Comparison of tissue reactions in the tracheal mucosa surrounding a bioabsorbable and silicone airway stents

BACKGROUND: Treatment of tracheobronchial stenosis is problematic. Conservative methods include stenting the stenotic area, but an ideal stent has not yet been developed. Bioabsorbable airway stents offer benefits; the extraction of the device is unnecessary, and the airway preserves its normal function after stent resorption. The aim of this study was to examine the suitability of self-reinforced poly-L-lactide as a material for an airway stent. METHODS: A spiral airway stent made of 0.7-mm wire of self-reinforced poly-L-lactide was implanted operatively in 9 rabbits intratracheally; silicone stents served as controls. RESULTS: Silicone stents had a tendency to become stenosed with encrustation material and to develop a hyperplastic polyp at both ends. Self-reinforced poly-L-lactide stents were well tolerated and caused no foreign body reaction, and they had a tendency to penetrate into the tracheal wall. They had disappeared at the end of the follow-up of 10 months. CONCLUSIONS: This experimental study showed that bioabsorbable self-reinforced poly-L-lactide is a promising material for an airway stent for treatment of airway stenosis.     

Cyclodextrins: Production,properties and applications in food chemistry

Cyclodextrins have diverse, important applications in food industry. These applications are based on the ability of cyclodextrins to form molecular complexes with small—molecular compounds. Cyclodextrins are harmless in oral administration and advantageous effects by cyclodextrins are achieved by simple mixing of small amounts of them to the material being stabilized. Development of convenient and cost‐effective processes for production of cyclodextrins are undergoing and there are promises in the near future for obtaining cyclodextrins which are realistic in price to be used in foods. While cyclodextrins have been used for more than ten years in Japan as natural additives in foods, the legislation for their approval in foods is still under development in Europe and USA.     

Effect of curing process on simulated antisoiling properties of sol–gel coating on pine sapwood

Recently, inorganic–organic hybrid coatings produced by the sol–gel route have proven to be a potential protective treatment for wooden surfaces. In this study, the effect of curing process on simulated antisoiling properties of sol–gel coating was investigated. The sol–gel coating was spray-coated on pine sapwood and cured with different temperature and time combinations. The antisoiling properties were studied by measuring the water contact angle of the coating after different curing processes. In addition, abrasion resistance and contact angle of oleic acid were measured. An optical profilometer was used to investigate surface roughness of the coating. Sufficient hydro- and oleophobicity were obtained with all of the curing parameters. The comparison between curing parameters showed that lower temperature and 1–3 h curing time leads to significant improvement in the durability of the water and oil repellent properties of the coating.     

Evaluation of the anti-fouling properties of nm thick atmospheric plasma deposited coatings

Both organic and inorganic fouling are significant problems for stainless steel surfaces used in industrial applications as diverse as shipping and paper making. The objective of this study is to evaluate the anti-fouling properties of a range of fluoropolymer, fluorinated and non-fluorinated siloxane coatings on stainless steel substrates. These nm thick coatings were deposited using the atmospheric plasma jet system called PlasmaStream™. The surface properties of the plasma polymerised coatings were examined using optical profilometry, SEM-EDX, ellipsometry, contact angle measurement and FTIR. Accelerated wear testing of the coated heat exchangers indicated that coating durability was a significant issue for the nanometre thick coatings investigated. A crystallization fouling study was carried out using a laboratory scale heat exchanger test apparatus. In this the heated steel surface was in contact with flowing fluid containing CaCO₃ particles. The coated steel exhibited both a delay before fouling was initiated and in addition a decrease in the fouling rate. A lubricant oil fouling study was also carried out involving a comparison between both coated and uncoated stainless steel separator discs over a 30 day period, in the engine of a passenger ferry. A significant reduction in the level of oil fouling was observed for the fluorosiloxane and fluoropolymer coated separator discs compared with the uncoated discs.     

Removal of bis(2-ethylhexyl) phthalate at a sewage treatment plant

Bis(2-ethylhexyl) phthalate (DEHP) concentrations were measured at different stages in a full-scale sewage treatment plant (STP) and mass balances were calculated. The DEHP load to treatment process coming from the sewer system and the internal load comprising returned supernatants and filtrate from sludge treatment and excess secondary sludge were at the same level. The DEHP removal efficiency from the water phase at the STP was on average 94% of sewage DEHP, the main removal process being sorption to primary and secondary sludges. On average 29% of DEHP was calculated to be removed in the biological nitrifying-denitrifying activated sludge process, which was much less than expected from laboratory biodegradation studies described in literature. Monoethylhexyl phthalate, the primary biotransformation product of DEHP, was not detected at any treatment stage. Approximately 32% of DEHP in sewage was removed during anaerobic digestion of the sludge, while 32% remained in the digested and dewatered sludge.     

