木材におけるドライングセットの発生と回復の機構(林学部門)

本研究は, 木材のドライングセットの発生と回復の条件, セット材の性質及び組織構造などについて検討し, セットの発生と回復の機構に関する新らたな解釈を提起したものである。主な内容は次のとおりである。1.木材含水率の減少と材温の急速な上昇がみられ, これによって数10%にも及ぶセットを発生するマイクロ波乾燥と, 温度が50℃一定で含水率の減少のみが進行する熱気乾燥におけるセットの発生について比較した。この検討によって, 従来不明なところが多かったセットに及ぼす湿熱の影響を100℃前後の温度域にわたって明確にし, この影響が動態水分に比べて顕著なものであることを明らかにした。2.一連の検討に供試した多くの樹種を針葉樹, 広葉樹散孔材と環孔材に分け, これらグループ間の比較からセットの発生及び回復に及ぼす動態水分の影響が, ヘミセルロース含有量の大きい広葉樹の両グループにおいて, また熱の影響が, リグニン含有量の大きい針葉樹グループにおいて顕著であることをみいだした。3.セットの発生と回復に伴う細胞の形状と壁の内表面にみられる変化をSEM観察し, 水分・熱による細胞壁の軟化で, 細胞壁の破壊や分離を伴うことなくセットが発生し, ほぼ可逆的に回復することを裏付けた。4.一連の検討結果に基づき, セットの発生・回復の機構は, セルロースからなるミクロフィブリルの弾性変形とヘミセルロース, リグニンからなるマトリックスのガラスーゴム状態間の変化ならびに凝集力の変化によるとする解釈を与えた。この解釈は従来の動的水分を中心に展開された機構に, 湿熱の影響を加え, これを重視したもので木材にみられる数%から数10%にも及ぶセットの説明に耐えうるものである。しかも, 検証実験を行った結果は, いずれも以上の解釈がほぼ妥当であることを示唆するものであった。In the present paper, an interpretation on the mechanism of drying set has been given by investigating the formative and the recoverable conditions of set, the properties of set-woods and these anatomical structures. The details of contents are as follows; 1. The amount of set that occurred with accompanied by the reduction of moisture content and the rapit rise of temperature by means of the microwave radiation and those that occurred with only the reduction of moisture content by means of the hot-air drying were compared, and the influence of the moisture and the heat on the development of set were investigated to cover high temperature of about 100℃. The results indicated that the remarkable set is not the results of moisture content change, rather it is the results of heating under the water-saturated state. 2. The many species used a series of the experiments were classfied into the groups of the coniferous woods, the diffuse-porous woods and the ring-porous woods. From the comparison of set between those groups, the effects of moisture content change on the set is greatly affected for the both groups of hardwoods having a high hemicellulose content in comparison with the group of coniferous woods. And the hygrothermal effect is greatly affected for the group of the coniferous woods having the high lignin content in comparison with the group of hardwoods. 3. The cell shape and the inside surface of the cell wall of the set-woods and the recovered woods were observed to using the scanning electon microscope. The wood cell wall softened by the moisture and heat is able to developed the set without the destraction and the separation of cell wall, and moreover if the set-woods undergo again the moisture and heat treatments, it is recovered the set by the reversible changes. 4. From results obtained, an interpretation on the mechanism of the set is given in terms of the elastic deformation of the microfibriles composed of cellulose and the reversible changes between the grassly state and the rubbery state of matrix composed of lignin and hemicelluloses including the change of cohesive. Furthermore, the results of the inspected experiments also showed a good agreement with the above mentioned interpretation on the mechanism of set

