Morphological characterization of microcellular carbon foams

Microcellular carbon foams have been prepared by the high-temperature carbonization of polyacrylonitrile (PAN) foams in an inert atmosphere. The PAN precursor foams were first prepared by thermally induced phase separation of PAN solutions followed by gelation/extraction or freezing/freeze-drying processes. The resulting carbon foams have low densities and open-celled morphologies. We have developed two complementary techniques to characterize objectively carbon foam morphologies, BET surface area measurements and mercury porosimetry. These two measurement techniques, when used in conjunction with known stereological rules, allow us to calculate densities and average cell sizes or cell size distributions. As a bonus, values of the bulk modulus for low-density carbon foams also can be determined from mercury porosimetry. Unlike other techniques, our determinations do not require carefully prepared surfaces (such as for microscopy) or an assumed morphological model (required for most other techniques).     

Composition of proteins in wheat grain streams obtained by sieve classification

Sieve classification was used to prepare grain streams of distinct protein content and composition. Both reverse‐phase high‐performance liquid chromatography and two‐dimensional electrophoresis revealed differences in protein composition between large (F1), medium (F2–F3), and small (F4) kernel fractions of three Polish cultivars: Sukces and Tonacja (winter wheats) and Nawra (spring wheat). Statistical analysis indicated that grain protein composition is affected by the cultivar and kernel size, as well as by interaction of these traits. The albumin/globulin and glutenin fractions showed a tendency to decrease with diminishing kernel size. The gliadin content was affected to a greater extent by the kernel size than by the wheat genotype. The highest content of gliadins was observed in the smallest and the largest kernel fractions. Copyright © 2007 Society of Chemical Industry     

The use of long-chain plant polyprenols as a means to modify the biological properties of new biodegradable polyurethane scaffolds for tissue engineering. A pilot study

Microporous membranes for tissue engineering were produced from new biodegradable polyurethane based on hexamethylene diisocyanate, poly(ε-caprolactone) diol and 1,4:3,6-dianhydro-d-sorbitol. The interconnected pores had an average size in the range of 5–100 μm. The tensile strength at break, the Young’s modulus and elongation at break of the membranes were 3.2 ± 0.3 MPa, 25.2 ± 1.5 MPa and 190 ± 12%, respectively, while nonporous foils from the same polymers had a tensile strength at break of 40 ± 2 MPa, a Young’s modulus of 91 ± 6 MPa, and an elongation at break of 370 ± 10%. The membranes were incubated for 10 days in a 2.65 vol% solution of long-chain plant polyprenol in n-hexane to promote their interaction with cells and tissues. The polyprenol was isolated from leaves of Magnolia cobus and was a mixture of prenol-10 and prenol-11. The prenol-impregnated membranes and nonimpregnated membranes (control) were tested in cell culture to assess whether impregnation has a beneficial effect on cell-material interaction. The cells used in the test were chondrocytes isolated from the articular-epiphyseal cartilage of leg bones of 5-day-old inbred LEW rats. The time of culture was 2 and 5 weeks. Both, the nonimpregnated and impregnated polyurethane membranes supported attachment and growth of rat chondrocytes. The cells firmly attached to the surface of the microporous membranes, invaded the pores and maintained the round shape characteristic for chondrocyte-like-morphology. Abundant fibrillar extracellular matrix produced by the cells resembled the network formed by chondrocytes in vivo. The cells produced relatively more extracellular matrix in the membranes impregnated with polyprenol than in the control membranes. Impregnation of polyurethane scaffolds with biologically active amphiphilic polyprenols may be a route to facilitate the cell–material interaction.     

