Synthesis and properties of new thermosensitive polymer systems

The controlled thermal release of aqueous solvent mixtures from polymeric gel particles was investigated. A new type of a polymeric gel consisting of a maleic anhydride/poly(ethylene glycol) condensation product as a crosslinking macromonomer and acrylamides was synthesized by solution or inverse emulsion polymerization for the investigation. Afterward a shell of crosslinked polystyrene was coated to stabilize this new kind of “microcontainer” for the application. This concept was shown as generally useful for various mixtures of organic solvents and water. The cloud point temperature of the polymer gel strongly depended on the following parameters: the type and content of organic cosolvent, the degree of polymerization and constituents of the polyester moiety, and the type and content of the comonomers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Balanced reciprocal translocation mosaicism associated with an abnormal phenotype

Balanced reciprocal translocation mosaicism is rarely reported in humans. Only two previous cases have been associated with an abnormal phenotype. We report on a third case of apparently balanced reciprocal translocation mosaicism associated with an abnormal phenotype, largely different from those reported previously. Since low levels of mosaicism may not be detected in routine cytogenetic analyses, balanced reciprocal translocation mosaicism may be associated with an abnormal phenotype more often than has been recognized to date.     

Analytical models of adhesively bonded joints—Part II: Comparative study

The literature survey presented in Part I describes the major analytical models for adhesively bonded joints, especially for single lap joints. By consulting the summary table given in Part I, the designer can choose from a wide range of models which is the best for a particular situation. However, the information given in the summary table is not sufficient for a proper selection. The designer also needs to know the time required for setting up an analysis and solving it. Another important factor is the accuracy of strength prediction. Therefore, models of increasing complexity were selected from the summary table and a comparative study was made in terms of time requirements and failure prediction for various cases. Three main situations were considered: elastic adherends and adhesive, elastic adherends with nonlinear adhesive, and nonlinear analyses for both adherends and adhesive. The adherends were both isotropic (metals) and anisotropic (composites). The effects of the overlap length and the adhesive thickness were also considered.     

Interviews3D: a platform for interactive handling of massive data sets.

Interviews3D confronts the CAD data explosion problem with new approaches that let users process fully detailed 3D models in real time, even on standard PCs or 32-bit laptops. It has demonstrated efficiency in real-time rendering and clash detection for automotive, aerospace, and construction models too large for previous systems.     

Photopolymerization of urethane dimethacrylates synthesized via a non-isocyanate route

Urethane dimethacrylate monomers were synthesized via a non-isocyanate route from the reaction of a urethane diol with methacrylic anhydride. The urethane diols were synthesized through the reaction of ethylene carbonate with 1,6-hexanediamine, 3-amino-1-propanol and 2,2-dimethyl-1,3-propanediamine. ¹H NMR, ¹³C NMR and FTIR spectroscopies confirmed the structure of the monomers. Elemental analysis confirmed the purity of the monomers. Photopolymerization of these multifunctional monomers was investigated with respect to polymerization rates and conversions using photoinitiated differential scanning calorimetry. Irgacure 651^® was used as an initiator at 2 mol%. Photopolymerization results indicate high peak polymerization rates, 0.09 s⁻¹ compared to 0.06 s⁻¹ for bis-GMA and 0.07 s⁻¹ for HDDMA polymerized under the same conditions. Overall bulk conversions were 70-78%, compared to 68 and 76% for bis-GMA and HDDMA, respectively.The methodology developed here utilizes diamines and amino-alcohols that are members of commercially available families possessing a large range of structures, thus allowing synthetic flexibility in obtaining new urethane dimethacrylates with desirable properties.     

Causes of sudden unexpected cardiac death in the first two decades of life

Sudden, unexpected cardiac death in the age group 1 to 21 years usually is due to myocarditis, hypertrophic cardiomyopathy, aortic valvar stenosis, and coronary arterial abnormalities. The hearts of 70 patients <21 years of age who died suddenly were reviewed. Twenty patients were <1 year of age and 50 were 1 to 21 years old. The cardiac findings were compared with those in 68 age-matched controls with known cardiac disease who did not die suddenly. Significant cardiac abnormalities were present in 13 (65%) of the 20 infants; 10 (50%) had anomalies of the aortic origin of the coronary arteries. Among the 50 older patients, cardiac abnormalities were found in 40 (80%), among whom coronary arterial anomalies existed in 12 (24%). Anomalies of aortic origin more frequently involved the left main than the right coronary artery in both groups.