Phytochemical composition and in vitro antimicrobial and antioxidant activities of essential oils of three endemic Soqotraen Boswellia species

The chemical composition of three essential oils obtained from the barks of three endemic Boswellia species namely, Boswellia dioscorides, Boswellia elongata and Boswellia socotrana which were collected from the Soqotra Island (Yemen), was investigated. In parallel to that evaluation of their antimicrobial and antioxidant activities was also carried out. The investigation led to the identification of 72, 70 and 67 constituents for B.dioscorides, B. elongata, and B. socotrana, respectively. The B. dioscorides oil was found to have a high content of monoterpene hydrocarbons (32.8%) with α-thujene (9.3%) and α-pinene (8.3%) as main components. Whereas, the essential oil of B. elongata was characterised by high diterpene content (31.7%), in which incensol (14.8%) was found to be the major constituent. On the other hand, the oil obtained from the B. socotrana was found to be predominated of monoterpene hydrocarbons (26.4%) and oxygenated monoterpenes (30.7%) with p-cymene (13.0%), 2-hydroxy-5-methoxy-acetophenone (16.3%) and camphor (11.6%). All essential oils possessed antimicrobial activity especially against Gram-positive bacteria with MIC-values between 1.8 and 17.2 mg/ml. Furthermore, the DPPH-radical scavenging assay exhibited only weak antioxidant activities (28%) at 1.0 mg/ml.     

Native and modified porcine plasma protein as wall materials for microencapsulation of natural essential oils

Porcine plasma protein (PPP) is of interest as a wall material to encapsulate lemongrass oil, turmeric oil and eucalyptus oil using emulsion technique and freeze drying. The properties of microcapsules were used to evaluate two types of wall material (native porcine plasma protein; NPPP and modified porcine plasma protein; MPPP) at two different ratios of wall material (W) and core material (C) (W:C; 4:1 and 3:1). All NPPP and MPPP emulsions showed Bingham plastic fluid flow behaviours. Moreover, MPPP microcapsules showed lower free oil content on their surface (0.10–0.50%) with higher encapsulation efficiency (91–98%). Fourier-transform infrared spectroscopy showed the outstanding chemical structure of microcapsules. Furthermore, scanning electron microscopy indicated holes on the surface of microcapsules encapsulated with essential oils. Both PPPs can be used as encapsulation material for natural extract and food additives to improve the food texture and as a biopolymer film to maintain the quality of food products.     

现场双经纬仪三维坐标测量系统

分析了经纬仪透视投影模型以及双经纬仪三维坐标测量模型。采用线性与非线性相结合的方法来求解双经纬仪坐标测量系统的参数,首先由8个以上空间点在两台经纬仪投影平面内对应的投影坐标计算出本质矩阵E,通过本质矩阵E的奇异值分解以及空间绝对距离的约束采用线性方法求出右经纬仪的投影矩阵,然后建立包含空间点在两台经纬仪投影平面内投影点固有约束以及空间点三维坐标在内的目标函数,并以线性方法求出的参数为初值,采用非线性优化的方法求解最优测量系统的参数。该方法保证了求解参数为全局最优,且求解速度快。试验结果表明,该方法切实可行。     

微波消解-ICP-MS法测定卷烟纸中主要元素和重金属元素

建立了卷烟纸中5种主要元素和6种重金属元素的电感耦合等离子体质谱测定方法,优化了样品前处理方法,考察了普通卷烟纸和彩色卷烟纸中5种主要元素和6种重金属元素的含量水平。结果表明:采用HNO_3和H_2O_2消解体系能够将卷烟纸完全消解,方法定量限在0.010~0.053mg/kg之间,样品加标回收率为93%~107%,精密度(RSD)小于6.7%。该方法样品前处理简单快速、结果准确可靠,适合于卷烟纸中Na、Mg、K、Ca、Ti、Cr、Ni、As、Cd、Hg和Pb的测定。     

