Variations of maximum tracheid and pit pore dimensions from pith to bark for ponderosa pine and redwood before and after drying determined by liquid displacement

Summary Measurements of the gas pressure just required to displace saturating liquids and allow a slow continuous stream of gas to pass through ponderosa pine and redwood cross sections over a broad range of thicknesses at varying distances from pith to bark, together with the surface tensions of the liquids, have been used to calculate: (1) maximum lumen radii and maximum fiber lengths from the data for the thinner specimens, and (2) maximum pit pore radii for the specimens thicker than the maximum fiber lengths. Maximum lumen radii and maximum fiber lengths both increase from pith to bark and with increasing height in the tree. Maximum effective pit pore radii increase from the pith to the sapwood transition point, then increase abruptly followed by a variable zone in the sapwood. Displacement of water or a wetting agent solution gave comparable results for never-dried wood. Drying from water and resoaking reduced the maximum effective pit pore size. Drying from a wetting agent soaked condition followed by resoaking reduced the loss in permeability but not to the degree anticipated. ponderosa pine sapwood, that had been exposed to bacterial action, showed a large increase in the maximum effective communicating opening sizes.     

Electrospinning and mechanical properties of polymeric fibers using a novel gap-spinning collector

Tissue engineering is an interdisciplinary field which combines the basic principles of life sciences and engineering. One promising idea is the combination of scaffolds and living cells in order to produce new functional tissue. The scaffolds play the role of a microenvironment that guides the cells towards tissue formation and regeneration. One of the most frequently used techniques to produce scaffolds is electrospinning. Tissue engineered constructs have to exhibit physiological and mechanical properties comparable to the native tissue they are intended to replace. To create polymeric fibers with controlled orientation, a cylindrical collector that rotates at a certain speed could be used, creating fibers that run longitudinally. The process of gap-spinning enables the production of specifically aligned fibers. Aim of this study was to develop a novel setup capable of producing multilayered structures with controlled fiber angle. The structural, morphological and mechanical characteristics of the fibers were accessed using scanning electron microscopy and uniaxial tensile tests. Longer pre-stretching led to thinner (in the sub-micron scale), more brittle and less elastic fibers. In a nutshell, the results indicated that fiber mats of desired orientation, fiber diameter and mechanical properties could be produced by controlled gap-spinning with a translational collector.     

New terpolymers from n-butyl acrylate,glycidyl methacrylate and tetrahydrofurfuryl acrylate: Synthesis,characterisation and estimation of reactivity ratios

Development and practical application of multicomponent copolymerisation systems, such as terpolymerisation, is an on-going process because even a small addition of a particular comonomer may have a significant impact on the desired property. Commonly, three separate pairs of binary polymerisation experiments are carried out to obtain monomer reactivity ratios (MRR) values that relates to the ternary polymerisation reactions. However, the reaction conditions in each binary system may not be representative of the whole ternary system. The error-in-variables model (EVM) method is a relatively recent statistical approach to solving multi-response parameter estimation problems, with the advantage that all MRR parameters can be directly estimated from terpolymerisation data. New ternary copolymers derived from n-butyl acrylate (nBA), glycidyl methacrylate (GMA) and tetrahydrofurfuryl acrylate (THFA) were synthesised in solution at 70±1 °C in the presence of benzoyl peroxide (BPO) as a free radical initiator. The terpolymers were characterised by ¹H NMR, ¹³C NMR and FTIR spectroscopic techniques. The terpolymer compositions were determined using ¹H NMR analysis. The polydispersities of the terpolymers with values between 1.66 and 1.85 suggest a strong tendency for chain termination by disproportionation. The glass transition temperatures of the terpolymers are found to be between those of the corresponding homopolymers and relative to their content. Increase in the nBA or THFA contents and decrease in the GMA content in terpolymers results in a decrease in the glass transition temperatures. The determination of MRR for the ternary system was obtained by employing the EVM model. Experimental terpolymerisation data agree well with calculations based on the Alfrey-Goldfinger equation and the unitary and binary azeotropes were calculated.     

Dimensional stabilization of wood with water soluble fire retardant bulking chemicals compared with polyethylene glycol-1000

Summary Mono and diammonium acid phosphate, ammonium sulfamate, and sodium silicate were compared with polyethylene glycol-1000 as bulking dimension stabilizing agents using Engelmann spruce cross sectional wafers. Limiting antiswell efficiencies are equal to the volume fraction of chemical in a saturated solution. The experimental antiswell efficiencies due to bulking are the percent increase in the dry cross sectional area of the wafers caused by deposition of dry chemical within the cell walls divided by the percent swelling in water. These values for the phosphates, the sulfamate, and the polyethylene glycol approach the limiting values from solubility indicating that chemical continues to diffuse into the cell walls as the wood is dried to virtually attain a saturated solution within that structure. The sodium silicate gave an apparent negative antiswell efficiency as collapse of the fibers on drying exceeded the actual bulking. Antiswell efficiencies between 0 and 30% relative humidity, 0 and 90% relative humidity and 30 and 90% relative humidity were in general still lower. This is largely due to the treated systems taking up more water than the controls, especially at the higher relative humidity. Antiswell efficiencies for the mono ammonium acid phosphate ranged from 20 to 27%, for the diammonium acid phosphate from 28 to 37%, the ammonium sulfamate from 51 to 66% and the polyethylene glycol from 63 to 77%.Paper No. 4245 of the Journal Series of North Carolina State University Agricultural Experiment Station, Raleigh, North Carolina     

