40 research outputs found
Fatty acid synthesis in the developing brain.
No full textThe study of biochemical aspects of brain metabolism is very complex because brain tissue is composed of different cell types. The two major cell types are neurones and oligodendroglia. These two cell types have differing roles but are very closely associated with normal brain development and function. Oligodendroglia are responsible
for the synthesis and maintenance of the myelin membrane. In the developing brain, the myelin membrane is formed during a very short period of time. The aims of this study are (i) to investigate age-dependent changes in the activity of the lipogenic enzymes, fatty acid synthetase and palmitoyl-CoA synthetase which are
intimately involved in the synthesis and activation of
fatty acids for the formation of phospholipids for
incorporation into the myelin membrane;(ii) to determine the sub-cellular location of these enzymes;(iii) to investigate the effect of thyroid hormone on the activity of these enzymes and (iv) to determine the route of fatty acid incorporation into myelin lipids. The results presented indicate (i) that the activities of fatty acid
synthetase and palmitoyl-CoA synthetase increase during the period of myelination; (ii) fatty acid synthetase is found predoninantly in the cytoplasmic fraction from brain homogenates, whereas palmitoyi-CoA synthetase activity is present in all menribrane fractions, although activity measured in myelin may be due to contamination; (iii) the administration of thyroid hormone has no effect on palmitoyl-CoA, synthetase, whereas
its specific antagonist, propylthiouracil, causes
a decrease in enzyme activity in the mitochondria enriched fraction; (iv) the accumulation of radioactivity
in the myelin fraction from labelled fatty.: acid
involves all subcellular organelles
including the cytoplasm and no precursor-product relationship is apparent. The results will be considered in the light of data available for lipo- genic and other enzymes involved in lipid synthesis
Reconstructing time of flight detector values of angular streaking using machine learning
No full textAngular streaking experiments enable for experimentation in the attosecond regions. However, the deployed time of flight TOF detectors are susceptible to noise and failure. These shortcomings make the outputs of the TOF detectors hard to understand for humans and further processing, such as, for example, the extraction of beam properties. In this article, we present an approach to remove high noise levels and reconstruct up to three failed TOF detectors from an arrangement of 16 TOF detectors. Due to its fast evaluation time, the presented method is applicable online during a running experiment. It is trained with simulation data, and we show the results of denoising and reconstruction of our method on real world experiment dat
ChemInform Abstract: Synthesis and Pharmacodynamic Activity of 2-(3-(2-Phenylethyl) benzofuran-2-yl)-N-propylethanamine.
No full textBayesian probabilities for occurrence of large earthquakes in the seismogenic sources of Japan and Phillipine during the period 1998-2017
No full textΣτην μελέτη αυτή γίνεται χρήση της στατιστικής Bayes με σκοπό την εκτίμηση των πιθανοτήτων γένεσης μελλοντικών μεγάλων σεισμών, υιοθετώντας την υπόθεση ότι οι σεισμοί ακολουθούν κατανομή Poisson. Η μέθοδος που χρησιμοποιείται εκτιμά την πιθανότητα υπέρβασης σεισμών με καθορισμένο κατώφλι μεγέθους σε χρονικό διάστημα 20 ετών, δηλ. 1998-2017. Αυτό το κατώφλι επιλέγει να είναι το μέγεθος μεγαλύτερο ή ίσο του Μ=7.0. Οι πιθανότητες που εκτιμήθηκαν με τον τρόπο αυτό μπορεί να θεωρηθούν ότι παρουσιάζουν την σεισμικότητα. Στην συνέχεια με τα αποτελέσματα αυτά χαράσσονται γραμμές (καμπύλες) που παρουσιάζουν την διακύμανση της σεισμικότητας μεταξύ των σεισμογενών πηγών των περιοχών της Ιαπωνίας και των Φιλιππίνων. Οι γραφικές αυτές παραστάσεις, όπου εμφανίζεται η μεταβαλλόμενη σεισμικότητα είναι πολλαπλά χρήσιμες τόσο για θεωρητικούς όσο και για πρακτικούς σκοπούς.The Bayesian statistics is adopted in 11 seismic sources of Japan and 14 of Philippine in order to estimate the probabilities of occurrence of large future earthquakes, assuming that earthquakes occurrence follows the Poisson distribution. The Bayesian approach applied represents the probability that a certain cut-off magnitude (or larger) will exceed in a given time interval of 20 years, that is 1998-2017. This cut-off magnitude is chosen the one with M=7.0 or greater. In this case we can consider these obtained probabilities as a seismic hazard presentation. More over curves are produced which present the fluctuation of the seismic hazard between these seismic sources. These graphs of varying probability are useful either for engineering or other practical purpose
Site-specific interrogation of an ionic chiral fragment during photolysis using an X-ray free-electron laser
No full textUltrashort circularly polarised light pulses from free-electron lasers offer a route for exploring chiral molecules and their dynamics, but remain challenging to harness. Here, X-ray pump-probe experiments enable a site-specific photoelectron circular dichroism measurement on a dissociating chiral molecule
Controlling Fragmentation of the Acetylene Cation in the Vacuum Ultraviolet via Transient Molecular Alignment
No full textAn open-loop control
scheme of molecular fragmentation based on
transient molecular alignment combined with single-photon ionization
induced by a short-wavelength free electron laser (FEL) is demonstrated
for the acetylene cation. Photoelectron spectra are recorded, complementing
the ion yield measurements, to demonstrate that such control is the
consequence of changes in the electronic response with molecular orientation
relative to the ionizing field. We show that stable C2H2+ cations are mainly produced when the molecules
are parallel or nearly parallel to the FEL polarization, while the
hydrogen fragmentation channel (C2H2+ → C2H+ + H) predominates when the molecule
is perpendicular to that direction, thus allowing one to distinguish
between the two photochemical processes. The experimental findings
are supported by state-of-the art theoretical calculations
