Synthesis and characterization of cellulose acetate with high degree of substitution from miscanthus

以芒草为原料,用Na OH/H_2O_2溶液体系预处理制备芒草纤维,在冰醋酸环境下,以浓硫酸为催化剂与醋酸酐酯化制备芒草醋酸纤维素。优化了预处理条件:温度、时间、次数和酯化条件:催化剂量、温度、时间、醋酸酐量,最佳条件下制备出的芒草纤维的纤维素、半纤维素和木质素的质量分数分别为75.3%、17.3%、5.1%,制备出芒草醋酸纤维素的取代度DS=2.8,特性黏度[η]=1.24 d L/g,达到美国联邦贸易委员会指南认定的三醋酸纤维素标准。利用扫描电镜(SEM)和热分析(TG、DSC)对制得样品进行表征。结果表明,可以利用Na OH/H_2O_2水溶液体系预处理芒草原料制备芒草纤维,并进一步酯化制备出高取代度的醋酸纤维素。A procedure for synthesizing cellulose acetate with high degree of substitution from miscanthus biomass is developed. The miscanthus fiber is prepared by pretreatment of miscanthus biomass with Na OH / H_2O_2,which is then reacted with acetic anhydride in an acetic acid solvent to synthesize cellulose acetate by using concentrated sulfuric acid as catalyst. The effects of the pretreatment factors( such as pretreatment temperature,time and number of times) and the esterification factors( such as catalyst volume,reaction temperature,reaction time and acetic anhydride volume) are studied. Under the optimal conditions,the contents of cellulose,hemicellulose and lignin for prepared miscanthus fiber are75. 3%,17. 3% and 5. 1%,respectively. The degree of substitution( DS) and the intrinsic viscosity( [η ]) of the obtained miscanthus cellulose acetate are 2. 8 and 1. 24 d L / g,respectively. The miscanthus biomass,fiber and cellulose acetate are characterized by SEM,TG and DSC. This study shows that cellulose acetate with high degree of substitution can be prepared from miscanthus biomass pretreated with Na OH / H_2O_2.国家自然科学基金(21303142;31170067);; 福建省中青年教师教育科研项目(JA14010);; 厦门市海洋经济发展专项资金项目(14GZP59HJ29);; 福建省海洋高新产业发展专项项目(闽海洋高新[2014]25号);; 厦门大学校长基金(20720150090

Experimental effects study of total flavonoids of Ajuga on nuclear transcriptional factor of kappa B in mesangial proliferative glomerulonephritis rats

目的探讨筋骨草总黄酮(TfA)治疗系膜增生性肾小球肾炎(MSPgn)大鼠后核转录因子-κb(nf-κb)及下游转化生长因子-β1(Tgf-β1)的变化。方法采用改良慢性血清病MSPgn大鼠模型,于造模第5周末检测尿蛋白,将尿蛋白阳性者随机分为模型组、雷公藤多甙(TWP)组、不同剂量TfA组。于造模第6周开始给药,6周后,测定各组大鼠的24 H尿蛋白定量、血生化和肾组织病理变化,MAXVISIOnTM即用型快速免疫组化一步法检测大鼠肾组织中nf-κb P65的表达,双抗体夹心法检测血清中Tgf-β1的变化。结果 TfA可显著降低尿蛋白,明显减小系膜区面积占毛细血管丛面积的百分比(P0.05)。模型对照组大鼠肾组织nf-κb P65、血清Tgf-β1的表达明显高于正常对照组[nf-κb P65:28.93±4.45 VS.4.51±0.96,P0.05).The renal tissue NF-κB(Integral optical density, IOD) and serum TGF-β1(pg/ml) in model control was significantly higher than that in normal control group, NF-κB p65 28.93±4.45 vs.4.51±0.96, P<0.01; TGF-β1:(247.63±51.55)pg/ml vs.(127.52±27.84)pg/ml, P<0.01; With the intervention trerapy of high-dosage TFA, middle-dosage TFA and TWP, the expression of NF-κB in renal tissue and TGF-β1 in serum was significantly decreased compared with model control group, NF-κB p65: 10.35±2.81, 15.21±4.71,11.70±3.97, P<0.01; TGF-β1:(181.96±52.93)pg/ml,(204.33±38.30)pg/ml,(188.07±42.92)pg/ml, P<0.05.Conclusion Reducing the expression of NF-κB and successive TGF-β1 may be one of the mechanisms of total flavonoids of Ajuga treatment on MsPGN rats.福建省卫生厅中医药科研重点课题(wzzsb0906); 陈可冀中西医结合发展基金·福建省中西医结合老年性疾病重点实验室开放课题资助项目(CKJ2008088); 福建中医药大学校管课题(X2009069

