Polysomes can be extracted from Escherichia coli by freezing and thawing in the presence of lysozyme, followed by treatment with sodium deoxycholate. The method is simple and convenient; the yields consistently high.

Some natural bers like ax, hemp and others show excellent mechanical properties that make them a promising choice for the reinforcement of polymers. The increasing research on natural ber reinforced composites has still left important questions open, mainly concerning the ber-matrix interface. Compared to the well optimized glass bers, cellulose bers show very different interaction with matrix polymers and adhesion promoters. The hydrophilic cellulose structure allows for the penetration of a considerable amount of water into the amorphous regions of the bers, eventually exceeding 20% by mass, depending on ber type, preparation and environmental humidity. Even embedded in totally apolar polymers the cellulose partly retains its ability for water sorption, which results in unfavorable effects, such as dimensional changes, decrease in strength, roughening of the surface, etc.The interaction of differently prepared bers with water vapor and the effect of surface treatment is investigated by measuring the dynamics of water vapor sorption. An exponential model is used for the numerical evaluation of the sorption and desorption kinetics. The model not only allows for an excellent t of the experimental isotherms, but without any further assumptions it immediately gives evidence of the existence of two distinct mechanisms for the exchange of water vapor, related to different sorption sites. These speci c mechanisms are represented by individual sorption-desorption isotherms as components of the total isotherms. The model provides a clearer differentiation of the effects of ber preparation and modi cation with respect to interfacial interactions.

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A B S T R A C TBackground: Calcific atherosclerosis is a major challenge to intraluminal drug delivery in peripheral artery disease (PAD). Objectives: We evaluated the effects of orbital atherectomy on intraluminal paclitaxel delivery to human peripheral arteries with substantial calcified plaque. Methods: Diagnostic angiography and 3-D rotational imaging of five fresh human lower limbs revealed calcification in all main arteries. The proximal or distal segment of each artery was treated using an orbital atherectomy system (OAS) under simulated blood flow and fluoroscopy. Explanted arterial segments underwent either histomorphometric assessment of effect or tracking of 14 C-labeled or fluorescent-labeled paclitaxel.Radiolabeled drug quantified bulk delivery and fluorescent label established penetration of drug over finer spatial domain in serial microscopic sections. Results were interpreted using a mathematical model of bindingdiffusion mediated arterial drug distribution. Results: Lesion composition affected paclitaxel absorption and distribution in cadaveric human peripheral arteries. Pretreatment imaging calcium scores in control femoropopliteal arterial segments correlated with a loglinear decline in the bulk absorption rate-constant of 14 C-labeled, declining 5.5-fold per calcified quadrant (p = 0.05, n = 7). Compared to controls, OAS-treated femoropopliteal segments exhibited 180 μm thinner intima (p < 0.001), 45% less plaque calcification, and 2 log orders higher paclitaxel bulk absorption rate-constants. Correspondingly, fluorescent paclitaxel penetrated deeper in OAS-treated femoropopliteal segments compared to controls, due to a 70% increase in diffusivity (p < 0.001).Conclusions: These data illustrate that calcified plaque limited intravascular drug delivery, and controlled OAS treatment of calcific plaques resulted in greater drug permeability and improved adjunct drug delivery to diseased arteries.