Determination of the percentage of wood failure by 3D scanning of the adhesive bondline

The quality of the wood-adhesive bond is usually determined by its shear strength and the percentage of wood failure, the latter usually being determined by visual evaluation and prone to the examiner’s subjective evaluation. A new technique of 3D scanning was used to evaluate the percentage of wood failure, and the results obtained were compared to those obtained by means of existing methods, i.e. the visual evaluation and image analysis techniques. Evaluation by 3D scanning showed comparable values for samples with a high percentage of wood failure, but large differences in the case of samples showing mainly adhesive failure.     

Quantitative determination of vitamin A in liver and liverwurst using high pressure liquid chromatography (HPLC)

Samples of liver sausage and liver tissue from slaughtered animals were analysed for pre-formed vitamin A. A sensitive reversed phase HPLC method with fluorescence detection was used to determine the amount of free and esterified retinol in extracts of these samples. Under our chromatographic conditions retinyl myristate and linoleate run together as do retinyl palmitate and oleate. The contents of all forms of vitamin A were expressed in milligrams of all-trans retinol per 100 g wet weight. The average concentrations of total vitamin A for turkey, pig, calf, beef, and chicken liver were 42.31, 38.15, 22.74, 14.98, and 13.22, respectively. In addition to these differences, the fatty acid composition of liver retinyl esters, as well as the amount of retinol, also varied considerably among species. Approximately 95% of the hepatic vitamin A was present as retinyl ester with retinyl palmitate/oleate as the main ester fraction. The second most abundant fatty acid in the retinyl ester fraction of calf, beef, and chicken liver was stearic acid followed by myristic/linoleic acid. An increment of retinol, however, was also found in these tissue samples. By contrast, in turkey liver the retinol fraction was increased and therefore both retinyl stearate and retinol were present in nearly equal amounts, whereas the retinyl ester fatty acids from pig liver contained relatively more myristate/linoleate and less stearate than those from liver of the other domestic animals (apparently a hallmark of pig liver). The retinol and retinyl ester pattern present in liver sausage was similar to, but not identical with, that of pig liver.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of the Na+/H+-exchange inhibitor Hoe 642 on intracellular pH, calcium and sodium in isolated rat ventricular myocytes

The inhibitors of the Na+/H+-exchange (NHE1) system Hoe 694 and Hoe 642 possess cardioprotective effects in ischaemia/reperfusion. It is assumed that these effects are due to the prevention of intracellular sodium (Nai) and calcium (Cai) overload. The purpose of the present study was to investigate the effects of Hoe 642 on intracellular pH, Na+ and Ca2+ (pHi, Nai and Cai) in isolated rat ventricular myocytes under anoxic conditions or in cells in which oxidative phosphorylation had been inhibited by 1.5 mmol/l cyanide. In cells which were dually loaded with the fluorescent dyes 2, 7-biscarboxyethyl-5,6-carboxyfluorescein (BCECF) and Fura-2, anoxia caused acidification of the cells (from pHi 7.2 to pHi 6.8) and an increase in Cai from about 50 nmol/l to about 1 micromol/l. The decrease in pHi began before the cells underwent hypoxic (rigor) contracture, whereas Cai only began to rise after rigor shortening had taken place. After reoxygenation, pHi returned to its control value and Cai oscillated and then declined to resting levels. It was during this phase that the cells rounded up (hypercontracture). When 10 micromol/l Hoe 642 was present from the beginning of the experiment, pHi and Cai were not significantly different from control experiments. At reoxygenation, pHi did not recover, but Cai oscillated and returned to its resting level. To monitor Nai, the cells were loaded with the dye SBFI. After adding 1.5 mmol/l cyanide or 100 micromol/l ouabain, Nai increased from the initial 8 mmol/l to approximately 16 mmol/l. Hoe 642 or Hoe 694 (10 micromol/l) did not prevent the increase in Nai. In contrast, the blocker of the persistent Na+ current R56865 (10 micromol/l) attenuated the CN--induced rise in Nai. The substance ethylisopropylamiloride was not used because it augmented considerably the intensity of the 380 nm wavelength of the cell's autofluorescence. In conclusion, the specific NHE1 inhibitor Hoe 642 did not attenuate anoxia-induced Cai overload, nor CN--induced Nai and Cai overload. Hoe 642 prevented the recovery of pHi from anoxic acidification. This low pHi maintained after reoxygenation may be cardioprotective. Other possible mechanisms of NHE1 inhibitors, such as prevention of Ca2+ overload in mitochondria, cannot be ruled out. The increase in Nai during anoxia is possibly due to an influx of Na+ via persistent Na+ channels.     

