Properties of Bark Particleboard Bonded with Demethylated Lignin Adhesives Derived from Leucaena leucocephala Bark

Lignin extraction from bark can maximize the utilization of biomass waste,offer cost-effectiveness,and promote environmental friendliness when employed as an adhesive material in bark particleboard production.Particles of fine(0.2 to 1.0 mm),medium(1.0 to 2.5 mm),and coarse(2.5 to 12.0 mm)sizes,derived from the bark of Leucaena leucocephala,were hot-pressed using a heating plate at 175℃for 7 min to create single-layer particleboards measuring 320 mm×320 mm×10 mm,targeting a density of 700 kg/m^(3).Subsequently,the samples were trimmed and conditioned at 20℃and 65%relative humidity.In this study,we compared bark particleboard bonded with urea formaldehyde(UF)adhesive to fine-sized particleboard bonded with demethylated lignin adhesive.The results indicated that bark particleboards utilizing demethylated lignin and UF adhesives exhibited similar qualities.Coarse particleboard showed differences in modulus of elasticity(MOE)and modulus of rupture(MOR),while medium-sized particles exhibited significant variations in moisture content(MC)and water absorption(WA).Furthermore,the thickness swelling of coarse and medium-sized particles under wet and oven-dried conditions exhibited notable distinctions.Overall,the demethylated lignin adhesive extracted from L.leucocephala bark demonstrated similar quality to UF adhesive,with particle size correlating inversely to the strength of the bark particleboard.

The rate of deadwood decomposition processes in tree stand gaps resulting from bark beetle infestation spots in mountain forests

Decaying wood is an essential element of forest ecosystems and it affects its other components.The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in the gaps formed in the montane forest stands.The research was carried out in the Babiog orski National Park.The research plots were marked out in the gaps of the stands,which were formed as a result of bark beetle gradation.Control plots were located in undisturbed stands.The research covered wood of two species–spruce and beech in the form of cubes with dimensions of 50 mm×50 mm×22 mm.Wood samples were placed directly on the soil surface and subjected to laboratory analysis after 36 months.A significant influence of the wood species and the study plot type on the physicochemical properties of the tested wood samples was found.Wood characteristics strongly correlated with soil moisture.A significantly higher mass decline of wood samples was recorded on the reference study plots,which were characterized by more stable moisture conditions.Poorer decomposition of wood in the gaps regardless of the species is related to lower moisture.The wood species covered by the study differed in the decomposition rate.Spruce wood samples were characterized by a significantly higher decomposition rate compared to beech wood samples.Our research has confirmed that disturbances that lead to the formation of gaps have a direct impact on the decomposition process of deadwood.

Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-TOF)-Mass Spectrometry and^(13)C-NMR-Identified New Compounds in Paraberlinia bifoliolata(Ekop-Beli)Bark Tannins

Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica extracts.Yield by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of extracts.These are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid.The identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors.This information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the tannin.Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.

FrFT-Bark域特征提取与CNN残差收缩网络心音分类算法

为充分挖掘心音信号的生理、病理信息,提高心音自动分类的准确率,提出一种不依赖于分割和去噪的心音自动分类新算法.首先提取心音信号Bark域分数傅里叶变换的时频特征,然后将深度残差收缩网络引入卷积神经网络中构建新的分类模型,该模型能够自动去除与当前任务无关的特征信息,提高模型预测的准确率及稳定性.研究所用心音样本5000例,其中1000例用于测试.实验结果表明,提出算法的准确率、灵敏度、特异度分别为0.925、0.902、0.948,F1值为0.923.该方法整体性能较以往方法有明显提升,具有较强的鲁棒性和泛化能力,有望应用于先心病的临床筛查.

