Optimization and Characterization of Combined Degumming Process of Typha angustata L. Stem Fibers

Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to study their physical,chemical,and mechanical properties.In this context,the present study relates to the extraction,characterization,and optimization of Typha angustata L.stem fibers.For this purpose,desirability functions and response surface methodology were applied to simultaneously optimize the diameter(D),linear density(LD);yield(Y),lignin fraction(L),and tenacity(T)of Typha stem fibers.Typha stems have been subjected to both alkali(NaOH)and enzymatic(pectinex ultra-SPL)treatments.Three levels of process variables including enzyme concentration(10,15,and 20 ml/L)and treatment duration(10,15,and 20 days)were used to design the experiments according to the factorial design.Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis.The Derringer’s desirability function released that the values of process variables generating optimized diameter,linear density,yield,lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration,respectively.Confirmation was performed and high degree of correlation was found between the experimental and statistical values.Moreover,the morphological structure has been investigated by the scanning electron microscope,showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber.Compared to Typha stem non-treated fibers(TSNTF),Typha stem combined treated fibers(TSCTF),brings to improve mechanical properties.This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of(66.86%)and lignin ratio of(10.83%)with a crystallinity index of(58.47%).

Physico-Chemical and Thermal Characterization of a Lignocellulosic Fiber, Extracted from the Bast of <i>Cola lepidota</i>Stem

In this research work, fiber extracted from the bark of Cola lepidota (CL) plant, grown in the flora of Southern part of Cameroon, was investigated for composites reinforcement. The investigation was carried via evaluation of water absorption capacity, moisture content, real density, porosity, chemical composition, chemical structure and thermal behaviour. It was discovered that the new fiber has relatively low moisture content and water absorption capacity similar to those of other investigated natural fibers such as flax, sisal, coconut, hemp and jute. Its porosity was found appropriate for composite production and the fiber was found to be thermally stable up to 230°C, with maximum degradation temperature of 325°C. The main constituents of the fibre include cellulose, hemicellulose and lignin. In conclusion, based on the properties investigated, this fiber is considered suitable for composite manufacture.

莲杆纤维多孔碳的制备及其CO_(2)吸附性能

由于大气中CO_(2)浓度不断上升,迫切需要高效的CO_(2)吸附剂。以废弃生物质莲杆纤维为原料,通过两步碳化法制备了具有发达孔隙结构的氮掺杂多孔碳样品。合成过程包括莲杆纤维碳化、KOH活化衍生莲杆纤维多孔碳及使用壳聚糖进行改性。通过壳聚糖改性,提高多孔碳表面碱度和氮元素掺杂,增加对CO_(2)的吸附性能。结果表明,掺氮多孔碳比表面积达到1550 m^(2)/g,在20℃和0℃、1bar条件下,吸附量分别高达4.59 mmol/g和6.31 mmol/g,表现出优异的CO_(2)吸附性能,且循环性能优异,该法制备的多孔碳在CO_(2)吸附方面具有广阔前景。

不同外加纤维对烟草复合滤嘴棒用纸性能的影响

为了提高烟草复合滤嘴棒用纸的性能指标,采用6种外加纤维(漂白针叶木浆、漂白竹浆、马尼拉麻浆、棉浆、绒毛浆和未漂针叶木浆)对烟梗浆进行替代。由于外加纤维具有不同的纤维特性,所以分别研究外加纤维的打浆度和替代比对烟草复合滤嘴棒用纸物理指标的影响。研究结果表明:随着外加浆料替代比的增加,烟草复合滤嘴棒用纸的强度和伸长率均有所提升,其中马尼拉麻浆替代的烟草复合滤嘴棒用纸的性能优于其他5种外加纤维。当马尼拉麻浆的打浆度为50°SR、马尼拉麻浆替代比为90%时,烟草复合滤嘴棒用纸的抗张指数为76.3 N·m/g,伸长率为3.10%。因此,本研究为烟草复合滤嘴棒用纸的开发奠定了理论基础。

