Measurements with multi-point microprobes: Effect of suspended solids on the hydrodynamics of bubble columns for application in chemical and biotechnological processes

Many experimental studies reveal that suspended solids considerably alter the coalescence behaviour and hydrodynamic functions of wo-phase flow. But no systematic efforts have yet been undertaken to separate the effects of different particle properties on local gas hold-up, bubble size and interfacial area gas/liquid. The aim of this paper is to present the local values of these parameters in three-phase fluidized beds of different solids, using miniaturized optical fiber and conductivity needle probes. It is shown that particle concentration, size and, in particular, density are decisive for the change in coalescence behaviour. Ranges of normal (?_S > ?_L) and inverse fluidization (?_S < ?_L) must be distinguished and the flow regime also exerts a strong influence on the interactions between the dispersed phases, the transition point itself being a function of particle properties can be observed, This effect is evaluated for different column diameters, between 0.1 and 0.3 m.     

Fast and accurate analytic formulas for calculating the parametersof a general broadside-coupled coplanar waveguide for (M)MICapplications

Fast and accurate analytic formulas for calculating the quasistatic transverse electromagnetic (TEM) parameters of a general broadside-coupled coplanar waveguide (GBSC CPW) are presented. Simplicity, high speed of computation, and accuracy suggest the use of these formulas for (M)MIC CAD (monolithic) microwave integrated circuit computer-aided design programs. Numerical calculations are presented to investigate various electrical properties of the structure. An asymmetrical BSC CPW and the single CPW resulting from connecting the two coupled strips of the GBSC CPW at the input and the output ports are analyzed. Criteria are obtained to ensure the coplanar behavior of the structure     

Adjuvant interferon alfa-2a treatment in resected primary stage II cutaneous melanoma. Austrian Malignant Melanoma Cooperative Group

PURPOSE: Patients with primary cutaneous melanoma with a Breslow thickness > or = 1.5 mm have only a 30% to 70% probability of survival after surgery, and no adjuvant therapy has so far improved this outcome. Since interferon alfa-2a (IFNalpha2a) exhibits antitumor activity in metastatic melanoma, we investigated whether adjuvant IFNalpha2a diminishes the occurrence of metastases and thus prolongs disease-free survival in melanoma patients after excision of the primary tumor. PATIENTS AND METHODS: In a prospective randomized study, 311 melanoma patients with a Breslow thickness > or = 1.5 mm were assigned to either adjuvant IFNalpha2a treatment (n = 154) or observation (n = 157) after excision of the primary tumor. IFNalpha2a was given daily at a dose of 3 mIU subcutaneously (s.c.) for 3 weeks (induction phase), after which a dose of 3 mIU s.c. three times per week was given over 1 year (maintenance phase). RESULTS: Prolonged disease-free survival was observed in patients treated with IFNalpha2a versus those who underwent surgery alone. This difference was significant (P = .02) for all patients enrolled onto the study (intention-to-treat analysis) at a mean observation time of 41 months. Subgroup analysis showed that Breslow tumor thickness had no influence on treatment results in the groups of patients investigated. CONCLUSION: Adjuvant IFNalpha2a treatment diminishes the occurrence of metastases and thus prolongs disease-free survival in resected primary stage II cutaneous melanoma patients.     

Charge-shielding and the "paradoxical" stimulation of tubulin polymerization by guanidine hydrochloride

Low concentrations of guanidine hydrochloride (GuHCl) increase the rate (and to a lesser degree, the extent) of tubulin polymerization as assessed by light scattering. Maximum enhancement occurs at 120-160 mM GuHCl followed by decreases at higher GuHCl. The latent period is decreased, and there is a 3-4 fold reduction in the critical concentration of polymerization. Electronmicrographs reveal microtubules in the controls and an increasing fraction of total polymers present as aberrant microtubules as the GuHCl concentration is increased from 20 to 100 mM. The GuHCl effect is markedly reduced, but not abolished, in tubulin S (in which the anionic C termini of both monomers have been removed). The GuHCl-induced polymerization has an absolute requirement for GTP and taxol or DMSO, is very sensitive to podophyllotoxin inhibition, and can overcome urea-mediated inhibition of polymerization. Guanidinium analogues mimic the GuHCl effect roughly as a function of the number of potential hydrogen bonds. The anions of the guanidine salts superimpose their inhibitory action on the guanidinium cation effect according to the lyotropic series. At higher GuHCl concentrations (peak effect 500-700 mM), a different polymer (type II) is formed that is GTP and taxol independent, but whose polymerization is retarded but not prevented by podophyllotoxin. Its structure resembles the fibrillar network seen in unfolding intermediates of other proteins. We conclude that both charge and hydrogen-bonding ability are major contributors to the GuHCl-induced promotion of tubulin polymerization, and that charge-shielding is likely to be the basis for this effect.     

