Tannin-caprolactam and Tannin-PEG formulations as outdoor wood preservatives: weathering properties

Key message

This article presents the leaching, fire and weathering resistance improvements of samples treated with tannin-based wood preservatives added of caprolactam. PEG-added formulations show limited applicability. The FT-IR and ¹³ C-NMR analyses of the caprolactam-added formulations show some evidences of copolymerization.

Context

Tannin-boron wood preservatives are known for their high resistance against leaching, biological attacks, fire as well as for the good mechanical properties that they impart to wood. These properties promoted these formulations for being a candidate for the protection of green buildings. However, the low elasticity of these polymers and their dark colour implied limited weathering resistances.

Aims

The aim of the study is to find suitable additives for tannin-based formulations to overcome their limited weathering resistances, without compromising the other properties.

Methods

Treatment, leaching and fire tests, dimensional stability as well as artificial and natural weathering of the timber treated with caprolactam-added and PEG-added formulations were performed. FT-IR and ¹³C-NMR of the formulations were presented.

Results

The presence of caprolactam improved the properties of the formulation with particularly significant results in terms of resistance against leaching and dimensional stability. These enhancements were imparted also to the weathering resistance of the tannin-caprolactam formulations. Indeed, the colour changes during the artificial and natural exposures were stable for longer periods. FT-IR and ¹³C-NMR investigations of the advanced formulations were led, and covalent copolymerization of the caprolactam with the tannin-hexamine polymer was observed.

Conclusion

The tannin formulations with caprolactam improved the durability of the wood specimens, while the PEG-tannin presented strong application drawbacks.

     

Chlorophyll a fluorescence analysis along a vertical gradient of the crown in a poplar (Oxford clone) subjected to ozone and water stress

An experiment in open-top chambers was carried out in summer 2008 at Curno (Northern Italy) in order to study the effects of ozone and mild water stress on poplar cuttings (Oxford clone). In this experiment direct fluorescence parameters (JIP-test) were measured in leaves from different sections of the crown (L: lower; M: medium; U: upper parts of the crown). The parameters considered were calculated at the different steps of the fluorescence transient, and include maximum quantum yield efficiency in the dark-adapted state (F(v)/F(M)); the L-band, at 100?∝?s, that expresses the stability of the tripartite system reaction centre-harvesting light complex-core antenna; the K-band, at 300?∝?s, that expresses the efficiency of the oxygen-evolving complex; the J-phase, at 2 ms, that expresses the efficiency with which a trapped exciton can move an electron into the electron transport chain from Q(A)(-) to the intersystem electron acceptors; the IP-phase, which expresses the efficiency of electron transport around the photosystem 1 (PSI) to reduce the final acceptors of the electron transport chain, i.e., ferredoxin and NADP; and finally the performance index total (PItot) for energy conservation from photons absorbed by PSII to the reduction flux of PSI end acceptors. The main results are: (i) different dynamics were observed between leaves in the lower section, whose PItot decreased over time, and those in the upper sections in which it increased, with a dynamic connected to the leaf age; (ii) ozone depressed all the considered fluorescence parameters in basal leaves of well-watered plants, while it had little or no damaging effect on medium-level or upper-section leaves; (iii) PItot and IP-phase increased in upper leaves of plants subjected to ozone stress, as well as the net photosynthesis; (iv) water stress increased PItot of leaves in all levels of the crown. The results suggest that ozone-damaged poplar plants compensate, at least partially, for the loss of photosynthesis with higher photosynthetic rates in young leaves (in the upper section of the crown), more efficient to fix carbon.     

Degradation of dicarboximidic fungicides in wine. Part II: Isolation and identification of the major breakdown products of chlozolinate,vinclozolin and procymidone

The main degradation products formed from the dicarboximidic fungicides chlozolinate, vinclozolin and procymidone in wine have been isolated and identified using spectroscopic and chromatographic methods. The fungicides were added to wine after fermentation. Chlozolinate underwent a rapid hydrolytic loss of the ethoxy-carbonyl substituent, to give an oxazolidine that underwent hydrolytic cleavage to give 3′,5′-dichloro-2-hydroxypropanilide. The oxazolidine ring of vinclozolin underwent a similar hydrolysis to give the corresponding anilide 3′,5′-dichloro-2-hydroxy-2-methylbut-3-enanilide. Both these anilides were stable in wine for 150 days. A different degradation behaviour was observed with procymidone and led to the formation of 3,5-dichloroaniline (3,5-DCA), which, in turn, broke down but the derivatives could not be isolated. After consideration of the different behaviours of the fungicides on degradation in wine and in aqueous ethanol at pH4, together with their kinetic data, breakdown pathways are proposed.     

