Home About us Contact
|
Home About us Contact | ||
|
|
||
Time Regardless (time + regardless)
Selected AbstractsProduction of a Laccase and Decrease of the Phenolic Content in Canola Meal during the Growth of the Fungus Pleurotus ostreatus in Solid State Fermentation ProcessesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 1 2004J. Hu Abstract Solid state fermentation of canola meal was carried out with the fungus Pleurotus ostreatus DAOM 197961, which is a producer of laccase. The aim of this study was to examine the effects of moisture content, inoculum size, homogenisation of inoculum and particle size of canola meal on the growth of the fungus, the production of a laccase and the decrease of the content of sinapic acid esters (SAE) in a solid state process. The results showed that the optimum moisture content, which was varied in the media between 50% and 75%, for the growth and enzyme production was 60%. The initial rate of SAE content decrease was faster in the media with 70% and 75% moisture than in those with lower moisture levels. In the study of the effects of inoculum concentration in the range of 1.1 mg to 5.5 mg/g of the medium, it was found that larger amounts of biomass and enzyme were produced in the media with inoculum concentrations from 1.1 mg to 3.3 mg/g of the medium than in the media with a higher inoculum concentration. The final and approximately the same concentrations of SAE were reached at the same time regardless of the inoculum concentration. Considering that the fungus formed pellets under the conditions at which it was grown during the inoculum preparation, it was necessary to break them by homogenisation prior to their utilisation as an inoculum. The homogenisation was carried out during a period between 15s and 200s. Although higher biomass concentrations and enzyme activities were obtained in the media which were inoculated with the inoculum homogenised for 15s and 30s, the maximum enzyme activities and biomass concentrations were reached in the media inoculated with the inoculum, which was homogenised for 120s and 200s. The time of inoculum homogenisation did not influence the kinetics of the SAE decrease. When the effects of the particle size of canola meal on the process were studied, it was found that larger particles of the meal in the solid media were more favourable for the production of the biomass and enzyme, and for a faster decrease of the SAE content than those of smaller sizes. From the obtained results it can be concluded that the tested variables have a significant influence on the growth of the fungus Pleurotus ostreatus DAOM 197961, the production of laccase and the decrease of the SAE content in canola meal. The data could be useful for the development of a solid state process for the production of laccase and for the decrease of the phenolics content in canola meal. [source] Is the Left Ventricular Lateral Wall the Best Lead Implantation Site for Cardiac Resynchronization Therapy?PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p2 2003MAURIZIO GASPARINI GASPARINI, M., et al.: Is the Left Ventricular Lateral Wall the Best Lead Implantation Site for Cardiac Resynchronization Therapy?Short-term hemodynamic studies consistently report greater effects of cardiac resynchronization therapy (CRT) in patients stimulated from a LV lateral coronary sinus tributary (CST) compared to a septal site. The aim of the study was to compare the long-term efficacy of CRT when performed from different LV stimulation sites. From October 1999 to April 2002, 158 patients (mean age 65 years, mean LVEF 0.29, mean QRS width 174 ms) underwent successful CRT, from the anterior (A) CST in 21 patients, the anterolateral (AL) CST in 37 patients, the lateral (L) CST in 57 patients, the posterolateral (PL) CST in 40 patients, and the middle cardiac vein (MCV) CST in 3 patients. NYHA functional class, 6-minute walk test, and echocardiographic measurements were examined at baseline, and at 3, 6, and 12 months. Comparisons were made among all pacing sites or between lateral and septal sites by grouping AL + L + PL CST as lateral site (134 patients, 85%) and A + MC CST as septal site (24 patients, 15%). In patients stimulated from lateral sites, LVEF increased from 0.30 to 0.39(P < 0.0001), 6-minute walk test from 323 to 458 m(P < 0.0001), and the proportion of NYHA Class III,IV patients decreased from 82% to 10%(P < 0.0001). In patients stimulated from septal sites, LVEF increased from 0.28 to 0.41(P < 0.0001), 6-minute walk test from 314 to 494 m(P < 0.0001), and the proportion of NYHA Class III,IV patients decreased from 75% to 23%(P < 0.0001). A significant improvement in cardiac function and increase in exercise capacity were observed over time regardless of the LV stimulation sites, either considered singly or grouped as lateral versus septal sites. (PACE 2003; 26[Pt. II]:162,168) [source] A class of sequential tests for two-sample composite hypothesesTHE CANADIAN JOURNAL OF STATISTICS, Issue 2 2006Edit Gombay Abstract The authors propose a class of statistics based on Rao's score for the sequential testing of composite hypotheses comparing two treatments (populations). Asymptotic approximations of the statistics lead them to propose sequential tests and to derive their monitoring boundaries. As special cases, they construct sequential versions of the two-sample t-test for normal populations and two-sample z-score tests for binomial populations. The proposed algorithms are simple