Synthesis,Purification, and Acyl Migration Kinetics of 2-Monoricinoleoylglycerol

2‐Monoricinoleoylglycerol (2‐MRG) was synthesized by the Novozym 435 catalyzed alcoholysis of castor oil in excess ethanol (1:70 mol:mol) at ambient temperature. Due to the fatty acid C12‐OH group, conventional liquid–liquid extraction methods developed for less polar, non‐hydroxylated 2‐monoacylglycerols (2‐MAG) proved inadequate for 2‐MRG purification. Alternatively, 2‐MRG was purified by normal‐phase flash chromatography (FC) on silica gel using a binary acetone‐hexane gradient mobile phase. Gram quantities of 2‐MRG were isolated in 63 % yield and contained no residual diacylglycerol (DAG), which fail to separate using liquid–liquid extraction methods. The 2‐MRG was obtained at ~90 mol% relative to 1‐MRG, proving that the FC method did not appreciably catalyze acyl migration. ¹H‐NMR spectroscopy was used to monitor the spontaneous acyl migration of isolated 2‐MRG from 20 to 80 °C. The relative energy of activation calculated from the Arrhenius relationship of the 2‐MRG acyl migration rate constants was 82.9 kJ/mol. This was ~two‐fold higher than the theoretical ΔG_298.15 calculated from molecular modeling using density functional calculations (B3LYP/6?31 + G*) of 2‐MRG, the ketal ring transition state, and 1‐monoricinoleoylglycerol (1‐MRG). The synthesis and isolation methods reported herein provide a convenient means to access useful intermediates for functionalized structured lipids.     

Acyl Migration Kinetics of 2-Monoacylglycerols from Soybean Oil via <Superscript>1</Superscript>H NMR

The acyl migration kinetics of neat 2-monoacylglycerol (2-MAG) to form 1-MAG was determined using ¹H NMR spectroscopy to monitor the β-proton integration ratios of the two species over time. 2-MAG was synthesized by the Novozym 435-catalyzed alcoholysis of soybean oil and isolated by solvent extraction or molecular distillation at a mole fraction (X _2-MAG) of 0.94 relative to total MAG. The kinetics parameters of the neat 2-MAG acyl migration were investigated over the temperature range of 23–80 °C. The 2-MAG mol fraction remained unchanged at 23 °C over the course of 168 h and reached an equilibrium of X _2-MAG = 0.09 at only 80 °C. Modeling of the kinetics data revealed a 2-MAG half life (t _1/2) of 3,500 and 22.8 h at 23 and 80 °C, respectively, with an activation energy of 79.0 ± 6.5 kJ mol⁻¹. The use of ¹H NMR spectroscopy proved an expedient method for monitoring the acyl migration in 2-MAG compared to other reported methods (e.g. GC, HPLC, and ¹³C-NMR spectroscopy), requiring no sample manipulation and minimizing the deleterious effects of high temperatures and solvent exposure. Product names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may be suitable.     

Influence of Fatty Acid Desaturation on Spontaneous Acyl Migration in 2-Monoacylglycerols

The effect of desaturation from the C9 to the C15 carbon of 2-monoacylglycerol (2-MAG) fatty acids on spontaneous acyl migration is described. Three 2-MAG species, 2-monooleoylglycerol (C18:1 cis-Δ9), 2-monolinoleoylglycerol (C18:2 cis-Δ9,12), and 2-monolinolenoylglycerol (C18:3 cis-Δ9,12,15) were synthesized by lipase-catalyzed ethanolysis of their respective triacylglycerols and isolated in >60?% yield and at 2-MAG purities of >95?% relative to 1-monoacylglycerol (1-MAG). ¹H-NMR spectroscopy was used to monitor the spontaneous acyl migration of the 2-MAG species over a temperature range from 20 to 80?°C. The relative energies of activation calculated from the Arrhenius relationships of the 2-MAG acyl migration rate constants were 73.3, 68.0, and 72.9?kJ?mol^?1 for the three 2-MAG species, respectively. Density functional calculations performed using the B3LYP functional at the 6-31+G* basis set on the three ketal ring intermediate of the three 2-MAG species followed a similar trend with a lack of relative energetic preference associated with the degree of desaturation. The kinetically determined relative activation energies were approximately twofold higher than the theoretical relative Gibbs free energies of the intermediates, suggesting that other factors influence acyl migration. In general, increasing desaturation after the C9 carbon of 2-MAG fatty acids had no appreciable effect on acyl migration rates.     

