Evaluation of various chemical treatments to prevent the abiotic deterioration of southern pine surfaces through outdoor screening trials

Rapid discoloration and checking of wooden surfaces when exposed outdoors has caused wood to fall out of favor as an outdoor building material, especially in applications where appearance is important. The surface appearance of wood products exposed outdoors can be improved through the application of film forming coatings or by reducing exposure to solar radiation and moisture. A shift towards environmentally friendly building materials has renewed interest in the outdoor application of wood products, where both biotic and abiotic durability is required, often in the absence of large overhangs or maintenance-intensive film forming coatings. The deterioration processes of wood surfaces have been extensively investigated. It is generally accepted that the loss of lignin and hemicellulose from the surface due to free radical reactions initiated by UV light absorption and moisture leads to discoloration and erosion. In addition, it is thought that these chemical reactions also weaken the wood surface, resulting in checking. Further, a large body of research has been assembled investigating different treatments, primarily film forming, that prevent the effects of weathering. Yet, only chromic acid treatments have emerged as an economical means for reducing the effects of outdoor exposure without obscuring the natural figure of the wood. However, due to the toxic nature of these compounds, these treatments have never been commercialized. In this body of work, two outdoor screening weathering studies were conducted to investigate the interactions between the wood surface and four classes of promising surface protection compounds. Representative water repellents, pigments, organic UV inhibitors, and carbon based wood preservatives were selected for the initial study. Samples were pressure impregnated with the candidate systems and subjected to exterior exposure at two sites. Exposure sites were located in the high desert of Oregon and on the leeward side of the island of Hawaii. These locations represent the extremes experienced by most wood based building materials. The Oregon site has low rainfall but high UV exposure while the Hawaiian site has both high rainfall and high UV. Samples were removed from the Oregon site at predetermined radiation intervals over a one year period, while the samples exposed in Hawaii were removed after six months of weathering. Following exposure, the samples were evaluated for discoloration, checking and changes in the chemical composition of the surface. The results from this study indicated that none of the selected treatments completely prevented the effects of weathering on the wood surface; yet some fared better than others in at least some of the categories analyzed. The study also indicated that the mode of deterioration differed significantly between the two exposure locations and that chemical degradation of the surface did not necessarily correlate with checking or discoloration. Red and yellow iron oxide impregnated loblolly pine (Pinus taeda) samples experienced less discoloration and reduced lignin loss during the first study at both exposure locations, suggesting that iron oxides may alter the interaction between UV light and the wood polymers. In a follow up, study loblolly pine samples were impregnated with iron oxide pigments differing in particle size, shape and loading to determine what characteristics of iron oxide influenced surface protection properties. These samples were only exposed at the eastern Oregon location and removed over a three month period at predetermined radiation intervals. The results from this work suggest that crystal shape, size and pigment concentration influenced polymer losses from the wood surface as well as surface discoloration. However, the results suggested that checking was not affected by any of the variables investigated. While these studies suggest that the abiotic deterioration of wood surfaces can be controlled through the application of different transparent and semitransparent treatments, no single compound was completely effective. This implies that combinations of partially effective compounds should be investigated. In addition, the data suggest that, lignin and hemicellulose loss do not substantially affect check formation during the first months of outdoor exposure. Instead, the data suggests that wood / water relations dominate. The different exposure locations used in the first study also highlighted differences in weathering characteristics caused by climate. More research must be conducted to understand the effects of different climates on performance and to use these data to tailor surface protection systems to match exposure conditions.Keywords: Checking and discoloration, Water repellents, Iron oxide pigments, Hawaii, Eastern Oregon, Wood surfaces, Surface protection, Climate, Weathering, Fourier transform infrared spectroscopy (FTIR

