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State Analysis (state + analysis)

Distribution by Scientific Domains

Life Sciences	80%

Selected Abstracts

Magnetoencephalographic gamma power reduction in patients with schizophrenia during resting condition

HUMAN BRAIN MAPPING, Issue 10 2009
Lindsay Rutter
Abstract Objective: The "default network" represents a baseline condition of brain function and is of interest in schizophrenia research because its component brain regions are believed to be aberrant in the disorder. We hypothesized that magnetoencephalographic (MEG) source localization analysis would reveal abnormal resting activity within particular frequency bands in schizophrenia. Experimental Design: Eyes-closed resting state MEG signals were collected for two comparison groups. Patients with schizophrenia (N = 38) were age-gender matched with healthy control subjects (N = 38), and with a group of unmedicated unaffected siblings of patients with schizophrenia (N = 38). To localize 3D-brain regional differences, synthetic aperture magnetometry was calculated across established frequency bands as follows: delta (0.9,4 Hz), theta (4,8 Hz), alpha (8,14 Hz), beta (14,30 Hz), gamma (30,80 Hz), and super-gamma (80,150 Hz). Principle Observations: Patients with schizophrenia showed significantly reduced activation in the gamma frequency band in the posterior region of the medial parietal cortex. As a group, unaffected siblings of schizophrenia patients also showed significantly reduced activation in the gamma bandwidth across similar brain regions. Moreover, using the significant region for the patients and examining the gamma band power gave an odds ratio of 6:1 for reductions of two standard deviations from the mean. This suggests that the measure might be the basis of an intermediate phenotype. Conclusions: MEG resting state analysis adds to the evidence that schizophrenic patients experience this condition very differently than healthy controls. Whether this baseline difference relates to network abnormalities remains to be seen. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source]

The State in World History: Perspectives and Problems

AUSTRALIAN JOURNAL OF POLITICS AND HISTORY, Issue 3 2002
Gregory Melleuish
This paper investigates the role of the state in world history and analyses some of the major issues confronting such an investigation with a particular focus on the relationship between the modern European state and the other historical forms of the state. Firstly it considers the problems raised by the fact that the terminology of state analysis is derived from a discourse that arose to explain the particularity of European state development. Secondly it considers the problem of the origins of the state. It examines two major issues: van Creveld's argument that only modern European states are real states and the chiefdom/state distinction. It argues that new political forms occurred both with the emergence of civilisation and the "state" in the ancient world and with the development of the modern European state after 1300. Thirdly it considers the issue of a typology of states through an examination of the model developed by Finer in his The History of Government. It argues that this model is only really effective in dealing with pre,modern political forms and that the modern European state needs to be understood as a deviant from the Eurasian norm of the agrarian empire. [source]

Feed development for fed-batch CHO production process by semisteady state analysis

BIOTECHNOLOGY PROGRESS, Issue 3 2010
Sarwat F. Khattak
Abstract Semisteady state cultures are useful for studying cell physiology and facilitating media development. Two semisteady states with a viable cell density of 5.5 million cells/mL were obtained in CHO cell cultures and compared with a fed-batch mode control. In the first semisteady state, the culture was maintained at 5 mM glucose and 0.5 mM glutamine. The second condition had threefold higher concentrations of both nutrients, which led to a 10% increase in lactate production, a 78% increase in ammonia production, and a 30% reduction in cell growth rate. The differences between the two semisteady states indicate that maintaining relatively low levels of glucose and glutamine can reduce the production of lactate and ammonia. Specific amino acid production and consumption indicated further metabolic differences between the two semisteady states and fed-batch mode. The results from this experiment shed light in the feeding strategy for a fed-batch process and feed medium enhancement. The fed-batch process utilizes a feeding strategy whereby the feed added was based on glucose levels in the bioreactor. To evaluate if a fixed feed strategy would improve robustness and process consistency, two alternative feeding strategies were implemented. A constant volume feed of 30% or 40% of the initial culture volume fed over the course of cell culture was evaluated. The results indicate that a constant volumetric-based feed can be more beneficial than a glucose-based feeding strategy. This study demonstrated the applicability of analyzing CHO cultures in semisteady state for feed enhancement and continuous process improvement. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]

Rapid media transition: An experimental approach for steady state analysis of metabolic pathways

BIOTECHNOLOGY PROGRESS, Issue 1 2010
Hannes Link
Abstract Commonly steady state analysis of microbial metabolism is performed under well defined physiological conditions in continuous cultures with fixed external rates. However, most industrial bioprocesses are operated in fed-batch mode under non-stationary conditions, which cannot be realized in chemostat cultures. A novel experimental setup,rapid media transition,enables steady state perturbation of metabolism on a time scale of several minutes in parallel to operating bioprocesses. For this purpose, cells are separated from the production process and transferred into a lab-scale stirred-tank reactor with modified environmental conditions. This new approach was evaluated experimentally in four rapid media transition experiments with Escherichia coli from a fed-batch process. We tested the reaction to different carbon sources entering at various points of central metabolism. In all cases, the applied substrates (glucose, succinate, acetate, and pyruvate) were immediately utilized by the cells. Extracellular rates and metabolome data indicate a metabolic steady state during the short-term cultivation. Stoichiometric analysis revealed distribution of intracellular fluxes, which differs drastically subject to the applied carbon source. For some reactions, the variation of flux could be correlated to changes of metabolite concentrations. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source]