Abstract: Information sent by biological materials (plant leaves) into environment is determined by
the morphology and by the physiological activity of an assembly. This information can be related to
the luminescence spectra emitted by the leaf, being specific for the corresponding photosystem
pigments. Such an analysis can provide an increase in our understanding of particular changes in
this biological material.
Abstract: In order to obtain more accurate properties after compaction of hydroxyapatite
(HAp)/poly-L-lactide (PLLA) composite, high-resolution measurement of mechanical properties
method is proposed to determine the properties of each phase separately, leading to information that
are valuable for the development of new materials as well as for predictive modeling purposes. The
PLLA polymer processing conditions used in hot pressing of the composite strongly influence final
mechanical properties of the material in the solid state. Since the aim was to measure PLLA
material properties, acceptable findings could only be made using unconstrained, cured in situ
nanoindentation tests. A finite element analysis of the in situ indentation experiment was performed
to determine required size of plain polymer area, needed for indentation test, which would minimize
the particle influence on the matrix elastic behavior.
Abstract: Composite biomaterials based on calcium phosphate ceramic due to their high bioactivity
are of interest for biological application and bone tissue repair. Structural and microstructural
parameters of inorganic constituent of these materials are very important for the synthesis and
characterization of composites. Quantitative and qualitative content, crystallite size of phases, as
well as the degree of crystallinity have a great influence on the quality of composites, their
application and bone tissue repair. X-ray diffractometry was employed to investigate the
components of biocomposite materials, calcium phosphate (CaP) ceramic and poly-DL-lactide-coglycolide
(DLPLG) polymer, as well as the biocomposite obtained from the mentioned components.
Composite biomaterial was obtained by modified emulsion process. Using the Rietveld refinement,
we analyzed CaP as an inorganic component of the composite, whence we have determined
structural and microstructural properties of ceramic component of the investigated composite. The
results obtained by structure refinement show that calcium phosphate ceramic materials synthesized
at room temperature contain hydroxyapatite HAp as a predominant phase. The calculated Ca/P ratio
is 1.667. The Rietveld analysis revealed lattice parameters a(Å)=9.4324(7) and c(Å)=6.8785(6) that
are in agreement with the theoretical values.
Abstract: Cytotoxic activity of four series of coordinated complexes of Zn(II) and Fe(II) with
hydrazone/hydrazide ligands against HeLa and B16 cells was evaluated. The ligands N’,N'2-
bis[(1E)-1-(2-pyridyl)ethylidene]ethanedihydrazide (H2L1) and N’,N'2-bis[(1E)-1-(2-pyridyl)
ethylidene]propanedihydrazide (H2L2) and their Zn(II) complexes showed IC50 values in the low
micromolar range, while the other ligands and complexes were less active or inactive.
Abstract: The nonlinear dynamics of brewing yeast cell growth in porous Ca-alginate matrices is
considered experimentally and theoretically. The applications of alginate matrices include the
reduction of internal mass transfer resistance, minimized cell leakage and growth restriction due to
interactions between matrices and cell membranes comparatively to free cell culture conditions. The
effects of micro-bead diameters in the range 0.3-2.0 mm on yeast cell growth were investigated.
The stochastic mathematical model from the Langevin class is proposed for the interpretation of cell
growth, affected by four micro-processes: micro-environmental quality changes due to nutrient
diffusion into the micro-beads, cell leakage, repulsive interactions between boundary layers around
the cells themselves, which contribute to the dynamics of cell growth as a negative, nonlinear feedback
restriction and random kinetics effects. Such a model is used for the prediction of the optimal
diameter of micro-beads, which ensures maximal final cell concentration. The results of cell growth
in alginate matrices study have indicated an optimal diameter of 0.5-0.6 mm for micro-beads.
Immobilized cells in these beads were not restricted significantly by mass transfer of nutrients and
by cell leakage. The highest final cell concentration value indicated the largest feed-back restriction
quantified by the constitutive parameter b.