The phytosanitation of solid wood packaging materials using wood preservatives

New species introductions have been associated with the movement of people for thousands of years. For instance, horses were introduced into North America by Spanish explorers, while pigs were introduced by the Polynesians into many Pacific islands long before the establishment of permanent European settlements. Both of these species introductions resulted in significant changes in both the biological and cultural composition of these places. However, during the past century, the amount of material transported by people has greatly increased due to the globalization of the economy and breakthroughs in material handling technology. These breakthroughs, such as the steel shipping container and the wooden pallet, allow goods to be moved rapidly in a protected environment. This protected environment prevents goods from being damaged while in transit, but it has also improved the ability of pests to survive transit and resulted in invasive species introductions. The volume of goods being transported has steadily increased during the past 50 years and, thus, the number of species introductions has increased as well, resulting in a number of high profile pest introductions. For instance, the introduction of the Asian long horned beetle into Chicago and New York cost millions of dollars to eradicate and resulted in the loss of hardwood trees that previously lined the streets of these cities. In response to the Asian long-horned beetle and the introduction of the pine wood nematode into Europe, the Food and Agriculture Organization of the United Nations drafted and approved International Standard for Phytosanitary Measures Number 15. This measure recognizes solid wood packaging materials as an invasive species pathway and recommends sanitization through heat treatment or fumigation with methyl bromide. However, heat treatment or fumigation are imperfect mitigation tools. Thus, researchers continue to search for alternative methods. Wood preservatives have long been formulated to prevent insect and fungal attack of wood products exposed to warm humid climates, but the ability of these chemicals to eliminate existing insect and fungal colonies has not been investigated. In this study, a number wood preservative systems were investigated to determine if these chemical formulations can be used for this application and to determine if wood preservatives, in general, are suited for use in phytosanitary applications. A method for detecting the presence of wood boring insects through acoustic emissions was investigated. It was thought that a system of microphones and accelerometers could be used to detect wood boring insect presence and activity within a particular wood sample. These assumptions were based on earlier work conducted with termites. This system was to be used to determine if a sample contained wood boring insects prior to using it in the main study. However, acoustic emissions were not useful for this application, since feeding of the wood boring insects was sporadic, unlike termites which feed constantly. Determining the feasibility of using wood preservatives in phytosanitary applications was addressed in three trials: the ability of preservatives to penetrate insect galleries, the ability of the insect larvae and pupae to penetrate a treated barrier and the ability of established wood boring insect populations to complete their life cycle under field conditions in wood pressure treated with preservatives Preservatives completely penetrated between 80-100% of all insect galleries in western redcedar treated with ammoniacal copper quaternary compound, disodium octaborate tetrahydrate, or imidacloprid. However, barriers containing any of these three chemicals failed to prevent larvae from exiting the treated material, even in instances where the barrier was more than 6mm thick. The wood boring insects were unable to complete their life cycle under field conditions in pressure treated wood, while a large number of new house borer adults emerged from the untreated controls. The wood preservatives investigated act more as insecticides than larvacides. However, vacuum pressure impregnation of solid wood packaging materials with the appropriate chemicals could provide lasting protection against invasive species introductions, allowing for the rapid, yet safe transportation of goods around the world

Comparison of Water Quality Program Efforts for Non-Governmental Organizations Within Northern Gulf of Mexico Watersheds

Non-governmental organizations concerned with water quality issues within the Northern Gulf of Mexico were surveyed to compare their program differences. The objectives of the study were to determine the extent of water quality programs and priority program emphasis for non-governmental organizations in the Northern Gulf of Mexico. The study utilized a methodology that identified the program elements of four different watersheds in four southeastern states. The results demonstrate that evaluating non-governmental program efforts in a region reveals targeted priorities that may help to define future program needs

Performance of wood treated with prospective organic surface protectants upon outdoor exposure: FTIR spectroscopic analysis of weathered surfaces