A Functional SNP in BNC2 Is Associated with Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity. We previously conducted a genome-wide association study (GWAS) and detected two loci associated with AIS. To identify additional loci, we extended our GWAS by increasing the number of cohorts (2,109 affected subjects and 11,140 control subjects in total) and conducting a whole-genome imputation. Through the extended GWAS and replication studies using independent Japanese and Chinese populations, we identified a susceptibility locus on chromosome 9p22.2 (p = 2.46 × 10−13; odds ratio = 1.21). The most significantly associated SNPs were in intron 3 of BNC2, which encodes a zinc finger transcription factor, basonuclin-2. Expression quantitative trait loci data suggested that the associated SNPs have the potential to regulate the BNC2 transcriptional activity and that the susceptibility alleles increase BNC2 expression. We identified a functional SNP, rs10738445 in BNC2, whose susceptibility allele showed both higher binding to a transcription factor, YY1 (yin and yang 1), and higher BNC2 enhancer activity than the non-susceptibility allele. BNC2 overexpression produced body curvature in developing zebrafish in a gene-dosage-dependent manner. Our results suggest that increased BNC2 expression is implicated in the etiology of AIS

立木注入法による木材の染色(第 5 報) : 染色材の退色防止について(林学部門)

前報までに, スギ間伐材や未利用広葉樹材を有効に利用する一つの方法として, 立木の樹液流や葉の蒸散作用を活用した木部の染色を試み, 極めて特徴を有する染色材が得られることを示した。この一連の研究に関係して本報告は, 染色材の退色とその防止について調べた。得られた結果は以下の通りである。1)染色材のΔEは, 染色していない材のそれの最大3.1倍を示し著しく大きいことを認めた。2)染色材に市販のポリウレタン塗料(Pu), フッ素樹脂塗料(Fc)を塗布しても退色の程度を小さくすることは出来なかった。しかし, 紫外線吸収剤の添加されたフッ素樹脂塗料は退色程度が1/2程度に減少した。3)Pu及びFc塗料に紫外線吸収剤5種をそれぞれ添加して検討した結果, 塗料によって最適の紫外線吸収剤が異なることを認めた。最適の紫外線吸収剤による退色の減少程度は, 1/5∿1/10になることを認めた。4)紫外線吸収剤の塗料溶液中への添加濃度は, いずれの場合も最大1%で十分である。In the previous papers, we indicated the dyeing wood which was treated by using sap-flow method for effective utilization of lesser-used species. This dyeing wood has been shown to grow comparatively large discoloration in the color. This paper is to make clear the improvement of discoloration. For finding the method of reasonable treatment and the best condition on prevention of discoloration in the dyeing wood, the effects of the several painting, the types of ultraviolet rays-absorbent and its concentration on the prevention of discoloration of the dyeing wood were evaluated. Result obtained are as follow; 1) It was recognized that ΔE of the dyeing wood were lager maximum 3.1 times than it of the untreated wood. From the result of decomposition of the constituent element, The change amount of b-values have influence greatly to the change of values of ΔE. Therefore, improvement of discoloration is necessity to take the minimum value for the change of b-values. 2) Polyurethane resin paint and fluorine resin paint could not prevailed discoloration by coating the surface of the dyeing wood. However, Fluorine resin paint including ultraviolet rays-absorbent was shown more large the prevention of discoloration. 3) The best effect of prevention was appeared difference by the kind of the ultraviolet rays-absorbent. In the case of Pu, it are best condition for the Tinuvin 320. In the case of Fc, it are Tinuvin P. Especially, the later become the the ΔE values of about from 1/5 to 1/10 times. 4) The concentration of the range of 1%-10% for the ultraviolet rays-absorbent were investigated. And its result indicated no difference for the prevention of discoloration. Therefore, the best concentration was interpret to be 1.0 percent

樹液流を利用した材の染色と寸法安定化処理(林学部門)