Purification of specific structured lipids by distillation: Effects on acyl migration

The cause and effects of acyl migration during the purification of specific structured lipids by distillation were studied in a conventional batch deodorizer with stripping steam. The mixture of specific structured lipids produced by lipase-catalyzed acidolysis between rapeseed oil and capric acid contained a large amount of free fatty acids and a small amount of partial acylglycerols besides triacylglycerols. Therefore, the effect of steam, free fatty acids, diacylglycerols, and monoacyl-glycerols on acyl migration was studied in a palm oil midfraction model. The results showed that all these factors influenced the rate of acyl migration, and their combinations made the effect more severe. However, diacylglycerols were found to be the main reason for acyl migration. In the distillation of the specific structured lipid product mixture, distillation temperature and time were the main factors to determine the degree of acyl migration and the extent of separation of free fatty acids. The results indicate that more efficient separation technology should be used to improve the quality of the purified structured lipids. In order to reduce the distillation temperature, vacuum should be made as low as possible with more effective pumps. To reduce the distillation time, thin-film principle in a packed column should be used, or other more efficient distillation techniques such as molecular distillation or short-path distillation should be exploited.     

酶法酯交换过程中不饱和脂肪酸对其酰基位移的影响

酶法制备结构酯的过程中,由于酰基位移的发生而生成了副产品．并影响了产品质量。研究了Lipozyme IM和猪胰脂酶催化橄榄油与硬脂酸甲酯反应,油酸、亚油酸、亚麻酸的相对酰基位移率的比较。结果显示：双键越多酰基位移越小,猪胰脂酶催化时脂肪酸酰基位移程度大于Lipozyme IM。     

Purification of β‐Galactosidase by Ion Exchange Chromatography: Elution Optimization Using an Experimental Design

β‐Galactosidase is an enzyme industrially used to hydrolyze milk lactose, generating dairy products destined for people intolerant to this sugar. Its importance is due to its galactosiltransferase activity. The effects of elution pH and salt gradient volume were evaluated for purification of β‐galactosidase by ion exchange chromatography using an experimental design and response surface techniques. The best conditions for purification of β‐galactosidase were pH 5.5 with an elution volume of 62.8 mL, obtaining a yield of 85.5 % and a 12‐fold increase in the purification factor in a one‐step chromatography process. Purification of β‐galactosidase by application of a single stage of ion exchange and evaluation of the important process parameters using an experimental design provided good results in the recovery and purification factor that could subsequently be scaled up.     

超高效液相色谱法测定食品包装材料中五种抗氧化剂迁移量

采用水基模拟物(蒸馏水、3%乙酸水溶液、10%乙醇水溶液)和油脂模拟物(异辛烷),建立了超高效液相色谱法测定食品包装材料中BHA、BHT、DLTP、DMTP、抗氧化剂CA等5种抗氧化剂迁移量的检测方法。结果表明:在2.00~100.00 mg/kg浓度范围内,具有良好的线性关系,相关系数≥0.999 5;检出限0.50~1.00 mg/kg、定量限范围1.50~3.00 mg/kg;加标回收率在80.7%~115.7%之间,相对标准偏差(RSD)在0.5%~2.8%之间,表明该方法简便、准确,可用于食品包装材料中5种抗氧化剂迁移量的同时检测。     

固相萃取-气相色谱法测定水果、蔬菜中的氯丹

建立一种简单、灵敏的用于测定水果、蔬菜中氯丹残留量的气相色谱检测方法.样品用乙腈提取,经Florisil(弗罗里硅土)SPE小柱净化,由配有ECD检测器的气相色谱(GC-ECD)进行测定.该方法对水果、蔬菜中氯丹检出限为0.0002 mg/kg,工作曲线在0.001～0.08 μg/mL范围内呈良好的线性关系.在该线性范围内,苹果、柿子、西红柿和鲜笋中回收率为82.6％ ～93.1％.     

