Interaction of glassy fertilizers and Cd^(2+) ions in terms of soil pollution neutralization

Immobilization of cadmium contamination in soils by precipitation of nonassimilable for plants Cd-phosphates was considered. Glassy fertilizer of controlled release rate of the nutrients for plants as a source of phosphate anions was applied. The negative role of Cd complexing citric acid solution simulating the natural soil conditions, which inhibits the Cd-phos-phates formation, was stated.

A Mathematical Model and Simulations of Low Temperature Nitriding Katarzyna Tkacz-Smiech Deceased.We dedicate this article to the memory of Professor Katarzyna Tkacz-Smiech

Low-temperature nitriding of steel or iron can produce an expanded austenite phase,which is a solid solution of a large amount of nitrogen dissolved interstitially in fcc lattice.It is characteristic that the nitogen depth profiles in expanded austenite exhibit plateau-type shapes.Such behavior cannot be considered with a standard analytic solution for diffusion in a semi-infinite solid and a new approach is necessary.We formulate a model of interdiffusion in viscoelastic solid(Maxwellmodel)during the nitriding process.It combines themass conservation and Vegard’s rule with the Darken bi-velocity method.The model is formulated in any dimension,i.e.,a mixture is included in R^(n),n=1,2,3.For the system in one dimension,n=1,we transform a differential-algebraic system of 5 equations to a differential system of 2 equations only,which is better to study numerically and analytically.Such modification allows the formulation of effective mixed-type boundary conditions.The resulting nonlinear strongly coupled parabolic-elliptic differential initial-boundary Stefan type problem is solved numerically and a series of simulations is made.

Effect of Zr on the Oxidation Properties of Fe3Al Intermetallic Compound

This review is concerned with the effect of the addition of zirconium as a third element on the heat-resisting properties of Fe_3Al intermetallic compounds and explains their high-temperature oxidation mechanism.The Fe_3Al and Fe_3Al-0.05Zr specimens were isothermally oxidized in the temperature range of 1173～1473 K in synthetic air for 100 h.The formation of the alumina layer approximately obeyed the parabolic rate law,with the exception of short initial stage.The parabolic rate constant values for the Zr-doped Fe_3Al decreased at all tested temperatures.Fe_3Al revealed massive spallation,whereas Fe_3AlZr produced a flat,adherent oxide layer.The microstructure investigations of the alumina scales grown thermally on the Fe_3Al-Zr alloy by means of SEM-EDS showed that they were 1.5～2μm thick and consisted of a small inner columnar layer and an equiaxed outer grain layer.Additionally,very fine(50～150 nm) oxide particles rich in Zr were found across the alumina scales.The addition of Zr significantly affected the oxidation behavior of Fe_3Al by improving the adherence of theα-Al_2O_3 scale.TEM-SAD investigations of the alumina scales on samples prepared using the FIB(Focused Ion Beam) method confirmed the presence of small tetragonal zirconia grains near the scale/gas and alloy/scale interfaces,most of which were formed along alumina grain boundaries(gbs).Zr gb-segregation was found using HRTEM.The role of preferential formation of zirconium oxide along the alumina scale grain boundaries and the effect of Zr gb-segregation on oxidation and scale growth mechanisms were analyzed by means of two-stage oxidation experiments using ^(16)O_2/^(18)O_2.The SIMS oxygen isotope profiles for the Fe_3Al-Zr alloy oxidized at 1373 K, after two-stage oxidation experiments,revealed that oxygen anion diffusion is predominant compared to that of aluminum cation diffusion.

Salt-Assisted SHS Synthesis of Aluminium Nitride Powders for Refractory Applications

Powders of aluminum nitride can be prepared by self-sustain high-temperature synthesis (SHS) between aluminum and nitrogen but its high exothermic effect causes melting and evaporation of aluminum and low efficiency of such reaction. A presence of inorganic salt in the starting powder mixture can decrease a heat evolved in the SHS reaction, hinders melting and coalescence of aluminum, and facilitates penetration of nitrogen into interior of a powder bed. Mixtures of alumina powders with different grain sizes and different amounts of aluminum carbonate were subjected to the SHS reaction under 0.05, 0.1 or 1 MPa nitrogen. The powders were composed of aluminum nitride, unreacted aluminum, aluminum oxynitride and in some cases corundum and aluminum oxycarbonate. The finale effects are strongly dependent on the amount of the salt, a grain size of aluminum and a nitrogen pressure.