Attentional orienting and reorienting is indicated by human event-related brain potentials

We investigated event-related potential indications for the orienting towards task-irrelevant, distracting aspects of stimulation and for the subsequent reorienting towards task-related aspects of stimulation. An identical experimental protocol was run in three conditions manipulating the task relevance of the sounds. As to be expected, distractors elicited the MMN (reflecting the brain's pre-attentive change detection) in each condition (even when the sounds were ignored) and subsequent N2b and P3 (reflecting orienting towards the distractor) when the sounds were attended. A late negativity was confined to a condition in which subjects discriminating long from short sounds were distracted by task-irrelevant frequency deviations. The 'reorienting negativity' (RON) probably reflects processes in the context of reorienting towards task-relevant aspects of stimulation following distraction.     

Association rule mining in peer-to-peer systems

We extend the problem of association rule mining--a key data mining problem--to systems in which the database is partitioned among a very large number of computers that are dispersed over a wide area. Such computing systems include grid computing platforms, federated database systems, and peer-to-peer computing environments. The scale of these systems poses several difficulties, such as the impracticality of global communications and global synchronization, dynamic topology changes of the network, on-the-fly data updates, the need to share resources with other applications, and the frequent failure and recovery of resources. We present an algorithm by which every node in the system can reach the exact solution, as if it were given the combined database. The algorithm is entirely asynchronous, imposes very little communication overhead, transparently tolerates network topology changes and node failures, and quickly adjusts to changes in the data as they occur. Simulation of up to 10,000 nodes show that the algorithm is local: all rules, except for those whose confidence is about equal to the confidence threshold, are discovered using information gathered from a very small vicinity, whose size is independent of the size of the system.     

A longitudinal study of the moderating role of extraversion: Leader-member exchange, performance, and turnover during new executive development.

Identifying factors that help or hinder new executives in "getting up to speed" quickly and remaining with an organization is vital to maximizing the effectiveness of executive development. The current study extends past research by examining extraversion as a moderator of relationships between leader-member exchange (LMX) and performance, turnover intentions, and actual turnover for an executive sample. The sample consisted of 116 new executives who were surveyed prior to starting their employment and at 3 months postentry. A total of 67 senior executives rated these new executives in terms of overall performance at 6 months postentry. Turnover data were gathered from company records 3 1/2 years later. Hierarchical regression results showed that LMX was not related to performance or turnover intentions for those high in extraversion; but for individuals low in extraversion, there was a relation between LMX, performance, and turnover intentions. Furthermore, survival analyses showed that LMX was only related to turnover-hazard rate for individuals low in extraversion. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Food and packaging interactions: determination of the kinetic parameters of olive oil diffusion in polypropylene using concentration profiles.

The penetration of olive oil into polypropylene was studied in order to allow a complete modellization of food and packaging interactions. Oil concentration profiles through polypropylene food trays were determined by FTIR-microscopy measurements along the thickness at various times. Calculations of the relevant parameters characterizing Fickian diffusion, namely constant diffusivity, coefficient of convective mass transport on the surface and concentration at equilibrium were carried out. This way of working has proven to be considerably shorter and more accurate than the method consisting of recording the global absorbance of the substance absorbed, especially when the amount of diffusing fat is low. Major conclusions are: that absorption of olive oil is strongly influenced by convection; the diffusion coefficient of olive oil in polypropylene is constant. Possible consequences to simplify global migration testing are discussed.     

Beta-galactosidase-labelled relay neurons of homotopic olfactory bulb transplants establish proper afferent and efferent synaptic connections with host neurons

The vertebrate olfactory system has long been an attractive model for studying neuronal regeneration and adaptive plasticity due to the continuous neurogenesis and synaptic remodelling throughout adult life in primary and secondary olfactory centres, its precisely ordered synaptic network and accessibility for manipulation. After homotopic transplantation of fetal olfactory bulbs in bulbectomized neonatal rodents, newly regenerated olfactory neurons form glomeruli within the graft, and the efferent mitral/tufted cells of the transplant innervate the host brain, terminating in higher olfactory centres. However, the synaptic connections of the transplanted relay neurons within the graft and/or host's olfactory centres could not be characterized mainly because of lack of suitable cell-specific markers for these neurons. In this study, we have used olfactory bulbs from transgenic fetuses, in which the majority of the mitral/tufted cells express the bacterial enzyme beta-galactosidase, for homotopic olfactory bulb transplantation following complete unilateral bulbectomy. In the transplants, the cell bodies and terminals of the donor mitral/tufted cells were identified by beta-galactosidase histochemistry and immunocytochemistry at both light and electron microscope levels. We demonstrate that transplanted relay neurons re-establish specific synaptic connections with host neurons of the periphery, source of the primary signal and central nervous system, thereby providing the basis for a functional recovery in the lesioned olfactory system.