Changes in Heartwood Chemistry of Dead Yellow-Cedar Trees that Remain Standing for 80 Years or More in Southeast Alaska

We measured the concentrations of extractable bioactive compounds in heartwood of live yellow-cedar (Chamaecyparis nootkatensis) trees and five classes of standing snags (1–5, averaging 4, 14, 26, 51, and 81 years-since-death, respectively) to determine how the concentrations changed in the slowly deteriorating snags. Three individuals from each of these six condition classes were sampled at four sites spanning a 260-km distance across southeast Alaska, and the influence of geographic location on heartwood chemistry was evaluated. Cores of heartwood were collected at breast height and cut into consecutive 5-cm segments starting at the pith. Each segment was extracted with ethyl acetate and analyzed by gas chromatography. Concentrations of carvacrol, nootkatene, nootkatol, nootkatone, nootkatin, and total extractives (a sum of 16 compounds) for the inner (0–5 cm from pith), middle (5–10 cm from pith), and surface (outer 1.1–6.0 cm of heartwood) segments from each core were compared within each tree condition class and within segments across condition classes. Heartwood of class 1 and 2 snags had the same chemical composition as live trees. The first concentration changes begin to appear in class 3 snags, which coincides with greater heartwood exposure to the external environment as decaying sapwood sloughs away, after losing the protective outer bark. Within core segments, the concentrations of all compounds, except nootkatene, decrease between snag classes 2 and 5, resulting in the heartwood of class 5 snags having the lowest quantities of bioactive compounds, although not different from the amounts in class 4 snags. This decline in chemical defense is consistent with heartwood of class 5 snags being less decay-resistant than heartwood of live trees, as observed by others. The unique heartwood chemistry of yellow cedar and the slow way it is altered after death allow dead trees to remain standing for up to a century with a profound impact on the ecology of forests in southeast Alaska where these trees are in decline.     

ANTITERMITIC ACTIVITY OF ESSENTIAL OILS AND COMPONENTS FROM TAIWANIA (Taiwania cryptomerioides)

Antitermitic activity of Taiwania (Taiwania cryptomerioides Hayata) against Coptotermes formosanus Shiraki was demonstrated in laboratory tests. Blocks of sapwood and heartwood from T. cryptomerioides exhibited antitermitic activity. Bioassays revealed that heartwood essential oil exhibited the highest antitermitic activity, followed by sapwood essential oil and then the n-C₆H₁₄soluble fraction when tested at 10 mg/g. The order of termite mortality of three compounds purified from n-C₆H₁₄soluble extracts of heartwood was cedrol > -cadinol > ferruginol. The termite resistance of T. cryptomerioides wood can be attributed to the termiticidal activity of cedrol and -cadinol.     

ANTIOXIDANT AND ANTI-LIPASE COMPOUNDS ISOLATED FROM HEARTWOOD OF YAKUSHIMA NATIVE CEDAR (Cryptomeria japonica)

This article describes the biological activities of heartwood extracts from Yakushima native cedar (Cryptomeria japonica) and identifies their main active compounds. Black heartwood and red heartwood were each divided into two parts from the center (the pith) to outer heartwood (the cambium). The methanol extracts of those parts were screened for antioxidant and anti-lipase activities. The extract from the pith of the red heartwood showed the highest ORAC activity among the samples. Regarding anti-lipase activity, all the extracts showed relatively high activity (the IC₅₀ value were 9.71–37.24?μg mL^?1). In addition, four compounds were isolated and identified from the pith of red heartwood by NMR and MS analyses. Agatharesinol (3) and sequirin C (4) were thought to be the main active compounds responsible for the antioxidant and anti-lipase activities.     

Benefits of low kenaf loading in biobased composites of poly(L‐lactide) and kenaf fiber

Bast fibers from stems of kenaf (Hibiscus cannabinus, L.), a warm‐season tropical herbaceous annual plant, were dispersed into poly‐L ‐lactide (PLLA) matrix by melt‐mixing followed by compression molding. Low fiber fractions (1–5%) were investigated. The composites showed a slight lowering of thermal stability when evaluated by thermogravimentric analysis. X‐ray diffraction and differential scanning calorimetry indicated an influence of kenaf on the crystallization of PLLA. The fiber dispersion in the polymer matrix was established by polarized optical microscopy. Scanning electron microscopy showed good fiber–matrix adhesion as revealed by the combination of dispersion, interaction, and crystallinity, which enabled an increase in the mechanical properties of the composite that scaled with concentration. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and Theoretical Study of New Guanylated Cyclophosphazenes and Their Use in the CO2 Fixation into Styrene Carbonate

