Pulp and Papermaking Properties of Gypsy Moth-Killed Trees

A study was undertaken to evaluate the pulp and papermaking properties of gypsy moth-killed trees. Red oak (Quercus rubra), white oak (Quercus alba), and red maple (Acer rubrum) trees dead 1, 2, 3, 4, and 5 years were harvested, chipped, kraft pulped, and compared to pulped live control trees. No statistical differences (P < 0.05) in total kraft pulp yields were measured with time after tree death for the species evaluated. Handsheet strength evaluations were conducted using these pulps and they were compared at four CSf levels. With but a few exceptions, no statistical differences (P < 0.05) in handsheet tear and tensile properties were measured; however, wide variations in MIT fold and burst properties were observed. The differences observed in sheet properties over the freeness levels tested could not be related to wood degradation that may have occurred with time after tree death.Evaluation of the top, middle, and bottom sections of pulped red and white oak trees dead five years was conducted and no statistical differences in total pulp yields were measured. Significant differences in pulp yields due to advanced wood decay were measured in red maple; however in most cases no differences in handsheet strength properties were measured for all species within the freeness range tested.On the basis of the results observed in this study, it was concluded that neither the total pulp yields nor the papermaking properties would be drastically affected by the introduction of gypsy moth-killed trees into the kraft pulping process

A viable mouse model of factor X deficiency provides evidence for maternal transfer of factor X.

BackgroundActivated factor X (FXa) is a vitamin K-dependent serine protease that plays a pivotal role in blood coagulation by converting prothrombin to thrombin. There are no reports of humans with complete deficiency of FX, and knockout of murine F10 is embryonic or perinatal lethal.ObjectiveWe sought to generate a viable mouse model of FX deficiency.MethodsWe used a socket-targeting construct to generate F10-knockout mice by eliminating F10 exon 8 (knockout allele termed F10(tm1Ccmt), abbreviated as '-'; wild-type '+'), and a plug-targeting construct to generate mice expressing a FX variant with normal antigen levels but low levels of FX activity [4-9% normal in humans carrying the defect, Pro343--&gt;Ser, termed FX Friuli (mutant allele termed F10(tm2Ccmt), abbreviated as F)].ResultsF10 knockout mice exhibited embryonic or perinatal lethality. In contrast, homozygous Friuli mice [F10 (F/F)] had FX activity levels of approximately 5.5% (sufficient to rescue both embryonic and perinatal lethality), but developed age-dependent iron deposition and cardiac fibrosis. Interestingly, F10 (-/F) mice with FX activity levels of 1-3% also showed complete rescue of lethality. Further study of this model provides evidence supporting a role of maternal FX transfer in the embryonic survival.ConclusionsWe demonstrate that, while complete absence of FX is incompatible with murine survival, minimal FX activity as low as 1-3% is sufficient to rescue the lethal phenotype. This viable low-FX mouse model will facilitate the development of FX-directed therapies as well as investigation of the FX role in embryonic development

A Study of Loblolly Pine Growth Increments—Part V. Effects of Chemical and Morphological Factors on Tensile Behavior of Paper

Loblolly pine growth increments were divided into five fractions: two earlywood, a transition, and two latewood growth zones. Each fraction was kraft-pulped to four different time schedules, Valley beaten, made into handsheets, and investigated for tensile strength properties. Differences in tensile strength properties were related to inherent characteristics of individual tracheids. It was shown that the number of tracheids per unit volume of paper was the most important attribute to strength. Of secondary importance was the strength of the individual tracheid-to-tracheid bonds, which was influenced by residual lignin in the pulp. Using tensile energy values, the number of hydrogen bonds active in resisting tensile forces was estimated. This number was also related to the number of tracheids per unit volume as well as to residual lignin. The above variables were explained on the basis of the intraincremental chemical and anatomical properties of wood

Lignin Biodegradation of Nitrogen Supplemented Red Oak (Quercus Rubra) Wood Chips with Two Strains of Phanerochaete Chrysosporium

Red oak (Quercus rubra L.) wood chips were treated at two levels of nitrogen content (0.95% and 2.87% N level based on oven-dry wood chips) with either anhydrous liquid ammonia or ammonium nitrate in attempts to enhance the lignin degradation rate of a wild and mutant strain of Phanerochaete chrysosporium. As growth time increased, significant changes in weight loss, alkali solubility, alcohol/benzene extractive content, holocellulose content, and klason lignin content were observed.Experimental results showed that lignin biodegradation rate of both a wild and a mutant strain of P. chrysosporium was increased by pretreating the wood chips with either liquid ammonia at low levels (0.95% N) or by treating wood chips with additions of ammonium nitrate at the 0.95% N and 2.87% N level. Treating red oak chips with liquid ammonia at the 2.87% N level not only caused a reduction in holocellulose content of red oak wood chips, but also inhibited the growth of both strains of P. chrysosporium during incubation. When ammonium nitrate was added to the red oak wood chips at the 2.97% N level, biodegradation capabilities of the wild strain were suppressed. However, the red oak wood chips treated to the 2.87% N level with ammonium nitrate did not affect the growth of the mutant strain of P. chrysosporium. An increase in lignolytic activity was found to occur using the mutant strain of fungus.Significant differences in lignin and carbohydrate content of fungus-degraded wood were observed. The wild strain appeared to attack the lignin and carbohydrate constituents of wood simultaneously, resulting in a loss in both components as incubation time increased from 0 to 30 days. However, the mutant strain appeared to attack the lignin constituents while leaving the carbohydrate components largely intact. Comparison between the two strains (30 days of incubation) showed the red oak wood chips degraded by the mutant strain had a higher holocellulose content than did the wood chips degraded by the wild strain. These results suggest that the mutant strain may be the preferred fungus to use in manufacturing biomechanical pulps and the biodegradation rate may be slightly increased with the addition of nitrogen to the substrate