Visual appeal of wood is as important as its structural integrity in outdoor applications. Discoloration and checking of wood favor the utilization of alternative materials for outdoor cladding and decking. Lignin depolymerization is one of the critical processes leading to weathering. In the present paper, the potential of different classes of surface protection agents has been assessed on loblolly pine ( Pinus taeda ) impregnated with water repellents, organic UV inhibitors, and an organic biocide. The treated samples were exposed to predetermined doses of solar radiation in Eastern Oregon, and the chemical changes occurring on the surfaces were evaluated by FTIR spectroscopy. After 1-year exposure, lignin loss was complete on all surfaces; however, some treatments provided longer term protection than others. Organic UV light inhibitors were most effective in this regard. A petroleumbased water repellent with a melting point of 54 – 58 ° C also provided protection against lignin degradation.Keywords: FTIR spectroscopy, chromic acid, weathering, wood surfaces, Pinus taeda, water repellents, hindered amine light stabilizer (HAL), wax, lignin, isothiazolone, loblolly pine, 4,5-dichloro-2-n-octyl-3-isothiazolinone (DCOIT), hydroxyphenyl bezotriazole, UV stabilizer

Inhomogeneity of the intrinsic magnetic field in superconducting YBa2Cu3OX compounds as revealed by rare-earth EPR-probe

X-band electron paramagnetic resonance on doped Er3+ and Yb3+ ions in Y0.99(Yb,Er)0.01Ba2Cu3OX compounds with different oxygen contents in the wide temperature range (4-120)K have been made. In the superconducting species, the strong dependencies of the linewidth and resonance line position from the sweep direction of the applied magnetic field are revealed at the temperatures significantly below TC. The possible origins of the observed hysteresis are analyzed. Applicability of the presented EPR approach to extract information about the dynamics of the flux-line lattice and critical state parameters (critical current density, magnetic penetration depth, and characteristic spatial scale of the inhomogeneity) is discussedComment: 17 pages, 5 Figures. Renewed versio

Recurrence of Diabetic Pedal Ulcerations Following Tendo-Achilles Lengthening

Foot and ankle surgeons are frequently challenged by the devastating systemic consequences of diabetes mellitus manifested through neuropathy, integumentary and joint breakdown, delayed healing, decreased ability to fight infection, and fragile tendon/ligaments. Diabetic neuropathic pedal ulcerations lead to amputations at an alarming rate and also carry a high mortality rate. This article will discuss causes of diabetic pedal ulcerations that persist or recur after tendo-Achilles lengthening and will highlight areas that need to be addressed by the practitioner such as infection, vascular and nutritional status, glucose control, off-loading, biomechanics, and patient compliance

Visualization of Spatiotemporal Energy Dynamics of Hippocampal Neurons by Mass Spectrometry during a Kainate-Induced Seizure

We report the use of matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry combined with capillary electrophoresis (CE) mass spectrometry to visualize energy metabolism in the mouse hippocampus by imaging energy-related metabolites. We show the distribution patterns of ATP, ADP, and AMP in the hippocampus as well as changes in their amounts and distribution patterns in a murine model of limbic, kainate-induced seizure. As an acute response to kainate administration, we found massive and moderate reductions in ATP and ADP levels, respectively, but no significant changes in AMP levels—especially in cells of the CA3 layer. The results suggest the existence of CA3 neuron-selective energy metabolism at the anhydride bonds of ATP and ADP in the hippocampal neurons during seizure. In addition, metabolome analysis of energy synthesis pathways indicates accelerated glycolysis and possibly TCA cycle activity during seizure, presumably due to the depletion of ATP. Consistent with this result, the observed energy depletion significantly recovered up to 180 min after kainate administration. However, the recovery rate was remarkably low in part of the data-pixel population in the CA3 cell layer region, which likely reflects acute and CA3-selective neural death. Taken together, the present approach successfully revealed the spatiotemporal energy metabolism of the mouse hippocampus at a cellular resolution—both quantitatively and qualitatively. We aim to further elucidate various metabolic processes in the neural system

