Effect of temperature and compression on the mechanical behavior of steam-treated wood

The mechanical behavior of steamed spruce wood changes dramatically with compression along the grain, the change being much more moderate perpendicular to the grain. The stiffness decrement due to increased temperature is greatest in the tangential material direction. The stiffness decrement due to compression is greatest along the grain. Compression to 80% compressive strain at 131°C inverts the order of the material directions regarding stiffness, the stiffness being the least along the grain. Plastic strain due to compression is greater at higher temperatures. The compression-induced decrement of stiffness along the grain is greater at higher temperatures, but the off-axis decrement of stiffness is less at higher temperatures.     

On-line Analysis of Stack Gas Composition by a Low Resolution FT-IR Gas Analyzer

Stack gases of wood and oil burning boilers were analyzed by a low resolution FT-IR gas analyzer. Concentrations of carbon dioxide (CO₂), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO₂), nitrous oxide (N₂O), hydrogen cyanide (HCN), sulfur dioxide (SO₂), methane (CH₄), and water vapor (H₂O) were predicted in real time by multicomponent analysis. Detection limits, linearity, analysis accuracy and long time repeatability were experimentally determined for selected gas components. Applicability of the measurement method was demonstrated by analysis of stack gas mixtures of known concentrations. The results indicate that all the primary stack gas components can be measured by the low resolution FT-IR gas analyzer with comparable results to single component measurement methods.     

The impact of elbow and knee joint lesions on abnormal gait and posture of sows

Background

Joint lesions occur widespread in the Danish sow population and they are the most frequent cause for euthanasia. Clinically, it is generally impossible to differentiate between various types of non-inflammatory joint lesions. Consequently, it is often necessary to perform a post mortem examination in order to diagnose these lesions. A study was performed in order to examine the relation of abnormal gait and posture in sows with specific joint lesions, and thereby obtaining a clinical diagnostic tool, to be used by farmers and veterinarians for the evaluation of sows with joint problems.

Methods

The gait, posture and lesions in elbow- and knee joints of 60 randomly selected sows from one herd were scored clinically and pathologically. Associations between the scorings were estimated.

Results

The variables ''fore- and hind legs turned out'' and ''stiff in front and rear'' were associated with lesions in the elbow joint, and the variables ''hind legs turned out'' and ''stiff in rear'' were associated with lesions in the knee joint.

Conclusion

It was shown that specified gait and posture variables reflected certain joint lesions. However, further studies are needed to strengthen and optimize the diagnostic tool.     

Compensation point of NOx exchange: Net result of NOx consumption and production

The compensation point of bidirectional NO_x fluxes of plants is often determined in chamber measurements by varying the NO_x concentration and searching for the point where the net flux is zero. We hypothesized that the compensation point can vary with changing conditions so much that one constant value is not sufficiently accurate. The compensation point for NO_x fluxes of Scots pine was analysed with a model describing the NO_x consumption and production processes. Consumption was assumed to occur via the stomata and on needle surfaces, with the rate depending on ambient concentration and degree of stomatal opening. Production was assumed to occur on the needle surfaces depending on solar UV-A irradiance. We used NO_y flux data measured with two gas-exchange chambers in southern Finland to parameterize the model. The estimated compensation points increased with increasing UV-A irradiance and decreased with increasing stomatal conductance. With open stomata, it varied several ppb even under field conditions.     

Transglutaminase catalyzed cross-linking of sodium caseinate improves oxidative stability of flaxseed oil emulsion

Sodium caseinate was modified by transglutaminase catalyzed cross-linking reaction prior to the emulsification process in order to study the effect of cross-linking on the oxidative stability of protein stabilized emulsions. The extent of the cross-linking catalyzed by different dosages of transglutaminase was investigated by following the ammonia production during the reaction and using SDS-PAGE gel. O/W emulsions prepared with the cross-linked and non-cross-linked sodium caseinates were stored for 30 days under the same conditions. Peroxide value measurement, oxygen consumption measurement, and headspace gas chromatography analysis were used to study the oxidative stability of the emulsions. The emulsion made of the cross-linked sodium caseinate showed an improved oxidative stability with reduced formation of fatty acid hydroperoxides and volatiles and a longer period of low rate oxygen consumption. The improving effect of transglutaminase catalyzed cross-linking could be most likely attributed to the enhanced physical stability of the interfacial protein layer against competitive adsorption by oil oxidation products.     