芦笋老茎可溶性膳食纤维提取及结构表征和功能性研究

为研究芦笋老茎可溶性膳食纤维(SDF)的结构表征和功能性,将芦笋老茎经纤维素酶酶解处理后,以酶法(淀粉酶、糖化酶)提取SDF,采用单因素及响应面分析法优化提取工艺,并对SDF的微观结构、功能性进行研究。结果表明,经纤维素酶酶解后的芦笋老茎SDF最佳提取工艺为:淀粉酶添加量0.5%、糖化酶添加量0.20%、酶解时间2h、酶解温度65℃,在此提取条件下酶解SDF(Ms)与未酶解SDF(Ws)经红外光谱扫描后均具有典型的多糖特征。电镜扫描表明,Ms结构相较于Ws具有更大表面积且呈蜂窝状。Ms与Ws相较,持水性提高1.2倍,持油性提高1.55倍,热稳定性较强。本研究结果为芦笋老茎可溶性膳食纤维的再利用提供了相应理论依据。

高聚物的STEM象观察

将分析电子显微镜的扫描透射电子象模式(STEM)应用于两种高分子物的研究。以 ABS/PVC高分子合金和角蛋白纤维为试验材料,叙述了样品制备过程和电镜观察的结果。实验证明,STEM具有对试样穿透能力强和电子束损伤小的特点,特别适用于高聚物材料。在高放大倍数下的观察,能获得直接透射象(TEM)难以观察到的某些微结构情景。

Transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury:A Web of Science-based literature analysis

OBJECTIVE： To identify global research trends in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. DATA RETRIEVAL： We performed a bibliometric analysis of studies on transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury published from 2002 to 2011 and retrieved from the Web of Science, using the key words spinal cord injury along with either neural stem cell, Schwann cell or olfactory ensheathing cell. SELECTION CRITERIA： Inclusion criteria： （a） peer-reviewed published articles on neural stem cells, Schwann cells or olfactory ensheathing cells for spinal cord injury indexed in the Web of Science; （b） original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial materials and news items; and （c） published between 2002 and 2011. Exclusion criteria： （a） articles that required manual searching or telephone access; （b） documents that were not published in the public domain; and （c） corrected papers. MAIN OUTCOME MEASURES： （1）Annual publication output, distribution by journal, distribution by institution and top-cited articles on neural stem cells; （2） annual publication output, distribution by journal, distribution by institution and top-cited articles on Schwann cells; （3） annual publication output, distribution by journal, distribution by institution and top-cited articles on olfactory ensheathing cells. RESULTS： This analysis, based on articles indexed in the Web of Science, identified several research trends among studies published over the past 10 years in transplantation of neural stem cells, Schwann cells and olfactory ensheathing cells for spinal cord injury. The number of publications increased over the 10-year period examined. Most papers appeared in journals with a focus on neurology, such as Journal of Neurotrauma, Experimental Neurology and Gila. Research institutes publishing on the use of neural stem cells to repair spinal cord injury were mostly in the USA and Canada. Those publishing on the use of Schwann cells were mostly in the USA and Canada as well. Those publishing on the use of olfactory ensheathing cells were mostly in the UK, the USA and Canada. CONCLUSION： On the basis of the large number of studies around the world, cell transplantation has proven to be the most promising therapeutic approach for spinal cord injury.

Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 （Schwann cell marker） and glial fibrillary acidic protein （glial cell marker） at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvi- ronment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.

