the major sources of pahs are anthropogenic. these may be generated by pyrolytic and petrogenic processes. low molecular weight pahs come into the aquatic system through the accidentally leakage of oil spills. incomplete combustion at high temperature will release high molecular weight pahs by products of pyrolytic processes. the methods for assigning sources of pahs include paired isomeric rat...

   High strength and elastic biodegradable membranes are of great demand in modern technology. Similar membranes have been developed by irradiating different weight poly (vinyl alcohol) (PVA) – hydroxypropyl guar gum (HPG) blends and followed by combining with ex situ nanosilica. Polarized light microscopic (PLM) study indicates that electron beam irradiation produced crosslinks and develop...

This Application Note shows the determination of protein molecular weight and size, together with linear quantifi cation using the Agilent 1260 Infi nity Multi-Detector Bio-SEC Solution. The molecular weights and sizes of proteins, ranging from cytochrome C (11 kDa) to thyroglobulin (670 kDa) were correctly determined, independent of sample loading. Using the dual angle light scattering detecto...

in the present work, a titanium-based ziegler-natta catalyst was employed to synthesize ultra molecular weight polyethylene in a slurry medium. the effect of different parameters such as ethylene pressure, temperature, catalyst composition, and hydrogen pressure was studied. as the results indicate, increasing either [al]/[ti] ratio or temperature causes polymerization rate to go through a maxi...

1. The gram molecular weight of a substance may be calculated from the osmotic pressure of its solution. 2. The radius of the hydrated molecule and, hence, the gram molecular volume of the hydrated solute may be determined from diffusion measurements. The hydration of the molecules may, therefore, be calculated from osmotic pressure and diffusion measurements. 3. Hydration may also be determine...

Time-resolved X-ray solution scattering is an increasingly popular method to measure conformational changes in proteins. Extracting structural information from the resulting difference X-ray scattering data is a daunting task. We present a method in which the limited but precious information encoded in such scattering curves is combined with the chemical knowledge of molecular force fields. The...