水溶液中2-氰基吡啶的气相色谱分析

采用气相色谱法,选用加碱的PEG 20M不锈钢填充柱及预柱,以3 氰基吡啶为内标物,测定2 氰基吡啶水溶液含量。方法的标准偏差为0.006,回收率为99.44%～101.28%。方法准确、简便快速,适用于生产中质量控制。     

Pharmacological Inhibition of mTORC2 Reduces Migration and Metastasis in Melanoma

Despite recent advances in therapy, liver metastasis from melanoma is still associated with poor prognosis. Although targeting the mTOR signaling pathway exerts potent anti-tumor activity, little is known about specific mTORC2 inhibition regarding liver metastasis. Using the novel mTORC2 specific inhibitor JR-AB2-011, we show significantly reduced migration and invasion capacity by impaired activation of MMP2 in melanoma cells. In addition, blockade of mTORC2 induces cell death by non-apoptotic pathways and reduces tumor cell proliferation rate dose-dependently. Furthermore, a significant reduction of liver metastasis was detected in a syngeneic murine metastasis model upon therapy with JR-AB2-011 as determined by in vivo imaging and necropsy. Hence, our study for the first time highlights the impact of the pharmacological blockade of mTORC2 as a potent novel anti-cancer approach for liver metastasis from melanoma.     

Q Sepharose^TM-XL强阴离子交换色谱快速纯化精氨酸激酶及其多克隆抗体的研究

利用QSepharose^TM-XL强阴离子交换色谱从虾的精氨酸激酶粗提液中纯化出精氨酸激酶。以其免疫大白兔．然后利用QSepharose^TM-XL强阴离子交换色谱从高免疫兔血清中纯化精氨酸激酶的多克隆抗体。采用SDS-PAGE检测精氨酸激酶及其抗体的纯度,并进行了活性测定。结果表明．利用QSepharose^TM-XL强阴离子交换色谱纯化出的精氨酸激酶及其多克隆抗体纯度高、活性强。建立了快速高效、操作方便而又适合实际应用的制备精氨酸激酶及其多克隆抗体的方法．可为精氨酸激酶及食品过敏的相关研究提供帮助。     

Flash co-pyrolysis of biomass with polylactic acid. Part 1: Influence on bio-oil yield and heating value

High amounts of water present in bio-oil are one of the major drawbacks for its utilisation as a fuel. One technology that shows the potential to satisfy the demand for bio-oil with a reduced water content is the flash co-pyrolysis of biomass with polylactic acid, PLA. The influence of PLA on the pyrolysis of willow is investigated with a semi-continuous home-built pyrolysis reactor. Flash co-pyrolysis of willow/PLA blends (10:1, 3:1, 1:1 and 1:2) show synergetic interaction. A higher bio-oil yield and a lower water content as a function of the willow/PLA ratios are obtained. Among the tested blends, the 1:2 willow/PLA blend shows the most pronounced synergy: a reduction in the production of pyrolytic water of almost 28%, accompanied by an increase of more than 37% in the production of water-free bio-oil. Additionally, PLA shows to have a positive influence on the energetic value of the bio-oil produced and on the resulting energy recuperation.     

Plectin Downregulation Inhibits Migration and Suppresses Epithelial Mesenchymal Transformation of Hepatocellular Carcinoma Cells via ERK1/2 Signaling

Plectin, as a cytoskeleton-related protein, is involved in various physiological and pathological processes of many cell types. Studies have found that plectin affects cancer cell invasion and metastasis, but the exact mechanism is not fully understood. In this study, we aim to investigate the role of plectin in the migration of hepatocellular carcinoma (HCC) cells and explore its relevant molecular mechanism. Herein, we found that the expression of plectin in HCC tissue and cells was significantly increased compared with normal liver tissue and cells. After downregulation of plectin, the migration ability of HCC cells was significantly lower than that of the control group. Moreover, the expression of E-cadherin was upregulated and the expression of N-cadherin and vimentin was downregulated, suggesting that plectin downregulation suppresses epithelial mesenchymal transformation (EMT) of HCC cells. Mechanically, we found that plectin downregulation repressed the extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Activation of ERK1/2 recovered the plectin downregulation-inhibited migration and EMT of HCC cells. Taken together, our results demonstrate that downregulation of plectin inhibits HCC cell migration and EMT through ERK1/2 signaling, which provides a novel prognostic biomarker and potential therapeutic target for HCC.     