香蕉梗纤维的提取及其纤维毡抗菌性能研究

香蕉梗纤维的提取及利用报道较少。本文通过NaOH/Na_(2)CO_(3)、NaOH/尿素、过碳酸钠/尿素三种脱胶方法,以不同的比例提取香蕉梗纤维并研究纤维性能特点及其纤维毡抗菌特性。结果表明:提取的香蕉梗纤维线密度范围为71.59 dtex-150.41 dtex、纤维平均长度为2.59±0.12 cm。扫描电镜和3D超景深显微镜结果显示,得到的纤维表面为沟壑状结构,随着脱胶体系浓度增加,纤维线密度呈减小趋势。FTIR和XRD结果显示,脱胶后香蕉纤维中半纤维素和木质素含量减少,纤维素含量增加。进一步通过湿法成网、加固等工艺,得到香蕉梗纤维非织造毡。抗菌测试结果表明:香蕉梗纤维非织造毡对金黄色葡萄球菌和大肠杆菌的抑菌率分别为20.00%、57.52%。本实验为香蕉梗纤维提取及其在复合材料、装饰纺织品等领域应用奠定基础。同时,也可为其他生物质纤维提取和再生利用提供借鉴意义。

玻纤增强塑料成型参数优化及阀杆性能研究

选择模压压力、保温时间、成型温度3因素进行正交试验,以成型材料拉伸性能为指标,对乙烯基玻纤增强塑料成型参数进行优化。参数优化后得到材料成型的杨氏模量为10 GPa,泊松比为0.3。对玻纤增强塑料阀杆扭转性能进行有限元仿真,研究预埋件结构参数对阀杆扭转性能的影响。研究结果表明:对玻纤增强塑料拉伸强度影响因素的主次顺序为:模压压力>保温时间>成型温度,模压成型参数的最佳水平组合为:成型温度160℃、模压压力20 MPa、保温时间20 min,成型后材料拉伸强度为146.268 MPa,增加6%。当预埋件顶部高度为8 mm、预埋件深度为47 mm、预埋件底部形式为椭圆形时阀杆具有最佳抗扭性能,阀杆所能承受最大扭矩为160.62 N·m,杆体最大变形为0.192 mm,较无预埋件乙烯基玻纤增强塑料阀杆最大扭矩增加51%,最大形变量减小62%。

高水溶性膳食纤维香菇柄制备工艺及品质特性

为得到高水溶性膳食纤维香菇柄,以干香菇柄为原料,采用碾压超声辅助固态酶解工艺,应用Plackett-Burman设计试验、最陡爬坡试验联合Box-Behnken试验进行工艺优化,并与未经处理的香菇柄进行品质特性比较评价。结果表明,碾压超声辅助固态酶解制备高水溶性膳食纤维香菇柄的最佳工艺条件为超声波功率240 W、超声温度60℃、超声时间16 min、碾压间隙3.5 mm、半纤维素酶与纤维素酶的质量比1∶2、酶添加量0.32%、酶解温度65℃、酶解时间400 min。该工艺制备的香菇柄中水溶性膳食纤维含量为5.17%。与未经处理的香菇柄相比,其全质构指标咀嚼性、硬度、弹性、内聚性均显著降低,粘附性增加11.36%但无显著差异;其膨胀力、持水力显著提高,持油力增加6.61%但差异不显著;其胆固醇吸附能力、胆酸钠吸附能力、亚硝酸钠(模拟胃酸环境)吸附能力均显著提升。