Experimental Effects Study of Total Flavonoids of Ajuga on Interleukin-1 and Tumor Necrosis Factor-α in Mesangial Proliferative Glomerulonephritis Rats

目的:探讨筋骨草总黄酮对系膜增生性肾小球肾炎(MSPgn)大鼠的干预作用机制。方法:采用改良慢性血清病MSPgn大鼠模型,于造模第5W末检测尿蛋白,将尿蛋白阳性者随机分为模型组、雷公藤多甙(TWP)组、不同剂量筋骨草总黄酮(TfA)组,另设正常对照组。于造模第6W起开始给药,6W后,测定各组大鼠的24 H尿蛋白定量、血生化和肾组织病理变化,放射免疫分析法观察TfA对MSPgn模型大鼠血清中白细胞介素-1(Il-1)、肿瘤坏死因子-α(Tnf-α)的影响。结果:TfA可显著降低尿蛋白,明显减小系膜区面积占毛细血管丛面积的百分比、减轻肾脏损害(P0.05)。模型对照组大鼠血清中Il-1(ng.Ml-1)、Tnf-α(ng.Ml-1)的表达明显高于正常对照组(Il-1 0.829±0.251 VS0.238±0.081,P0.05)。结论:筋骨草总黄酮对MSPgn大鼠有较好的治疗作用,降低Il-1和Tnf-α的水平,可能是其治疗作用机制之一。Objective:To investigate the effects of total flavonoids of Ajuga(TFA) in mesangial proliferative glomerulonephritis(MsPGN) rats and its mechanism.Methods:MsPGN rat was induced by the improved chronic serum sickness model after five weeks.The rats with positive urinary protein rats were randomly divided into model group,triptergium wilfordii polyglycosidium(TWP) group and TFA group with different dosage,normal rats wasere considered as the control group.MsPGN rats were treated with drugs since the sixth week;six weeks after succussfully modelingeeding six weeks later,all rats were detected 24 h urinary protein,and blood biochemistry,pathomorphological change in renal tissue,serum Interleukin-1(IL-1) and tumor necrosis factor-α(TNF-α) wasere measured by radioimmunoassay.Results:Compared with model group,TFA can significantly reduce the urinary protein,decrease BUN,Scr,TG,Tch,mitigate the morphological damage,and significantly increase TP(P0.05).The serum levels of IL-1 and TNF-α(ng·mL-1) in model control wasere significantly higher than that in normal control group;.With the intervention trherapy of high-dosage TFA,middle-dosage TFA and TWP,the expressions of serum IL-1 and TNF-α wasere significantly decreased compared with model control group(.The expressions of IL-1 and TNF-α in high-dosage TFA,and middle-dosage TFA groups wasere slightly higher than those in TWP group,with no significant differences(P>0.05).Conclusion:Total flavonoids of Ajuga has a therapeutic effect on MsPGN rats;Rreducing the expressions of serum IL-1 and TNF-α,which may be one of the mechanisms of MsPGN treatment.福建省卫生厅中医药科研重点课题资助项目(wzzsb0906); 陈可冀中西医结合发展基金·福建省中西医结合老年性疾病重点实验室开放课题资助项目(CKJ2008088); 福建中医药大学校管课题资助项目(X2009069