Three new guanylated cyclophosphazenes G1–G3 have been synthesized through the catalytic guanylation of three different bi, tetra and hexa (p-aminophenoxy)-cyclophosphazenes by using N,N’-diisopropylcarbodiimide as guanylating agent, ZnEt₂ as catalyst and dry tetrahydrofuran as solvent. The resulting products have been characterized by ¹H, ¹³C{¹H} and ³¹P{¹H} NMR spectroscopy. The hexaguanylated cyclophosphazenes exhibit a deep purple colour, unusual for this type of compounds. The electronic structure of these compounds was investigated by carrying out density functional calculations at PBE-D3(BJ)/TZP level of theory. The molecular structural analysis reveals that aromatic rings are stacked and time dependent density functional calculations show that a charge transfer electronic transition occurs between the aromatic rings which absorb light around 500–700 nm. Finally, the catalytic usefulness of guanylated cyclophosphazene compounds G1–G3 has been proven by the preparation of styrene carbonate from the reaction between styrene oxide and carbon dioxide.

     

Pulping Yield and Delignification Kinetics of Heartwood and Sapwood of Maritime Pine

Abstract

In maritime pine (Pinus pinaster Ait.), heartwood represents a substantial part of the tree stem at final harvest age (80 years) corresponding to 42% at the base of the stem wood diameter and decreasing upward. The rate of heartwood formation was estimated at 0.35 rings/year, beginning at 18 years of age. Differences in the chemical composition between heartwood and sapwood were mainly in the extractives, 19.7% and 5.8%, respectively. The lignin content was 23.1% and 24.5% in the heartwood and sapwood, respectively. Pulping yield of the heartwood was lower than that of the sapwood (40.0% vs. 49.7%) and was negatively correlated with the extractives content. Extraction of heartwood prior to pulping increased the pulp yield and the delignification (lower residual lignin in pulps). Pulping kinetics showed lower yields for heartwood at all pulping stages, the difference occurring especially in the initial reaction phase. However, delignification rate constants were similar for heartwood and sapwood (3.1×10^?2 min^?1 and 2.7×10^?2 min^?1 for the main delignification phase for sapwood and heartwood, respectively), with a lower activation energy for sapwood (68.3 vs. 90.0 kJ · mol^?1). The presence of heartwood decreases the raw‐material quality for pulping and this should be taken into account when harvesting trees for pulping processes.     

Protein encapsulated in electrospun nanofibrous scaffolds for tissue engineering applications

The main purpose of tissue engineering is the preparation of fibrous scaffolds with similar structural and biochemical cues to the extracellular matrix in order to provide a substrate to support the cells. Controlled release of bioactive agents such as growth factors from the fibrous scaffolds improves cell behavior on the scaffolds and accelerates tissue regeneration. In this study, nanofibrous scaffolds were fabricated from biocompatible and biodegradable poly(lactic‐co‐glycolic acid) through the electrospinning technique. Nanofibers with a core–sheath structure encapsulating bovine serum albumin (BSA) as a model protein for hydrophilic bioactive agents were prepared through emulsion electrospinning. The morphology of the nanofibers was evaluated by field‐emission scanning electron microscopy and the core–sheath structure of the emulsion electrospun nanofibers was observed by transmission electron microscopy. The results of the mechanical properties and X‐ray diffraction are reported. The scaffolds demonstrated a sustained release profile of BSA. Biocompatibility of the scaffolds was evaluated using the MTT (3(4,5‐ dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay for NIH‐3T3 fibroblast cells. The results indicated desirable biocompatibility of the scaffolds with the capability of encapsulation and controlled release of the protein, which can serve as tissue engineering scaffolds. © 2013 Society of Chemical Industry     

Identification,SAR Studies,and X‐ray Co‐crystallographic Analysis of a Novel Furanopyrimidine Aurora Kinase A Inhibitor

Herein we reveal a simple method for the identification of novel Aurora kinase A inhibitors through substructure searching of an in‐house compound library to select compounds for testing. A hydrazone fragment conferring Aurora kinase activity and heterocyclic rings most frequently reported in kinase inhibitors were used as substructure queries to filter the in‐house compound library collection prior to testing. Five new series of Aurora kinase inhibitors were identified through this strategy, with IC₅₀ values ranging from ～300 nM to ～15 μM , by testing only 133 compounds from a database of ～125 000 compounds. Structure–activity relationship studies and X‐ray co‐crystallographic analysis of the most potent compound, a furanopyrimidine derivative with an IC₅₀ value of 309 nM toward Aurora kinase A, were carried out. The knowledge gained through these studies could help in the future design of potent Aurora kinase inhibitors.     

