Comparison of the Morphological and Structural Characteristic of Bioresorbable and Biocompatible Hydroxyapatite-Loaded Biopolymer Composites

Calcium phosphate (CaP)-based ceramic–biopolymer composites can be regarded as innovative bioresorbable coatings for load-bearing implants that can promote the osseointegration process. The carbonated hydroxyapatite (cHAp) phase is the most suitable CaP form, since it has the highest similarity to the mineral phase in human bones. In this paper, we investigated the effect of wet chemical preparation parameters on the formation of different CaP phases and compared their morphological and structural characteristics. The results revealed that the shape and crystallinity of CaP particles were strongly dependent on the post-treatment methods, such as heat or alkaline treatment of as-precipitated powders. In the next step, the optimised cHAp particles have been embedded into two types of biopolymers, such as polyvinyl pyrrolidone (PVP) and cellulose acetate (CA). The pure polymer fibres and the cHAp–biopolymer composites were produced using a novel electrospinning technique. The SEM images showed the differences between the morphology and network of CA and PVP fibres as well as proved the successful attachment of cHAp particles. In both cases, the fibres were partially covered with cHAp clusters. The SEM measurements on samples after one week of immersion in PBS solution evidenced the biodegradability of the cHAp–biopolymer composites.

Variation of some meat quality indices in ectoparasite polyparasitized and antiparasitic treated hens

As a result of the conducted research it was established, that the meat quality of hens polyparasitized with malophages (Cuclotogaster heterographus, Eomenacanthus stramineus, Goniocotes gallinae, Goniocotes maculatus, Goniodes dissimilis, Lipeurus caponis, Menopon gallinae, Menacanthus cornutus, Menacanthus pallidulus) fleas (Ceratophylus gallinae, C. hirundinis) and mites (Dermanyssus gallinae, D. hirundinis), then treated with Ectostop T5%, Ectostop P5%, showed a protein content of 20.5±0.20%, a pH of 5.3±0.12 and a moisture content of 65.4±0.21%, these indices reaching the level of the non-infested batch (control). The protein level is low in the meat samples of batch II (untreated infested), constituting 16.22±0.03%, and in batch VII treated with Ivomec chemical preparation 17.02±0.87%. The meat moisture index is characterized by a greater difference for batch II and VII constituting 74.52±0.18% and 70.1±0.05% respectively. The pH assessed in untreated infested and Ivomec-treated hens is alkaline, which will lead to decreased keeping capacity.

Definition of rate of dynamic water deposition in horizontal cylindrical tanks

One of the problems in petroleum industry is the process of thermo-chemical preparation of crude oil developed from wells containing water, gas and other mechanical impurities. Herewith, the path of water drops in horizontal cylindrical tank is specified with powers affecting them. In this case the size and form of the tank are necessary as well. The paper studies the issue of destruction of oil emulsions and dynamic deposition of water drops. A mathematical model for description of motion rate of water drops in the tank considering the powers affecting them and the tank parameters has been developed as well.

Photodynamic therapy in endodontics: literature review.

Endodontic therapy seeks to prevent and when necessary to eliminate endodontic infections. The persistence of microorganisms to the mechanical chemical preparation or the intracanal medication is considered the main cause of the failures of the endodontic treatment. In these cases Enterococcus faecalis is the most commonly found microorganism. Photodynamic therapy (PDT) emerges as a promising adjuvant therapy to conventional endodontic treatment to eliminate these persistent microorganisms. This therapy consists in the association of a specific light source with a photosensitizer in the presence of oxygen, producing cytotoxic species to the microorganisms. Thus, the present article aims at a review of the literature on the use of photodynamic therapy in endodontics, a test that is shown to assist in the preparation of the root canal.

Chemical Preparation, Thermal Behavior and IR Studies of the New Chromium Diphosphate Hydrate and Crystal Structure of its Corresponding Anhydrous

Chemical preparation, thermal behavior, and IR studies are given for the diphosphate Cr4(P2O7)3.28H2O and its anhydrous form Cr4(P2O7)3. Cr4(P2O7)3.28H2O, is monoclinic P2/m with the following unit-cell dimensions : a = 16.169(1)Å, b = 9.336(5)Å, c = 9.446(4)Å, β = 124.796(5)°, and Z = 4. The total dehydration of Cr4(P2O7)3.28H2O, between 90°C and 450°C, leads to its anhydrous form, Cr4(P2O7)3. Cr4(P2O7)3 is isotopic to V4(P2O7)3, crystallizing in the orthorhombic system, space group Pmcn, Z = 4 with the following unit-cell dimensions: a = 7.25(2), b = 9.38(1)Å and c = 21.00(4)Å. Cr4(P2O7)3 is stable until its melting point at 1050°C. The thermal behavior of Cr4(P2O7)3.28H2O has been investigated and interpreted by comparison with IR absorption spectrometry and X-ray diffraction experiments.