Preparation of Poly(ethylene terephthalate)‐g‐Methacrylamide Copolymers Initiated by Azobisizobutyronitrile: Characterization and Investigation of Some Properties

Poly(ethylene terephthalate)‐g‐methacrylamide (PET‐g‐MAAm) copolymer was prepared by graft copolymerization in organic solvent/water mixtures by using azobisizobutyronitrile (AIBN) as an initiator. The highest graft yield was obtained in 20/80 (v/v) acetonitrile/water mixture as 30.0%. The effect of polymerization parameters such as the ratio of solvent/water mixture, concentrations of initiator and monomer, temperature and time on the graft yield was studied. The moisture regain of the PET fiber increased with grafting from 0.42% to 3.01%. Thermogravimetric data showed that the thermal stability of PET fibers decreased with grafting and 85% of total weight of 29.7% grafted fiber was lost at 500°C. On the other hand, fiber density decreased with increasing graft yield. At SEM micrographs, the layers oriented in the direction of fiber length were observed on the surface of PET fiber as a result of grafting.     

Comparative toxicity of [3]ferrocenophane and ferrocene moieties on breast cancer cells

Recent results suggest that [3]ferrocenophane may be an interesting motif in the development of cytotoxic anti-cancer agents. We here report the synthesis of three such compounds based on the 1-[(p-R-phenyl)-phenyl-methylidenyl)]-[3]ferrocenophane skeleton with R = OH, NH₂ and NHC(O)CH₃ substitution on one of the phenyl rings. Cytotoxicity studies show that these compounds are up to four times more powerful against hormone-independent breast cancer cells than their corresponding ferrocene analogs.     

Chemical Determination of Uranium in Natural Waters with DBM by the Adsorption of U(VI) on Fe(OH)3

The feasibility of determining uranium in natural waters for uranium exploration using dibenzoil methane (DBM) by the adsorption of U(VI) on ferric hydroxide, was investigated. The yields of coprecipitation were determined by a Scintrex UA-3 laser fluorimetric uranium analyser using standard uranium solutions. After dissolving the coprecipitate, uranium was selectively separated by carbonate precipitation and determined with DBM. Fe(OH)₃ - DBM method was controlled using both standard solutions and uranium analyser measurements of some natural water samples taken from Northern Ege Region where detailed radiometric investigation has been going on. The advantage of this method     

Preparation of hydrogels by photopolymerization of acrylates in the presence of Type I and one-component Type II photoinitiators

Hydrogels were prepared by photoinduced polymerization of poly(ethylene glycol)monoacrylate (PEGMA) and poly(ethylene glycol)diacrylate (n = 200 and 700) (PEGDA) with Type I, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (I-2959) and one-component Type II initiators: (9-oxo-9H-thioxanthen-2-yloxy)-acetic acid (TXOCH₂COOH) and (9-oxo-9H-thioxanthen-2-yloxy)-sodium acetate (TXOCH₂COO^?Na⁺). The swelling properties of hydrogels were investigated and observed to be excellent. Smooth morphology and no phase separation were observed from SEM micrographs of the hydrogels.     

Mathematical modelling,analysis and numerical simulations for the influence of heat shock proteins on tumour invasion

Invasion is a key property of tumour cells for building metastasis. A class of functionally related proteins called heat shock proteins (HSPs), the expression of which is increased when cells are exposed to elevated temperatures or other stress, play an important role in the invasion. In this paper we develop a mathematical model focusing on the effect of HSPs on the tumour cell migration. The resulting multiscale setting accounts both for the microscopic, intracellular level on which these proteins are acting and for the macroscopic level of the cell population. We prove the local existence of a unique positive solution and perform numerical simulations in order to illustrate the behaviour of cancer cells w.r.t. the fibre density of the tissue and the matrix degrading enzymes, along with the effect of HSPs.     

Robust model selection criteria for robust Liu estimator

In linear regression analysis, outliers often have large influence in the model/variable selection process. The aim of this study is to select the subsets of independent variables which explain dependent variables in the presence of multicollinearity, outliers and possible departures from the normality assumption of the error distribution in robust regression analysis. In this study to overcome this combined problem of multicollinearity and outliers, we suggest to use robust selection criterion with Liu and Liu-type M(LM) estimators.     

Combinatorics of rational singularities

A normal surface singularity is rational if and only if the dual intersection graph of a desingularization satisfies some combinatorial properties. In fact, the graphs defined in this way are trees. In this paper we give geometric features of these trees. In particular, we prove that the number of vertices of valency 3 in the dual intersection tree of the minimal desingularization of a rational singularity of multiplicity m 3 is at most m - 2.     

The structure of ethyl allyl 1,4-dihydro-2,6-dimethyl-4-[4-(4H-4-oxo-1-benzopyran-2-yl)phenyl]-3,5-pyridine dicarboxylate

The crystal and molecular structure of the title compound has been determined by direct methods, and refined to a finalR of 0.070 for 1466 observed reflections. The compound crystallizes in space group P2_l/n with cell dimensionsa=10.706(8),b=21.127(11),c=12.038(10) Å, Z=4.1,4-dihydropyridine ring adopts a boat shaped conformation. The flavon molecule is planar and it's phenyl ring is almost perpendicular to the 1,4-DHP. The C36 atom of the allyl group shows disorder.     

Kinetic studies of uranium(VI) adsorption on a composite ion exchanger

In this paper, we studied the continuous adsorption of uranium on a composite ion exchanger. The experimental study was carried out at optimum conditions of uranium uptake found in the previous study. For these conditions first the adsorption isotherm was determined. This isotherm shows non-linear sorption according to the Langmuir model. Then we investigated uranium adsorption at different time intervals at temperatures of 30°C and 60°C, respectively.