Durability of phenolic-resin-treated oil palm wood against subterranean termites a white-rot fungus

Oil palm wood (OPW) is seen as a strategic alternative wood material, especially in a country with huge oil-palm-planted areas such as Malaysia. The material is low in quality and various techniques have been used to improve its quality. This study was carried out to evaluate the resistance of low-molecular-weight phenol formaldehyde (Lmw-PF) resin treated OPW against subterranean termites and a white-rot fungus. Four sample groups including untreated OPW and treated OPW samples with three different compression levels (0%, 25%, and 50%) were prepared. Five specimens for each sample group were tested for resistance against subterranean termites (Coptotermes curvignathus) and the white-rot fungus Pycnoporous sanguineus, based on ASTM D 3345-74 and ASTM D 1413-99, respectively. Results showed that both treatment and compression level had significant effects on the percentage weight loss and mean decayed surface of the samples. Treated OPW with 50% compression yielded the best performance with the lowest weight loss on both termite and decay tests. Overall, Lmw-PF resin treated OPW with 25–50% compression can be used as an effective method to improve the durability of OPW.     

Temperature effect on kinetics of uptake, transfer, and clearance of [14C]noviflumuron in eastern subterranean termites (Isoptera: Rhinotermitidae)

[14C]Noviflumuron uptake, clearance, rate of excretion, and transfer from treated to untreated termite workers were evaluated at 15,19, 23, and 27 degrees C. Feeding units were constructed from plastic containers provisioned with washed sand, distilled water, [14C]noviflumuron-treated feeding discs (0.05 or 0.5% [AI]), and Reticulitermes flavipes (Kollar) workers. Feeding units were held in environmental growth chambers preset at 15, 19, 23, and 27 degrees C. The amount of [14C]noviflumuron present within R. flavipes was measured by scintillation counting and subsequently quantified. Uptake of noviflumuron by R. flavipes workers at 15 degrees C was approximately 2.8 times less than at 19 or 23 degrees C and approximately 4.4 times less than at 27 degrees ighest uptake of [14C]noviflumuron occurred at 27 degrees C and 144 h. Most transfer of [14C]noviflumuron from treated to untreated termite workers occurred between 19 and 27 degrees C. [14C]Noviflumuron had a half-life in R. flavipes workers of approximately 31-45 d, dependent on temperature. A higher amount of [14C]noviflumuron was lost through excretion at > or = 19 degrees C (approximately 15-22%) compared with 15 degrees C (0.27%). Results indicated that increased uptake, transfer, and clearance of noviflumuron by R. flavipes occurred at warmer temperatures (19-27 degrees C), and all of these processes were significantly lower at 15 degrees C.     

Survival and feeding responses of Anacanthotermes ochraceus (Hodotermitidae: Isoptera) to local and imported wood

Forty-six local and imported wood were tested for resistance to feeding damage by the termite Anacanthotermes ochraceus (Burmeister), the most dominant species in the United Arab Emirates and the Arab Gulf region. Wood was used for construction, wall paneling, and furniture. Wood was evaluated in a 4-wk forced feeding bioassay. Each wood block was graded by the amount of termite damage by using a damage rating index (DRI) of 0 to 5 and wood rating index from very resistant to very susceptible wood. Local wood was mostly susceptible to feeding of termites; imported wood varied in resistance to feeding damage. Wood was placed in groups according to the percentages of weight loss (WL), termite survival (TS), and DRI. Wood was classified as very resistant (%WL from 0.0 to 0.3, %TS from 0.01 to 0.5, and DRI of 0.01), resistant (%WL from 1.1 to 4.9, %TS from 0.8 to 4.8, and DRI of 1.0), moderately resistant (%WL from 6.6 to 9.3, %TS from 6.3 to 8.3, and DRI of 2.0-2.3), slightly resistant (%WL from 10.1 to 19.9, %TS from 9.5 to 28.0, and DRI of 2.5-3.5), susceptible (%WL from 21.5 to 48.6, %TS from 37.3 to 64.8, and DRI of 4.0-4.3) and very susceptible (%WL from 50.0 to 59.8, %TS from 72.8 to 79.0, and DRI of 4.5-5.0). The characterization of the extracts of resistant wood may prove of economic value and lead to the development of new chemicals (repellents or antifeedants) for termite control.     

