Comparison of oxygen mass transfer coefficient in simple and extractive fermentation systems

Aeration and agitation are important variables to ensure effective oxygen transfer rate during aerobic bioprocesses: therefore, the knowledge of the volumetric mass transfer coefficient (k(L)a) is required. In view of selecting the optimum oxygen requirements for extractive fermentation in aqueous two-phase system (ATPS), the k(L)a values in a typical ATPS medium were compared in this work with those in distilled water and in a simple fermentation medium. in the absence of biomass. Aeration and agitation were selected as the independent variables using a 2(2) full factorial design. Both variables showed statistically significant effects on k(L)a, and the highest values of this parameter in both media for simple fermentation (241 s(-1)) and extractive fermentation with ATPS (70.3 s(-1)) were observed at the highest levels of aeration (5 vvm) and agitation (1200 rpm). The k(L)a values were then used to establish mathematical correlations of this response as a function of the process variables. The exponents of the power number (N(3)D(2)) and superficial gas velocity (V(s)) determined in distilled water (alpha = 0.39 and beta = 0.47, respectively) were in reasonable agreement with the ones reported in the literature for several aqueous systems and close to those determined for a simple fermentation medium (alpha=0.38 and beta=0.41). On the other hand, as expected by the increased viscosity in the presence of polyethylene glycol, their values were remarkably higher in a typical medium for extractive fermentation (alpha=0.50 and beta=1.0). A reasonable agreement was found between the experimental data of k(L)a for the three selected systems and the values predicted by the theoretical models, under a wide range of operational conditions. (C) 2009 Elsevier B.V. All rights reserved.

Viability of Lactobacillus acidophilus La-5 added solely or in co-culture with a yoghurt starter culture and implications on physico-chemical and related properties of Minas fresh cheese during storage

The effect of a probiotic culture of Lactobacillus acidophilus (La-5), added solely or in co-culture with a starter culture of Streptococcus thermophilus, on texture, proteolysis and related properties of Minas fresh cheese during storage at 5 degrees C was investigated. Three cheese-making trials were prepared and produced with no addition of cultures (T1 - control), supplemented with La-5 (T2), and with La-5 + S. thermophilus (T3). Viable counts of La-5 remained above 6.00 log cfu g(-1) during the whole storage for T2, reaching 7.00 log cfu g(-1) on the 14th day. For T3, the counts of La-5 remained above 6.00 log cfu g(-1) after 7 days of storage. Due to the presence of S. thermophilus, T3 presented the highest proteolytic index increase and titratable acidity values. Nevertheless, these results and S. thermophilus addition had no influence on viability of La-5 which presented satisfactory populations for a probiotic food. Moreover, the use of a yoghurt culture for the production of Minas fresh cheese T3 supplemented with La-5 resulted in a good quality product, with a small rate of post-acidification, indicating that traditional yoghurt culture could be employed in co-culture with La-5 to improve the quality of this cheese. (C) 2008 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.

Detailed H-1 and C-13 NMR structural assignment and relative stereochemistry determination for three closely related sesquiterpene lactones

A complete analysis of H-1 and C-13 NMR spectra of the trypanocidal sesquiterpene lactone eremantholide C and two of its analogues is described. These structurally similar sesquiterpene lactones were submitted to H-1 NMR, C-13 (H-1) NMR, gCOSY, gHSQC, gHMBC, J-resolved and DPFGSE-NOE NMR techniques. The detailed analysis of those results, correlated to some computational calculations (molecular mechanics), led to the total and unequivocal assignment of all H-1 and C-13 NMR data. The determination of all H-1/H-1 coupling constants and all signal multiplicities, together with the elimination of previous ambiguities were also achieved. Copyright (C) 2008 John Wiley & Sons, Ltd.