Damage to mangroves from extreme cold in early 2008 in southern China

通讯作者Author for correspondence (E-mail: [email protected])2008年初,我国南方19个省经历了50年一遇的持续低温雨雪冰冻天气。极端气候对华南沿海各省的红树林区造成不同程度的危害。2008年3月,在我国南方各省红树林区的10个代表性地点,对这次寒害造成的红树植物伤害程度进行了系统的调查。结果表明:冬季低温对红树林的影响极为显著,特别是在低纬度的海南、广西和广东湛江,由于极端低温正值夜间退潮,对红树林的影响更为显著;在纬度较高的福建,本地红树种类秋茄(Kandelia obovata)、桐花树(Aegiceras corniculatum)和白骨壤(Avicennia marina)及引种的木榄(Bruguiera gymnorrhiza)等,由于长期适应于冬季较低的气温或在种植前经过抗寒锻炼,具有较强的抗寒能力。各地主要红树植物中,广布种秋茄、桐花树和白骨壤最为耐寒,其耐寒性均大于红树科的木榄、海莲(Bruguiera sexangula)和红海榄(Rhizophora stylosa)。海桑(Sonneratia caseolaris)对温度的敏感性最强,抗寒能力最低,因此,即使在其原产地海南也受到较为严重的寒害,在纬度更高的引种地出现大面积受害甚至全部死亡,而从孟加拉国引种的无瓣海桑(Sonneratia apetala)却显示出一定的抗寒能力。同一地点的红树植物幼苗的抗寒能力低于大树。此次寒害也造成了苗圃场的种苗大量死亡,成熟的植株提前落花落果,这势必会影响后继一两年内红树林的自然更新和人工造林。因此,在未来红树林造林或人工引种中,一定要考虑到红树植物的抗寒能力。国家自然科学基金(30671646和30700092);厦门大学“闽江学者”启动基

Research Progress of Acetyl Xylan Esterase

半纤维素是一类丰富可再生而又亟待开发利用的生物质资源,将半纤维素降解为糖类进而生产木糖醇及其它化学品是利用生物质资源的关键一步。乙酰木聚糖酯酶是降解半纤维素的一个重要酶,它能够水解乙酰化木聚糖中的木糖残基上的2位和3位的O乙酰基,在工业、农业及食品业具有广阔的应用前景。综述了乙酰木聚糖酯酶的分类、酶学性质、催化机制、基因克隆和协同酶解等方面的研究进展,同时对该研究进行了展望。Hemicellulose is an abundant and renewable plant biomass yet untapped utilization. The bioconversion of hemicellulose to sugars is essential in the production of xylitol and other chemicals. Acetyl xylan esterase is the key enzyme in hydrolyzing hemicellulose,which can deacetylate on the O-2 and O-3 positions of xylopyranosyl residue. It has broad application prospect in agriculture and industry. The recent research progresses on catalysis mechanism,structure,characterization,gene cloning and synergetic hydrolysis of acetyl xylan esterase were addressed.国家自然科学基金(21303142);; 厦门南方海洋研究中心海洋经济发展专项资金项目(14GZP59HJ29);; 福建省海洋高新产业发展专项(闽海洋高新[2014]25号)资助项

Analysis of the Present conditions of Xiamen Community Sports for the Old and the Ideas of Its Development

当厦门正在加快海湾型城市建设,全面建设小康社会之际,有必要对厦门市社区老年体育活动的发展现状和存在问题进行探讨与分析。并针对新时期我市老年体育事业发展面临机遇与挑战同时,提出厦门市社区老年体育发展的应对策略,进而促使厦门市社区老年体育活动在新的形势下继续保持健康的发展态势。When the bay city Xiamen is speeding up its construction and moving towards a better-off society, it is needed to have an exploration and analysis of the status quo and existing problems of community sports for elders in Xiamen whose development is faced with both chances and challenges. The paper raises some measures for the sound and further development of community sports for elders in Xiamen under the new situations.2003年度集美大学科研基金重点课

实测端元光谱和多光谱图像之间的模拟与细分

地物光谱特性是遥感应用的基础。本文以渭干河－库车河三角洲绿洲为研究区，首先选取裸土、植被两类地物作为研究对象，通过TM 传感器的光谱响应函数，实现了将野外实测端元光谱拟合为多光谱离散光谱。其次在对TM 图像的光谱波段进行细分的基础上，利用光谱知识库的数据支持来模拟获取具有更高光谱分辨率的细分光谱光学遥感图像，深入开展两种尺度相互转换的研究。结果表明：一、拟和的多光谱与TM 像元光谱具有很好的相关性，在此基础上，采用线性算法建立端元光谱与遥感图像像元光谱的转换模型，实现了从实测端元光谱尺度向遥感多光谱像元尺度的定量光谱转换，为遥感定量分析奠定了一定基础。二、细分光谱模拟图像的方法能够较为可靠的模拟出真实高光谱分辨率图像的信息，模拟方法可信，达到了推广和验证的效果