Useful Guideline (useful + guideline)

Distribution by Scientific Domains

Selected Abstracts

An overview of the mathematical modelling of liquid membrane separation processes in hollow fibre contactors

E Bringas
Abstract Liquid membranes have traditionally been employed for liquid/liquid mass transfer and have found applications in industrial, biomedical and analytical fields as well as in hydrometallurgical processes, wastewater treatment and remediation of polluted groundwater. However, in spite of the known advantages of liquid membranes, there are few examples of industrial application. The development of reliable mathematical models and design parameters (mass transport coefficients and equilibrium or kinetic parameters associated with the interfacial reactions) is a necessary step for design, cost estimation, process optimisation and scale-up. This work reports an overview of the different approaches that have been proposed in the literature to the mathematical modelling of liquid membrane separation processes in hollow fibre contactors providing, at the same time, a useful guideline to characterise the mass transport phenomena and a tool for the optimal design and intensification of separation processes. Copyright 2009 Society of Chemical Industry [source]

Primary tooth emergence in Australian children: timing, sequence and patterns of asymmetry

S Woodroffe
Abstract Background:, Information on the timing and sequence of human tooth emergence is valuable when analysing human growth and development, predicting the age of individuals, and for understanding the effects of genetic and environmental influences on growth processes. This paper provides updated data on the timing and sequence of primary tooth emergence in Australian children for both clinicians and researchers. Methods:, Twins were recruited from around Australia with data collected through parental recording of twins' primary tooth emergence. One twin from each pair was then randomly selected to enable the calculation of descriptive statistics for timing, sequence and asymmetry in tooth emergence. Results:, The first and last primary teeth emerged, on average, at 8.6 months and 27.9 months, respectively, with teeth emerging in the order: central incisor, lateral incisor, first molar, canine, second molar. Left-side antimeric teeth were more likely to emerge before their right-side counterparts but this was not statistically significant. At least 35% of all antimeric pairs had emerged within two weeks of each other, serving as a useful guideline for assessing symmetrical versus asymmetrical development. Conclusions:, Primary tooth emergence in Australian twins is occurring later than reported previously for Australian singletons but is consistent with findings for singletons in other ethnic groups. The most common sequence of primary tooth emergence appears to be consistent in twins and singletons and has not changed over time. [source]

Construction of hybrid peptide synthetases for the production of ,- l -aspartyl- l -phenylalanine, a precursor for the high-intensity sweetener aspartame

FEBS JOURNAL, Issue 22 2003
Thomas Duerfahrt
Microorganisms produce a large number of pharmacologically and biotechnologically important peptides by using nonribosomal peptide synthetases (NRPSs). Due to their modular arrangement and their domain organization NRPSs are particularly suitable for engineering recombinant proteins for the production of novel peptides with interesting properties. In order to compare different strategies of domain assembling and module fusions we focused on the selective construction of a set of peptide synthetases that catalyze the formation of the dipeptide ,- l -aspartyl- l -phenylalanine (Asp-Phe), the precursor of the high-intensity sweetener ,- l -aspartyl- l -phenylalanine methyl ester (aspartame). The de novo design of six different Asp-Phe synthetases was achieved by fusion of Asp and Phe activating modules comprising adenylation, peptidyl carrier protein and condensation domains. Product release was ensured by a C-terminally fused thioesterase domains and quantified by HPLC/MS analysis. Significant differences of enzyme activity caused by the fusion strategies were observed. Two forms of the Asp-Phe dipeptide were detected, the expected ,-Asp-Phe and the by-product ,-Asp-Phe. Dependent on the turnover rates ranging from 0.01,0.7 min,1, the amount of ,-Asp-Phe was between 75 and 100% of overall product, indicating a direct correlation between the turnover numbers and the ratios of ,-Asp-Phe to ,-Asp-Phe. Taken together these results provide useful guidelines for the rational construction of hybrid peptide synthetases. [source]

The development of the School Function Assessment , Chinese version for cross-cultural use in Taiwan

Jeng-Liang Hwang
Abstract The primary purpose of this research project was to translate and adapt the School Function Assessment (SFA), a standardized criterion-referenced instrument that measures school-related functional skills, for its cross-cultural use in Taiwan. The project consisted of four study phases: translation, cultural adaptation, pilot testing, and field testing for standardization. A series of rigorous procedures including the method of translation and back-translation, team consensus for cultural adaptation, and Rasch modelling techniques were used to address various dimensions of cross-cultural equivalence and psychometric properties of the translated SFA. The protocols that were developed as well as technical issues that were addressed in this project provide useful guidelines for international occupational therapists who are interested in translating and adapting instruments for cross-cultural use. Copyright 2004 Whurr Publishers Ltd. [source]