一种变种留兰香精油化学成分的研究

本文采用GC/MS法 ,研究了一变种留兰香精油的化学成分。鉴定出 39种化合物 ,主要成分为胡椒烯酮醚(30 .5 11) %、1,8-桉叶素 (2 8.791% )、烯 (9.986 % )、β -月桂烯 (8.4 81% )和 β -蒎烯 (4 .796 % ) ,而作为一般留兰香油主成分的香芹酮则未能检测到。     

浅议先进企业文化的内涵

先进的企业文化对于促进企业实现又好又快发展具有十分重要的意义。具体而言,企业文化的内涵涵盖企业标准、企业目标、信息平台、人才培养、激励创新、文化创新、不断学习等方面。对此,各个企业必须引起高度重视,加强企业文化建设,从而提升企业核心竞争力。     

流行语翻译中的文化再现

针对网络时代的网络语存在和流行的客观事实,探讨了这些流行语中呈现的文化现象和进行翻译时应该遵循的原则,并对网络流行语进行了分类,探讨了相关翻译原则与技巧。     

风景园林师职业基本价值观探讨

在风景园林事业繁荣的同时,设计市场出现了不少误区。分析误区产生原因,建构风景园林师正确、理性的职业基本价值观,对当今中国风景园林建设和行业的发展非常必要。     

Egg Yolk as Means for Providing Essential and Beneficial Fatty Acids

The new American Dietary Guidelines now recommend optimizing the types of fat consumed instead of reducing or eliminating fat from the diet. Chicken eggs are a means to deliver essential and beneficial human dietary fatty acids (FA), and can be staple component of healthy eating behavior. Additionally, polyunsaturated fatty acids can be increased in the avian egg yolk by simply incorporating selected lipid sources into the avian diet. Poultry feed rich in omega‐3 FA (omega‐3) has allowed commercialization of enriched eggs containing up to 600 mg of omega‐3. Conjugated linoleic acid (CLA) has also been used in the research setting to enrich eggs to provide a portion of the 3–4 g CLA day^?1 needed to promote weight loss to combat obesity. However, Americans consume only 50% of the omega‐3 recommended adequate intake, and average CLA consumption is under 600 mg day^?1. While a variety of foods are naturally rich in omega‐3, conventional sources of CLA are limited to bovine milk and meat, which do not provide enough CLA to produce clinical effects in a balanced diet. Since eggs and egg‐based products are common in the Western diet, eggs enriched with both omega‐3 and CLA using dietary additions to poultry feed may promote consumption of the recommended levels of these FA. This article reviews the design of poultry eggs with enhanced lipid profiles through dietary intervention, and discusses the future direction of enriched egg research.     

Assessing the kinetic model of hydro-distillation and chemical composition of Aquilaria malaccensis leaves essential oil

This study aimed to model the kinetic of hydro-distillation of Aquilaria malaccensis leaves oil in order to understand and optimize the extraction process. In addition, this study, for the first time, aimed to identify the chemical compositions of the A. malaccensis leave-oil. By assessing both first-order kinetic model and the model of simultaneous washing and diffusion, the result indicated that the model of simultaneous washing and diffusion better describes the hydro-distillation mechanism of the essential oil from A. malaccensis leaves.The optimum time, solid to liquid ratio, and the heating power for extracting the highest amount of essential oil were found to be around 3 h, 1:10(g·ml-1), and 300 W respectively. Yellow essential oil with a strong smell and a yield of 0.05 v/w was extracted by hydro-distillation Clevenger apparatus. Chemical compounds of the essential oil were analyzed using gas chromatography–mass spectroscopy(GC/MS), which resulted in identification of 42 compounds that constitute 93% of essential oil. Among the identified components,Pentadecanal(32.082%), 9-Octadecenal,(Z)(15.894%), and Tetradecanal(6.927%) were the major compounds.Considering the fact that all the identified major components possess pesticidal properties, A. malaccensis leaves can be regarded as a promising natural source for producing pesticides.