Collapse of Eucalyptus nitens Wood After Drying Depending on the Radial Location Within the Stem

Collapse is almost certain to occur in the industrial drying of Eucalyptus nitens and, as such this prevents the lumber manufacturing industry in Chile from producing commercial solid wood products from this species. This problem is still unsolved, and different studies to reduce collapse are currently underway. In this exploratory study, shrinkage and collapse after drying of Eucalyptus nitens was measured for boards cut from different radial locations within the stem (core, transition, and outer wood from pith to bark) and having different annual ring orientations (flat-sawn and quarter-sawn). Though exploratory, the results appear to confirm that pieces that were cut from the center of the trees were less susceptible to collapse than pieces cut from the transition zone between the center and the periphery. On average, collapse in transition wood was approximately 50% higher than the collapse observed in wood cut from the central zone of the trees.     

Antimicrobial Activity of Extractable Conifer Heartwood Compounds Toward <Emphasis Type="Italic">Phytophthora ramorum</Emphasis>

Ethyl acetate extracts from heartwood of seven western conifer trees and individual volatile compounds in the extracts were tested for antimicrobial activity against Phytophthora ramorum. Extracts from incense and western redcedar exhibited the strongest activity, followed by yellow-cedar, western juniper, and Port-Orford-cedar with moderate activity, and no activity for Douglas-fir and redwood extracts. Chemical composition of the extracts varied both qualitatively and quantitatively among the species with a total of 37 compounds identified by mass spectrometry. Of the 13 individual heartwood compounds bioassayed, three showed strong activity with a Log₁₀ EC₅₀ less than or equal to 1.0 ppm (hinokitiol, thymoquinone, and nootkatin), three expressed moderate activity ranging from 1.0–2.0 ppm (nootkatol, carvacrol, and valencene-11,12-diol), four compounds had weak activity at 2.0–3.0 ppm [α-terpineol, valencene-13-ol, (+)-β-cedrene, (−)-thujopsene], and three had no activity [(+)-cedrol, δ-cadinene, and methyl carvacrol]. All of the most active compounds contained a free hydroxyl group, except thymoquinone. The importance of a free hydroxyl was demonstrated by the tremendous difference in activity between carvacrol (Log₁₀ EC₅₀ 1.81 ± 0.08 ppm) and methyl carvacrol (Log₁₀ EC₅₀ >3.0 ppm). A field trial in California, showed that heartwood chips from redcedar placed on the forest floor for 4 months under Umbellularia californica (California bay laurel) with symptoms of P. ramorum leaf blight significantly limited the accumulation of P. ramorum DNA in the litter layer, compared with heartwood chips from redwood.     

Fragment Velocity Distribution of Cylindrical Rings Under Eccentric Point Initiation

A design mode, in which a casing is filled with a charge initiated off‐centre (eccentric point initiation), is common in the field of explosion and structural protection. The fragment velocity distribution along the circumference of the casing is distinctly non‐uniform due to the difference in blast loading around the circumference of the casing. To quantify the fragment velocity distribution, two kinds of cylindrical rings with different structural parameters were adopted. Static explosive experiments with three eccentric coefficients (0, 0.5, 1.0) were conducted with pulsed X‐ray diagnostics. Using coefficients derived from experimental data and calculating the effects of both the eccentricity of initiation and angle around the circumference, an angle‐dependent ratio β_θ of charge mass to casing mass has been derived as a mean to modify the fragment velocity formula of Gurney for this application. The derived formula was shown to correctly predict the fragment velocity distribution around the circumference of the cylindrical ring. The calculated velocity distributions show good agreement with the experimental results.     