玉米茎秆营养品质性状全基因组关联分析及候选基因筛选

【目的】从分子水平对玉米茎秆主要营养品质性状进行遗传解析,为玉米茎秆主要营养品质性状的遗传改良提供理论依据。【方法】以381份不同类型玉米自交系作为关联群体,2016年、2017年在河南省鹤壁市农业科学院试验园区进行随机区组种植,于玉米抽雄期、灌浆期和成熟期调查茎秆营养品质性状酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)和消化率(IVDMD)。利用Maize SNP50基因芯片获得高质量的461053个SNP用于全基因组关联分析。【结果】利用广义线性模型(GLM)分析,在玉米10条染色体上两年共检测出不同生育时期茎秆营养品质性状392个显著相关的SNP(P<1.08×10^(-7)),表型变异解释率为9.69%~17.34%,发现2次以上独立关联到的SNP有97个,共获得77个与茎秆营养品质性状关联的候选基因;利用混合线性模型(MLM)分析,两年共检测出257个显著相关的SNP(P<2.17×10^(-6)),表型变异解释率为9.82%~20.20%,发现2次以上独立关联到的SNP有17个,共获得82个候选基因,与GLM模型候选基因重合的有10个。GLM和MLM两种模型共鉴定出159个候选关联基因,有43个候选基因被2次以上重复检测到;其中,Zm00001d021261在多个位点发现31次与不同年份ADF、NDF和IVDMD相关联,该基因编码产物为ATP结合蛋白和叶绿体传感器激酶,在成熟期叶片中表达量最高;Zm00001d021255在两个位点发现10次与茎秆营养品质性状相关联,该基因编码产物为富半胱氨酸受体样蛋白激酶25,只在发育节间和雌穗中表达,可进一步深入研究验证。【结论】采用GLM和MLM两种模型可以快速、有效地关联到玉米茎秆营养品质相关性状显著性位点,通过重复性显著位点筛选出HC-SNP,进而挖掘出关联基因富集区域。

酶解对芦笋老茎中可溶性膳食纤维与抗氧化活性的影响

芦笋采摘加工过程中产生的大量废弃老茎,其中含有丰富的膳食纤维及活性物质,具有一定的抗氧化作用。以富含膳食纤维的芦笋老茎为原料,通过纤维素酶酶解提高其可溶性膳食纤维的含量,继而提升其抗氧化活性。通过测定酶解前后芦笋老茎液的抗氧化活性及可溶性膳食纤维含量,以单因素及正交优化试验对酶解时间、酶添加量、酶解温度进行研究,确定最佳酶解条件。结果显示:在纤维素酶添加量为1.0%、酶解时间1.75 h、酶解温度50℃的条件下,与非酶解相比,酶解后芦笋老茎的可溶性膳食纤维含量提高2.9倍,羟自由基清除能力提高1.69倍,活性物质多糖、黄酮及皂苷含量分别提高1.39、1.56和1.84倍。本研究可为芦笋老茎的再利用提供一定的理论依据。

打浆对烟梗纤维成纸性能的影响

采用造纸法对烟梗制烟草薄片纸基进行了实验研究,探讨了浸渍对烟梗中几种化学组分含量变化的影响,研究了打浆对烟梗纤维形态和纸浆物理性能的影响。结果表明,浸渍提取之后烟梗中水溶性糖、总植物碱、氯和总氮含量都有不同程度的下降,综纤维素质量分数相对提高了12.4%。烟梗浆打浆度从10度增加到48度,烟梗浆的纤维长度从1.62 mm下降至0.36 mm,细小纤维从6.90%上升到37.17%;抗张指数先由13.39 N.m/g上升到33.20 N.m/g后再下降到30.94 N.m/g,撕裂指数从1.54 mN.m2/g下降至0.88 mN.m2/g,松厚度从2.08 cm3/g下降到1.43 cm3/g,透气度从59.58μm/(Pa.s)下降到0.03μm/(Pa.s),耐破指数从0.88 kPa.m2/g上升至1.63 kPa.m2/g。

木薯茎秆纤维形态和化学成分的初步研究

木薯作为一种新型的生物质能源作物,近年来在中国特别是广西发展迅速。其种植和加工过程中产生的大量废弃物(如木薯渣、木薯茎秆)已成为制约木薯产业发展面临的重要问题。文章对木薯茎秆的纤维形态和化学成分进行了初步研究,旨在探索木薯茎秆增值利用的新途径。结果表明:3种木薯茎秆的纤维长度和宽度种间差异性显著,种A、种B、种C的平均纤维长度与宽度分别为976、920、815μm与34、32、36μm。3种木薯茎秆的总平均纤维长度为904μm,宽度为34μm,双壁厚为7.32μm,长宽比为27,壁腔比为0.27。种A木薯茎秆的纤维素含量为41.49%,木质素含量为21.44%,灰分含量为3.46%,苯醇抽出物含量为6.96%,1%Na OH抽出物含量为22.22%,冷水抽提物为11.89%,热水抽提物为14.15%。综合分析表明:木薯茎秆纤维属于中短长度类纤维原料,长宽比小,壁薄,纤维素含量高,可作为纤维板及造纸原料,但需要与其他长纤维原料搭配使用。