Preparation and Characterization of Activated Carbons from Asparagus Palm (Laccosperma robustum) Bark by Chemical Activation with H3PO4 and KOH

The present work deals with the preparation and characterization of activated carbons from the bark of the asparagus palm (Laccosperma robustum) by chemical activation with phosphoric acid and potassium hydroxide. The process was optimized on the basis of the analysis of the iodine number, methylene blue number and activated carbons yield as a function of the preparation parameters (concentration of the activating agents and the pyrolysis temperature). It emerges that the pyrolysis temperature and the concentration of activating agents influence the activated carbons preparation process. Their values were 500°C and 20% respectively for activated carbon with H3PO4 (ACP) and 700°C and 1.5% for activated carbon with KOH (ACK). The iodine numbers obtained were 850.26 mg/g for ACP and 865.49 mg/g for ACK. The methylene blue numbers obtained were 149.35 mg/g for ACP and 149.25 mg/g for ACK. The activated carbons yields obtained were 25% for ACP and 5.9% for ACK. The activated carbons prepared under optimal conditions have shown the pH of zero-point charge (pHzpc) of 4.4 and 7.0 for ACP for ACK respectively. The determination of the surface functions revealed that ACP had a strong acidic character while ACK had neutral character. The Fourier transformed infrared spectroscopy also showed the presence of different functional groups on the surface of the precursor and activated carbons.

Analysis of Subcellular Localization and Pathogenicity of Plum Bark Necrosis Stem-Pitting Associated Virus Protein P6

Infection of plum bark necrosis stem pitting associated virus(PBNSPaV)has been reported in many Prunus species in several countries,causing significant economic losses.The very small proteins encoded by plant viruses are often overlooked due to their short sequences and uncertain significance.However,numerous studies have indicated that they might play important roles in the pathogenesis of virus infection.The role of small hydrophobic protein P6,encoded by the open reading frame 2 of PBNSPaV,has not been well explored.In this study,we amplified the P6 fragment from a PBNSPaV isolate by RT-PCR using specific primers and found that it is 174 bp long and encodes a protein of approximately 6.3 kD with a transmembrane domain.Subcellular localization analysis of P6 proteins in tobacco leaves showed that P6 localizes to the cytomembrane and nuclear membrane.To further clarify the pathogenicity of P6 proteins,we constructed a PVX-P6 expression vector by inserting the p6 fragment into a potato virus X(PVX)-based vector and transformed it into Agrobacterium tumefaciens GV3101.Infiltration of Nicotiana benthamiana(N.benthamiana)with the PVX vector-transformed A.tumefaciens led to slight mosaic symptoms at 14 days of post-inoculation.Meanwhile,infiltration with the PVX-P6 vector-transformed A.tumefaciens resulted in no significant symptoms.These results demonstrated that heterologous expression of P6 in N.benthamiana could not enhance the pathogenicity of PVX.Our study indicates that P6 may not be a potential pathogenic factor associate with the causing of symptoms,and the mode of action of PBNSPaV-P6 protein remains to be further studied.

古代高丽纸纤维原料科学分析与相关问题研究

古代朝鲜半岛曾出产著名的高丽纸,因纸质洁白坚韧在明清时广受文人追捧,并在清宫建筑中大量应用。关于高丽纸的原料,近年有学者曾以为是桑皮。本研究采用纤维染色显微分析法、傅里叶变换红外光谱法和热裂解-气相色谱法对几种古代高丽纸及现代韩纸、朝鲜纸进行纤维成分分析和鉴别,并对照我国及朝鲜半岛相关古籍记载及韩国现代手工纸原料记录。研究发现,古今高丽纸的原料均为楮皮,桑皮的说法很可能为误传。

生态美学视域下鄂伦春族桦树皮画的历史发展与时代传承

鄂伦春族在世代与森林相伴成长的历程中,形成了特色鲜明的桦树皮文化。鄂伦春族的桦树皮画不仅是传统桦树皮文化的历史传承,也是其朴素生态美学观的时代延续。传统桦树皮器物上装饰的出现与发展,可以看作是鄂伦春族桦树皮画的历史源流。在下山定居与“禁猎转产”之后,摆脱了实用性的束缚,鄂伦春族的桦树皮画在内容题材与创作技法等方面都展现出了新的时代风貌。研究表明,鄂伦春族桦树皮画的创新与发展,应坚守民族文化核心,并赓续传统生态审美观,才能根基稳固并持续向前创新发展。