未利用樹の有効利用をはかる一つの方法として, 立木注入法による材の染色ならびに寸法安定性の付与について検討し, 樹高方向の染色程度, 横断面の染色模様, 抗収縮能, ならびにこれらの樹種, 染料による差異を調べた。染料水溶液の吸液量は, 染料の種類によって異なる。供試4染料によるその順位はスギ材について, マラカイトグリーン>メチレンブルー>酸性フクシン》ニグロシンで, マラカイトグリーンの場合には17日間で96l吸液した。染料による吸液量の大きさの順位と材の等しい高さにおける染色程度の順位はニグロシンを除き一致せず, 染色程度は酸性フクシンで最大であった。木口染色面積割合は, 環孔材グループの樹種に比べ散孔材グループの樹種で大きく, 高さ2m位置において散孔材は横断面の平均約70%を染色しているが環孔材は約33%であった。染色材横断面の染色模様は広葉樹の場合, 樹種によってFig.4に示しているように特徴的なものとなる。スギ材は高さ2.8mまで抗収縮能約66%を示し, 割れなしに円盤を乾燥できるが, 広葉樹材は乾燥中に割れが発生し, 処理効果は十分でなかった。For effective utilization of lesser-used species the impregnation of dye aqueous solution and dimensional stability agents to green trees using the sap-flow and transpiration actions of leaves is described. The effect of using different dyes and species on the shape of the dye patterns in the cross section, antishrink efficiency (ASE) and the extent of dyeing in the height of tree (ratio of dyeing areas to cross section) were investigated. The amount of adsorption of the dye aqueous solution differs with dyeing materials and adsorption of four dye aqueous solutions for sugi wood has been shown to decrease in the following order : Malachite green>Methylen blue>Acid fuchusin>Nigroshin. Malachite green aqueous solution was absorbed 96 liters in 17 days by Sugi wood. In the same height of tree the adsorption of dye aqueous solution did not correspond to the extent of dyeing area except Nigroshin and the extent of dyeing areas was maximum inthe Acid fuchusin. The ratio of dyed area to cross section was bigger in the diffuse porous woods than in the ring porous woods : at the 2m height of tree the dyed area of cross section was about 70% for the diffuse porous woods and about 33% for the ring porous woods. The hardwoods showed the characteristic dye patterns in the cross section as shown in Fig.4. Sugi wood showed about 66% ASE up to the 2.8m height of tree. Sugi wood discs could be dried without checking from green to oven-dry state, but the checking was found in hardwoods discs during drying and this treatment did not give enough efficiency for hardwoods

飽水木材中の溶質拡散 IV : (3) 2 価電解質の拡散速度について(林学部門)