PCL and PCL/bioactive glass biomaterials as carriers for biologically active polyphenolic compounds: Comprehensive physicochemical and biological evaluation

In this work,polymeric and bioactive glass(BG)-modified composite films were successfully loaded with polyphenols(PPh)extracted from sage.It was hypothesized that PPh,alone and in combination with BGs particles,would affect physicochemical and biological properties of the films.Furthermore,sol-gel-derived BG particles would serve as an agent for control the release of the polyphenolic compounds,and other important properties related to the presence of PPh.The results showed that polyphenolic compounds significantly modified numerous material properties and also acted as biologically active substances.On the one hand,PPh can be considered as plasticizers for PCL,on the other hand,they can act as coupling agent in composite materials,improving their mechanical performance.The presence of PPh in materials improved their hydrophilicity and apatite-forming ability,and also provided antioxidant activity.What is important is that the aforementioned properties and kinetics of PPh release can be modulated by the use of various concentrations of PPh,and by the modification of PCL matrix with sol-gel-derived BG particles,capable of binding PPh.The films containing the lowest concentration of PPh exhibited cytocompatibility,significantly increased alkaline phosphatase activity and the expression of bone extracellular matrix proteins(osteocalcin and osteopontin)in human normal osteoblasts,while they reduced intracellular reactive oxygen species production in macrophages.Furthermore,materials loaded with PPh showed antibiofilm properties against Gram positive and Gram negative bacteria.The results suggest that obtained materials represent potential multifunctional biomaterials for bone tissue engineering with a wide range of tunable properties.

Physico-chemical and biological evaluation of doxycycline loaded into hybrid oxide-polymer layer on Ti-Mo alloy

Oxide-polymer coatings were formed on the surface of the vanadium-free Ti–15Mo titanium alloy.The Ti alloy surface was modified by the plasma electrolytic oxidation process,and then,the polymer layer of a poly(D,Llactide-co-glycolide)with doxycycline was formed.The polymer evenly covered the porous oxide layer and filled some of the pores.However,the microstructure of the polymer surface was completely different from that of the PEO layer.The surface morphology,roughness and microstructure of the polymer layer were examined by scanning electron microscopy(SEM)and a confocal microscope.The results confirmed the effectiveness of polymer and doxycycline deposition in their stable chemical forms.The drug analysis was performed by highperformance liquid chromatography.The 1H NMR technique was used to monitor the course of hydrolytic degradation of PLGA.It was shown that the PLGA layer is hydrolysed within a few weeks,and the polyglycolidyl part of the copolymer is hydrolysed to glycolic acid as first and much faster than the polylactide one to lactic acid.This paper presents influence of different microstructures on the biological properties of modified titanium alloys.Cytocompatibility and bacterial adhesion tests were evaluated using osteoblast-like MG-63 cells and using the reference S.aureus and S.epidermidis strains.The results showed that the optimum concentration of doxycycline was found to inhibit the growth of the bacteria and that the layer is still cytocompatible.

Sodium alendronate loaded poly(L-lactideco-glycolide)microparticles immobilized on ceramic scaffolds for local treatment of bone defects

Bone tissue regeneration in critical-size defects is possible after implantation of a 3D scaffold and can be additionally enhanced once the scaffold is enriched with drugs or other factors supporting bone remodelling and healing.Sodium alendronate(Aln),a widely used anti-osteoporosis drug,exhibits strong inhibitory effect on bone resorption performed by osteoclasts.Thus,we propose a new approach for the treatment of bone defects in craniofacial region combining biocompatible titanium dioxide scaffolds and poly(L-lactide-co-glycolide)microparticles(MPs)loaded with Aln.The MPs were effectively attached to the surface of the scaffolds’pore walls by human recombinant collagen.Drug release from the scaffolds was characterized by initial burst(2466% of the drug released within first 24 h)followed by a sustained release phase(on average 5 mg of Aln released per day from Day 3 to Day 18).In vitro tests evidenced that Aln at concentrations of 5 and 2.5 mg/ml was not cytotoxic for MG-63 osteoblast-like cells(viability between 8166% and 9863% of control),but it prevented RANKL-induced formation of osteoclast-like cells from macrophages derived from peripheral blood mononuclear cells,as shown by reduced fusion capability and decreased tartrateresistant acid phosphatase 5b activity(5665% reduction in comparison to control after 8 days of culture).Results show that it is feasible to design the scaffolds providing required doses of Aln inhibiting osteoclastogenesis,reducing osteoclast activity,but not affecting osteoblast functions,which may be beneficial in the treatment of critical-size bone tissue defects.

