支链醇对生物柴油低温性能的影响研究

研究了用大豆油、甲醇和一种支链醇作为原料来制备含有脂肪酸支链醇酯的生物柴油,其中支链醇为异丙醇、异丁醇和仲丁醇中的一种.特别考察了反应时间、温度、催化剂和异丙醇与甲醇物质的量之比等因素对产物中脂肪酸异丙酯(IPE)含量的影响.用异丙醇和甲醇混合制备生物柴油,异丙酯的GC含量可达50%以上,但发现异丙酯的GC含量高于20%时,甘油不易分离.测定了IPE不同含量产物的黏度、冷凝点和冷滤点,发现其黏度比用纯甲酯制得的生物柴油略高,其冷凝点和冷滤点与之相比降低幅度可达5～8℃.     

Histologic Evaluation of Palmar Digital Nerves after Perineural Injection of 2% Ammonium Chloride in Miniature Horses

Neurolytic compounds are widely used by equine practitioners for the management of lameness, mostly related to the foot. The present study aimed to evaluate the neurotoxicity of 2% ammonium chloride (2% AC) applied adjacent to the palmar digital nerves in six miniature horses. The 2% AC and 0.9% saline solution were randomly injected into three and one palmar digital nerve of each horse, respectively. Nerve samples were collected by neurectomy performed under general anesthesia at 5, 12, 19, 35, 47, and 62 days after treatment, with one horse per day of surgery. The inflammatory reaction to perineural injection was evaluated by an increase of pastern superficial skin temperature through thermography 24 hours after treatments. Histological lesions were classified as absent, mild, moderate, and severe Wallerian degeneration. An increase of 2.43 ± 0.79°C and 1.69 ± 0.55°C was observed in the 2% AC and control groups, respectively (P > .05). Moreover, histologic lesions were observed after perineural injection of 2% AC (severe, n = 5/18; moderate, n = 4/18; mild, n = 5/18; and absent, n = 4/18) and saline solution (moderate, n = 3/6; mild, n = 1/6; and absent, n = 2/6) (P = .46). The 2% AC demonstrated to be as safe as 0.9% saline solution, producing mild to severe Wallerian degeneration for up to 62 days after injection with no interference in further neurectomy.     

过渡金属氧化物对木粉/PVC复合材料燃烧性能的影响

用锥形量热仪(CONE)和热重分析法(TGA)研究金属氧化物CuO、La2O<,3>和TiO2对木粉/PVC复合材料(WF-PVC)燃烧性能的影响.结果表明,这3种过渡金属氧化物的加入对WF-PVC均有阻燃作用.其中,CuO使热释放速率(HRR)和总热释放量(THR)降低较多,阻燃效果明显;加入金属氧化物使WF-PVC的烟释放速率(SPR)和总烟释放量(TSP)都有所降低,其中,CuO在有焰燃烧阶段烟释放量最低,抑烟效果最好.这3种氧化物都能增加成炭量.结合热重分析的结果,3种金属氧化物对WF-PVC的热降解影响是不同的.PVC和木粉之间存在相互作用,PVC显著促进了木粉的热降解,木粉的加入推迟了PVC的降解,明显提高了PVC体系的成炭量;WF-PVC的热降解行为,具有更多的PVC降解的特征.     

水基二异氰酸酯交联聚乙烯醇环保新型木材粘合剂

以水基中甲苯二异氰酸酯（TDI）交联改性聚乙烯醇（PVA）的反应原理为理论依据，以交联反应后粘胶体系中游离TDI量的检测结果及其颜色的稳定性，说明在20～35℃的常温和催化剂的作用下，少量TDI关联PVA胶水，可以合成出性能优良的绿色粘合剂，采用正交实验法，探讨在水基中反应物料的组成，交联反应的温度，交联反应进行的时间等因素对TDI交联PVA粘胶体系的环保性能和粘结性能的影响。     

甲醛交联碱木质素-聚乙烯醇-尿素薄膜氮元素缓释性能研究

采用交联法制备了碱木质素-聚乙烯醇-尿素-甲醛(AL-PVA-U-F)交联薄膜,分析碱木质素(AL)和交联剂甲醛(F)的加入量对氮元素缓释的影响,研究薄膜对氮元素的缓释机理,并采用XRD和FT-IR-ATR方法分析薄膜的结晶度和化学结构,结果显示碱木质素的加入可降低薄膜中氮元素的缓释速率,使氮元素达到释放平衡的时间增大,碱木质素和聚乙烯醇质量比5∶5时复合薄膜192 h时达到释放平衡,释放平衡时间最长,氮元素累积释放率最大为77.73%。加入适量的甲醛交联剂使碱木质素、聚乙烯醇、尿素、甲醛之间发生化学反应,线性和网状结构交互从而使薄膜中氮元素缓释减慢。与共混薄膜(ALPVA-U)相比,甲醛的交联作用使薄膜的结晶度降低。薄膜的氮元素累积释放率曲线呈"S"型趋势,Ritger-Peppas模型和2次多项式模型拟合较好,相关系数(R2)分别为0.976 3和0.950 9,Ritger-Peppas模型中n为0.816 7,说明氮元素释放规律是扩散和溶蚀综合作用的结果。     