Influence of Vibration on Density of Polymer Solid Granules in Single Screw Extruder

In an especially compaction apparatus the vibration force field is applied to the solids conveying process by the axial vibration of the piston. Through the experimental investigation of solid granule compaction, it is demonstrated that the effect of vibration field and temperature on the density of polymer solid granules is very significant. The experimental results show that the pressure exerted on the solid granules increases with the increase in the amplitude or frequency of the vibration force field, which accelerates the compaction of loosely solid granules.     

Catalytic Influence of Oxide Component in Ni‐Based Cermet Anodes for Ammonia‐Fueled Solid Oxide Fuel Cells

Recently, the promising prospect of ammonia as a hydrogen carrier for solid oxide fuel cells (SOFCs) has attracted significant interests. In this work, the effects of temperature, fuel content, and total flow rate of anode gas on the performance of Ni/yttria‐stabilized zirconia (Ni/YSZ) anode for ammonia‐fueled SOFCs were investigated. Based on obtained results, the utilization route of ammonia on Ni/YSZ anode was discussed; the results of electrochemical experiments were related with the catalytic decomposition bahavior of ammonia over Ni/YSZ. Moreover, the catalytic activity for ammonia decomposition and anode performance of Ni/samarium‐doped ceria (Ni/SDC) and Ni/yttrium‐doped barium cerate (Ni/BCY) were also investigated. Among these anode materials, Ni/BCY exhibited the highest ammonia decomposition activity and anode performance for ammonia‐fueled SOFCs at intermediate temperatures.     

Flash sintering of lead zirconate titanate (PZT) ceramics: Influence of electrical field and current limit on densification and grain growth

Flash sintering of lead zirconate titanate ceramics were investigated under DC electric fields ranging from 300 to 600?V/cm. The onset temperature for flash sintering significantly decreased with the electrical field to a lower limit of furnace temperature of 538?°C at 600?V/cm. The retardation of grain growth was observed, and the grain size decreased with increasing the electrical field. The current limit had a great influence on the density and grain size of specimen. During the flash sintering process, power dissipation first rose abruptly to a maximum value, then declined sharply to a steady state. Meanwhile, optical glow of specimen was observed. Using black body radiation model, the actual specimen temperature was estimated, which was too low to obtain the full dense ceramics in 30?s. It was suggested that Joule heating, ultra-high heating rate and high concentrations of defects were responsible for flash sintering of PZT ceramics.     

氟化钙对高温自蔓延合成法制备纳米二氧化锡的影响

为研究CaF2对高温自蔓延合成(SHS)法制备纳米二氧化锡的影响,本文进行了6组关于CaF2添加量与SnO2纳米线产量的平行实验以及1组验证实验,并利用X射线衍射分析及扫描电子显微镜对产物进行表征.实验结果表明:(1) CaF2的添加量与产物的产量之间存在指数关系,且在CaF2添加量为1.5％时,产量实现最大化;(2) CaF2的添加能够提高产物的纯度,并且不改变产物原有的一维纳米形貌.     

Flash co-pyrolysis of biomass with polyhydroxybutyrate: Part 1. Influence on bio-oil yield, water content, heating value and the production of chemicals

Bio-oil obtained via flash pyrolysis shows potential to be applied as a renewable fuel. However, bio-oil often contains high amounts of water, which is a major drawback for its application. The influence of a biopolymer - polyhydroxybutyrate (PHB) on the pyrolysis of willow is investigated using a semi-continuous home-built pyrolysis reactor. The flash co-pyrolysis of willow/PHB blends (w/w ratio 7:1, 3:1, 2:1 and 1:1) clearly shows particular merits: a synergetic increase in pyrolysis yield, a synergetic reduction of the water content in bio-oil, an increase in heating value, and a production of easily separable chemicals. The occurrence of synergetic interactions is observed based on a comparison between the actual pyrolysis results of the willow/PHB blends, the theoretical pyrolysis results calculated from the reference pyrolysis experiments (pure willow and pure PHB) and their respective w/w ratio. The co-pyrolysis of 1:1 willow/PHB shows the best overall results.