Chitosan-Based Anti-Oxidation Delivery Nano-Platform: Applications in the Encapsulation of DHA-Enriched Fish Oil

Refined cobia liver oil is a nutritional supplement (CBLO) that is rich in polyunsaturated fatty acids (PUFAs), such as DHA and EPA; however, PUFAs are prone to oxidation. In this study, the fabrication of chitosan-TPP-encapsulated CBLO nanoparticles (CS@CBLO NPs) was achieved by a two-step method, including emulsification and the ionic gelation of chitosan with sodium tripolyphosphate (TPP). The obtained nanoparticles were inspected by dynamic light scattering (DLS) and showed a positively charged surface with a z-average diameter of between 174 and 456 nm. Thermogravimetric analysis (TGA) results showed the three-stage weight loss trends contributing to the water evaporation, chitosan decomposition, and CBLO decomposition. The loading capacity (LC) and encapsulation efficiency (EE) of the CBLO loading in CS@CBLO NPs were 17.77–33.43% and 25.93–50.27%, respectively. The successful encapsulation of CBLO in CS@CBLO NPs was also confirmed by the Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. The oxidative stability of CBLO and CS@CBLO NPs was monitored by FTIR. As compared to CBLO, CS@CBLO NPs showed less oxidation with a lower generation of hydroperoxides and secondary oxidation products after four weeks of storage. CS@CBLO NPs are composed of two ingredients that are beneficial for health, chitosan and fish oil in a nano powdered fish oil form, with an excellent oxidative stability that will enhance its usage in the functional food and pharmaceutical industries.     

Dynamic modeling of dry non-woven fabric roller carding and control of web density uniformity. I. Precisely industrial controller design

This series of paper discussed the dynamic modeling of non-woven fabric roller carding and the control of web density uniformity. The dynamic system of dry non-woven fabric roller carding was set up to analyze the dynamic model; then in the process of derivation, theoretical exploration and studies were carried out on one carding unit in the system, consisting of cylinder, worker roller, stripper roller. After that, we probed into the relation between rotation angle and angular velocity of carding unit, and analyzed the time-delay of carding unit. With Pade approximation, the time-delay was taken as the simplification of the system model. The above conditions were utilized to derive the transfer function of carding unit and it was extended to the dry non-woven fabric roller carding system combining four of carding units, feed roller, take-in and doffer in series to obtain the transfer function of this whole system. After confirmed by the designed controller, the system was obviously improved in its tracking property. The steady-state error was also eliminated. Meanwhile, with the participation of the controller, this system might produce the maximum overshoot during its transient response. Therefore, this research regulated the reference input according to the designed dominant poles. This combination scheme effectively control the occurrence of the maximum overshoot and make for good system objectives.     

Quality control of card web uniformity for a vertical-type cross-lapper machine. I. Dynamic system modeling and industrial controller design

This series of paper addressed the quality control of a vertical-type cross-lapper machine, which is used to produce uniform layers of fibers with suitable widths and thicknesses. The nonlinear model of the system was derived, and the corresponding state space representation was obtained. The linearized model based on the equilibrium position of the nonlinear model was generated, and the associated control property was analyzed. The high order linearized model would be reduced to a verified lower order model for control system design. The designed traditional and modern controller could make the crosslapper machine for good card web quality control.     

Lipoxygenase from banana leaf: purification and characterization of an enzyme that catalyzes linoleic acid oxygenation at the 9-position

The objective of the present study was to purify and characterize the lipoxygenase (LOX) from banana leaf (Giant Cavendishii, AAA), an unutilized bioresource. LOX was extracted, isolated, and purified 327-fold using 25-50% saturation of ammonium sulfate fractionation, hydroxyapatite column separation, and gel filtration on Superdex 200. The molecular mass of the purified LOX was 85 kDa, K(m) was 0.15 mM, and V(max) was 2.4 microM/min.mg using linoleic acid as substrate. Triton X-100 was required in the extraction medium; otherwise, no LOX activity was detected. LOX activity increased with the concentration of Triton X-100 with an optimum at 0.1%. The optimal pH of the purified LOX from banana leaf was 6.2, and optimal temperature was 40 degrees C. The LOX showed the highest reactivity toward 18:2 followed by 18:3 and 20:4. A very low reaction rate was observed toward 20:5 and 22:6. On the basis of retention time in normal phase HPLC, the products of 18:2 or 18:3 catalyzed by purified LOX were hydroperoxyoctadecadienoic acid or hydroperoxyoctadecatrienoic acid. It seems that 9-LOX is the predominant enzyme in banana leaf. Banada leaf dried at 110 degrees C for 2 h developed algal aroma. Banana leaf extract stored at 10 degrees C for 12 h formed an oolong tea-like flavor. Banana leaf extract reacted with 18:2 or soybean oil pretreated with bacterial lipase produced green and melon-like aroma, whereas the same reaction with 18:3 produced a sweet, fruity, cucumber-like flavor note.     

Antioxidant activity and constituents of extracts from the root of Garcinia multiflora

The methanolic extract of the root of Garcinia multiflora and its derived soluble fractions, namely those soluble in ethyl acetate (EtOAc), n-butanol, and water, were screened for their antioxidant activities. Among them, the EtOAc-soluble fraction exhibited the highest scavenging activity against the 1,1-dipheny1,2-picrylhydrazyl radical, the highest superoxide radical scavenging activity, and the strongest reducing power. In addition, according to the bioactivity-guided isolation, 26 specific phytocompounds, including 3 aromatics, 3 benzophenones, 3 flavonoids, 3 isocoumarins, 1 phloroglucinol, 6 steroids, and 7 xanthones, were isolated from the EtOAc-soluble fraction and identified. Of these, 2,4,3′,4′-tetrahydroxy-6-methoxybenzophenone and 1,3,6,7-tetrahydroxyxanthone were found to be the major bioactive constituents, present in the crude extract in concentrations of 3.9 and 15.6 mg/g, respectively. These two compounds had similar antioxidant activities to (+)-catechin, a well-known antioxidant.     