and easy to compute, as no numerical integration is required. Furthermore, the user can analyze the data at any time regardless of how many inspections have been made. Monte Carlo simulations allow the authors to compare the power and the average stopping time (also known as average sample number) of the proposed tests to those of nonsequential and group sequential tests. A two-armed comparative clinical trial in patients with adult leukemia allows them to illustrate the efficiency of their methods in the case of binary responses. Une classe de tests séquentiels pour des hypothèses composites sur deux échantillons Les auteurs proposent une classe de statistiques, basées sur le score de Rao, pouvant servir à tester séquentiellement des hypothèses composites comparant deux traitements (ou populations). Des approximations asymptotiques les conduisent à proposer des tests séquentiels dont ils déterminent les zones de rejet. Comme cas particulier, ils construisent des versions séquentielles du test de Student pour deux échantillons normaux et du test du score z pour deux populations binomiales. Les algorithmes proposés sont simples et faciles à mettre en ,uvre, puisqu'ils ne nécessitent aucune intégration numérique. De plus, l'utilisateur peut analyser ses données à n'importe quel moment, sans égard au nombre d'inspections déjà effectuées. Des simulations de Monte-Carlo permettent aux auteurs de comparer la puissance et le temps d'arr,t moyen (aussi appelé l'effectif moyen) des tests proposés à ceux de tests non séquentiels ou séquentiels groupés. Une étude clinique comparative à deux bras effectuée sur des patients atteints de leucémie adulte leur permet d'illustrer l'efficacité de leurs méthodes pour des réponses binaires. [source] Effect of the geometry on the performance of the MaxblendÔ impeller with viscous Newtonian fluidsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Yoann Guntzburger Abstract Experimental and numerical investigations have been carried out to assess the effect of the vessel geometry (number of baffles) and the shape of the Maxblend impeller (configuration of the bottom paddle and angle of the upper grid) with viscous Newtonian fluids in the laminar and lower turbulent mixing regimes. Two parameters have been explored namely the power consumption of the impeller and the mixing time. Videos of the discoloration process have also been taken to get access to the mixing patterns. A nominal 50-l vessel has been used in the experiments. The number of baffles has been varied from 1 to 4, and the bottom paddle has been modified by making openings to allow flow passage. Finally, the effect of using a straight grid in the upper part of the Maxblend has been studied under the same conditions. It is shown that the number of baffles does not have a significant effect on the power consumption, the mixing evolution, and the mixing time regardless of the flow regime. Making openings in the bottom paddle allows for the destruction of the segregated zones at the bottom of the tank at the expense of a very slight increase in power consumption and mixing time. Finally, the power and mixing time are both increased with a straight grid Maxblend. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] A Computational Study of Feedback Effects on Signal Dynamics in a Mitogen-Activated Protein Kinase (MAPK) Pathway ModelBIOTECHNOLOGY PROGRESS, Issue 2 2001Anand R. Asthagiri Exploiting signaling pathways for the purpose of controlling cell function entails identifying and manipulating the information content of intracellular signals. As in the case of the ubiquitously expressed, eukaryotic mitogen-activated protein kinase (MAPK) signaling pathway, this information content partly resides in the signals' dynamical properties. Here, we utilize a mathematical model to examine mechanisms that govern MAPK pathway dynamics, particularly the role of putative negative feedback mechanisms in generating complete signal adaptation, a term referring to the reset of a signal to prestimulation levels. In addition to yielding adaptation of its direct target, feedback mechanisms implemented in our model also indirectly assist in the adaptation of signaling components downstream of the target under certain conditions. In fact, model predictions identify conditions yielding ultra-desensitization of signals in which complete adaptation of target and downstream signals culminates even while stimulus recognition (i.e., receptor-ligand binding) continues to increase. Moreover, the rate at which signal decays can follow first-order kinetics with respect to signal intensity, so that signal adaptation is achieved in the same amount of time regardless of signal intensity or ligand dose. All of these features are consistent with experimental findings recently obtained for the Chinese hamster ovary (CHO) cell lines (Asthagiri et al., J. Biol. Chem.1999, 274, 27119,27127). Our model further predicts that although downstream effects are independent of whether an enzyme or adaptor protein is targeted by negative feedback, adaptor-targeted feedback can "back-propagate" effects upstream of the target, specifically resulting in increased steady-state upstream signal. Consequently, where these upstream components serve as nodes within a signaling network, feedback can transfer signaling through these nodes into alternate pathways, thereby promoting the sort of signaling cross-talk that is becoming more widely appreciated. [source] | ||||||||||