Survey of subterranean termites (Isoptera: Rhinotermitidae) in a managed silvicultural plantation in Portugal, using a line-intersection method (LIS)

Subterranean termites (Reticulitermes grassei) were surveyed over successive seasons in a managed eucalyptus plantation in southeastern Portugal for 26 months. Termite activity in seven diameter categories of lying dead wood was investigated by a modified line intersection method (LIS). Each item sampled was inspected and assessed for termite attack and for general (i.e. fungal) decay status using standard protocols. Line intersection is quantitative to the extent that it can link foraging and decay parameters to woody biovolume. It was found that termites selected items with larger diameter, the observed trend showing an exponential character with greater termite attack as diameter increased. Attack by termites was positively associated with prior decay by fungi. A clear positive relationship was shown between rainfall and total woody biovolume containing live termites, underlining the importance of moisture for termite activity. Subterranean termites appeared to be important wood decomposers in the woodland studied, with an average of 30% of lying dead wood branches showing signs of termite attack.     

Responses of Coptotermes formosanus and Reticulitermes flavipes (Isoptera: Rhinotermitidae) to three types of wood rot fungi cultured on different substrates

This study examined the responses of two termite species, the Formosan subterranean termite, Coptotermes formosanus Shiraki, and the eastern subterranean termite, Reticulitermes flavipes (Kollar), to three types of wood decay fungi: a brown rot fungus, Gloeophyllum trabeum (Persoon: Fries) Murrill; a white rot fungus, Phanerochaete chrysosporium Burdsall; and a litter rot fungus, Marasmiellus troyanus (Murrill) Singer. We also examined the responses of termites to these three types of fungi grown on different substrates. For all three fungal species, both termite species showed a strong preference for fungus-infected sawdust over uninfected sawdust. In choice tests, both termite species preferred sawdust infected with either M. troyanus or P. chrysosporium over G. trabeum. However, termites did not show any preference for fungus-infected potato dextrose agar over uninfected potato dextrose agar. Tunneling activity of C. formosanus was greater in sand treated with methanol extracts of fungus-infected sawdust than in sand treated with extracts of uninfected sawdust. Because chemicals in the fungal extracts caused termites to tunnel further into treated sand than untreated sand, these chemicals could potentially be used to direct termite foraging toward bait stations in the field.     

Resistance of insecticide-treated foam board insulation against the eastern subterranean termite and the Formosan subterranean termite (Isoptera: Rhinotermitidae)

Three foam board types, one untreated control, one containing 2,000 ppm disodium octaborate tetrahydrate (DOT), and one containing 1,000 ppm deltamethrin, were exposed to field populations of the eastern subterranean termite, Reticulitermes flavipes (Kollar), and the Formosan subterranean termite, Coptotermes formosanus Shiraki. There was no significant difference in termite damage between foam boards treated with 2,000 ppm DOT and the untreated control. Form boards containing 1,000 ppm deltamethrin were not damaged by R. flavipes, whereas only minor damage occurred after exposure to C. formosanus.     

Termite feeding deterrent from Japanese larch wood

Extraction of flavonoids from Japanese larch (Larix leptolepis) wood with water was carried out to prepare a termite feeding deterrent. A two-stage procedure for the extraction was adopted. The first extraction step was performed at ambient temperature (22 degrees C) and the second at elevated temperatures ranging 50-100 degrees C. The first step mainly gave a mixture of polysaccharides together with small amount of flavonoids. At the second step, the yield of extract and its chemical composition were greatly affected by the temperature. The yield of solubilised carbohydrates steadily increased with a rise in the temperature, while the overall yield of flavonoids reached its optimum at 70 degrees C. An additional increase in the temperature resulted in a decrease in the yield. Model experiments using dihydroflavonols confirmed the occurrence of oxidative dehydrogenation and/or intramolecular rearrangement during the hydrothermal treatment at higher temperatures. The crude water extracts showed strong feeding deterrent activities against the subterranean termite, Coptotermes formosanus, in a choice paper disc assay. The extracts containing flavonoids in large quantities exhibited potent termite feeding deterrent activities.     