Phytate degradation,intestinal microbiota,microbial metabolites and immune values are changed in growing pigs fed diets with varying calcium–phosphorus concentration and fermentable substrates

The present study assessed effects of diets containing varying calcium–phosphorus (CaP) concentration and fermentable substrates on digestibility of diets, intestinal microbiota and immune system using 32 crossbred pigs (initial BW 54.7 kg). In a 2 × 2 factorial arrangement, pigs were fed either a corn–soybean meal (CSB) or corn–field pea (CFP) diet with either low [‐] (4.4 g Ca/kg; 4.2 g total P/kg) or high [+] (8.3 g Ca/kg; 7.5 g total P/kg; supplemented with monocalcium phosphate) CaP content for a period of 9 weeks. In week 8, blood samples were taken, and at the end of the trial, all pigs were euthanized to collect digesta and mesenteric lymphoid tissue. Apparent total tract digestibility (ATTD) of P was greater (p < 0.05) for pigs fed the CaP+ and CFP diets than CaP‐ and CSB diets. The myo‐inositol 1,2,3,4,5,6‐hexakis (dihydrogen phosphate) (InsP₆) concentration in jejunal digesta was higher (p < 0.05) for CaP+ than in CaP‐ fed pigs. In addition, caecal and faecal InsP₅ isomer concentration were greater (p < 0.05) for CSB than CFP diets. In the caecum, gene copy numbers of saccharolytic bacteria, such as Eubacterium rectale and Roseburia spp., as well as SCFA concentration were higher (p < 0.05) for CaP+ than CaP‐ diets. In particular, innate immune cell numbers, such as natural killer cells, dendritic cells, monocytes and neutrophils, were greater (p < 0.05) for CaP+ than CaP‐ fed pigs. Diets high in CaP resulted in higher abundance of potential beneficial bacteria and might promote the first line of defence enhancing the activation of the cellular adaptive immune response, thereby possibly decreasing the risk for intestinal disturbances. These results strongly suggest that both, CaP supply and dietary ingredients differing in fermentability, may beneficially affect gut health through increase in SCFA‐producing bacteria and/or bacteria with anti‐inflammatory properties.     

Using commercial tree nurseries to monitor visible ozone injury—An evaluation

Ozone damage on trees leaves no residue that can be detected analytically; therefore visible assessment is the only easily detectable method for collecting evidence. Here we present an evaluation of an assessment method using damaged detected on trees grown in commercial tree nurseries. The extent of visible ozone injury to susceptible species was investigated on a total of 95 species across 13 nurseries, over four European countries during the 2006 season. Commercial nurseries were chosen because nurseries stock a wide range of accessible, susceptible species which are irrigated when necessary and therefore represent the optimum conditions for assessment of potential risk. Ozone climate at each site was characterised using a combination of passive and active samplers to estimate the accumulated ozone exposure over a threshold of 40 ppb (AOT40). Meteorological and ozone monitoring data were used to calculate cumulative ozone flux using the DO₃SE model (Emberson et al., 2000). Ozone injury was observed in all countries demonstrating that the impacts of ozone are not restricted to countries with higher ozone concentrations; the longer day-length, higher moisture availability and cooler conditions in northern Europe resulted in a greater potential for ozone uptake. Further use of commercial nurseries as an important, unofficial, bioindicator network is warranted.     

Identification of non-alkaloid acetylcholinesterase inhibitors from Ferulago campestris (Besser) Grecescu (Apiaceae)

Inhibition of Acetylcholinesterase (AChE) is still considered as a strategy for the treatment of neurological disorders such as Alzheimer's disease. Many plant derived alkaloids (such as galantamine and rivastigmine) are known for their AChE inhibitory activity. Recently, other classes of natural compounds such as terpenoids, sesquiterpene glycosides and coumarins have been studied as new AChE inhibitors, with the aim to discover less toxic compounds compared to alkaloidal ones. The Ferulago campestris roots dichloromethane extract was used for a bioassay-guided fractionation for the search of AChE inhibitors. Three coumarin derivatives (umbelliprenin 1, coladonin 2 and coladin 3), three daucane ester derivatives (siol anisate 4, ferutinin 5 and 1-acetyl-5-angeloyl lapiferol 6), two phenol derivatives (2-epilaserine 7 and epielmanticine 8) and one polyacetylene (9-epoxyfalcarindiol 9) were isolated by the bioassay-guided approach. Their structures were characterized on the basis of spectral methods (1D and 2D NMR, and MS spectroscopy). All the isolated compounds were able to inhibit the AChE (IC₅₀ 1.2–0.1 mM) although at higher doses if compared to galantamine (6.7 μM) measured in the same conditions. The most active compounds were the daucane derivative siol anisate 4 and the epielmanticine 8, with IC₅₀ of 0.172 and 0.175 mM respectively.     