Adhesive properties of cured epoxide resin containing the intermolecular compound of 2,4-diamino-6-vinyl-s-triazine and isocyanuric acid

The intermolecular compound of 2,4-diamino-6-vinyl-s-triazine and isocyanuric acid was synthesized, and the glass transition temperature and the adhesive properties of the cured epoxide resin containing the above compound were studied. Epoxide reacted with amino groups of 2,4-diamino-6-vinyl-s-triazine and isocyanuric acid at the curing conditions of 150 to 180°C for 60 min and formed the cured compounds. The infrared spectra showed that epoxide reacted with isocyanuric acid in the presence of imidazole compounds and converted to 2-oxazolidinone compound on the curing process. The glass transition temperatures of the cured compounds having isocyanurate and 2-oxazolidinone rings in their structures were higher than that of the epoxide resin cured with imidazole and rise as the curing temperature rises, but fall as 2-oxazolidinone ring content increases in their cured compounds. The tensile shear and peel strengths of the steel and steel bonded with the cured compounds and the cured epoxide resin were measured at 25 and 150°C. The adhesive strengths were improved due to isocyanurate and 2-oxazolidinone rings formed in their cured compounds.     

Major antitermitic components of the heartwood of southern catalpa

The heartwood of southern catalpa,Catalpa bignonioides Walt., is resistant to attack by the eastern subterranean termiteReticulitermes flavipes (Kollar), but extraction with a ternary solvent mixture of acetone-hexanewater (54442) by volume removed the antitermitic characteristics from the heartwood. Four compounds comprised approximately 98% of the antitermitic fraction of the extract: the sesquiterpene alcohol, catalponol (67%); its epimer, epicatalponol (5%); a structurally related ketone, catalponone (1%); and the phthalide, catalpalactone (25%). Pure compounds were isolated by semipreparative scale reversed-phase HPLC and identified by GC-MS and UV spectroscopy. The structure of catalponol was further confirmed by the formation of derivatives. Bioassays indicated that catalponol had the greatest toxicity in cellulose pad tests, but in tests using vacuum impregnation of these compounds into termite-susceptible wood blocks at levels approximating those found in catalpa heartwood, catalpalactone exhibited the highest antitermitic activity.     

Localization of Phenolics in Phloem Parenchyma Cells of Norway Spruce (Picea abies)

Norway spruce (Picea abies) bark contains specialized phloem parenchyma cells that swell and change their contents upon attack by the bark beetle Ips typographus and its microbial associate, the blue stain fungus Ceratocystis polonica. These cells exhibit bright autofluorescence after treatment with standard aldehyde fixatives, and so have been postulated to contain phenolic compounds. Laser microdissection of spruce bark sections combined with cryogenic NMR spectroscopy demonstrated significantly higher concentrations of the stilbene glucoside astringin in phloem parenchyma cells than in adjacent sieve cells. After infection by C. polonica, the flavonoid (+)‐catechin also appeared in phloem parenchyma cells and there was a decrease in astringin content compared to cells from uninfected trees. Analysis of whole‐bark extracts confirmed the results obtained from the cell extracts and revealed a significant increase in dimeric stilbene glucosides, both astringin and isorhapontin derivatives (piceasides A to H), in fungus‐infected versus uninfected bark that might explain the reduction in stilbene monomers. Phloem parenchyma cells thus appear to be a principal site of phenolic accumulation in spruce bark.     

Synthesis and characterization of CdS nanocrystals embedded on solid electrolyte films

In this article nano‐sized CdS crystal embedded in a PEO matrix was successfully prepared by a complex transformation method that is universal for preparing nanosized compounds containing transition metals. The size of embedded CdS particles was in the nanoscale from 2 to 10 nm determined by X‐ray diffusion. The nanosized CdS displayed the expected blue shift of the onset absorbance in the UV spectrum. The amount of blue shift depends upon the dipping time of the PEO–cadmium complex film in a sodium sulfide solution as well as its concentration. The most effective means for adjusting the size of CdS nanocrystals is to change the ratio of the oxygen along with the PEO chain to the cadmium ion in the complex film. The alkali salt in the film would contribute to the conductivity of the composite film. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1263–1268, 2002; DOI 10.1002/app.10459     

Effect of methanol on optical property of irradiated poly(methyl methacrylate)

The effect of methanol on optical property of irradiated poly(methyl methacrylate) (PMMA) has been investigated. The gamma irradiation enhances the methanol transport in PMMA. The activation energies of diffusivity for case I and velocity for case II decreases with increasing gamma ray dose. For the same wavelength, in the range 350–800 nm, the transmittance decreases with increasig gamma ray dose. The equation of transmittance I with gamma ray dose ? at the wavelength 405 nm is I = I₀ exp(?0.06?^1/2), where I₀ is the transmittance of virgin PMMA. When the irradiated PMMA is immersed into methanol bath, the yellow color fades out gradually. The recovery of transmittance increases with methanol content in irradiated PMMA. The boundary to separate the outer region (solvent affected zone) from the inner region (no solvent-affected zone) is also studied. The rate of boundary movement increases with gamma ray dose.     