Efficacy of vetiver oil and nootkatone as soil barriers against Formosan subterranean termite (Isoptera: Rhinotermitidae).

Vetiver oil and its components nootkatone and cedrene were assessed as sand treatments for their efficacy to disrupt food recruitment by Coptotermes formosanus Shiraki. Termites were required to tunnel through sand treated with vetiver oil, nootkatone, cedrene, or untreated sand to reach a food source. Results showed that sand treated with vetiver oil or nootkatone disrupted termite tunneling behavior. As a consequence, after 21 d, wood consumption and termite survival were significantly lower compared with cedrene-treated or untreated sand treatments. Sand treated with vetiver oil or nootkatone at 100 microg/g substrate were effective barriers to termites.     

Comparison of the inactivation of canine and bovine parvovirus by freeze-drying and dry-heat treatment in two high purity factor VIII concentrates.

The inactivation of bovine parvovirus (BPV) and canine parvovirus (CPV) by freeze-drying and terminal dry-heat treatment at 80 degrees C for 72 h has been investigated in two high purity factor VIII concentrates. In one product, CPV was slightly more resistant to freeze-drying compared to BPV, i.e. 0.7 vs. 1.4 log. However, BPV was substantially more resistant to heat-treatment compared to CPV, i.e. 1.3 vs. > 3.1 log inactivation after 72 h at 80 degrees C. In a second product, CPV was also slightly more resistant to freeze-drying than BPV, i.e. 0.2 vs. 1.3 log inactivation. However, heat-treatment gave essentially similar inactivation for both viruses, i.e. 2.8-3.4 log after 72 h at 80 degrees C. In conclusion, the resistance of these parvovirus models is dependent both on the type of virus and on the specific product involved.     

Assessment of methods of destruction of Syphacia muris eggs

An investigation was performed to identify methods suitable for decontamination of equipment being transferred from a facility contaminated with Syphacia muris to a new facility. Perianal samples were taken on clear sticky tape from rats known to be infected with S. muris. Tapes and attached worm eggs were treated with ethylene oxide, formaldehyde fumigation, potassium peroxysulphate, chlorine dioxide and didecyl di-methyl ammonium chloride, chlorine dioxide, alcohol/chlorhexidine, 100 degrees C dry heat for 30 min, ultraviolet light (UV), or left for 4 weeks at room temperature. The subsequent viability of the eggs was compared to untreated control samples. Heat and ethylene oxide produced a 100% kill rate of S. muris eggs. Formaldehyde gas and chlorine dioxide treatments showed marked effectiveness, with the number of eggs killed at 94% and 96%, respectively, while the other agents showed less efficacy (36-78% eggs killed). The percentage of eggs not hatching in the controls was 21%. Since so few agents were effective against S. muris eggs, care should be taken when choosing a method for decontaminating a facility.     

Changes in the Chemical Composition and Decay Resistance of Thermally-Modified Hevea brasiliensis Wood

In this study the effect of thermal treatment on the equilibrium moisture content, chemical composition and biological resistance to decay fungi of juvenile and mature Hevea brasiliensis wood (rubber wood) was evaluated. Samples were taken from a 53-year-old rubber wood plantation located in Tabapuã, Sao Paulo, Brazil. The samples were thermally-modified at 180°C, 200°C and 220°C. Results indicate that the thermal modification caused: (1) a significant increase in the extractive content and proportional increase in the lignin content at 220°C; (2) a significant decrease in the equilibrium moisture content, holocelluloses, arabinose, galactose and xylose content, but no change in glucose content; and (3) a significant increase in wood decay resistance against both Pycnoporus sanguineus (L.) Murrill and Gloeophyllum trabeum (Pers.) Murrill decay fungi. The greatest decay resistance was achieved from treatment at 220°C which resulted in a change in wood decay resistance class from moderately resistant to resistant. Finally, this study also demonstrated that the influence of thermal treatment in mature wood was lower than in juvenile wood.     

