annals of “dunArea de jos” university of galaTi – fascicle II █████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████
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ANNALS OF “DUNAREA DE JOS” UNIVERSITY OF GALATI
MATHEMATICS, PHYSICS, theoretical mechanics
FASCICLE II, YEAR II (XXXIII) 2010
No.1
Pages 5-11
SPECTRAL STUDY ON THE SOLVENT INFLUENCE UPON A FLUORESCENT MOLECULE - CHLORTETRACYCLINE
C. Nădejde, V. Pohoată, D.E. Creangă, D.O. Dorohoi
Faculty of Physics,“Al.I. Cuza” University, 11A Carol I Bld., 700506, Iasi, Romania
E-mail:
Abstract
The effect of solvents on absorption and fluorescence spectra of chlortetracycline hydrochloride (CTC) has been studied in several alcohols and water-alcohol mixtures at room temperature. The studied compound was chlortetracycline chloride powder – a pharmaceutical item with antibiotic effect. The spectral behavior to the increase of water percentage in ternary solutions with n-butanol and with n-propanol respectively, was investigated; the gradual response of the main electronic bands was studied considering the theory of intermolecular interactions in diluted solutions.
Keywords: chlortetracycline, alcohols, solvent effect
Pages 12-18
SUNFLOWER SEEDLING GROWTH UNDER MAGNETIC NANOPARTICLE INFLUENCE
M. Ursache-Oprişan, E.L. Focanici-Ciurlică, D.E. Creangă
Al.I.CuzaUniversity, Faculty of Physics, Iasi, Romania
Abstract
The issue of magnetic particles contamination is more and more considered as an actual challenge for the environmental protection research. Iron oxides in the form of submicron grains as generated from natural sources but more from human activities are present in all biosphere compartments. The response of young plant seedlings to the magnetic nanoparticle pollution was studied in the frame of an experiment designed for laboratory research. The magnetic nanoparticles were synthesized in the form of Zn ferrite powders coated with sodium oleate to assure the uniform dispersion in water. The sunflower seeds with controlled genetic origin were let to germinate and growth in the presence of various levels of magnetic oxide particles delivered in the form of diluted aqueous suspension. The young plant response to laboratory simulated pollution with magnetic particles was investigated by measuring the concentrations of chlorophyll A, chlorophyll B and carotene like pigments in samples harvested from their green tissue. Negative influence of zinc oxide was assumed especially for the highest concentration of mixed iron and zinc oxides (100 microl/l) where the pigment biosynthesis was either diminished (as in the case of carotenes) either increased with non-significant percentage.
Keywords: magnetic nanoparticles, photosynthetic pigments, magnetic pollution
Pages 19-26
MAGNETIC SUBMICRON PARTICLES COATED IN DRUG MOLECULE – EXPERIMENTAL STUDY FOCUSED ON RIFAMPICIN INTERACTIONS WITH IRON ATOMS
E. Focanici1, C.Nadejde1, A.C. Ciocan1, A. Carlescu1, D. Creanga1, O. Caltun1, I. Sandu2, I.I. Sandu2
1”Al.I.Cuza” University of Iasi, Romania, Faculty of Physics, e-mail:
2Arheoinvest Group, Faculty of Theology, “Al.I.Cuza” University of Iasi, Romania
Abstract
Magnetic submicron particles are more and more used for biomedical applications since their stabilization in water can be accomplished using various molecular shells. In this study the magnetite submicron particles were prepared based on the co-precipitation of ferric and ferrous oxides from FeIII and FeII salt solutions. The stabilization in deionized water was further carried out using the molecule of rifampicin that was found to present four sites of interaction with iron ions such as those from magnetite structures. The structural features of the magnetic particles coated with rifampicin were investigated by X-rays diffraction and IR spectroscopy. Good crystalline and adequate stability in time were evidenced. Rheological properties were also investigated by measuring superficial tension coefficient and dynamic viscosity. The colloidal suspension prepared this way could be of interest for medical utilization either in magnetically targeted drug delivery or in MRI diagnosis with magnetic fluids as contrast agent.
Keywords: magnetite, rifampicin, colloidal suspension
Pages 27-33
TEMPORAL VARIATION OF THE BIOLOGICAL SIGNAL RECORDED FROM THE VISUAL SYSTEM
D.E. Creanga, L.M. Oancea
“Al.I.Cuza” University, Faculty of Physics, 11 A Blvd. Carol I 700506, Iasi, Romania,
e-mail:
Abstract
In this paper some issues regarding the variability of the biological signal extracted from the visual system are presented. The electric activity of the photoreceptor cells as well as of the neural cells from the first optical ganglion of the compound eye - specific to invertebrate organisms, which can be recorded in the form of the electroretinographic signal, was studied by quantitative means. The results of the measurements carried out on the amplitudes of the eletroretinographic signal components were analyzed from the viewpoint of the temporal variability. The influence of the exciting light intensity upon the biological signal amplitudes was also discussed.
Keywords: visual system, bioelectrogenesis, signal aquisition and processing.
Pages 34-40
COMPUTATIONAL ANALYSIS OF BRAIN ACTIVITY
Dorina Creanga, Ramona Focea, Paul Gasner
Al.I.CuzaUniversity, Faculty of Physics, Iasi, Romania, 11 A Blvd. Carol I, 700506,
e-mail:
Abstract
The computational approach of the diurnal brain activity was accomplished based on some numerical tests derived from the application of complex system theories, particularly deterministic chaos theory. Probability distribution, power spectra, portraits in the phase state, correlation dimension and Lyapunov exponents were analyzed in the case of raw data series and numerically smoothed series. The qualitative and semi-quantitative differences resulted from the study revealed the suitability of numerical smoothing procedure in the evidence of the chaotic trend in the brain complex dynamics.