Thermal properties of AlN polycrystals obtained by pulse plasma sintering method

Aluminum nitride(AlN)polycrystals were prepared by pulse plasma sintering(PPS)technique.The starting AlN powder mixtures were composed with 3.0 wt%,5.0 wt%and 10 wt%of yttrium oxide(Y_(2)O_(3)),respectively.Relative density of each polycrystal was measured by hydrostatic method and evaluated higher than 97%.X-ray diffraction(XRD)method was used for phase examination of the samples after heat treatment.Microstructure examination supported by computer-aided analysis was performed by scanning electron microscopy(SEM)and energy dispersive spectrometry(EDS).The results were correlated with thermal conductivity of the samples carried out by laser pulse method(LFA).The influence of the rapid sintering technique and yttrium oxide additive content on the thermal conductivity and microstructure appearance of AlN polycrystals was clearly shown.

Antibacterial and cytocompatible coatings based on poly(adipic anhydride) for a Ti alloy surface

This paper describes a formation of hybrid coatings on a Ti-2Ta-3Zr-36Nb surface.This is accomplished by plasma electrolytic oxidation and a dip-coating technique with poly(adipic anhydride)((C6H8O3)n)that is loaded with drugs:amoxicillin(C16H19N3O5S),cefazolin(C14H14N8O4S3)or vancomycin(C66H75Cl2N9O24·xHCl).The characteristic microstructure of the polymer was evaluated using scanning electron microscopy and confocal microscopy.Depending on the surface treatment,the surface roughness varied(between 1.53μm and 2.06μm),and the wettability was change with the over of time.X-ray photoelectron spectroscopy analysis showed that the oxide layer did not affect the polymer layer or loaded drugs.However,the drugs lose their stability in a phosphate-buffered saline solution after 6.5 h of exposure,and its decrease was greater than 7%(HPLC analysis).The stability,drug release and concentration of the drug loaded into the material were precisely analyzed by high-performance liquid chromatography.The results correlated with the degradation of the polymer in which the addition of drugs caused the percent of degraded polymer to be between 35.5%and 49.4%after 1 h of material immersion,depending on the mass of the loaded drug and various biological responses that were obtained.However,all of the coatings were cytocompatible with MG-63 osteoblast-like cells.The drug concentrations released from the coatings were sufficient to inhibit adhesion of reference and clinical bacterial strains(S.aureus).The coatings with amoxicillin showed the best results in the bacterial inhibition zone,whereas coatings with cefazolin inhibited adhesion of the above bacteria on the surface.

Sodium alendronate loaded poly(L-lactideco-glycolide)microparticles immobilized on ceramic scaffolds for local treatment of bone defects

Bone tissue regeneration in critical-size defects is possible after implantation of a 3D scaffold and can be additionally enhanced once the scaffold is enriched with drugs or other factors supporting bone remodelling and healing.Sodium alendronate(Aln),a widely used anti-osteoporosis drug,exhibits strong inhibitory effect on bone resorption performed by osteoclasts.Thus,we propose a new approach for the treatment of bone defects in craniofacial region combining biocompatible titanium dioxide scaffolds and poly(L-lactide-co-glycolide)microparticles(MPs)loaded with Aln.The MPs were effectively attached to the surface of the scaffolds’pore walls by human recombinant collagen.Drug release from the scaffolds was characterized by initial burst(2466%of the drug released within first 24 h)followed by a sustained release phase(on average 5 mg of Aln released per day from Day 3 to Day 18).In vitro tests evidenced that Aln at concentrations of 5 and 2.5 mg/ml was not cytotoxic for MG-63 osteoblast-like cells(viability between 8166%and 9863%of control),but it prevented RANKL-induced formation of osteoclast-like cells from macrophages derived from peripheral blood mononuclear cells,as shown by reduced fusion capability and decreased tartrateresistant acid phosphatase 5b activity(5665%reduction in comparison to control after 8 days of culture).Results show that it is feasible to design the scaffolds providing required doses of Aln inhibiting osteoclastogenesis,reducing osteoclast activity,but not affecting osteoblast functions,which may be beneficial in the treatment of critical-size bone tissue defects.

