A Multi-Drug Pharmacokinectic Optimal Control Approach in Cancer Chemotherapy

Journal of Optimization Theory and Applications - The mathematical study of the growth and treatment of cancer has been of great interest to researchers in the recent past as that can help clinical...     

Converging strong shock waves in magnetogasdynamics under isothermal condition

The similarity solutions to the problem of cylindrically symmetric strong shock waves in an ideal gas with a constant azimuthal magnetic field are presented. The flow behind the shock wave is assumed to spatially isothermal rather than adiabatic. We use the method of Lie group invariance to determine the possible class of self-similar solutions. Infinitesimal generators of Lie group transformations are determined by using the invariance surface conditions to the system and on the basis of arbitrary constants occurring in the expressions for the generators, four different possible cases of the solutions are reckoned and we observed that only two out of all possibilities hold self-similar solutions, one of which follows the power law and another follows the exponential law. To obtain the similarity exponents numerical calculations have been performed and comparison is made with the existing results in the literature. The flow patterns behind the shock are analyzed graphically.

     

Tellurium azamacrocycles: synthesis, characterization and coordination studies

The metal-free condensation of bis(2-formylphenyl) telluride (1) with a series of diamines affords macrocyclic tellurium ligands 2-7. Crystals of the protonated macrocycle 8 are monoclinic, space group P2/n with a=10.890(5), b=7.414(4), c=24.334(13) Å, Z=2. The reaction of tellurium containing macrocyclic Schiff base 2 with Pd(C₆H₅CN)₂Cl₂ gives the expected 1:1 product [Pd(II) 2] Cl₂ (9). Complex 9 was treated with excess of NH₄PF₆ in methanol to give the analogous PF₆⁻ salt [Pd(II) 2] (PF₆)₂ (10). The crystals of 10 are monoclinic, space group P2₁/n, a=8.2250(10), b=21.280 (4), c=21.150 (4), Z=4. However, the reaction of 2 with Pt(COD)Cl₂ proceeds via novel transmetallation to yield an organoplatinum complex (11). The crystals of 11 are also monoclinic, space group P2₁/n, a=12.3253 (14), b=14.6557 (14), C=13.4054 (11), Z=4. The octahedral Ni(II) complex 12 was prepared by the reaction of NiCl₂ · 6H₂O with 2 and NH₄PF₆ under an inert atmosphere. For 12: triclinic, space group ; Z=2; a=10.800(8), b=13.468(9), c=13.918(11), α=89.67(6)°, β=101.53(7)°, γ=81.49(3)° and V=1961(3). Cyclic voltammetry of 12 in MeCN solution shows a well-behaved quasi-reversible (ΔE=100 mV) Ni(III) ↔ Ni(II) couple.     

Analysis of a combat problem: The turret game

The turret game is defined and solved to illustrate the nature of games of combat. This game represents a highly simplified version of air combat, yet it is sufficiently complex so as to exhibit a rich variety of combat phenomena. A review of the formulation of -combat games is included in this paper.on sabbatical leave from Technion, Israel Institute of Technology, Haifa, Israel.     

Cobalt and magnesium ferrite nanoparticles: preparation using liquid foams as templates and their magnetic characteristics

An easy and convenient method for the synthesis of cobalt and magnesium ferrite nanoparticles is demonstrated using liquid foams as templates. The foam is formed from an aqueous mixture of an anionic surfactant and the desired metal ions, where the metal ions are electrostatically entrapped by the surfactant at the thin borders between the foam bubbles and their junctions. The hydrolysis is carried out using alkali resulting in the formation of desired nanoparticles, with the foam playing the role of a template. However, in the formation of ferrites with the formula MFe(2)O(4), where the metal ion and iron possess oxidation states of +2 and +3, respectively, forming a foam from a 1:2 mixture of the desired ionic solutions would lead to a foam composition at variance with the original solution mixture because of greater electrostatic binding of ions possessing a greater charge with the surfactant. In our procedure, we circumvent this problem by preparing the foam from a 1:2 mixture of M(2+) and Fe(2+) ions and then utilizing the in situ conversion of Fe(2+) to Fe(3+) under basic conditions inside the foam matrix to get the desired composition of the metal ions with the required oxidation states. The fact that we could prepare both CoFe(2)O(4) and MgFe(2)O(4) particles shows the vast scope of this method for making even multicomponent oxides. The magnetic nanoparticles thus obtained exhibit a good crystalline nature and are characterized by superparamagnetic properties. The magnetic features observed for CoFe(2)O(4) and MgFe(2)O(4) nanoparticles are well in accordance with the expected behaviors, with CoFe(2)O(4) particles showing higher blocking temperatures and larger coercivities. These features can easily be explained by the contribution of Co(2+) sites to the magnetocrystalline anisotropy and the absence of the same from the Mg(2+) ions.     

Spectrophotometric determination of mebeverine hydrochloride

Three simple, sensitive and reproducible visible spectrophotometric methods (A-C) for the determination of mebeverine hydrochloride (MVH) in bulk samples and pharmaceutical formulations are described. Methods A and B are based on the formation of ion-association complexes between the drug and fast green FCF (FGFCF, _max 625 nm) or bromothymol blue (BTB, _max 405 nm). Method C is based on the formation of a molecular complex between the drug and cobalt thiocyanate (CTC, _max 625 nm). Regression analysis of Beer's plots showed good correlation in the concentration ranges 2–40, 2–25 and 100–600 g/ml for methods A, B and C respectively. No interference was observed from the usually existing additives in pharmaceutical formulations and the applicability of the methods was examined by analysing tablets containing MVH. Standard deviations were typically 0.75 mg per dose (RSD: 0.25–0.5%). Recoveries were 99.0–100.2%.     

Structure of naphazoline nitrate

2-(l-Naphthylmethyl)-2-imidazoline nitrate, C₁₄H₁₅N₃O₃,M _r =273.29, orthorhombic,Pbca, a=12.033(4),b=14.387(4),c=15.913(4)Å,V=2754.9(4)Å₃,Z=8,D _m=1.32(3) (flotation),D _x=1.318 Mgm^–3, (CuK)=1.5418 Å,=7.45 cm^–1,F(000)=1152,T=296K, finalR=0.078,wR=0.058 for 1397 reflections withI> 2(I). The naphthalene ring exhibits orientational disorder. The N-HO hydrogen bonds involving both the nitrogen atoms of the imidazoline ring serve to form infinite chains of alternating naphazoline cations and nitrate anions.DCB Contribution No. 811.     

Determination of uranium(VI) in monazite sand

The design and characterization of an argon segmented-solid phase extraction system is described. A 200 ul volume micro-column has been constructed for the preconcentration of rare earth elements (REEs) from salt matrices containing uranium. An inductively coupled plasma atomic emission spectrometer has been utilized for simultaneous detection of Sr, Y and the REEs (namely Ce, Eu, La, Nd, Pr, Sm) at levels ranging from 5- to 2000 ppm in LiC1/KCl samples containing U. Preconcentration factors of 100 fold have been demonstrated. The precision, linear dynamic range and column performance of the system will be presented.     

Preparation of ion exchange resin based elemental standards for use in activation analysis

Various methods of preparing standards for activation analysis have been reported in the literature. This paper describes the feasibility of preparing ion exchange resin based standards containing predetermined levels of ions. Using a solution of known initial concentration of the ion, and given the value of its distribution coefficient, it is possible to predict the resin concentration that will be obtained. Resins containing ppm levels of copper and manganese have been prepared and their stabilities evaluated over a period of time. The feasibility of preparing a multielement standard has been studied with five rare earth elements (La, Ce, Sm, Eu and Dy).