超声提取法对杜仲不同“发汗”品经不同加工炮制后总黄酮成分的影响研究

目的:比较杜仲生品及不同发汗品经四种不同炮制方法对杜仲总黄酮成分的影响,为杜仲加工炮制提供依据。方法:将杜仲生品及不同发汗品经姜制、酒制、盐制、蜜制四种炮制后制备各样品,用芦丁作对照品,采用紫外分光光度法,于510 nm波长处,分别测定不同发汗品经四种炮制后超声提取物中的总黄酮含量。结果:杜仲生品及不同发汗品不同炮制方法对杜仲总黄酮的含量有影响,烘至半干后“发汗”品(E5)酒制品总黄酮含量最高。结论:若以杜仲总黄酮为主的药理作用进行临床应用时,建议杜仲采取烘至半干“发汗”后采用酒制处理的加工炮制方法。

黑河桦树皮手工艺产教融合模式的探索与实践

围绕国家文化强国的战略目标,从文化层面认知和重视黑河桦树皮手工艺文化产业发展,实施产教融合,从理论层面思考及构建发展振兴路径与策略,将桦树皮手工艺的研发、创作转化为实实在在的文化产业,助推桦树皮文化艺术教育的传承与黑龙江省文旅产业发展的需求。

桑白皮总黄酮对小鼠肺癌模型的影响及相关机制

目的 探讨桑白皮总黄酮对小鼠肺癌模型的影响及相关机制。方法 将小鼠分为空白对照组(20只),模型组(14只),桑白皮总黄酮低(16只)、中(16只)、高剂量组(18只)。使用乌拉坦诱导建立小鼠肺癌模型,从造模首日开始,桑白皮总黄酮低、中、高剂量组分别灌胃桑白皮总黄酮15、30、60 mg/kg,对照组、模型组灌胃给予等体积的蒸馏水,1次/d,连续16周,第16周试验结束时统计各组存活小鼠的肺癌发生率、肺肿瘤结节数量。酶联免疫吸附法检测血清鳞状上皮细胞癌抗原、癌胚抗原、神经特异性烯醇化酶(NSE)、糖类抗原125(CA125)、糖类抗原199(CA199)浓度;免疫组化法检测小鼠肺组织中N-钙黏蛋白、E-钙黏蛋白表达阳性率;Western blot检测小鼠肺组织中PI3K、AKT、p-AKT蛋白表达水平。结果 肺癌发生率、肺肿瘤结节数量在各组间比较差异具有统计学意义(P<0.01),各剂量桑白皮总黄酮组肺癌发生率、肺肿瘤结节数量均明显低于模型组(P<0.05);随着桑白皮总黄酮剂量的增加,肺癌发生率、肺肿瘤结节数量下降幅度逐渐明显。模型组血清鳞状上皮细胞癌抗原、癌胚抗原、NSE、CA125、CA199明显高于空白对照组(P<0.01),各剂量桑白皮总黄酮组血清鳞状上皮细胞癌抗原、癌胚抗原、NSE、CA125、CA199明显低于模型组(P<0.01);随着桑白皮总黄酮剂量的增加,血清鳞状上皮细胞癌抗原、癌胚抗原、NSE、CA125、CA199浓度逐渐降低。模型组小鼠肺组织中N-钙黏蛋白表达阳性率明显高于空白对照组,E-钙黏蛋白表达阳性率明显低于空白对照组(P<0.01),与模型组比较,各剂量桑白皮总黄酮组小鼠肺组织中N-钙黏蛋白表达阳性率明显降低,E-钙黏蛋白表达阳性率明显升高(P<0.05);随着桑白皮总黄酮剂量的增加,上述变化逐渐明显。模型组小鼠肺组织中PI3K、AKT、p-AKT蛋白表达水平明显高于空白对照组(P<0.01),与模型组比较,各剂量桑白皮总黄酮组小鼠肺组织中PI3K、AKT、p-AKT蛋白表达水平明显降低(P<0.05);随着桑白皮总黄酮剂量的增加,PI3K、AKT、p-AKT蛋白表达水平逐渐下降。结论 桑白皮总黄酮能够有效抑制乌拉坦诱导的小鼠肺癌发生及血清肿瘤标志物和上皮-间质转化过程,可能与抑制PI3K/AKT信号通路活化有关。