Zur Mäusenahrung des Fischreihers

Ohne Zusammenfassung     

The nutrient and glycoalkaloid content of a new potato meal

The nutrient and glycoalkaloid content of a new potato meal produced as a by-product of starch manufacture using low temperature dehydration was determined. Comparisons were made between the new potato meal and the previously manufactured meal which was prepared by high temperature dehydration. The glycoalkaloid content of the new potato meal was 15.53mg α-chaconine and 4.75mg α-solanine per 100g meal compared to 15.79mg α-chaconine and 7.83mg α-solanine in the potato meal produced by high temperature dehydration. The new potato meal contained 2% more protein and 1.9, 3.4 and 1.2 times more niacin, riboflavin and thiamin, respectively than the previous by-product. The potassium and phosphorus concentrations were approximately 2.0 and 0.2%, respectively. Other minerals were found in lesser concentrations with the sodium content being only 7.4mg/100g potato meal. A 28g serving would provide approximately 5, 7 and 4% of the RDA for protein, niacin and thiamin, respectively.     

Response of selected drought tolerant wheat (Triticum aestivum L.) genotypes for agronomic traits and biochemical markers under drought-stressed and non-stressed conditions

ABSTRACT

Genetic improvement of wheat for drought tolerance can be achieved by developing suitable ideotypes with enhanced yield-response associated with agronomic traits and biochemical markers. The objective of this study was to determine drought response of elite drought tolerant wheat genotypes using agronomic and biochemical traits to select promising lines for breeding. Fourteen wheat genotypes selected from the International Maize and Wheat Improvement Center’s heat and drought tolerance nursery and one standard check variety were evaluated under drought-stressed (DS) and non-stressed (NS) conditions using a randomised complete block design in three replications. Significant (P?<?0.05) genotype, drought condition and genotype?×?drought condition interaction effect were detected for the tested traits suggesting differential response of genotype for selection. Grain yield positively correlated with sucrose (r?=?0.58; P?<?0.05), fructose (r?=?0.52; P?<?0.05) and total sugar (r?=?0.52; P?<?0.05) contents under NS condition and with sucrose (r?=?0.80; P?<?0.001), total sugar (r?=?0.84; P?<?0.001) content, proline content (r?=?0.74; P?<?0.001) and number of grains per spike (r?=?0.58; P?<?0.05) under DS condition. Genetically unrelated wheat genotypes such as SM04, SM19, SM29, SM32, SM45 and SM97 possessing key agronomic and biochemical traits were selected for cultivar development for drought-stressed environments.     

Effect of acid modification on dyeing properties of Rajshahi silk fabric with different dye classes

In this paper, Rajshahi silk fabric was modified by acetic acid, tannic acid and their mixture. After acid modification, the silk fabric was dyed with three dyes classes namely: Reactive Orange 14, Direct Yellow 29 and Mordant Blue 9. Results revealed that the fabric modified with acid mixture of 30 % acetic acid and 20 % tannic acid improved the colorfastness of the dyed fabric after 7 days exposure on simulated sunlight and washing with hot soap solution. Also, the acid modification could improve the dyed fabrics’ colorfastness properties to acids and alkalis. Optimum dyeing condition was observed at 1.5, 2.0, and 2.0 % dyes for Reactive Orange 14, Direct Yellow 29 and Mordant Blue 9 respectively. The optimum dyeing time was observed 50, 60, and 50 min; and temperature was 90, 100 and 80 °C respectively. Modification of silk fabrics with acids improves the dyeability and colorfastness of Rajshahi silk fabrics. However, the acid modification could reduce the loss in tenacity of silk fabric upon exposure to sunlight.     

Red fluorescence in reef fish: A novel signalling mechanism?

Background  

At depths below 10 m, reefs are dominated by blue-green light because seawater selectively absorbs the longer, 'red' wavelengths beyond 600 nm from the downwelling sunlight. Consequently, the visual pigments of many reef fish are matched to shorter wavelengths, which are transmitted better by water. Combining the typically poor long-wavelength sensitivity of fish eyes with the presumed lack of ambient red light, red light is currently considered irrelevant for reef fish. However, previous studies ignore the fact that several marine organisms, including deep sea fish, produce their own red luminescence and are capable of seeing it.