长链燃料醇生物合成研究进展

简单介绍了长链醇作为液体燃料的优良性能,综述了长链醇生物合成的3条主要途径(Ehrlich途径、非发酵途径和光合途径),并进一步从宿主菌株选择、耐受菌株选育、代谢通路疏通以及产醇工艺优化等方面概述了提高长链醇产量的方法,最后对长链醇未来的研发方向进行了展望。     

有机改性硅藻土对聚乙酸乙烯酯乳液吸附性能及其动力学的研究

以木质素阳离子表面活性剂为改性剂制备有机改性硅藻土,并研究其对溶解和胶体性物质(DCS)模型物聚乙酸乙烯酯(PVAc)的吸附效果。主要探讨了PVAc质量浓度、吸附时间、吸附温度对吸附效果的影响,并在此基础上进一步推算得到了吸附过程的动力学和热力学参数:动力学模型相关系数R2均高于0.99;热力学参数ΔS=-61.39 J/mol,ΔH=-12.03 KJ/mol。实验发现,有机改性硅藻土对PVAc有良好的吸附效果,符合Langmuir吸附模型,升高温度可以增强PVAc在有机硅藻土上的吸附性能,对吸附过程的进行有促进作用;该吸附过程符合伪二阶动力学模型,属于物理吸附过程。     

Study on the hypoglycemic activities and metabolism of alcohol extract of Alismatis Rhizoma

The Alisma rhizoma is widely used in the therapy of diabetes in traditional folk medicine of China. Compositional analysis of the alcohol extract of Alismatis Rhizoma (AEA) revealed that the eight compounds gotten from AEA are all belonging to protostane-type triterpenes. The AEA and compounds were incubated with 3T3-L1 preadipocytes, glucose level in the 3T3-L1 adipocytes culture medium and lipid content in 3T3-L1 adipocytes were measured, and analysis of alpha-glucosidase inhibition of AEA and compounds. At the same time, the uptake of AEA by 3T3-L1 adipocytes and the metabolism of AEA in SD rats were analyzed by HPLC-ESI/MS. As result, AEA increased glucose uptake in 3T3-L1 adipocyte model, not increase adipogenesis; AEA inhibited alpha-glucosidase activity; alisol A-24-aceate (8) was absorbed by 3T3-L1 adipocytes; and two compounds were detected in blood and three were detected in urine in SD rats. So AEA had protostane-type triterpenes, these type compounds in AEA may have hypoglycemic activity via inhibition of alpha-glucosidase activity and promotion of glucose uptake. In contrast to the anti-diabetic drug thiazolidinediones, they did not induce adipogenesis, avoiding the displeased effects of rosiglitazone.     

Biosynthesis of a syringyl 8-O-4′ neolignan in Eucommia ulmoides: formation of syringylglycerol-8-O-4′-(sinapyl alcohol) ether from sinapyl alcohol

To investigate the biosynthesis and stereochemistry of syringylglycerol-8-O-4′-(sinapyl alcohol) ether (SGSE), a syringyl 8-O-4′ neolignan, feeding experiments and enzyme assays using Eucommia ulmoides were carried out. Diastereoselective formation of erythro-SGSE was found. When [8-¹⁴C]sinapyl alcohol was administered to excised shoots of E. ulmoides, ¹⁴C was incorporated into free SGSE and SGSE glucosides. In stems, incorporation into (+)-erythro-[¹⁴C]SGSE (0.037%) with 9.1% enantiomeric excess (% e.e.) was found; incorporation into the threo isomer was not detectable. Erythro-[¹⁴C]SGSE glucosides (0.047%) dominated over threo forms (0.007%) with 74.0% diastereomeric excess (% d.e.); both diastereomers were levorotatory with 32.0% e.e. and 18.3% e.e., respectively. In leaves, higher incorporation into (−)-erythro-[¹⁴C]SGSE (0.500%, 15.9% e.e.) than into the threo isomer (0.206%, 7.4% e.e.) was observed (41.6% d.e.). (−)-Erythro-[¹⁴C]SGSE glucosides (1.692%, 25.0% e.e.) were produced at higher rates than threo isomers (0.177%, 16.4% e.e.) with 81.0% d.e. In incubations of a mixture of [8-¹⁴C]sinapyl and [8-¹⁴C]coniferyl alcohols with an insoluble enzyme preparation from stems of E. ulmoides, erythro-SGSE was preferentially produced. The highest % d.e. (82.8) was observed at 60 min with the (+)-erythro isomer (21.4% e.e.) and the (−)-threo form (4.3% e.e.).Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002, and the 47th Lignin Symposium, Fukuoka, October 2002