The cuticular hydrocarbons profiles in the stingless bee Melipona marginata reflect task-related differences

Members of social insect colonies employ a large variety of chemical signals during their life. Of these, cuticular hydrocarbons are of primary importance for social insects since they allow for the recognition of conspecifics, nestmates and even members of different castes. The objectives of this study were (1) to characterize the variation of the chemical profiles among workers of the stingless bee Melipona marginata, and (2) to investigate the dependence of the chemical profiles on the age and on the behavior of the studied individuals. The results showed that cuticular hydrocarbon profiles of workers were composed of alkanes, alkenes and alkadienes that varied quantitatively and qualitatively according to function of workers in the colony. (C) 2010 Elsevier Ltd. All rights reserved.

A new thrombospondin-related anonymous protein homologue in Neospora caninum (NcMIC2-like1)

Neospora caninum is an Apicomplexan protozoan that has the dog as a definitive host and cattle (among other animals) as intermediate hosts. It causes encephalopathy in dogs and abortion in cows, with significant loss in worldwide livestock. As any Apicomplexan, the parasite invades the cells using proteins contained in the phylum-specific organelles, like the micronemes, rhoptries and dense granules. The aim of this study was the characterization of a homologue (denominated NcMIC2-like1) of N. caninum thrombospondin-related anonymous protein (NcMIC2), a micronemal protein previously shown to be involved in the attachment and connection with the intracellular motor responsible for the active process of invasion. A polyclonal antiserum raised against the recombinant NcMIC2-like1 functional core (thrombospondin and integrin domains) recognized the native form of NcMIC2-like1, inhibited the in vitro invasion process and localized NcMIC2-like1 at the apical complex of the parasite by confocal immunofluorescence, indicating its micronemal localization. The new molecule, NcMIC2-like1, has features that differentiates it from NcMIC2 in a substantial way to be considered a homologue dagger.

The effect of organisational culture perceptions on the relationship between budgetary participation and managerial job-related outcomes

The impact of managers' perceptions of their organizational culture (OC) on the relationship between budgetary participation (BP) and managerial job-related outcomes, operationalized as managerial performance and job-related tension (JRT) is examined. Data supported predictions that increasing BP would lower JRT for managers perceiving a high emphasis on innovation within their OC, regardless of their perceptions of an emphasis on attention to detail. When managers perceived low innovation, however, their perception of level of attention to detail had a significant effect on the relationship between BP and JRT.

The Coefficient of Variance as an index of L2 lexical processing skill

The Coefficient of Variance (mean standard deviation/mean Response time) is a measure of response time variability that corrects for differences in mean Response time (RT) (Segalowitz & Segalowitz, 1993). A positive correlation between decreasing mean RTs and CVs (rCV-RT) has been proposed as an indicator of L2 automaticity and more generally as an index of processing efficiency. The current study evaluates this claim by examining lexical decision performance by individuals from three levels of English proficiency (Intermediate ESL, Advanced ESL and L1 controls) on stimuli from four levels of item familiarity, as defined by frequency of occurrence. A three-phase model of skill development defined by changing rCV-RT.values was tested. Results showed that RTs and CVs systematically decreased as a function of increasing proficiency and frequency levels, with the rCV-RT serving as a stable indicator of individual differences in lexical decision performance. The rCV-RT and automaticity/restructuring account is discussed in light of the findings. The CV is also evaluated as a more general quantitative index of processing efficiency in the L2.

Effects of memory load and distraction on performance and event-related slow potentials in a visuospatial working memory task

Brain electrical activity related to working memory was recorded at 15 scalp electrodes during a visuospatial delayed response task. Participants (N = 18) touched the remembered position of a target on a computer screen after either a 1 or 8 sec delay. These memory trials were compared to sensory trials in which the target remained present throughout the delay and response periods. Distracter stimuli identical to the target were briefly presented during the delay on 30% of trials. Responses were less accurate in memory than sensory trials, especially after the long delay. During the delay slow potentials developed that were significantly more negative in memory than sensory trials. The difference between memory and sensory trials was greater at anterior than posterior electrodes. On trials with distracters, the slow potentials generated by memory trials showed further enhancement of negativity whereas there were minimal effects on accuracy of performance. The results provide evidence that engagement of visuospatial working memory generates slow wave negativity with a timing and distribution consistent with frontal activation. Enhanced brain activity associated with working memory is required to maintain performance in the presence of distraction. © 1997 by the Massachusetts Institute of Technology

Cyclic peroxides and related norterpenes from a southern Australian marine sponge, Mycale sp.