Effects of agrochemical treatments on the occurrence of Fusarium ear rot and fumonisin contamination of maize in Southern Italy

The efficacy of agrochemical treatments, based on three different fungicides combined with an insecticide, was tested in southern Italy for two years on three maize hybrids to control Fusarium ear rot of maize and the accumulation in the maize kernels of the carcinogenic mycotoxins fumonisins. Insect damage incidence and severity, disease incidence and severity, identification of Fusarium species and levels of fumonisin contamination in kernels were determined. Field trials showed in both years that natural colonization of maize kernels by the fumonisin producing species Fusarium proliferatum and F. verticillioides (up to 81.5 and 26.5%, respectively) and total fumonisin contamination (up to 68.2 μg g⁻¹) were highly severe. For all hybrids and in both years, the treatment with the insecticide applied alone reduced the insect damage severity consistently and the content of fumonisins in the kernel only in half of the cases, whereas fungicide treatments applied in combination with the insecticide showed a further significant reduction of fumonisin contamination in the three hybrids and in both years.     

CT and MRI characterization of presumed persistent ossiculum terminale in dogs

Anecdotally, during the review of CT and MRI studies of canine patients including the cranial cervical spine, authors have identified a small osseous structure between the atlas (C1) and axis (C2) with no relevant clinical signs. This structure appeared comparable to a “persistent ossiculum terminale” in humans. The aim of this retrospective, multi-center, case series study was to describe the CT and MRI features of presumed persistent ossiculum terminale in a group of dogs presented with unrelated medical conditions.  Two databases (the imaging database of the teleradiology service VetCT Specialists and the clinical database of the University of Vienna) were scrutinized by different approaches. Medical records of dogs that underwent imaging investigation (CT and/or MRI) that included the atlanto-axial junction were reviewed. Data collected included signalment, sex, breed, age, presenting symptoms, and final diagnosis. Eighteen dogs met the inclusion criteria. Mean age was 85 months (6–166) and breed variation was present. A total of 20 imaging studies were evaluated: CT was performed in 17 dogs; MRI in three dogs; two dogs had both MRI and CT performed. In all cases the presence of at least one small osseous body on the cranial aspect of the odontoid process compatible with a persistent ossiculum terminale was identified as a possible incidental finding without any overt clinical implications. Findings indicated that a small osseous body on the cranial aspect of the odontoid process (presumed persistent ossiculum terminale) in CT and MRI studies may be present in dogs with no clinical signs of neurologic disease.     

Leaf morphology and chemistry in Fagus sylvatica (beech) trees as affected by site factors and ozone: results from CONECOFOR permanent monitoring plots in Italy

During summer 2001, leaf samples were collected from seven beech stands that are part of the Italian network of permanent monitoring plots (CONECOFOR). In each plot, sun leaves from the upper crown were collected from five trees and subjected to chemical analysis (C, N, P, S, K, Ca and Mg) and morphological analysis (area, dry mass, thickness and thickness of individual tissues). Based on the measurements, nutrient ratios (N/C, N/K, N/P, N/Ca, N/Mg, K/Ca, Mg/Ca), sclerophylly indices (leaf mass per area (LMA) and leaf density (LD)) and nitrogen content per leaf area unit (NLA) were determined. Stomatal density was also measured. Among stands, leaf area was smallest and sclerophylly (indicated as LMA) was greatest in the southernmost stands and under drought conditions. Reduced leaf area and increased LMA also appeared to be strongly related to tropospheric ozone concentrations, whereas crown transparency was related mainly to site factors such as rainfall and temperature and, to a lesser extent, ozone concentration. The southernmost stands had a lower N/C ratio than the more northern stands, suggesting that the apoplastic fraction of cells within the leaf played a greater role. In the northern stands (especially at Lombardy and in Piedmont) where ozone concentrations were high, nutrient ratios were unbalanced and the high value of LMA appeared to be related primarily to the contribution of plasmatic components. Overall, leaf morphology was most sensitive to climate stress at the southern plots and to environmental pollution (nitrogen deposition and tropospheric ozone concentration) at some of the northern plots.