Electrochemical treatment of aqueous solutions containing urea

Investigations on the anodic decomposition of urea using Ti/Pt and Ti/(RuO₂–TiO₂)_40:60 electrodes were carried out. The kinetics of the process were examined in a periodic electrolyser. The effect of anodic current density, initial urea concentration, and sodium chloride concentration on the effectiveness of the basic process (average rate of urea decomposition, current efficiency, and unit power consumption) is discussed. When a Ti/Pt electrode is applied for urea removal from aqueous solution urea is not decomposed directly at the surface of the electrode, but rather in the bulk of the solution by hypochlorite formed during the process. When the Ti/(RuO₂–TiO₂)_40:60 electrode is used for the removal of urea from aqueous solutions, the reaction of urea with chlorine adsorbed at the electrode predominates. In both cases non-toxic products of urea decomposition (N₂, CO₂,) are formed. Comparison of the effectiveness of anodic decomposition of urea for the Ti/Pt and Ti/(RuO₂–TiO₂)_40:60 electrodes in the periodic electrolyser at optimum process parameters has revealed that the former electrode is more favorable.     

Characterization of Polish Wines Produced from the Multispecies Hybrid and Vitis vinifera L. Grapes

Phenolic profile, antioxidant activity, and color parameters of Polish wines, produced from the multispecies hybrid and Vitis vinifera L. grapes were analyzed. A principal component analysis was applied, in order to differentiate the investigated wines in terms of content of phenolic compounds. The white wines turned out to be similar to each other in terms of color parameters and the results of principal component analysis, while the red wines strongly differed in this respect. However, the white wine produced from the multispecies hybrid grapes contained a higher level of phenolic acids and flavonoids, as compared to the white wines obtained from the hybrid cultivars. Out of the red wines, Rondo wine, produced from the multispecies hybrid grapevine was the richest in total phenolic and phenolic acids content. Caffeic acid and quercetin were the predominant phenolics in majority of the wines tested.     

Microporous biodegradable polyurethane membranes for tissue engineering

Microporous membranes with controlled pore size and structure were produced from biodegradable polyurethane based on aliphatic diisocyanate, poly(ε-caprolactone) diol and isosorbide chain extender using the modified phase-inversion technique. The following parameters affecting the process of membrane formation were investigated: the type of solvent, solvent–nonsolvent ratio, polymer concentration in solution, polymer solidification time, and the thickness of the polymer solution layer cast on a substrate. The experimental systems evaluated were polymer–N,N-dimethylformamide–water, polymer–N,N-dimethylacetamide–water and polymer–dimethylsulfoxide–water. From all three systems evaluated the best results were obtained for the system polymer–N,N-dimethylformamide–water. The optimal conditions for the preparation of microporous polyurethane membranes were: polymer concentration in solution 5% (w/v), the amount of nonsolvent 10% (v/v), the cast temperature 23°C, and polymer solidification time in the range of 24–48 h depending on the thickness of the cast polymer solution layer. Membranes obtained under these conditions had interconnected pores, well defined pore size and structure, good water permeability and satisfactory mechanical properties to allow for suturing. Potential applications of these membranes are skin wound cover and, in combination with autogenous chondrocytes, as an “artificial periosteum” in the treatment of articular cartilage defects. Various parts of this study were presented at the European Society for Biomaterials Meeting, Sorrento, Italy, September 11–15, 2005, and at the International Conference on Advanced Materials Design & Development (ICAMDD 2005), Goa, India, December 14–16, 2005. An experimental part of this work was carried out at the Polymer Research Department, AO Research Institute, Clavadelerstrasse 8, CH-7270 Davos, Switzerland.     

2-chlorodeoxyadenosine (cladribine) induced allergic cutaneous reactions with eosinophilia in a patient with B-cell chronic lymphocytic leukemia

We present a 68-year old patient with B-cell chronic lymphocytic leukemia (CLL) treated with 2-chlorodeoxyadenosine (2-CdA). This is the first reported patient with B-CLL in whom skin lesions and eosinophilia were observed simultaneously. The most frequent side effect of this drug is myelosuppression with pancytopenia. So far, there have been few reports of cases where either skin reactions or eosinophilia, occurring separately, were observed as side effects from 2-CdA treatment.