Kraft Pulp and Papermaking Properties of Phanerochaete Chrysosporium Degraded Red Oak

The kraft pulp and papermaking properties of Phanerochaete chrysosporium degraded red oak (Quercus rubra) were investigated. Phanerochaete chrysosporium was grown on rye media, and the rye spawn was used to establish mycelia growth on glucose-supplemented red oak wood chips for 0-, 10-, 20- and 30 days, respectively. Kraft pulps were produced from biodegraded and nondegraded red oak wood chips and evaluated for pulp yield, pulp refinability, and handsheet properties.Results showed that as time (0, 10, 20, and 30 days) of vegetative mycelial growth on wood chips increased, significant changes in pulp yield, kappa number, water retention value, and handsheet properties occurred. At a given pulp kappa number, higher kraft pulp yields were obtained from wood chips fungally degraded for 30 days (3-5% yield advantage) compared to pulps obtained from non-degraded red oak wood chips. Data indicated that pulps prepared from P. chrysosporium degraded red oak wood chips were more hydrophylic, responded faster to beating, and at comparable freeness levels had higher tensile, burst, and fold properties than pulps prepared from nondegraded wood. Sheet opacity was not affected by fungal degradation. Handsheets made from fungally degraded wood, however, showed marked reductions in brightness as fungal incubation time increased

Comparison Of Red Maple (Acer Rubrum L.) And Aspen (Populus Grandidentata Michx) 3-Layered Flakeboards

Three-layered flakeboards were fabricated using long and short flakes of red maple (Acer rubrum L.) and aspen (Populus grandidentata Michx). Panels were fabricated using three layers of a single species or face layers of a single species with a core layer of the other species. Static bending, internal bond, and nail withdrawal values indicated that red maple and aspen boards for the most part were comparable. A mixed species board with aspen in the face layers and red maple in the core layer had some of the highest static bending values. Dimensional stability values were acceptable among all boards with the mixed species boards producing some of the lowest values. Red maple 3-layered flakeboards were similar to aspen 3-layered boards and it appeared that red maple and aspen may be mixed to produce quality 3-layered flakeboards

The Effects of Mild Chemical Extractions on the Dimensional Stability of uf and pf Bonded Red Oak Flakeboard

Red oak (Quercus rubra L.) flakes were chemically extracted under mild conditions to determine the effects on red oak flakeboard properties, particularly dimensional stability. Flakes were extracted with weak acetic acid solutions or water under selected treatment pressures and treatment times. Weight loss values of extracted flakes ranged from 4 to 25%. Phenol formaldehyde (PF) and urea formaldehyde (UF) bonded flakeboards were manufactured using either red oak or chemically extracted red oak flakes. Physical and mechanical properties evaluated were modulus of elasticity, modulus of rupture, internal bond, water immersion related properties, and linear expansion. Static bending properties of flakeboards using extracted flakes for both resins, even at high levels of flake weight loss, were similar to boards from unextracted flakes. Internal bond average values for the extracted flakes were lower for the PF boards compared to the controls. Internal bond values for the UF boards were similar to the controls. Dimensional stability values for the PF boards were similar for the extracted and control boards. Dimensional stability tests on the UF boards produced the following results: (1) 2-hour dimensional stability values were improved for the extracted versus control boards; (2) 24-hour dimensional stability values for the extracted boards were similar to the control boards; and (3) linear expansion values for the extracted boards were similar to the control values

Laminating Creosote-Treated Hardwoods

A study was conducted to investigate the bondability of four selected hardwood species after being treated with creosote. A completely randomized block factorial design was employed. Experimental factors included five wood species (chestnut oak, red oak, red maple, yellow-poplar, and southern pine), five adhesive systems (elevated temperature cure phenol-resorcinol-formaldehyde, room temperature cure phenol-resorcinol-formaldehyde, resorcinol-formaldehyde, emulsion polymer isocyanate, and low-viscosity formulation emulsion polymer isocyanate) and two exposure levels (ambient room and vacuum/pressure/soak conditions). Exposure levels effects on the different wood species resulted in highly variable adhesive system performance. Exposure level effects were most evident for the higher density oaks. Shear strength and percent wood failure results for all wood species revealed a general trend towards a higher performance for the two phenol-resorcinol-formaldehyde systems. Res-orcinol-based adhesive systems had the highest shear strength values. Percent wood failure values were highest for the elevated temperature cure phenol-resorcinol-formaldehyde system for all species. Elevated temperature cure adhesive systems appeared to be required to successfully bond high-density creosote treated species. Successful bonding of medium-density species can be accomplished at room temperatures given proper adhesive system selection