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M Keskin

Publications and source records attributed to M Keskin.

9 recordsLinked to original sources
PubMed2001

Dynamics of a spin-1 Ising system in the neighborhood of equilibrium states.

The dynamics of a spin-1 Ising system containing biquadratic interactions near equilibrium states is formulated by the method of thermodynamics of irreversible processes. From the expression for the entropy production, generalized forces and fluxes are determined. The kinetic equations are obtained by introducing kinetic coefficients that satisfy the Onsager relation. By solving these equations a set of relaxation times is calculated and examined for temperatures near the phase transition temperatures, with the result that one of the relaxation times approaches infinity near the second-order phase transition temperature on either side, whereas it is sharply cusped at the first-order phase transition temperature. On the other hand, the other relaxation time has a cusp at the second-order phase transition temperature but displays a different behavior at the first-order phase transition, just a jump discontinuity. The behavior of both relaxation times is also investigated at the tricritical point. Moreover, the phase transition behaviors of the relaxation times are also obtained analytically via the critical exponents. Results are compared with conventional kinetic theory in the random-phase or generalized molecular-field approximation and a very good overall agreement is found.

Journal Article↗
PubMed2000

Computerized 3-dimensional study of the embryologic development of the human masticatory muscles and temporomandibular joint.

PURPOSE: In this study, the development of human embryonic temporomandibular joint (TMJ) and masticatory muscles were investigated by using computed 3-dimensional reconstructions. MATERIALS AND METHODS: Sixteen human embryos and fetuses, ranging from 6.5 to 107 mm crown-rump length, were examined. RESULTS: At 10 weeks, a band of mesenchyme extending from the attachment of the lateral pterygoid muscle to the condylar process was observed to pass through the medial side of the condylar process to attach to the malleus. The temporal, masseter, and pterygoid muscles develop from the so called "temporal muscle" primordium, and the temporal muscle was in continuity with the masseter muscle until 14 weeks of fetal life. CONCLUSIONS: The study shows that the muscles of mastication arise from a single primordium. It also confirms the presence of a ligamentous attachment between the lateral pterygoid muscle and the malleus.

Computer Simulation↗
PubMed2000

The extended V-Y flap for coverage of a mid-planatar defect.

A mid-plantar ulcer was successfully reconstructed with an extended V-Y flap incorporating part of the flexor digitorum brevis muscle to achieve more volume and increase the safety of the flap. This flap can be used as a reliable alternative to other techniques to repair a moderately sized defect of the plantar midfoot.

Adult↗
PubMed1994

In vitro adsorption of dichlorvos and parathion by activated charcoal.

Accidental and suicidal ingestions of organophosphate compounds continue to be a common occurrence in Turkey. Activated charcoal administration without gastric emptying has been advocated as primary therapy in most acute poisoning cases, although some references do not recommend activated charcoal use in organophosphate poisoning. This study was performed to determine the in vitro adsorption of dimethyl dichlorovinyl phosphate (dichlorvos) and parathion by activated charcoal over a wide range of charcoal:organophosphate ratios (1:1, 2.5:1, 5:1, 10:1 and 20:1, g:g). The charcoal binding ability of dichlorvos and parathion were studied in both pH 1.2 and pH 7 environments. The supernatant was extracted with n-hexane and then analyzed by gas chromatography. Each incremental increase in charcoal dose increased the percent adsorption of dichlorvos and parathion. At the 20:1 ratio, 82.8 +/- 2.0/87.3 +/- 2.9% (pH 1.2/7.0) of dichlorvos and 59.3 +/- 4.5/64.5 +/- 6.1% (pH 1.2/7.0) of parathion were bound by activated charcoal. There were no significant differences in amounts of compound bound in the acid and neutral solutions. Large doses of activated charcoal effectively bind dichlorvos and parathion in vitro. In vivo research should be performed to determine activated charcoal's role in organophosphate poisoning cases.

Adsorption↗