Abstract: Earlier investigation of fullerenol, C60(OH)24, features, in vitro, showed that fullerenol
have strong antioxidative potential. In this work, we examined the influence of fullerenol as a
potential antioxidative protector on doxorubicin induced cardiotoxicity in rats. Experiments were
performed on adult Wistar rats, both gender. Animals were divided into six groups, each containing
eight individuals. Doxorubicin was administrated i.v. (tail vein) in single dose of 8mg/kg.
Fullerenol C60(OH)24 in treated animals was administrated i.p. (in doses 50, 100, 200 mg/kg) for 30
min. before application of doxorubicin. Control group (intact animals) was given saline (1 mL/kg).
One group was treated only with fullerenol (100 mg/kg i.p.). Cardiotoxicity of doxorubicin as well
as cardioprotective effects of fullerenol were evaluated following the heart function monitored by
ECG recording during adrenalin i.v. infusion, and pathomorphological examination of the heart
tissue. These evaluations were performed on the day 2 and 7 after doxorubicin administration. Both
functional and pathomorphological investigations revealed no heart damage two days after given
treatments. However, on the day 7 after doxorubicin injection, changes in cardiovascular reflexes to
adrenalin as well as structural damage were manifest. The time for appearance of adrenalin-induced
reflex bradicardia in ECG record was significantly longer in doxorubicin treated group in
comparison with the control one. Also, pathomorphological examination of the heart tissue showed
vacuolization of cardiomyocites. In fullerenol pretreated groups these described changes were
ameliorated and corresponded to the control values. These results suggest that fullerenol might be
potential cardioprotector in doxorubicin treated individuals.
Abstract: Pressure pipes may be externally damaged in different ways: corrosion or notch due to
diving machines. These defects may initiate a fatigue crack, which will be first part-through, then
through the thickness. This results in a weakened region of the tube, then in leak of the pressure
fluid contained in the pipe. There are several ways to repair the tube: changing the portion of tube,
welding of extra metal in the defect, putting a welded metal sleeve or gluing a composite sleeve.
This last solution seems to be the easiest and the cheapest. The advantage is that the repairing sleeve
is made on site and can be put with a given pre-tension. The work presented here is the numerical
study of the fracture mechanics parameters of a part-through crack in a tube submitted to internal
pressure and repaired with a composite sleeve. As there is a transfer of loading from the cracked
tube to the repairing sleeve, the fracture mechanics parameters of the crack such as J-integral or
opening of the crack lips will be modified. The study can be used as a design procedure for such
Abstract: Considering the conditions to which steels used for the manufacture of steam pipelines
are exposed, the micromechanism of their destruction in exploitation is exclusively the ductile one.
In order to make an estimation of the level of the damage that occurs in exploitation, in this paper a
combined experimental and numerical procedure has been developed based on micromechanical or
local approach to the fracture mechanics of metallic materials. After the analysis of the results
obtained for micromechanical criterion of failure for virgin steel and that used in the steam pipeline,
a proposal for prolongation of the working life of tested steel for steam pipelines until the next
overhaul is given.
Abstract: This paper describes the general trends correlating mechanical and corrosion properties
with chemical composition of some Al-Fe-Si and Al-Fe-Mn-Si alloys for foils. These Al-rich
eutectic alloys based on Al-Fe-Si and Al-Fe-Mn, when roll cast and appropriately processed to give
fine and regular dispersion of intemetallic particles, can provide good combinations of strength and
ductility. These characteristics have been responsible for the alloy success in replacing
commercially pure (CP) aluminum for applications in thin sheet and foil gauges. The objective was
to obtain an opinion about the possible role of alloying elements in corrosion behavior and
mechanical properties of these commercial materials produced by cold rolling of twin roll cast
Abstract: Unidirectional and angle-ply carbon/epoxy laminates were gamma irradiated up to doses
of 12 and 20 MGy. Composites with two different, low and high temperature epoxy matrices have
been submitted to irradiation and subsequent mechanical testing. The radiation effects were studied
by measuring in-plane, interalminar shear and transverse tensile strength, as well as interlaminar
strain energy release rate of tested composites. The immersion of composite plate in water at 80 oC
and mechanical measurements at elevated temperatures emphasized irradiation effects on