Novel synthesis method combining a foaming agent with freeze-drying to obtain hybrid highly macroporous bone scaffolds

Three-dimensional macroporous scaffolds are commonly used in bone tissue engineering applications since they provide sufficient space for cell migration and proliferation, facilitating bone ingrowth and implant vascularisation. The aim of this work was to combine two simple methods, freeze-drying and gas-foaming, in order to fabricate highly macroporous bone scaffolds made of chitosan/agarose matrix reinforced with nanohydroxyapatite. The secondary goal of this research was to comprehensively assess biomedical potential of developed biomaterials. In this work, it was demonstrated that simultaneous application of freeze-drying and gas-foaming technique allows to obtain hybrid(as proven by ATR-FTIR)macroporous bone scaffolds(pore diameter > 50 um) characterized by high open(70%) and interconnected porosity. Novel scaffolds were non-toxic, favoured osteoblasts adhesion and growth and induced apatite formation on their surfaces, indicating their high bioactivity that is essential for good implant osseointegration. Biomaterials were also prone to enzymatic degradation, degradation in acidified microenvironment(e.g. osteoclast-mediated), and slow degradation under physiological p H of 7.4.Moreover, the scaffolds revealed microstructure(70% open porosity, SSA approx. 30 m2/g, high share of macropores with diameter in the range 100-410 um) and compressive strength(1–1.4 MPa) comparable to cancellous bone, indicating that they are promising implants for cancellous bone regeneration.

Inhalable microparticles as drug delivery systems to the lungs in a dry powder formulations

Inhalation-administrated drugs remain an interesting possibility of addressing pulmonary diseases.Direct drug delivery to the lungs allows one to obtain high concentration in the site of action with limited systemic distribution,leading to a more effective therapy with reduced required doses and side effects.On the other hand,there are several difficulties in obtaining a formulation that would meet all the criteria related to physicochemical,aerodynamic and biological properties,which is the reason why only very few of the investigated systems can reach the clinical trial phase and proceed to everyday use as a result.Therefore,we focused on powders consisting of polysaccharides,lipids,proteins or natural and synthetic polymers in the form of microparticles that are delivered by inhalation to the lungs as drug carriers.We summarized the most common trends in research today to provide the best dry powders in the right fraction for inhalation that would be able to release the drug before being removed by natural mechanisms.This review article addresses the most common manufacturing methods with novel modifications,pros and cons of different materials,drug loading capacities with release profiles,and biological properties such as cytocompatibility,bactericidal or anticancer properties.

Nanocarrier drug resistant tumor interactions: novel approaches to fight drug resistance in cancer

Cancer is one of the biggest healthcare concerns in our century,a disease whose treatment has become even more difficult following reports of drug-resistant tumors.When this happens,chemotherapy treatments fail or decrease in efficiency,leading to catastrophic consequences to the patient.This discovery,along with the fact that drug resistance limits the efficacy of current treatments,has led to a new wave of discovery for new methods of treatment.The use of nanomedicine has been widely studied in current years as a way to effectively fight drug resistance in cancer.Research in the area of cancer nanotechnology over the past decades has led to tremendous advancement in the synthesis of tailored nanoparticles with targeting ligands that can successfully attach to chemotherapy-resistant cancer by preferentially accumulating within the tumor region through means of active and passive targeting.Consequently,these approaches can reduce the off-target accumulation of their payload and lead to reduced cytotoxicity and better targeting.This review explores some categories of nanocarriers that have been used in the treatment of drug-resistant cancers,including polymeric,viral,lipid-based,metal-based,carbon-based,and magnetic nanocarriers,opening the door for an exciting field of discovery that holds tremendous promise in the treatment of these tumors.