Synthesis and properties of copolyesters of p,p′‐bibenzoic acid,dimer acid,and alkylene glycol

Copolyesters of p,p′‐bibenzoic acid, dimer acid, and an alkylene glycol are prepared by melt polycondensation of of dimethyl p,p′‐bibenzoate, dimer acid, and an alkylene glycol. The copolyesters are characterized by the inherent viscosity, FTIR, proton NMR, DSC, polarized microscopy, and X‐ray diffraction. The polymer composition and sequence distribution of the copolyesters can be seen from the NMR spectra. The copolyesters exhibit a degree of randomness of about 1, indicating that they are random copolymers. The glass‐transition temperature (T_g) and the melting point (T_m) of the copolyesters are found from the DSC heating curves. When the content of the flexible dimer acid unit increases, the T_g of the copolyesters decreases significantly. The copolymerization effect decreases the crystallinity and the T_m of the copolyesters. It can be seen from the DSC, polarized microscopy, and X‐ray diffraction data that some copolyesters derived from 1,6‐hexanediol and 1,5‐pentanediol exhibit a monotropic smectic phase. As the molar content of the dimer acid unit increases, the isotropic–mectic transition temperature and the smectic order decreases significantly. The liquid crystallinity is completely destroyed at certain molar contents of the dimer acid unit. The smectic order of the copolyesters derived from 1,6‐hexanediol is significantly higher than that of the copolyesters derived from 1,5‐pentanediol, and it is described as an odd–even effect. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 750–758, 2003     

Review of heat Conduction,Second Edition,S. Kakac and Y. Yener

In some species, such as subalpine fir (Abies lasiocarpa [Hook] Nutt), the water content of the confined zones in heartwood is as high as or greater than that of sapwood. Such wet zones of heartwood are referred to as “wetpocket” or “wetwood.” Wood products from subalpine fir forests are adversely affected by the wetwood-associated problems, particularly during the drying process. The objectives of the study were as follows: (1) to investigate feasibility of a high X-ray energy industrial computed tomography (ICT) scanner for imaging wetwood; and (2) to determine changes of the 2-D and 3-D moisture profiles (from core to shell) at different drying times.

Although medical CT scanning has been used for attaining signal intensity profiles of typical wood at different drying times, the technology has not, to date, been used for the study of wetwood phenomenon. This study presents, for the first time, results from the ICT imaging of the wetwood phenomenon. The results indicate that the ICT imaging system provides a powerful technique for imaging wetwood at different drying times. In addition, the results show that during the initial phase of drying, almost flat moisture profiles were observed in all wood types except for the wetwood, which showed a relatively higher moisture profile. A much slower (sluggish) drying development pattern at each increment from core to shell was found within the wetwood zone than normal wood regions along the width, thickness, and length of the board.     

三倍体毛白杨渗透率在径向的分布

依据木材并联毛细管模型的假设和Darcy渗透定律,通过气流法对普通气干处理的三倍体毛白杨的心材和边材流体渗透性进行了测定与分析。结果表明,三倍体毛白杨的边材总体平均渗透性比心材渗透性高,心材为140.802 cm/s,边材为221.829 cm/s,后者为前者的1.58倍。制作了三倍体毛白杨在径向的渗透率分布图,分布图显示,渗透率在径向的分布中呈很好的递增趋势。渗透率差异性是由于木材中导管中存在侵填体所造成的,只是所选试样树龄偏小,造成差异性不大。     

Neuroprotective Fatty Acids from the Stem Bark of Sorbus commixta

Phytochemical investigation of the bark from the stems of Sorbus commixta led to the isolation and characterization of a new fatty acid, sorcomic acid ( 1 ), along with nine known analogues ( 2 – 10 ). The structure of the new compound ( 1 ) was determined through NMR (¹H and ¹³C NMR, HSQC, HMBC, and NOESY), MS, and specific optical rotation. The known compounds ( 2 – 10 ) were identified by comparison of their spectroscopic data with those in the literature. The biological activities of all the isolated compounds ( 1 – 10 ) were evaluated: compounds 1 , 5 , and 7 potently induced NGF secretion from C6 glioma cells (233.40 ± 12.82, 194.40 ± 8.05, and 185.74 ± 10.25 %, respectively) and compound 10 reduced NO levels with an IC₅₀ value of 71.25 μM in murine microglia BV2 cells stimulated by LPS.