飽水木材中における2価電解質の拡散速度を検討するために, 濃度0.5mol/ℓの2価電解質7種と比較のために用いた1価電解質3種について(Table 1), 10∿40℃の条件下でヒノキの長軸(L)方向と接線(T)方向の拡散係数を測定した。測定装置や測定方法は前報のそれと全く同様で, 測定には直径5.0cm, 厚さ1.0cm(L-方向の拡散)および0.2cm(T-方向の拡散)の円板形の心材試片を用いた。得られた結果は次のとおりである。(1)木材組織に起因しての拡散係数の変動はNa_2SO_4,ZnSO_4,CaCl_2のT-方向, ならびにCuCl_2のL, T両方向において顕著であった(Table 2)。(2)拡散係数の対数と絶対温度の逆数をプロットした場合, 各電解質, 拡散方向いずれの場合も直線関係が得られた(Fig. 3)。(3)25℃の木材中における電解質の拡散係数(D_)と同温度の水中におけるそれ(D_)との間にはL, T両方向いずれの場合も放物線関係(Fig. 4), またD_と25℃の水中における陰, 陽イオンの拡散係数(D_)との間にはいずれの場合も直線関係(Fig. 5)が得られた。(4)ヒノキ飽水木材中における2価電解質の拡散速度は, 拡散通路内に存在する有効毛管の大きさとその数, 特に有縁壁孔の数に支配されるが, 拡散分子やイオンは飽水木材中を水中における場合とほぼ同様な挙動で拡散することが推測された。(5)D_をD_に比較すると, 1価電解質はL-方向で水中のそれの平均約1/2,T-方向で平均約1/50,2価電解質のそれはそれぞれ平均約1/2.4ならびに平均約1/93で, 特に2価電解質のT-方向における拡散の困難なことが認められた(Table 3,Table 4)。(6)拡散の見掛けの活性化エネルギーや平均の温度係数は, 極めて少数の例外を除いて拡散方向や電解質の種類には無関係であった(Table 5)。このことから仮道管壁に存在する有縁壁孔の数が両者の値に関係することが推測された。The differences in diffusion rates of the bivalent electrolytes through water-saturated wood have been measured in the longitudinal (L) and tangential (T) directions of Hinoki wood (Chamaecyparis obtusa ENDL.) using seven kinds of the bivalent electrolytes and three of the univalent electrolytes for a comparison (Table 1) at a concentration of 0.5mol/ℓ over the temperature range of 10∿40℃. The apparatus and the experimental procedure used for measurement of the diffusion rate were the same as those described in the previous report. The test specimens were the disks having the sizes of 5.0cm in diameter, and 1.0cm (for longitudinal (L) diffusion) or 0.2cm (for tangential (T) diffusion) in thickness, which were prepared from green blocks of Hinoki-heartwood. The results obtained are as follows : (1) The variations of the diffusion coefficient due to the wood structure were especially remarkable for T-direction in Na_2SO_4,ZnSO_4 and CaCl_2,and for both L-and T-directions in CuCl_2 (Table 2). (2) A plot of the logarithm of diffusion coefficient against the reciprocal of absolute temperature showed linear relationship for the diffusion of all electrolytes and of both L-and T-directions (Fig. 3). (3) The relationship between the diffusion coefficient of electrolytes in wood at 25℃ (D_) and that in water at the same temperature (D_) was approximately parabolic for L- and T-directions (Fig. 4), and that between D_ and the diffusion coefficient of positive or negative ions in water at 25℃ (D_) was linear in all cases (Fig. 5). (4) Although the diffusion rates of the bivalent electrolytes through the water-saturated Hinoki wood depend upon the dimension and number of effective capillaries, especially the number of the bordered pit, it was assumed that there is no interaction between the wood capillary walls and either the diffusing molecule or ion, and that the molecule or ion in wood diffuses with the similar behavior to that in water. (5) The ratio of the diffusion coefficient of electrolytes through wood (D_) to that in water (D_) was about 1/2 for L-direction, and about 1/50 for T-direction in univalent electrolytes, and about 1/2.4 for L-direction, and about 1/93 for T-direction in bivalent electrolytes (Tables 3 and 4). It was recognized from these results that the diffusion for T-direction in bivalent electrolytes was difficult. (6) As the apparent activation energy and the mean temperature coefficient in the diffusion process of the bivalent electrolytes were indepedent of the both of diffusion direction and kinds of electrolytes with only few exceptions, it was suggested that they might be dependent upon the number of the bordered pit on tracheid wall (Table 5)

飽水木材中の溶質拡散 IV : (4) 2 価電解質の拡散速度について(林学部門)