五种芳香植物精油对烟草疫霉的抑菌活性分析

为实现作物病害的绿色防控,从芳香植物源中筛选高效的杀菌活性成分,采用菌丝生长法测定了迷迭香精油、薰衣草精油、香叶天竺葵精油、香茅草精油和罗勒精油5种精油对烟草黑胫病病原烟草疫霉的抑菌活性。结果表明:当精油浓度达到225μg/m L时,5种精油对烟草疫霉均有显著的抑制作用,其中香茅草精油对烟草疫霉的抑制率均为100%。在熏蒸方式下,5种精油对烟草疫霉抑制的EC50值分别为317.8μg/m L、255.2μg/m L、151.0μg/m L、53.0μg/m L和142.8μg/m L。5种芳香植物精油对烟草疫霉菌丝生长形态均有一定的影响。研究结果表明香茅草精油具有作为防治烟草疫霉环境友好型杀菌剂的先导化合物的潜力。     

适应气候变化的中国农业种植结构调整研究

近百年来,全球正经历一次以变暖为主要特征的气候变化,随着气候变化及其所带来的影响日益显著,目前适应气候变化越来越成为全球关注的热点问题。我国已有的农业种植结构调整适应气候变化实践非常丰富,但诸多研究者并未进行过系统的梳理,对已有实践的适应气候变化内涵没有清晰地认识。为了更好的应对未来气候变化,从种植制度、作物布局、品种布局三个方面阐述了气候变化对中国农业种植结构调整的影响,结合东北水稻玉米扩种、冬麦北移、华北"两晚"技术、长江中下游双季稻改制、南方冬季农业开发等典型适应气候变化案例,探讨复种指数、间作套种模式、作物配置、种植界限、种植比例、抗旱品种、抗病虫害品种等农业种植结构调整的不同方面适应气候变化的内涵,提出了种植结构调整中适应气候变化工作面临的关键问题,倡导进一步加强气候变化各要素对种植熟制的综合影响研究,深入开展农业精细区划与作物布局优化配置研究以及适应气候变化的育种多目标优化决策研究。     

库尔勒香梨园土壤氧化亚氮的排放特征

为了掌握土壤氧化亚氮排放对库尔勒香梨园造成的氮肥损失率,从而为香梨园氮肥的科学施用,提高氮素利用效率及改善果园生态环境提供理论依据和实践指导,以新疆维吾尔自治区库尔勒市树龄为6 a的库尔勒香梨园为研究对象,采用静态箱-气相色谱法对香梨树整个生育期内香梨园土壤中氧化亚氮的排放通量及累积量进行了观测与分析。结果表明:(1)氧化亚氮的排放量在施肥后明显增大,其排放通量在施用基肥后第5天下午出现峰值(0.2498 g·hm~(-2)h~(-1)),其日累积量在施用基肥后第5天也出现峰值(4.216 g·hm~(-2)d~(-1));(2)土壤温度会显著影响氧化亚氮的排放量,氧化亚氮的排放量在一天内表现出下午(16:00—20:00)中午(12:00—16:00)上午(8:00—12:00)夜间(20:00—8:00)的变化特征;(3)每月中旬对试验样地进行灌水处理后,由于干湿交替过于频繁,氧化亚氮的排放量明显增大;在不施肥的月份里,氧化亚氮的排放量呈现出月中月初月末的变化特征;(4)氧化亚氮的月累积量,在施肥后的4月和6月均较高,分别达到106.564和97.276 g·hm~(-2)月-1;在香梨树的整个生育期内,氧化亚氮的累积总量达到了455.54 g·hm~(-2)。     

库尔勒香梨园土壤氨挥发速率及累积规律

为了掌握库尔勒香梨园土壤氨挥发特征与挥发损失量,以6年树龄库尔勒香梨园为研究对象,采用密闭式集气法对香梨整个生育期的香梨园土壤氨挥发速率及累积量进行研究。结果表明:施肥、灌溉及温度对库尔勒香梨园土壤氨挥发有显著影响。氨挥发速率在一天内的变化,由于温度的影响而具体表现为下午(16:00~20:00)、中午(12:00~16:00)、早上(8:00~12:00)、夜间(20:00~08:00)挥发速率依次降低,并在施肥后的第4天下午(16:00~20:00)时达到最大值0.032 kg/(hm~2·h);氨挥发日累积量在不施肥的情况下随着香梨生育期的推进而逐渐减少,最后趋于平稳。而在4月1日和6月1日对试验样地进行施肥后,氨挥发日累积量明显增加,在4月5日和6月5日分别达到0.411和0.318 kg/(hm~2·d)。在每个月10日对试验样地进行灌水后,氨挥发日累积量明显增加,在5月15日达到最大值0.24 kg/(hm~2·d);氨挥发月累积量在基施肥处理的4月和追施肥处理的6月较大,分别达到9.086和7.619 kg/(hm~2·m)。在香梨整个生育期内,氨挥发累积量达到36.52 kg/hm~2,占总施肥量的12.17%,损失量较大。