Effect of post treatment temperature and humidity conditions onfixation performance of CCA-C treated red pine and southern pine

Rates of fixation in chromated copper arsenate (CCA-C) treated red pine (Pinus resinosa Ait.) and southern pine (Pinus spp) sapwood specimens using retention of 1.5, 2.0, 6.4 kg·m?3 are compared at temperature (T) ranging from 70°C to 50°C and 5 different relative humidity (RH) conditions. The samples were investigated using the expressate method to follow chromium fixation. Red pine fixes faster than southern pine under all 11 post treatment schedules. The fixation rates for both species are not significantly different while the blocks were fixed under 6 fixation/drying schedules that differed only in the order of T/RH conditions applied. The rate of fixation of all samples in any fixation stage were reduced when the blocks were fixed under lower humidity conditions in spite of no change in chamber temperature. Some of this influence can be attributed to the effect of humidity on heat transfer into the wood and cooling of the wood surface.

Effects of Fixation Drying Conditions on Fixation Rate and Leachability in CCA-C Treated Red Pine and Southern Pine

The effects of fixation drying conditions on fixation rates and chemical leachab ility were investigated with CCA-C treated red pine (Pinus koraiensis Sieb. )and southern pine specimens at a retention of 6 4 kg·m -3 , and under 11 post-treatment schedules ra ng ing from 50～70℃ and 5 different relative humidity conditions. These samples w e re monitored by expressing residual liquid and analyzing it for hexavatent chrom ium content. Samples were subjected to AWPA E11-97 (AWPA 1997) standard leachi n g tests after fixation. Generally, red pine fixed slightly faster than southern pine for most fixation conditions. High temperature, high humidity, fixation co nditions during the fixation/drying schedules resulted in faster fixation and lo wer leaching of chromium and arsenic elements compared to low humidity condition s. Copper leaching showed no significant difference under 11 fixation /drying co nditions for both species. All of the CCA components were leached significantly more in red pine than southern pine. Further work is needed to examine the effec ts of different fixation/drying conditions on leaching from full\|size samples a n d to optimize dry/wet bulb depression for fixation/drying of CCA treated lumber.

Impact of fixation/drying conditions on fixation rate, leachability and bioefficacy in CCA-C treated red pine and southern pine

Red pine (Pinus resinosia Ait) and southern pine (Pinus spp.) sapwood blocks were pressure treated with CCA-C at retention of 6.4, 2.0, 1.5 kg(m-3 followed by fixation using 11 post-treatment schedules ranging from 50-70 (C and 5 different relative humidity conditions. The effect of these post-treatment schedules on fixation rate, chemical leachability and decay resistant once were evaluated to better understand the effects of fixation/drying conditions on leachability and biodeterioration. Southern pine blocks fixes slightly slower than red pine. Fixation of CCA at high temperature high humidity, essential initially fixation at high humidity for fixation/drying schedules, resulted in lower leaching of chromium and arsenic elements than high temperature low humidity or initially fixation at the high temperature low humidity conditions. Copper leaching was indicated no significant difference under 11 fixation/drying conditions for both species. Weight losses for southern pine by Chaetomium globosum was lower than red pine by Gloeophyllom trabeum. There were some different capacities of decay resistance for both species under those post treatment conditions.

中山杉单板防腐处理对胶合板性能的影响

以CCA为木材防腐剂,对中山杉单板进行防腐处理,然后热压成胶合板。研究结果表明:中山杉单板经防腐处理后制造的胶合板含水率、密度、胶合强度要略高于未经防腐处理的中山杉胶合板,且含水率与胶合强度均达到I类胶合板要求。单板经防腐处理后的胶合板弹性模量、静曲强度差异不显著。不同方法处理单板对胶合板载药量影响很大,其中满细胞法最高,浸泡法和双真空法相近,涂刷法最低。

Water-Borne Wood Preservation and End-of-Life Removal History and Projection

Use of water-borne wood preservatives began in approximately the 1950s. Residential and commercial uses rapidly developed for products such as decking, fences, and other outdoor structures. Nearly all such products were treated by preservatives using arsenic as a major ingredient. The most common preservative was chromated copper arsenate (CCA). A smaller volume used ammoniacal copper zinc arsenate (ACZA). Preservative label changes made in 2003 limited uses of these arsenical treatments to industrial or agricultural type uses, such as poles, piles, ties, bridges, and fencing. Use volumes of preservative-treated wood continued to grow after the label change, but the types of preservatives used changed greatly. The amounts of water-borne treated wood reaching end-of-life and being disposed also continued to grow, reflecting the increasing inventory of volume in service. However, the volume of arsenical-treated wood being disposed peaked in approximately 2008 and is now only approximately one-quarter of that volume. Most of the arsenical-treated wood now being disposed consists of large, easily identified and separated pieces, such as round poles, piles, and fence posts and timbers, which can be easily managed separated from other wood construction and demolition (C & D) waste. Thus, managing C & D waste to limit arsenic contamination of potential products, such as mulch, will be much more practical than some have feared.

外瓶霉属真菌耐药性和降解能力的研究

外瓶霉属(Exophiala)真菌对五氯酚和杂酚油都有很强的耐药性,其中以菌株P-3182对五氯酚和菌株P-2830、P-3182对杂酚油的耐药性最强。外瓶霉属真菌不但能在五氯酚和杂酚油溶液中生长,而且具有降解这两种防腐剂的能力。而在砷铬酸铜溶液中不能生长,对环烷酸铜和砷铬酸铜的耐药性与对照菌种相似或稍高。

基于分子机制的肝内胆管癌研究和诊疗进展

胆管癌(cholangiocarcinoma,CCA)是一种高度致命的肝胆系统恶性肿瘤,发病率处于逐步上升的趋势。其中,病灶发源于肝脏实质内胆管的称为肝内胆管癌(intrahepatic cholangiocarcinoma,ICC)或胆管细胞癌。根据大体形态,ICC可分为肿块形成型、导管周围浸润型、导管内生长型和混合型(肿块+管周浸润)。每个亚型都有不同的遗传变异性、临床表现和治疗方法。不同流行病学因素相关的ICC呈现显著的异质性,对于复发和不能切除的ICC病人,采用现有的治疗措施5年生存率依然欠佳,从而使临床诊治ICC成为一个非常棘手的难题。针对病理特点、分子发病机制的研究逐步深入,探索有效诊疗策略和干预措施显得极为重要和迫切。ICC是一种高度促结缔组织增生性癌症,分子靶向、免疫微环境等治疗可能是一种潜在的方法。此文对于ICC分子机制研究和治疗现状作一综述。