The buffering capacity of porcine muscles

The aim of this study was to investigate the buffering capacity (BC) of five porcine muscles. The pH of muscles with zero lactate was also estimated. The BC was calculated on the basis of the amount of lactate accumulating in the muscle between two sampling times and the simultaneous pH decline. Two muscle samples were obtained from each muscle (n=13–36): one as soon as possible after slaughter and the other 24 h post-mortem. The BCs (mmol lactate/(pH kg)) were in the light gluteus superficialis, longissimus dorsi and semimembranosus muscles 48.3 ± 8.8, 48.6 ± 9.2 and 46.8 ± 13.0, and in the dark infraspinatus and masseter muscles 45.3 ± 13.1 and 32.0 ± 11.5, respectively. The dark masseter muscle differed significantly from the other muscles studied (p<0.01). The estimated pH values of muscles with zero lactate were in the gluteus, longissimus dorsi, semimembranosus muscles 7.14 ± 0.06; 7.18 ± 0.06; 7.38 ± 0.08, and in the infraspinatus and masseter muscles 6.87 ± 0.07; 7.03 ± 0.08, respectively. It was suggested since lactate is continuously formed in the muscles, the resting pH of living light and dark muscles may, however, be the same. The approach used in this study to determine the BC resulted in values which are close to values previously reported in the literature (measured by using titration curves).     

Increase of N2O Fluxes in Agricultural Peat and Sandy Soil under Elevated CO2 Concentration: Concomitant Changes in Soil Moisture, Groundwater Table and Biomass Production of Phleum pratense

The effects of elevated atmospheric CO₂ concentration on soil moisture, N₂O fluxes, and biomass production of Phleum pratense were studied in the laboratory. Farmed peat and sandy soil mesocosms sown with P. pratense were fertilized with a commercial fertilizer. In peat soil 10 g N m⁻² of commercial fertilizer were added and in sandy soil 15 g N m⁻². In both experiments, soil moisture was regulated with deionized water; 18 mesocosms were tended to keep equally moist, and the other 18 were watered with equal amounts of water. Nine mesocosms from both watering treatments were grown under ambient (360 μmol mol⁻¹) CO₂ concentration and the remaining nine under doubled (720 μmol mol⁻¹) CO₂. N₂O efflux was monitored using a closed chamber technique and a gas chromatograph. The elevated supply of CO₂ increased production of above- and belowground biomass, soil moisture and N₂O fluxes, but decreased the total N content in the aboveground biomass, especially for the sandy soil. In similar water levels, N₂O efflux from the sandy soil was the same magnitude as that from the peat soil. In addition to moisture, N availability was the main limiting factor for N₂O production, but C availability also seemed to regulate the denitrification activity. In addition to an increase in C availability the increase in the N₂O efflux under the raised CO₂ concentration also required a simultaneous increase in soil moisture.     

Oxidative capacity and hemolytic activity of settled dust from moisture‐damaged schools

Exposure to moisture‐damaged indoor environments is associated with adverse respiratory health effects, but responsible factors remain unidentified. In order to explore possible mechanisms behind these effects, the oxidative capacity and hemolytic activity of settled dust samples (n = 25) collected from moisture‐damaged and non‐damaged schools in Spain, the Netherlands, and Finland were evaluated and matched against the microbial content of the sample. Oxidative capacity was determined with plasmid scission assay and hemolytic activity by assessing the damage to isolated human red blood cells. The microbial content of the samples was measured with quantitative PCR assays for selected microbial groups and by analyzing the cell wall markers ergosterol, muramic acid, endotoxins, and glucans. The moisture observations in the schools were associated with some of the microbial components in the dust, and microbial determinants grouped together increased the oxidative capacity. Oxidative capacity was also affected by particle concentration and country of origin. Two out of 14 studied dust samples from moisture‐damaged schools demonstrated some hemolytic activity. The results indicate that the microbial component connected with moisture damage is associated with increased oxidative stress and that hemolysis should be studied further as one possible mechanism contributing to the adverse health effects of moisture‐damaged buildings.