Two types of TTX-resistant and one TTX-sensitive Na+ channel in rat dorsal root ganglion neurons and their blockade by halothane

The clinically employed general anaesthetic halothane was shown to exert action on the peripheral nervous system by suppressing spinal reflexes, but it is still unclear which mechanisms underlie this action. The present study addressed the question whether blockade of tetrodotoxin-sensitive (TTXs) and -resistant (TTXr) Na+-channels in rat dorsal root ganglia (DRG) neurons by halothane could explain its peripheral effects. Two types of TTXr Na+-currents, fast and slow, with distinct activation and inactivation kinetics were found in small (< 25 micrometer) and medium sized (25-40 micrometer) DRG neurons. These currents were blocked by halothane with IC50 values of 5.4 and 7.4 mmol/L, respectively. Additionally, in a concentration-dependent manner halothane accelerated the inactivation kinetics of both currents and shifted the inactivation curves to more hyperpolarized potentials. Neither the activation curves of both TTXr Na+-currents were influenced by halothane nor a voltage-dependent block at test potentials of the currents was seen. In contrast to that of fast current, the time-to-peak for slow current was changed in the presence of halothane. The TTXs Na+-current which prevailed in large neurons (> 40 micrometer) was blocked by halothane with an IC50 of 12.1 mmol/L. Its inactivation curve was also shifted to more hyperpolarized potentials and the inactivation kinetics accelerated with increasing halothane concentration. Similarly to TTXr Na+-currents, the activation curve of TTXs Na+-current and its time-to-peak were not influenced by halothane. It is suggested that two types of TTXr Na+-currents can explain the heterogeneity in kinetic data for TTXr Na+-currents. Furthermore, the incomplete blockade of Na+-currents might underlie the incomplete reduction of spinal reflexes at clinically used concentrations of halothane.     

Nanostructured Silicon Oxide–Nickel Oxide Sol–Gel Films with Enhanced Optical Carbon Monoxide Gas Sensitivity

Sol–gel derived silica (SiO₂) films doped with nickel oxide (NiO) nanocrystals were fabricated. A bifunctional ligand was used, bearing amine groups capable of coordinating the nickel ions and hydrolysable siloxane groups for anchoring the metal complex moiety to the silicate matrix. Nickel oxide nanocrystals precipitated at 500°C while the film was still porous. The nanocomposite films showed a reversible change in the optical transmittance in the VIS-NIR range when exposed to carbon monoxide gas. The effects of residual porosity, testing temperature, and carbon monoxide gas concentration on optical transmittance were studied.     

Adhesive bonding of 3D-printed ABS parts and wood

Additive manufacturing, also known as 3D printing technology, has experienced massive growth in the last decade. Instead of printing the entire product, 3D printing can be used to produce only the most complex parts, which are then combined with simple, non-printed parts from other materials to make the final product. In addition to mechanical connections, adhesive bonding is most commonly used to combine printed parts with other elements. In this study, the influence of 3D-printing parameters on the bond shear strength of 3D-printed Acrylonitrile-butadiene-styrene copolymer parts bonded to beech wood was investigated. Three printing settings with different layer thicknesses (0.39, 0.19, 0.09 mm) and a posttreatment method that utilized acetone vapour were used. The three different adhesives applied were commercial one-component polyurethane adhesive, hot melt adhesive for edge bonding, and a two-component polyurethane adhesive. The results show that the type of adhesive had the biggest influence on the strength of the bond. The highest bond strength was achieved using a two-component polyurethane adhesive. The type of failure (failure in wood, plastic, adhesive, or cohesive failure) depended greatly on the type of adhesive and thickness of the printed layer.     

Microstructural study of aged ferrite powders for sensing layers

Nanosized powders of La_0.80Sr_0.20Fe_0.95Cu_0.05O_3?w were investigated in terms of structural, morphological, chemical and surface properties by using several characterization techniques. The XPS and IR measurements showed the presence of surface hydroxide and carbonates species. After calcination of the powders at 900 °C the amount of carbonates decreased but was still significant. The sensing activity of thick film based on La_0.80Sr_0.20Fe_0.95Cu_0.05O_3?w was tested as a function of relative humidity and the results indicate that (i) after one year of ambient storage the sensing material lost quite completely its sensitivity to humidity, (ii) the sensing activity of the film was mostly re-activated after a thermal treatment at 900 °C for 2 h, and (iii) the huge shift of the detection limit to low RH caused by the presence of 5 mol% Cu is also restored.