Sampling saproxylic beetles: lessons from a 10-year monitoring study

We sampled saproxylic beetles using trunk window traps in two birch-dominated forests in Finland during 1990-1999. The sampling scheme, 10 traps attached to living fruiting bodies of Fomes fomentarius growing on dead birches, remained unchanged in both forests throughout the study period. Beetles belonging to 32 selected families were identified every year, whereas all species were identified during the last 4 years. Total number of identified individuals was 40,294 and number of species 583, of which 258 were saproxylic (dependent on dead wood). Species richness of rare and threatened saproxylic beetles in the samples varied a lot between the years and did not fluctuate synchronously between the forests. Variation between years was smaller when all saproxylic species were pooled together and some abundant species fluctuated synchronously in the two forests. Similarity indices and DCA-ordination did not generally suggest decreasing similarity between samples with increasing temporal isolation. Incidence-based similarities of common saproxylic species within and between forests and years were high (means 0.7-0.8), whereas those of rare saproxylics were roughly 50% smaller and much more variable. More than 75% of the common saproxylic species found during the entire 10-year period were detected already after 3 years of sampling but accumulation of rare and threatened species was much slower. Our results suggest that: (1) occurrence of rare and threatened species in samples is much less predictable than that of common species and, e.g. reserve selection based on rarities should be made cautiously; (2) estimation of total number of threatened species in a forest is very difficult, because such species accumulate slowly in the samples; (3) samples from different years can be comparable in certain cases.     

Pasteurella multocida toxin induces IL-6, but not IL-1 alpha or TNF alpha in fibroblasts.

Pasteurella multocida toxin (PMT) is the major virulence factor in Progressive Atrophic Rhinitis of swine. Other workers' previous findings that PMT was mitogenic for 3T3 fibroblasts, were confirmed in the present study. In addition, PMT stimulated 3T3 cells to release IL-6, but IL-1 alpha or TNF alpha were not detected in fibroblast supernatants sampled 24, 48, or 72 h after stimulation. In view of the role of IL-6 in osteoclastic bone resorption, these findings provide a new working hypothesis for investigations into the molecular pathogenesis of this important disease.     

Model studies on acrylamide generation from glucose/asparagine in aqueous glycerol

Acrylamide formation from asparagine and glucose in different ratios in neutral glycerol/water mixtures was found to increase with decreasing water activity (0.33 < or = aw < or = 0.71 investigated) and increasing temperature (120 degrees C < or = T < or = 160 degrees C investigated). The initial rate of acrylamide formation was found to be approximately proportional to the asparagine concentration for an excess of asparagine, but less dependent on an excess of glucose. A steady-state concentration of acrylamide was established at 160 degrees C after 1 h for aw = 0.33 (30 microg x L-1 for GLU:ASN = 10:1, 11 microg x L-1 for GLU:ASN = 1:1, and 130 microg x L-1 for GLU:ASN = 1:10) and for aw = 0.47 (15 microg x L-1 for GLU:ASN = 10:1 and 80 microg x L-1 for GLU:ASN = 1:10), suggesting a protection by glucose against acrylamide degradation. The energy of activation, as estimated from the temperature dependence of the initial rate, increased with decreasing aw despite a higher rate of formation of acrylamide at low aw. For high aw, water elimination from a reaction intermediate is suggested to be rate determining. For low aw, the increase in energy of activation (and enthalpy of activation) is accordingly counteracted by a more positive entropy of activation, in agreement with decarboxylation as rate determining at low aw.