Heat shock protein induction in the freshwater prawn Macrobrachium malcolmsonii: acclimation-influenced variations in the induction temperatures for Hsp70

The intracellular build-up of thermally damaged proteins following exposure to heat stress results in the synthesis of heat shock proteins (Hsps). In the present study, the upper thermal tolerance and expression of heat shock protein 70 (Hsp70) were examined in juveniles of the freshwater prawn Macrobrachium malcolmsonii that had been acclimated at two different temperatures, i.e. 20 degrees C (group A) and 30 degrees C (group B), in the laboratory for 30 days. Upper thermal tolerance was determined by a standard method. For heat-shock experiments, prawns in groups A and B were exposed to various elevated temperatures for 3 h each, followed by 1 h recovery at the acclimation temperature. Endogenous levels of Hsp70 were determined in the gill, heart, hepatopancreas and skeletal muscle tissues by Western blotting analysis of one dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The critical thermal maximum (CT max) for prawns in groups A and B was 37.7+/-0.27 degrees C and 41.41+/-0.16 degrees C, respectively. In general, Western blotting analysis for Hsp70 revealed one band at the 70 kDa region, containing both constitutive (Hsc70) and inducible (Hsp70) isoforms, in the gill and heart tissues; these were not detected in the hepatopancreas and skeletal muscle tissues. The onset temperature for Hsp70 induction in both gill and heart tissues was 30 degrees C for prawns in group A and 34 degrees C for those in group B. The optimum induction temperatures (at which Hsp70 induction was maximum) were found to be 34 degrees C and 32 degrees C, respectively, in the gill and heart tissues of group A prawns, and 38 degrees C and 36 degrees C, respectively, for group B prawns. These results suggest that the temperature at which acclimation occurs influences both upper thermal tolerance and Hsp70 induction in M. malcolmsonii.     

Chemical constituents of tropical woods and resistance to the invasive drywood termite Cryptotermes brevis

Wood-feeding, nesting and production of secondary reproductives are key determinant traits of invasive species of drywood termites, and the West Indian drywood termite Cryptotermes brevis (Walker) is one of their major examples of worldwide concern as pest species of structural lumber, furniture and other wood products. The problem and losses by this species are determined by the prevailing wood characteristics. However, despite the current widespread occurrence of this species in the tropics, except Asia, tropical wood resistance and underlying mechanisms of resistance against this termite are scarcely known. Nonetheless, wood hardness and particularly wood density were recently recognized as important underlying traits for C. brevis resistance in tropical woods, but the chemical wood constituents were not considered. Here, we assessed tropical wood resistance to the invasive termite species C. brevis and tested the relevance of their holocellulose, lignin and (total) extractive contents preventing termite infestation. Free-choice and no-choice tests were carried out in parallel with wood chemical characterization. Resistance to the West Indian termite varied with wood species in terms of both colonization and consumption, but only under free-choice testing because without choice, no significant difference was detected among wood species. Regardless, none of these traits were significantly correlated with wood resistance to C. brevis. Therefore, wood physical resistance, particularly wood density, seems the main recognized determinant of tropical wood resistance against the West Indian drywood termite. The pattern of termite movement on the surface of soft, mid and hard wood was also consistent with this conclusion.     

