5'-degenerate 3'-dideoxy-terminated competitors of PCR primers increase specificity of amplification

Amplification of a product in PCR with specific primers may be viewed as an artificial Darwinian-type "selection of the fittest". In other selective systems, such as general evolution, immune system and probably brain cortex, the stringency of selection is not absolute but rather degenerate, with selection of many highly fit units, not limited, however, to only the fittest. In PCR also, annealing of the primers is not absolutely specific. The subsequent amplification frequently leads to amplification of not only the desired product but also to less-specific sequences. Using theoretical analysis of the degenerate mode of selection, we predict theoretically and prove experimentally that 5'-degenerate, 3'-dideoxy-terminated competitors of PCR primers can be used to dramatically improve the specificity of PCR amplification without affecting the quantitation of the final specific product.     

Rheology of chemically modified triglycerides

The rheology of chemically modified plant oils was determined to aid in their processing for polymers and other applications. Epoxidized and acrylated triglycerides were derived from various plant oils and model triglycerides. The viscosity of the unmodified oils decreased as the level of oil unsaturation increased. However, the viscosity of the epoxidized oils increased slightly as the level of epoxidation increased. Furthermore, the viscosity of the acrylated oils increased exponentially as the level of acrylation increased because of increased polarity. In addition, the viscosity of the acrylated oils increased as the average distance of the acrylate groups from the fatty acid chain ends decreased. Chemically modified and unmodified oils did not exhibit any shear‐thinning behavior or any memory of shear history. The temperature dependence of the viscosity followed the Arrhenius law, and the activation energy decreased linearly with the level of acrylation. The addition of comonomers, such as styrene, reduced the viscosity of the acrylated oils exponentially as the comonomer concentration increased. However, the glass‐transition temperature and modulus of the triglyceride‐based polymers decreased as the styrene content decreased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 774–783, 2005     

Interfaces in repair,recycling, joining and manufacturing of polymers and polymer composites

A basic set of 10 thermoset polymer–polymer interfaces has been identified to play a vital role in the technical and economic aspects of composite manufacturing (RIM/RTM, compression molding, autoclave lamination), recycling, repair, welding, and joining of polymer composites. Knowledge of the chemical interactions and molecular connectivity at these interfaces and their influence on processability and mechanical properties of the polymers and polymer composite is essential, and has been the focus of this research. Presented in this report are the results of an exploratory study performed to understand the interactions at the polymer–polymer interface and their influence on the interfacial fracture toughness of a thermoset vinyl ester, which is widely used in liquid molding applications. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 775–785, 1999     

Photolytic and free‐radical polymerization of monomethyl maleate esters of epoxidized plant oil triglycerides

Epoxidized soybean oil (ESO) was reacted with monomethyl maleate with AMC‐2 catalyst. Monomethyl maleate was found to react with 65% of the available epoxy groups to give the monomethyl maleic esters of ESO (MESO). ¹H‐NMR, ¹³C‐NMR, and IR spectra of the new derivative confirmed the proposed structure. The NMR spectra revealed that the average number of monomethyl maleate groups per triglyceride molecule was 2.6. MESO was photopolymerized with ultraviolet light and was free radically homopolymerized and copolymerized with styrene (STY), vinyl acetate (VA), and methylmethacrylate (MMA). MESO was also reacted with maleic anhydride at the newly formed hydroxyl groups to give maleinized MESO, (MESOMA), which now contained 4.9 maleate unsaturations per triglyceride. Dynamic mechanical analysis revealed the dynamic modulus for styrene copolymers of MESO and maleinized MESO as 105 and 140 MPa, respectively. Both of these plant oil derived monomers are good candidates for a practical and economical liquid molding resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 626–633, 2007     

Novel thermosetting resins for SMC applications from linseed oil: Synthesis,characterization, and properties

New thermosetting resins for applications of sheet‐molding compounds (SMCs) were successfully synthesized from linseed oil, which is the most molecularly unsaturated of all plant oils. The carbon–carbon double bonds were opened by epoxidation, followed by acrylation, and then maleinization, which provided more crosslink sites and added acid functionality on the triglyceride molecules to develop thickening. Dynamic mechanical analysis showed that the storage modulus of these new polymers was approximately 2.5 GPa at 30°C, and the glass‐transition temperature was above 100°C. During maturation the resins reached a molding viscosity quickly and stayed stable. Mechanical tests showed a flexural strength of 100 MPa and a flexural modulus of 2.8 GPa. Thermogravimetric analysis showed a single degradation ranging from 300°C–480°C, which was a result of the carbonization of the crosslinked network. These bio‐based resins are promising as replacements of some petroleum‐based resins in the SMC industry. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Natural killer and lymphokine-activated cytotoxicity following anaesthesia in patients with uveal malignant melanoma

OBJECTIVE: The aim of the study was to determine the pattern of health care utilization of people aged 55-74 years with arthritic pain in the knee or hip. DESIGN: People with current pain were identified in a population-based study. A filter model was used to describe the pattern of health care utilization of people who presented as patients at different levels (GPs or specialist) of the health care system in the Netherlands. SETTING: The study was carried out in the district of Ommoord in Rotterdam in an age- and gender-representative sample of 831 (response 83%; n = 691) people. STUDY PARTICIPANTS: A group of 186 people with current pain was identified. They completed a questionnaire and were interviewed. MAIN OUTCOME MEASURES: Background variables, illness-related variables (including radiological osteoarthritis), and self-reported diagnoses were described and compared for attenders and non-attenders of GPs and specialists. A reference group of patients of GPs was used to determine the validity and generalizability of the findings. RESULTS: Eighty-two per cent consulted a GP (passed filter 1). In 69% of the GP attenders, 'arthritis' was identified (passed filter 2), and 65% of them attended a specialist (passed filter 3). People who did not pass the various filters were different from those who did with respect to the body mass index (lower; OR 1.24), the chronicity of pain (less chronic pain; OR 4.9) and attendance of a physiotherapist (lower; OR 5.6). The chronicity of pain seems of more importance in determining the health care utilization pattern than the severity of pain, the level of disability or the presence of radiological osteoarthritis. We suggest that health promotion interventions could increase the self-management ability of patients and could lower costs.