前報の検討をも含め, 飽水木材中における2価電解質の拡散速度を明らかにするために, 濃度0.5mol/ιの2価電解質7種と比較のために用いた1価電解質1種について(Table 1), 20∿50℃の条件下でスギの長軸(L)方向と半径(R)方向の拡散係数を測定した。測定装置や測定方法は前報のそれと全く同様で, 測定には直径5.0cm, 厚さ1.0cm(L-方向の拡散)および0.2cm(R-方向の拡散)の円板形の心材試片を用いた。得られた結果は次のとおりである。(1)木材組織に起因しての拡散係数の変動はNH_4Cl, Na_2SO_4,CuSO_4のL, R両方向, Li_2SO_4,Cu(NO_3)_2のL-方向ならびに(NH_4)_2SO_4,CuCl_2のR-方向において顕著であった(Table 2)。(2)拡散係数の対数と絶対温度の逆数をプロットした場合, 各電解質, 拡散方向いずれの場合も直線関係が得られた(Fig.3)。(3) 25℃の水中における2価電解質の拡散係数(Dwater)と同温度の木材中におけるそれ(Dwood), ならびにDwoodと25℃の水中における陰, 陽イオンの拡散係数(Dion)との間にはいずれの場合も直線関係が得られた(Fig. 4,Fig. 5)。(4)スギ飽水木材中における2価電解質の拡散速度は拡散通路の毛管径に支配されるが, 拡散分子やイオンは飽水木材中を水中における場合とほぼ同様な挙動で拡散することが推測された。(5) DwoodをDwaterに比較すると, NH_4ClはL-方向で水中のそれの約1/4.6,R-方向で約1/103,2価電解質のそれはそれぞれ平均約1/8.8ならびに平均約1/368であり, 特に2価電解質のR-方向における拡散の困難なことが認められた(Table 3,Table 4)。(6)拡散の活性化エネルギー(E)や平均の温度係数(Q_)には拡散方向ならびに電解質の種類による差異がなく(Table 5), Eは水中のそれの1.6∿1.9倍に達した。このことから有縁壁孔や仮道管壁内の一時毛管が両者の値に関係することが推測された。In the previous paper some considerations were made on diffusion processes of the bivalent electrolytes through the water-saturated wood. Successively in order to discuss fully phenomena in this process, the differences in diffusion rates of the bivalent electrolytes through wood saturated with water have been investigated in the longitudinal (L) and radial (R) directions of Sugi wood (Cryptomeria japonica D. DON) using seven kinds of the bivalent electrolytes and one of the univalent electrolyte for a comparison (Table 1) at a concentration of 0.5mol/ι over the temperature range of 20∿50℃. The apparatus and the experimental procedure used for the measurement of diffusion rate were the same as those described in the previous report. The test specimens were the disks having the sizes of 5.0cm in diameter, and 1.0cm (for longitudinal (L) diffusion) or 0.2cm (for radial (R) diffusion) in thickness, which were prepared from green blocks of Sugi-heartwood. The results obtained are as follows : (1) The variations of the diffusion coefficient dependent on wood structure were especially remarkable in Li_2SO_4 and Cu (NO_3)_2 for L-direction, in (NH_4)_2SO_4 and CuCl_2 for R-direction and in NH_4Cl, Na_2SO_4 and CuSO_4 for both directions (Table 2). (2) The relationship between the logarithm of diffusion coefficient and the reciprocal of absolute temperature gave the straight line for all kinds of electrolytes used and for both L-and R-direction (Fig. 3). (3) The relationship between the diffusion coefficient of the bivalent electrolytes in the watersaturated wood at 25℃ (Dwood) and that of the electrolytes in water at the same temperature (Dwater) was linear, and also the relation between Dwood and the diffusion coefficient of positive and negative ions in water at 25℃ (Dion) showed the straight line in all cases (Fig. 4,Fig. 5). (4) Although the diffusion rates of the bivalent electrolytes through the water-saturated Sugi wood depend upon the diameters of capillaries in the passages of diffusion, assumedly the molecules or ions diffuse with the behavior similar to that in water for the diffusion in the water-saturated wood. (5) The ratio of the diffusion coefficient of electrolytes through wood (Dwood) to that in water (Dwater) was about 1/4.6 in L-direction, and about 1/103 in R-direction for NH_4Cl, and that for bivalent electrolytes was about 1/8.8 in L-direction and about 1/368 in R-direction in average. It was recognized from these facts that the diffusion in R-direction for bivalent electrolytes was difficult (Table 3,Table 4). (6) The apparent activation energy (E) and the mean temperature coefficient (Q_) in the diffusion process of the bivalent electrolytes were independent of diffusion directions and kinds of electrolytes (Table 5), and the ratio of the activation energy in wood to that in water was the value of 1.6 to 1.9. It was assumed from these facts that the transient capillaries existing in cell wall of tracheid and the bordered pit contributed to E and Q_