一种基于Bark域能量分布的噪声分类方法

对不同种类噪声的分类处理,可以提高噪声环境下语音信号处理的性能。为了能够准确地区分各类噪声,提出了一种基于Bark域噪声能量分布特性的噪声分类方法。通过将噪声能量从均匀时频空间映射到Bark空间,构造了一个能够有效区分各种噪声的22维特征向量,并使用支持向量机(SVM)进行模型训练和噪声分类。实验结果表明:所提出的噪声分类方法具有非常高的分类准确率,对用于实验的两种噪声数据集的平均分类准确率分别为99.50%和93.44%。

基于Bark域噪声估计及掩蔽效应的语音增强

针对非平稳环境下噪声估计和语音增强性能降低的特点,提出一种基于Bark域的快速自适应噪声谱估计算法。它基于听觉模型,将带噪信号变换到Bark域,并在Bark域内实现基于人耳掩蔽的语音增强。仿真实验表明该算法能充分利用Bark带内频带间的相关性,跟踪快变的背景噪声,提高语音增强性能,减少运算量和复杂度。

连朴泻心汤治疗脾胃湿热型慢性萎缩性胃炎临床研究

目的:观察自拟连朴泻心汤治疗脾胃湿热型慢性萎缩性胃炎的临床疗效。方法:将74例慢性萎缩性胃炎患者按照随机数字表法分为对照组和观察组,每组各37例。对照组予西医常规治疗,观察组在对照组治疗的基础上口服自拟连朴泻心汤。比较两组患者胃镜疗效、幽门螺杆菌(helicobacter pylori, Hp)清除率及治疗前后临床症状评分、临床症状分级情况。结果:对照组有效率为81.08%,观察组有效率为94.59%,两组患者有效率比较,差异具有统计学意义(P<0.05)。两组患者治疗后临床症状积分低于本组治疗前,且观察组低于同期对照组(P<0.05)。对照组Hp阳性12例,转阴3例,清除率为25%;观察组Hp阳性12例,转阴6例,清除率为40%,两组患者Hp清除率比较,差异具有统计学意义(P<0.05)。两组患者治疗后轻度患者例数多于本组治疗前,重度患者少于本组治疗前,且治疗后组间比较,差异具有统计学意义(P<0.05)。结论:自拟连朴泻心汤治疗脾胃湿热型慢性萎缩性胃炎临床疗效确切,可缓解患者胸脘部胀满、胃脘部热痛、口苦、口黏、头身重着、纳呆嘈杂等不适症状,并能修复损伤的胃黏膜。

基于Fisher比的Bark小波包变换的语音特征提取算法

为解决MFCC特征参数在噪声环境中识别率低的问题,提出一种基于Fisher比的Bark小波包变换特征提取算法.首先采用小波包变换构造Bark滤波器代替三角形的Mel滤波器.其次采用Fisher对Bark滤波后的特征参数进行选择,去除大量干扰信息,节省特征匹配的时间.仿真实验表明,该算法明显提高系统的识别率和鲁棒性.