Neuroprotective function for ramified microglia in hippocampal excitotoxicity

<p>Abstract</p> <p>Background</p> <p>Most of the known functions of microglia, including neurotoxic and neuroprotective properties, are attributed to morphologically-activated microglia. Resting, ramified microglia are suggested to primarily monitor their environment including synapses. Here, we show an active protective role of ramified microglia in excitotoxicity-induced neurodegeneration.</p> <p>Methods</p> <p>Mouse organotypic hippocampal slice cultures were treated with <it>N</it>-methyl-D-aspartic acid (NMDA) to induce excitotoxic neuronal cell death. This procedure was performed in slices containing resting microglia or slices that were chemically or genetically depleted of their endogenous microglia.</p> <p>Results</p> <p>Treatment of mouse organotypic hippocampal slice cultures with 10-50 μM <it>N</it>-methyl-D-aspartic acid (NMDA) induced region-specific excitotoxic neuronal cell death with CA1 neurons being most vulnerable, whereas CA3 and DG neurons were affected less. Ablation of ramified microglia severely enhanced NMDA-induced neuronal cell death in the CA3 and DG region rendering them almost as sensitive as CA1 neurons. Replenishment of microglia-free slices with microglia restored the original resistance of CA3 and DG neurons towards NMDA.</p> <p>Conclusions</p> <p>Our data strongly suggest that ramified microglia not only screen their microenvironment but additionally protect hippocampal neurons under pathological conditions. Morphological activation of ramified microglia is thus not required to influence neuronal survival.</p

Epilepsy in Dcx Knockout Mice Associated with Discrete Lamination Defects and Enhanced Excitability in the Hippocampus

Patients with Doublecortin (DCX) mutations have severe cortical malformations associated with mental retardation and epilepsy. Dcx knockout (KO) mice show no major isocortical abnormalities, but have discrete hippocampal defects. We questioned the functional consequences of these defects and report here that Dcx KO mice are hyperactive and exhibit spontaneous convulsive seizures. Changes in neuropeptide Y and calbindin expression, consistent with seizure occurrence, were detected in a large proportion of KO animals, and convulsants, including kainate and pentylenetetrazole, also induced seizures more readily in KO mice. We show that the dysplastic CA3 region in KO hippocampal slices generates sharp wave-like activities and possesses a lower threshold for epileptiform events. Video-EEG monitoring also demonstrated that spontaneous seizures were initiated in the hippocampus. Similarly, seizures in human patients mutated for DCX can show a primary involvement of the temporal lobe. In conclusion, seizures in Dcx KO mice are likely to be due to abnormal synaptic transmission involving heterotopic cells in the hippocampus and these mice may therefore provide a useful model to further study how lamination defects underlie the genesis of epileptiform activities

Nuclear Calcium Signaling Controls Expression of a Large Gene Pool: Identification of a Gene Program for Acquired Neuroprotection Induced by Synaptic Activity

Synaptic activity can boost neuroprotection through a mechanism that requires synapse-to-nucleus communication and calcium signals in the cell nucleus. Here we show that in hippocampal neurons nuclear calcium is one of the most potent signals in neuronal gene expression. The induction or repression of 185 neuronal activity-regulated genes is dependent upon nuclear calcium signaling. The nuclear calcium-regulated gene pool contains a genomic program that mediates synaptic activity-induced, acquired neuroprotection. The core set of neuroprotective genes consists of 9 principal components, termed Activity-regulated Inhibitor of Death (AID) genes, and includes Atf3, Btg2, GADD45β, GADD45γ, Inhibin β-A, Interferon activated gene 202B, Npas4, Nr4a1, and Serpinb2, which strongly promote survival of cultured hippocampal neurons. Several AID genes provide neuroprotection through a common process that renders mitochondria more resistant to cellular stress and toxic insults. Stereotaxic delivery of AID gene-expressing recombinant adeno-associated viruses to the hippocampus confers protection in vivo against seizure-induced brain damage. Thus, treatments that enhance nuclear calcium signaling or supplement AID genes represent novel therapies to combat neurodegenerative conditions and neuronal cell loss caused by synaptic dysfunction, which may be accompanied by a deregulation of calcium signal initiation and/or propagation to the cell nucleus