Investigation of a southern Australian marine sponge, Mycale sp., resulted in isolation of the known norsesterterpenes 1-3 as well as two new isomeric norsesterterpenes, mycaperoxide C methyl ester (4) and mycaperoxide D methyl ester (5), and six new norterpenes (6-11).

Young children, adolescents and alcohol - Part I: Exploring knowledge and awareness of alcohol and related issues

This article explores young children's and adolescents' views pertaining to: knowledge and awareness of alcohol and alcohol related issues; social situations in which. alcohol use is present; orientation to alcohol risk; perceived and actual alcohol use; social image and reputation; and short and long term health beliefs in relation to alcohol. Forty focus groups were conducted with 240 primary school students (118 males and 122 females) and 24 focus groups were conducted with 192 high school students (90 males and 102 females); the total being 64 focus groups comprising 432 school students. Participants ages ranged from five years three months to 16 years 10 months. The videotaped discussions revealed that approximately 75% of the primary school-aged children and almost all of the high school students reported that they had tasted alcohol. Parents were primarily responsible for providing the alcohol. Virtually all participants recognised and were able to correctly name a selection of alcoholic and non-alcoholic beverages, and levels of knowledge and awareness of the health and safety aspects of alcohol were relatively mixed. Presentation of bottles and cans was reported as being important in attracting young persons. These data suggest there is an urgent need for research addressed to the development of prevention/intervention education curriculum materials for use with primary school-aged children.

Mycaperoxides F and G and a related norterpene ketone from southern Australian marine sponges, Mycale species

Investigation of two southern Australian marine sponges, Mycale spp., resulted in isolation of the known norsesterterpene mycaperoxide F methyl ester (5) together with a new norsesterterpene mycaperoxide G methyl ester (10) and a new norterpene ketone 11. All structures were secured by spectroscopic analysis and chemical derivatization. The absolute stereochemistry previously assigned to 5 by application of the Horeau procedure has been revised by application of the Mosher procedure.

Coalbed methane sorption related to coal composition

Gas sorption by coal is closely related to its physical and chemical properties, which are, in turn, governed by coal type and rank. The role of coal type (sensu maceral composition) is not fully established but it is clear that coal type may affect both adsorption capacity and desorption rate. Adsorption capacity is closely related to micropore (pores <2 nm) development, which is rank and maceral dependent. Adsorption isotherms indicate that in most cases bright (vitrinite-rich) coals have a greater adsorption capacity than their dull (often inertinite-rich) equivalents. However, no differences, or even the opposing trend, may be observed in relation to coal type. Desorption rate investigations have been performed using selected bright and dull coal samples in a high pressure microbalance. Interpretation of results using unipore spherical and bidisperse pore models indicate the importance of the pore structure. Bright, vitrinite-rich coals usually have the slowest desorption rates which is associated with their highly microporous structure. However, rapid desorption in bright coals may be related to development of extensive, unmineralised fracture systems. Both macro-and micro-pore systems are implicated in the more rapidly desorbing dull coals. Some dull, inertinite-rich coals may rapidly desorb due to a predominance of large, open cell lumina. Mineral matter is essentially nonadsorbent to coal gases and acts as a simple diluent. However, mineral-rich coals may be associated with more rapid desorption. Coal rank and type (maceral composition) per se do not appear to be the critical factors in controlling gas sorption, but rather the influence they exert over pore structure development. (C) 1998 Elsevier Science B.V.