Decay and termite resistance of medium density fiberboard (MDF) made from different wood species

Medium density fiberboard (MDF) production worldwide is increasing due to the development of new manufacturing technologies. As a result, MDF products are increasingly utilized in traditional wood applications that require fungal and insect resistance. This study evaluated the ability of white and brown rot fungi and termites to decompose MDF consisting of different wood species by measuring weight loss. Furnish in the boards was prepared from heart and sapwood portions of pine (Pinus nigra Arnold var. pallasiana), beech (Fagus orientalis Lipsky), and European oak (Quercus robur L.) species. Fungal decay resistance tests were performed according to ASTM D 2017-81 standard method using two brown-rot fungi, Gloeophyllum trabeum (Pers. ex Fr.) Murr. (Mad 617), Postia placenta (Fries) M. Larsen et Lombard (Mad 698), and one white-rot fungus, Trametes versicolor (L. ex Ft.) Pilat (Mad 697). MDF and wood specimens were also bioassayed against the eastern subterranean termite, Reticulitermes flavipes (Kollar) in order to determine termite resistance of the specimens. MDF specimens containing oak and mixed furnish demonstrated increased durability against decay fungi. Only pine, oak, and mixed MDF specimens met the 25% or less weight loss limit to be classified resistant according to ASTM D 2017-81 standard method. Overall, MDF specimens made from oak showed better performance than oak solid wood specimens. Accelerated aging according to ASTM D 1037-96a standard method before fungal bioassay decreased fungal resistance of the specimens. In contrast to the fungal bioassay, MDF specimens made from beech and mixed furnish showed decreased weight losses from termite attack after 4 weeks. However, none of the MDF specimens were resistant to termite attack. In severe conditions, the MDFs may require the incorporation of chemical biocides prior to board production for increasing the resistance of MDF to termite attack.     

The effects of heat treatment on technological properties in Red-bud maple (Acer trautvetteri Medw.) wood

Heat treatment is often used to improve the dimensional stability of wood. In this study, the effects of heat treatment on technological properties of Red-bud maple (Acer trautvetteri Medw.) wood were examined. Samples obtained from Düzce Forest Enterprises, Turkey, were subjected to heat treatment at varying temperatures (120 degrees C, 150 degrees C and 180 degrees C) and for varying durations (2h, 6h and 10h). The technological properties of heat-treated wood samples and control samples were tested. Compression strength parallel to grain, bending strength, modulus of elasticity in bending, janka-hardness, impact bending strength, and tension strength perpendicular to grain were determined. The results showed that technological strength values decreased with increasing treatment temperature and treatment times. Red-bud maple wood could be utilized by using proper heat treatment techniques with minimal losses in strength values in areas where working, and stability such as in window frames, are important factors.     

Two-step freezing of cattle blastocysts with dimethylsulfoxyde (DMSO) or glycerol

Sixty five cattle blastocysts were frozen by the so-called two-step freezing method: The samples were seeded at -7 degrees C and then directly brought at -30 degrees C for 30 minutes before being taken into liquid nitrogen. Results in terms of survival rates at thawing and after short term cultures were compared to two controlled linear cooling rate procedures (i.e. 0.3 degrees C/min and 1.3 degrees C/min). The results demonstrate that: 1) two-step freezing yielded approximately the same survival rate as the two others techniques and 2) Glycerol yielded better survival rates than DMSO treatments (56 vs 31% after 24 hours in culture).     

Thermoelasticity of large lecithin bilayer vesicles.

