The addition of a macromolecular crowding agent to a dilute solution of polymer exerts a compressive force that tends to reduce the size of the chain. We study here the effect of changing the size ratio between the random coil and the crowding agent. The compression occurs at lower crowding agent concentration, Φ when polymer molecular weight increases. The Flory exponent ν(Φ) decreases from ν(...

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ii) a exible polymer with rigid bonds and iii) a exible polymer with exible bonds. The use of a very e cient pivot algorithm has made it possible to simulate very long chains, with up to several thousand titrating groups. The results have been compared to a mean eld approximation for a rigid rod and variational results emanating from a Flory type approach. It is found that the rigid rod mean el...

The renormalized elasticity Jheory for jsolated flexible polymers developed recently by de Gennes is extended to the case of strong elongation ( Z / R F >> 1,Z is the average end-to-end length in response to a uniform tension and R F is the excluded volume Flory radius !fa free coil). I t is shown that, in this regime, the elastic restoring force f is nonlinear in the distortion and varies as Z...

Carothers and Flory established the fundamental principles of homogeneous two-component polycondensation reactions by which a variety of commonly used polymers such as polyesters and polyamides (nylons) are synthesized even now. One of the most critical factors to achieve a high degree of polymerization is a strict adherence of stoichiometric balance of the two components. An imbalanced ratio o...

The interactions between spherical colloids covered with end-grafted polymers (brushes) immersed in a polymer melt are studied theoretically. We show that attractive enthalpic interactions between the two polymer species, characterized by a negative Flory parameter (chi<0), can stabilize the colloidal dispersion. The stabilizing mechanism is a result of a structural change from a dry brush, whe...

In the coming years, the frequency of unauthorised genetically modified organisms (GMOs) being present in the European food and feed chain will increase significantly. Therefore, we have developed a strategy to identify unauthorised GMOs containing a pCAMBIA family vector, frequently present in transgenic plants. This integrated approach is performed in two successive steps on Bt rice grains. F...

The rapid increase in the number of genetically modified (GM) varieties has led to a demand for high-throughput methods to detect genetically modified organisms (GMOs). We describe a new dynamic array-based high throughput method to simultaneously detect 48 targets in 48 samples on a Fludigm system. The test targets included species-specific genes, common screening elements, most of the Chinese...

Two new 5-oxomilbemycins, 27-aldehyde-5-oxomilbemycin β12 (1) and 2-hydroxymilbemycin K (2), were isolated from a genetically engineered strain Streptomyces bingchenggensis BCJ60. Their structures were determined by comprehensive analyses of its 1 H and 13 C NMR, COSY, HMQC, and HMBC spectroscopic, HRESI-MS mass spectrometric and comparison with data from the literature. Preliminary studies sho...

The scaling properties of self-avoiding polymerized 2-dimensional membranes are studied via renormalization group methods based on a multilocal operator product expansion. The renormalization group functions are calculated to second order. This yields the scaling exponent ν to order ε2. Our extrapolations for ν agree with the Gaussian variational estimate for large space dimension d and are clo...