Methadone maintenance and drug-related crime

Using data from an evaluation of methadone maintenance treatment, this study investigated factors associated with continued involvement irt crime during treatment, and in particular whether there appeared to be differences in effectiveness of treatment between different methadone clinics. The methodology was an observational study, in which 304 patients attending three low-intervention, private methadone clinics in Sydney were interviewed on three occasions over a twelve month period. Outcome measures were self-reported criminal activity and police department records of convictions. By self-report, crime dropped, promptly and substantially on entry to treatment, to a level of acquisitive crime about one-eighth that reported during the last addiction period. Analysis of official records indicated that rates of acquisitive convictions were significantly lower in the in-treatment period compared to prior to entry to treatment, corroborating the changes suggested by self-report. Persisting involvement in crime in treatment was predicted by two factors: the cost of persisting use of illicit drugs, particularly cannabis, and ASPD symptom count. Treatment factors also were independently predictive of continued involvement in crime. By both self-report and official records, and adjusting for subject factors, treatment at one clinic teas associated with greater involvement in crime. This clinic operated in a chaotic and poorly organized way. it is concluded that crime during methadone treatment is substantially lower than during street addiction, although the extent of reduction depends on the quality of treatment being delivered.

Health-related quality of life in Australian children with asthma: lessons for the cross-cultural use of quality of life instruments

The development of Australian forms of the Childhood Asthma Questionnaires (CAQs) is reported. Focus group methods and psychometric analyses were used to establish the conceptual, semantic and technical equivalence of these forms with the UK versions. Both versions also provide for data collection from non-asthmatic youngsters. The internal consistency was found to be acceptable (Cronbach's alpha 0.52-0.90) and the health-related quality of life (HRQoL) scores were found to vary with asthma severity (p < 0.05). Comparison with the UK data revealed that the non-asthmatic scores were higher for Australian than British children (p < 0.001) but that the scores for children with asthma did not differ between the two countries. It was only In the Australian sample that the group with asthma reported impaired HRQoL when compared to their healthy peers. These findings were interpreted in the context of cultural expectations of life quality and conclusions are presented regarding the importance of the gap between experience and expectations. The difficulties raised by the developmental and cultural issues inherent in paediatric HRQoL research were discussed. Qual. Life Res. 7:409-419 (C) 1998 Kluwer Academic Publishers

Epidermal iontophoresis: II. Application of the ionic mobility-pore model to the transport of local anesthetics

Purpose, An in vitro study was carried out to determine the iontophoretic permeability of local anesthetics through human epidermis. The relationship between physicochemical structure and the permeability of these solutes was then examined using an ionic mobility-pore model developed to define quantitative relationships. Methods. The iontophoretic permeability of both ester-type anesthetics (procaine, butacaine, tetracaine) and amide-type anesthetics (prilocaine, mepivacaine, lidocaine, bupivacaine, etidocaine, cinchocaine) were determined through excised human epidermis over 2 hrs using a constant d.c. current and Ag/AgCl electrodes. Individual ion mobilities were determined from conductivity measurements in aqueous solutions. Multiple stepwise regression was applied to interrelate the iontophoretic permeability of the solutes with their physical properties to examine the appropriateness of the ionic mobility-pore model and to determine the best predictor of iontophoretic permeability of the local anesthetics. Results. The logarithm of the iontophoretic permeability coefficient (log PCj,iont) for local anesthetics was directly related to the log ionic mobility and MW for the free volume form of the model when other conditions are held constant. Multiple linear regressions confirmed that log PCj,iont was best defined by ionic mobility (and its determinants: conductivity, pK(a) and MW) and MW. Conclusions. Our results suggest that of the properties studied, the best predictors of iontophoretic transport of local anesthetics are ionic mobility (or pK(a)) and molecular size. These predictions are consistent with the ionic mobility pore model determined by the mobility of ions in the aqueous solution, the total current, epidermal permselectivity and other factors as defined by the model.