Essential oils of Zingiber officinale var. rubrum Theilade and their antibacterial activities

The essential oils obtained by hydrodistilation of the leaves and rhizomes of Zingiber officinale var. rubrum Theilade were analysed by capillary GC and GC–MS. Forty-six constituents were identified in the leaf oil, while 54 were identified in the oil from the rhizomes. The leaf oil was clearly dominated by β-caryophyllene (31.7%), while the oil from the rhizomes was predominantly monoterpenoid, with camphene (14.5%), geranial (14.3%), and geranyl acetate (13.7%) the three most abundant constituents. The evaluation of antibacterial activities using the micro-dilution technique revealed that both the leaf and rhizome oils were moderately active against the Gram-positive bacteria Bacilluslicheniformis, Bacillus spizizenii and Staphylococcus aureus, and the Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae and Pseudomonas stutzeri.     

Method for Calculating Cartesian Coordinates of Operator’s Arm Joints for Anthropomorphic Manipulator Master-Slave Control Using Exoskeleton

The main goal of the work is to increase the accuracy of the anthropomorphic manipulator master-slave teleoperation by calculating the coordinates of the operator’s arm joints. The master device is an exoskeleton worn on the operator’s arm, and the slave device is an anthropomorphic manipulator. A method based on the solution of the forward kinematics and empirical simplifications is proposed in this paper. The position of the nodal points of the exoskeleton was calculated by solving the direct kinematics problem. The coordinates of the operator’s arm joints, which were rigidly connected to the exoskeleton nodal points, were calculated geometrically. For the operator’s arm elbow joint, which was flexibly connected to the exoskeleton, an empirical relation was proposed. It simplified the calculation of the elbow joint position. The experiment showed a decrease in the mismatch between the operator’s arm angles and the manipulator joint angles from 20.7° to 2.9°. The proposed method increases the convenience of the master-slave control.     

Determination of synthetic phenolic antioxidants in food items using reversed-phase HPLC

A HPLC with gradient elution method for the determination of the synthetic phenolic antioxidants (SPAs) propyl gallate (PG), tertiary butyl hydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in food items is described. A C18 column served as the stationary phase; the gradient elution was formed by acetonitrile and water:acetic acid (1%). The UV detector was set at 280 nm. Under the recommended conditions, separation of the four SPAs was achieved in less than 8 min. Analytical characteristics of the HPLC method such as limit of detection, linear range, and reproducibility were evaluated. Extraction parameters were optimized for the recoveries of the SPAs in different types of food items (cooking oil, margarine and butter, and cheese). Before the HPLC separation, the SPAs were extracted with methanol/acetonitrile (1:1, v/v) and were subjected to vortex/ultrasonic treatment. The extracts were next kept in a freezer (∼2 h) to precipitate co-extracted components. Recoveries of the SPAs when spiked to cooking oil, margarine, butter and cheese at 50 and 200 mg l⁻¹ were in the ranges 93.3–108.3% for PG, 85.3–108.3% for TBHQ, 96.7–101.2% for BHA and 73.9–94.6% for BHT. The method was applied to the determination of SPAs in 38 food items (16 cooking oils, ten margarine, six butter and six cheese samples). The levels of SPAs in positive samples are all below the legal limits of Malaysia.     

An Adaptive Resource Management Architecture for Active Networks

This paper presents a framework for resource management in highly dynamic active networks. The goal is to allocate and manage node resources in an efficient way while ensuring effective utilization of network and supporting load balancing. The framework supports co-existence of active and non-active nodes and proposes a novel Directory Service (DS) architecture that can be used to discover the suitable active nodes in the Internet and for selecting the best network path (end-to-end) and reserving the resources along the selected path. Intranode and internode resource management are facilitated through the DS, while within an active node the framework implements a composite scheduling scheme to schedule both the CPU and bandwidth resources to resolve the combined resource scheduling problems. In addition, a flexible active node database system and a simple adaptive prediction technique have been introduced in order to resolve the challenging problem of determining the CPU requirements of the incoming packets.     

Competence Assessment in Higher Education: A Dynamic Approach

Advances in the implementation of the European Higher Education Area have had a great impact on university environment and the process of design, evaluation, and implementation of new curricula. Identifying competence levels among students can help course organizers to improve both academic content and teaching/learning processes. The present study addresses this issue by examining the implementation of an Internet‐based competency assessment tool. We analyze the status and evolution of soft skills among students on the Official Masters program Creating and Managing Innovative Technology‐Based Companies at the University of Barcelona, using a tool known as Tricuspoid, specifically designed for evaluating entrepreneurial competences. The results show that the tool, first, enables students to identify their strong and weak points and to develop personal strategies for improvement; second, provides teachers with additional information about the effects of their input on student competences; and third, supplies useful information for quality management of the Master's programs, because it can detect trends in the training needs of new students and help to enhance content accordingly, and therefore match the design of the academic program to the requirements of labor market. © 2012 Wiley Periodicals, Inc.     

Antioxidant and anti food-borne bacterial activities of extracts from leaf and different fruit parts of Myristica fragrans Houtt

The main products of Myristica fragrans are the dried seed (nutmeg) and aril (mace), which are used as spices or condiments to flavor foods. In this study, its leaf and different parts of fruit (pericarp, aril, seed-kernel and shell) were compared for their total phenolic content, antioxidant and anti food-borne bacterial capacities. The 80% methanol extracts of aril, seed-kernel and shell shared the highest total phenolic content with shell extract acted as the greatest primary antioxidant, by having the highest ferric reducing antioxidant power (FRAP) activity (EC₅₀ 9.7 ± 0.1 μg/mL), β-carotene-bleaching activity (EC₅₀ 21.5 ± 2.7 μg/mL) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (EC₅₀ 160.9 ± 13.9 μg/mL), whereas the pericarp extract exhibited highest secondary antioxidant activity as a metal chelator (EC₅₀ 75.6 ± 14.4 μg/mL). Only the aril and seed-kernel extracts were found to inhibit the food-borne bacteria with the lowest minimum inhibition concentration of 50 μg/mL, against Staphylococcus aureus (ATCC12600) and Bacillus cereus (ATCC10876). Our findings suggest the possibility of using the aril and seed-kernel extracts as natural food preservative and other parts as a new source of natural antioxidant for food and pharmaceutical industries.     

Investigation of the rheological and technological properties of corundum-zirconia suspensions

Conclusions An investigation was made of the influence of the water content of slips on their viscosity and surface tension, and also on the strength, apparent density and porosity of the casts. We established the optimum parameters for the slips in order to obtain casts with the maximum strength and apparent density, and the minimum porosity in the wall of the cast.Translated from Ogneupory, No. 4, pp. 16–18, April, 1991.     

Hydrodynamic modelling of the filtration of molten metals through high-refractory cellular foam-ceramic filters

Conclusions A hydrodynamic model of the filtration process of molten metals through highly porous cellular filters was suggested. An expression for the required area of cross section of the filter for retaining the consumption of the molten metal was derived.Translated from Ogneupory, No. 6, pp. 11–13, June, 1992.