基于听觉掩蔽效应和Bark子波变换的语音增强

提出了一种适用于低信噪比下的提高语音的听觉效果的语音增强方法。该方法在谱减法的基础上有两个特点:首先减参数是根据人耳听觉掩蔽效应提出的且是自适应的;其次采用了与人耳听觉系统特性更为适应的Bark子波变换方法对增强前后的语音进行分析。对该算法进行了客观和主观测试,结果表明:与谱减法相比对低信噪比的语音信号,(1)能更好地抑制残留噪声和背景噪声,(2)增强后的语音具有更好的清晰度和可懂度。

基于BARK子波变换的语音增强方法研究

在Bark子波的构造的基础上,提出一种改进的Bark子波变换构造方法,即直接由临界带中心频率确定Bark子波的中心频率,保证了其通带和临界带的对应一致性,并与人耳的听觉系统十分吻合。采用Bark子波对带噪语音进行分解,在语音信号的子带层次上用一种类似于软阈值的无穷阶可导的函数进行阈值处理,并应用谱减法进行二次增强。仿真实验表明,构建Bark子波与增强算法使信噪比和PESQ得分都有较大提高,特别是在信噪比较高时,语音具有很好的清晰度和可懂度。

桑源药材的化学成分及治疗2型糖尿病的作用机制研究进展

桑叶、桑枝、桑白皮、桑葚等药材源于桑科植物桑Morus alba L,具有良好的生理活性。桑源药材中含有黄酮类、生物碱类、多糖类、酚酸类、Diels-Alder型和香豆素类等多种化学成分,其中黄酮类化合物、多糖或生物碱是其特征性活性成分。桑叶、桑枝、桑白皮、桑葚及其有效成分可能通过抑制α-葡萄糖苷酶的活性、保护胰岛β细胞、改善炎症反应、抗氧化应激、调节线粒体代谢、调节肠道菌群、改善糖尿病并发症等途径达到防治2型糖尿病的作用。本文对桑源药材的化学成分及其在2型糖尿病防治中的应用及作用机制进行了系统综述,以期为桑源药材的开发及临床合理应用提供指导。

基于PLC的橡胶树皮非线性力学性能探测装置设计与试验

为了获取橡胶树皮结构力学特性参数,解决机械化采胶装备研发中采胶深度精准探测和耗皮厚度精准控制技术无可靠依据提供参考的问题,设计一种基于可编程序逻辑控制器(programmable logic controller, PLC)的橡胶树皮非线性力学性能测量的试验装置,实现橡胶树皮力学特性的自动化连续探测和数据采集,以及树皮厚度的高精低损测量。并应用于热研7-33-97和PR107两个品系的15龄、20龄、25龄橡胶树上进行树皮力学性能试验研究,建立刺入过程中刺入力随刺入深度变化的数学模型。结果表明:该装置工作性能稳定,不同品系、不同树龄的树皮刺入力随刺入深度的变化曲线形态相近,均呈高-低-高的趋势变化,并与树皮结构分层特性高度相关;相同树龄下,热研7-33-97和PR107两个品系的刺入力情况差异不明显,同品系的大树龄比小树龄刺入力更大,在1.0 mm针刺下,刺入力最大峰值可达48.5 N。该试验装置满足橡胶树皮结构力学特性参数的探测需求,并为机械化采胶装备的研发提供理论基础。

仝小林应用桑白皮、地骨皮、白鲜皮治疗老年皮肤瘙痒症经验

仝小林院士认为老年皮肤瘙痒症发病往往由于老年阴分不足,郁生内热,煎灼上焦发为肺热,并生温燥扰动皮毛。临床常在滋阴润燥的基础上,加用桑白皮、地骨皮、白鲜皮组成的三皮止痒方清热养阴止痒。方中桑白皮清泻肺热,善治浮风燥痒;地骨皮常与桑白皮同用,滋阴降火解决老年患者阴虚体态,且平肺气、除郁热,使肺热宣泄而皮毛开;白鲜皮清热燥湿、祛风解毒,为治皮肤瘙痒之靶药。三者配伍,态靶结合,既合老年皮肤瘙痒症的病机特点,又能针对性减轻患者瘙痒症状,临床常用剂量均为15~30 g。