Core-shell macromolecules with dendritic polyphenylene core and polymer shells

Inhaltszusammenfassung in einer weiteren Sprache (englisch) Core-shell macromolecules with dendritic polyphenylene core and polymer shell Zusammenfassung / Abstract Core-shell macromolecular structures have become of great interest in materials science because they gave an opportunity to combine a large variety of chemical and physical properties in the single molecule, by combination of different (in terms of chemistry and physics) cores and shells. The interest in such complex structures was provoked by their potential applications in the coating and painting industry (latexes), as supports for catalysts in polymer industry, or as nano-containers and transporters for genes or drug delivery. The aim of this study was the synthesis, characterization and further application of core-shell macromolecules possessing a hydrophobic stiff core (polyphenylene dendrimers) surrounded with a hydrophilic, soft, covalently bonded polymer shell (poly(ethylene oxide) and its copolymers). The requirements for such complex substances were that they should be well-defined in terms of molecular weight (narrow molecular weight distribution) and in molecular structure. The preparation of core-shell molecules containing dendrimer as a core was possible via two synthetic routs: “grafting-onto” and “grafting-from”. The resulting core-shell macromolecules possessed narrow polydispersity as guaranteed by the excellent structural and functional definition of the dendrimer and the narrow polydispersity of the PEO, PS-b-PEO and PI-b-PEO attached to the dendrimer surface. Additional investigation of the size of the particles indicated a relation between both the length and the number of the polymer chains and the hydrodynamic radius determined by Dynamic Light Scattering and Fluorescent Correlation Spectroscopy. Core-shell nano-particles were applied as metallocene supports in heterogeneous olefin polymerizations. Our results indicate that such catalyst systems, that have a size of at least one order of magnitude smaller than the used by now organic supports, could be very useful as model compounds for investigations on catalyst fragmentation and its influence on the product parameters

New Integrable Multi-Component NLS Type Equations on Symmetric Spaces: Z_4 and Z_6 Reductions

The reductions of the multi-component nonlinear Schrodinger (MNLS) type models related to C.I and D.III type symmetric spaces are studied. We pay special attention to the MNLS related to the sp(4), so(10) and so(12) Lie algebras. The MNLS related to sp(4) is a three-component MNLS which finds applications to Bose-Einstein condensates. The MNLS related to so(12) and so(10) Lie algebras after convenient Z_6 or Z_4 reductions reduce to three and four-component MNLS showing new types of chi ^(3)-interactions that are integrable. We briefly explain how these new types of MNLS can be integrated by the inverse scattering method. The spectral properties of the Lax operators L and the corresponding recursion operator Lambda are outlined. Applications to spinor model of Bose-Einstein condensates are discussed.Comment: Reported to the Seventh International conference "Geometry, Integrability and Quantization", June 2--10, 2005, Varna, Bulgari

Fordy-Kulish models and spinor Bose-Einstein condensates

A three-component nonlinear Schrodinger-type model which describes spinor Bose-Einstein condensate (BEC) is considered. This model is integrable by the inverse scattering method and using Zakharov-Shabat dressing method we obtain three types of soliton solutions. The multi-component nonlinear Schrodinger type models related to symmetric spaces C.I Sp(4)/U(2) is studied.Comment: 8 pages, LaTeX, jnmp styl

The Market Reaction to Changes in Disclosure of Related-Party Transaction Rules

We examine the valuation effects of the 2004 changes in Romanian related -party transactions (RPT) disclosure rules. Because the rule changes apply only to companies listed on the Bucharest Stock Exchange (BSE), companies traded on an alternative market (RASDAQ) serve as a natural control group. We find that immediately following the adoption of the rules, BSE firms experience abnormal returns of 6% to 12% relative to matched RASDAQ firms with similar pre-reform characteristics. We also show that in the three-year period following the reforms, BSE firms experience a 20-25% increase in their Tobin’s q. Overall, the results suggest that the implementation of mandatory RPT disclosure rules can be effective in decreasing tunneling and increasing minority valuations in an emerging market

Simulation and Robust Modifications of Estimates in Branching Processes

This study is focused on the comparison and modification of different estimates arising in the branching processes. Simulations of models with or without migration are put through. Due to the complexity of the computations the algorithms are designed with the language of technical computing MATLAB. Using the simulations, estimates of the o spring mean of the generated processes are calculated. It is well known in the literature that under certain conditions the asymptotic distribution of the estimates is proved to be normal. Using the asymptotic normality a modified method of maximum likelihood is proposed. The aim is to obtain trimmed maximum likelihood estimates based on several sample paths with the same number of generations. Thus in a natural way the observations, inconsistent with the aprior information about the asymptotic normality are excluded from the model. The computation of the standard error allows the comparison of different types of estimates.This paper is supported by National Foundation for Scienti c Investigation - Bulgaria, grant MM-1101/2001 and PRO-ENBIS: GTC1-2001-43031

OUR EXPERIENCE IN THE DIAGNOSIS OF CHLAMYDIAL INFECTIONS

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Predictors for outcome after surgery for traumatic acute subdural hematoma

Introduction: Acute traumatic subdural hematoma (ASDH) is one of the most frequent conditions in neurosurgery demanding emergency surgery. The aim of the study was to identify factors influencing outcome in patients who had surgery for evacuation of ASDH.Methods: From 2005 to 2012 eighty-five patients at age above 18 years had surgery for evacuation of ASDH. Outcome was measured according GOS at discharge and was dichotomized as “favorable outcome” (GOS 4 to 5) and “unfavorable outcome” (GOS 1 to 3). These factors were evaluated with univariate and logistic regression analysis for significance with outcome.Results: The mean age of the 85 patients was 62.7 years (SD±18.5). 45.9% patients were with favorable outcome and 54.1% had unfavorable outcome. Patients with GCS score 3-8 (54.1%) had 80.4% unfavorable outcome whereas 78.6% of patients with GCS score 13-15 (32.9%) had favorable outcome. All patients with nonreactive pupils (bilaterally or unilaterally -31.8%) had unfavorable outcome whereas patients (36.5%) with both reactive pupils (36.5%) had in 80.6% favorable outcome. All patients (40%) with Rotterdam CT scores 5 and 6 had unfavorable outcome. The factors determining outcome were admission GSC score, Rotterdam CT scores, and prothrombin time.Conclusion: Patients who have GSC score of 3, unresponsive pupil(s) or have Rotterdam CT scores 5 and 6 have little chance of survival. Patients with coagulopathy have two times more unfavorable outcome. The patients with ASDH should have surgery as soon as possible after correction of vital parameters in order to avoid deterioration which can be very rapid and irreversible