超微粉碎对香菇柄功能成分和特性的影响

研究超微粉碎对香菇柄中多糖溶出率、膳食纤维含量和物理特性的影响。结果表明:经超微粉碎之后,香菇柄粉平均粒径降至8.05μm,多糖溶出率提升了1倍多,总膳食纤维含量由43.23%提高到48.91%,可溶性膳食纤维含量由5.66%提高到15.64%,持水力、持油力和膨胀力分别提高了37%、46%和109%。超微粉碎技术大幅提升了香菇柄中活性多糖的利用率,显著改善了其膳食纤维的功能特性,是香菇柄深度开发利用的一条可行途径。

五种菌对香蕉茎秆纤维素降解能力比较及菌群构建

香蕉茎杆的粗纤维含量较高,一直以来却未得到较好的利用。由于纤维素在环境中难以自然降解,随着香蕉种植面积的增大,其对环境的影响也日益增大。通过微生物对香蕉茎秆进行降解,可以实现香蕉杆的资源化和无害化利用。该研究通过CMC酶活、FPA酶活及粗纤维降解率三个指标综合评定了五种高效纤维素降解菌纯培养及组合培养时对香蕉茎秆的降解能力。结果表明:单独培养时,效果较好的菌种为无花果曲霉和康宁木霉,其CMC酶活、FPA酶活、粗纤维降解率分别为699.8 U/mL、30.48 U/mL、22.39%和332.02 U/mL、59.20 U/mL、20.89%。此外,通过菌群构建,得到一个效果较好的组合(康宁木霉和无花果曲霉组合)。该组合的三种指标测定值分别为:947.41 U/mL、115.27 U/mL和29.08%。

超声波提取香蕉茎干中水溶性膳食纤维的研究

探讨了以香蕉茎干为原料,用超声波提取水溶性膳食纤维的工艺及其操作条件,并与直接水提法进行比较。结果表明,超声波法最佳工艺条件为:提取时间20min、提取功率600W、液料比为3mL/g、pH为4;SDF干基产率达到9.90%;超声波法工艺明显优于直接水提法。

香蕉假茎纤维造纸技术的研究

[目的]对香蕉假茎纤维造纸技术进行研究。[方法]分别对纸质、出纸率、成本、原料基地投资进行分析。[结果]从香蕉假茎中提取的纤维制成的纸张不含酸性物质,很耐用,韧度是一般纸张的30倍,能防火、吸油却不透水;与其他植物纤维相比,香蕉假茎纤维虽然纤维素含量中等,但综合成本、环境各方面的因素,香蕉假茎纤维造纸技术具有一定优势。[结论]香蕉假茎作为造纸原料,具有很大的开发价值和应用前景。

香蕉茎杆纤维提取加工设备的结构改进

通过改进切割破片机的关键部件切割刀具结构和采用不切割茎杆芯部的工艺方案等,使设备功耗和切割阻力大大减少,解决了茎杆撕裂、折断和腐烂茎杆加工问题,大大提高了适应性;通过增加排渣槽上方侧板、刀轮罩内表面横板,增大刀轮罩与刀轮的间隙和增设刀轮罩两端消声孔等改进设计,使刮麻机喂料口风速降低约90.8%,空载噪声降低约6 dB(A),大大减少了茎杆渣飞溅现象,改善了喂料和工作条件,提高了加工效率。