Keywords: non-linear dynamics investigation, complex system, brain diurnal activity
Pages 41-47
INFLUENCE OF NITRATE REMOVALPARAMETERS FROM WATER BY USING PUROLITE A 100
Laura Bulgariu, Ceică Anca, Igor Creţescu, Ion Balasanian
Department of Environmental Engineering and Management,
Faculty of Chemical Engineering and Environmental Protection,
”Gh. Asachi” TechnicalUniversity of Iasi,
71A D. Mangeron Street, 700050, Iasi, Romania
Abstract
In this study, the removal of nitrate from aqueous solutions by using the anion exchange resin Purolite A 100, has been investigated using a batch technique. The influence of several experimental parameters, such as initial solution pH, resin dose, initial nitrate concentration, contact time and temperature, has been examined in batch experiments.
The results pointed out that the ion exchange process takes place efficiently at around 6.5 pH of the initial solution and to the ambient temperature, avoiding the high temperature which is not economically profitable. Optimum dose of resin was found as 6.00 g-resin/L-nitrate solution, when retention was about 90 %, for t = 20 ºC and pH around 6.5.
The experimental results on contact time showed that, for relatively low concentrations of nitrate (50 mg/L), and a dose of resin, 6 g resin/L, we obtain a retention in nitrate content of about 83 % in about 2 h. Due to low cost and various applications of the resin Purolite A 100 it could be an alternative process to remove nitrates from the water when the initial concentration does not exceed 200 mg NO3-/ L.
Keywords: Nitrates, Ion Exchange, Resin Purolite A100, Water treatment
Pages 48-52
SYMPLECTIC LAPLACE-BELTRAMI OPERATORS
Adara M. Blaga
Department of Mathematics and Computer Science, WestUniversity of Timişoara
Abstract
The aim of this paper is to define an analogue of Laplace-Beltrami operator on a symplectic manifold and study its properties. The gradient and divergence operators are introduced and discussed more detailed the case of a para-Kähler manifold.
Keywords: Laplace-Beltrami operator; symplectic manifold; symplectic connection.
Pages 53-55
A FIXED POINT METHOD FOR EXISTENCE SOLUTION OF
OPERATOR EQUATIONS INVOLVING A DUALITY MAPPING
Jenică Crînganu
University Dunarea de Jos of Galati, Dept Mathematics and Computer Science, Sciences Faculty,
47 Domneasca St, 800008. Galati
Abstract. In this paper we shall prove the existence of solution for the abstract equation
,
where is the duality mapping on a uniformly convex Banach space , corresponding to the gauge function , and is the Nemytskii operator generated by a Caratheodory function which satisfes some appropriate conditions. For this we use a fixed point method.
Keywords: Duality mapping, fixed point method, Nemytskii operator.
Pages 56-62
BIANCHI IDENTITIES IN THE RHEONOMIC LAGRANGE GEOMETRY
Camelia Frigioiu
University Dunarea de Jos of Galati, Dept. of Mathematic and Computer Science,
Sciences Faculty, 47 Domneasca, RO- 800008, Galati
Abstract
The aim of this paper is to obtain the local Bianchi identities for an N-linear connection on the space TMR, using the structure equations oftheN-linear connection. In this direction, we present the local expressions of the adapted components of the torsion and curvature d-tensors produced by theN-linear connection and we give the general local expressions of Bianchi identities which connect these d-torsions and d-curvatures.
Keywords: connection, N-linear connection, d-torsion, d-curvature, Bianchi identities.
Pages 63-71
SEQUENCES DEFINED BY LINEAR RECURRENCE RELATIONS
Ion Lixandru
University Dunarea de Jos of Galati, Dept Mathematics and Computer Science, Sciences Faculty,
47 Domneasca St, 800008. Galati
Abstract
Starting from the analogy that which exists between the sequences defined by linear recurrence relations and the linear differential equations of superior order, with the help of WRONSKI determinative, constructed for sequences, the finding of a general solutionof the homogenous relation, it returns to finding a fundamental system of solutions. When dealing with homogenous linear relations with constant coefficients, depending on the nature of the characteristic equation’s roots, there are presented and demonstrated the formulae used for finding out the general term of the row. For the heterogenous relation, depending on the nature of the „free term”, there are different indicated forms of the special solution of the heterogenous relation.
Keywords: linear recurrence relations, fundamental system of solutions, WRONSKI determinative, characteristic equa-tion, special solution of the heterogeneous relation, general term of the sequence.
Pages 72-78
the Approximation of a series of real numbers.
THE CONVERGENCE Speed OF A SERIES.
Ion Lixandru
University Dunarea de Jos of Galati, Dept Mathematics and Computer Science, Sciences Faculty,
47 Domneasca St, 800008. Galati
Abstract
Starting from the fact that in practice there are situations in which one can not calculate the sum of a series, we need the approximate calculation of a series in order to use them. This requires first an assessment of the error (how many terms should be considered in series to achieve the desired accuracy). Starting from the criteria which established the convergence of the series, the article presents various methods of approximation of a series. But it can happen that the number of terms that have to be added to be huge (thousands or tens of thousands). In this case appears the question of transforming slowly convergent series into a rapidly convergent one. This article contains mainly two methods of processing slow series into rapid ones.
Keywords: Convergent series, approximation, error, absolute error, speed of convergence, transformation.
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