. PBL depths in the likely source areas were calculated with the Eta meteorological model and evaluated against the mountain heights. Considerable amounts of Ambrosia pollen were recorded at several monitoring sites during the night or early in the morning of the investigated period. Trajectory analyses shows that the air masses arriving at the Polish sites predominantly came from the south, and were in the Czech Republic, Slovakia and Hungary the previous day indicating these countries as potential source areas. We have shown the progress of Ambrosia plumes into Poland from the south of the country, probably from Slovakia and Hungary, and demonstrated how Lagrangian back-trajectory models and meteorological models can be used to identify possible transport mechanisms of Ambrosia pollen from potential source regions

Thermal and microestructural characterization of epoxy-infiltrated hydroxyapatite composite

In this work, hydroxyapatite (HAp) obtained from the deorganification of bovine bones using hot NaOH solution was used to synthesize a HAp/epoxy infiltrated composite. Infiltration was carried out by vacuum assisted immersion in hot epoxy resin. The resulting composite was characterized regarding polymer content, morphological aspects and flexural strength. The infiltration method used resulted in thorough infiltration of the HAp but some residual porosity remained. Although the epoxy resin showed good interaction with the HAp, high polymer content was achieved and the flexural strength of the composite was higher than that of the original resin or the HAp, composite strength was lower than that of the human cortical bone