Micromechanical experiments on large lecithin bilayer vesicles as a function of temperature have demonstrated an essential feature of bilayer vesicles as closed systems: the bilayer can exist in a tension-free state (within the limits of experimental resolution, i.e., less than 10(-2) dyn/cm). Furthermore, because of the fixed internal volume, there is a critical temperature at which the vesicle becomes a tension-free sphere. Below this temperature, thermoelastic tension builds up in the membrane and the vesicle's internal pressure increases while the surface area remains constant. Above this temperature, the vesicle's surface area increases while the tension and internal pressure are negligible. Without mechanical support, the vesicles fragment into small vesicles because they have insufficient surface rigidity. In the upper temperature range we have measured the increase of surface area with temperature. These data established the thermal area expansivity to be 2.4 X 10(-3)/degrees C. At constant temperature, we used either pipet aspiration with suction pressures up to 10(4) dyn/cm2 or compression against a flat surface with forces up to 10(-2) dyn to produce area dilation of the vesicle surface on the order of 1%. The rate of increase of membrane tension with area dilation was calculated, which established the elastic area compressibility modulus to be 140 dyn/cm. The tension limit that produced lysis was observed to be 3-4 dyn/cm (equivalent to 2-3% area increase). The product of the elastic area compressibility modulus, the thermal area expansivity, and the temperature gives the reversible heat of expansion at constant temperature for the bilayer. This value is 100 ergs/cm2 at 25 degrees C, or approximately 5 kcal/mol of lecithin. Similarly, the product of the thermal area expansivity multiplied by the area compressibility modulus determines the rate of increase of thermoelastic tension with decrease in temperature when the area is held constant, i.e., -0.34 dyn/cm/degrees C.     

Evaluation of the decay resistance properties of Cerbera odollam extracts and their influence on properties of particleboard

Metallic-based wood preservatives currently face some restrictions over disposal and environmental issues; one possibility to develop new more benign systems is to study extractives in naturally durable woody plants. This study investigated the resistance of extracts from the leaf, fruit, wood, bark, seed and flower of Cerbera odollam to deterioration from fungus and termites. Antifungal assays with n-hexane, ethyl acetate, ethanol and methanol extracts were evaluated using paper discs. Termite mortality was evaluated with the methanol extract against Coptotermes gestroi. Physical and protective properties of particleboard impregnated with C. odollam extracts, including thickness swelling, internal bond strength, formaldehyde release, termite-decay and soil burial decay were investigated. Methanol wood extracts from C. odollam showed the highest activities against Trametes versicolor, Pycnoporus sanguineus, and Schizophyllum commune in the paper disc antifungal assay. Methanol flower extracts exhibited high performance in termite mortality, termite-decay and soil burial decay. Thickness swelling, internal bond strength and the formaldehyde emission of particleboard specimens treated with methanol extracts of C. odollam were up to the EN Standards.     

Effect of some autonomic drugs on heat defence in the pigeon.

As compared to the time of median control death (i.e. the time inducing 50% death in untreated birds at 50 degrees C), exogenous noradrenaline afforded 100% survival in the blue rock pigeon, Columba livia. The survival percentages with the other autonomic drugs were: chlorpromazine 70%; reserpine 60%; adrenaline 60%; pentolinium 50% and dihydroergotamine 30%. The time of median control death at 50 degrees C was found to be 3.5 hours in the pigeon. During 10-day exposure at 45 degrees C all the birds pre-treated with noradrenaline survived, and 47% of those treated with adrenaline and 42% of the untreated birds survived the stress. It is concluded that noradrenaline acts definitely as a "heat protective" hormone in the pigeon.     

Thermal behavior of fowl feather keratin

Differential scanning calorimetry (DSC) was applied to elucidate the thermal behavior of fowl feather keratins (barbs, rachis, and calamus) with different morphological features. The DSC curves exhibited a clear and relatively large endothermic peak at about 110-160 degrees C in the wet condition. A considerable decrease in transition temperature with urea and its helical structure content estimated by Fourier transform infrared spectroscopy (FT-IR), and the disappearance of one of the diffraction peaks with heating at 160 degrees C for 30 min, indicated that DSC could be used to evaluate the thermal behavior of keratin. Barbs showed a lower denaturation temperature than rachis and calamus. The pulverized samples showed a slightly higher denaturation temperature than the native samples. In the dry condition, thermal transition occurred in a markedly higher temperature region close to 170-200 degrees C. It is hence concluded that fowl feather keratins have very high thermal stability, and that the elimination of water brings about even greater thermal stability.