The remote associates test (RAT) is a complex verbal task with associations to both creative thought and general intelligence. RAT problems require not only lateral associations and the internal ...production of many words but a convergent focus on a single answer. Complex problem-solving of this sort may thus require both substantial verbal processing and strong executive function capacities. Previous studies have provided evidence that verbal task performance can be enhanced by noninvasive transcranial direct current stimulation (tDCS). tDCS modulates excitability of neural tissue depending on the polarity of the current. The after-effects of this modulation may have effects on task performance if the task examined draws on the modulated region. Studies of verbal cognition have focused largely on the left dorsolateral prefrontal cortex (F3 of the 10–20 EEG system) as a region of interest. We planned to assess whether modulating excitability at F3 could affect complex verbal abilities. In Experiment 1 (anodal, cathodal, or sham stimulation over F3 with the reference electrode over the contralateral supraorbital region), we found a significant overall effect of stimulation condition on RAT performance. Post hoc tests showed an increase in performance after anodal stimulation (1 mA) compared to sham (
= .025) and to cathodal stimulation (
= .038). In Experiment 2 (either anodal stimulation at F3 or separately at its homologue F4), we replicated the anodal effect of the first study, but also showed that anodal stimulation of F4 had no effect on RAT performance. These data provide evidence that anodal stimulation of the left dorsolateral prefrontal cortex can improve performance on a complex verbal problem-solving task believed to require significant executive function capacity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To establish a method for morphometric analysis of retrogradely labeled retinal ganglion cells (RGCs) of the mouse retina, to be used for the study of molecular aspects of RGC survival and ...neuroprotection in this model; to evaluate the effect of overexpression of Cu-Zn-superoxide dismutase (CuZnSOD) on RGC survival after severe crush injury to the optic nerve, and to assess the effect of the alpha2-adrenoreceptor agonist brimonidine, recently shown to be neuroprotective, on RGC survival.
A severe crush injury was inflicted unilaterally in the orbital portion of the optic nerves of wild-type and transgenic (Tg-SOD) mice expressing three to four times more human CuZnSOD than the wild type. In each mouse all RGCs were labeled 72 hours before crush injury by stereotactic injection of the neurotracer dye FluoroGold (Fluorochrome, Denver, CO) into the superior colliculus. Survival of RGCs was then assessed morphometrically, with and without systemic injection of brimonidine.
Two weeks after crush injury, the number of surviving RGCs was significantly lower in the Tg-SOD mice (596.6 +/- 71.9 cells/mm(2)) than in the wild-type control mice (863. 5 +/- 68 cells/mm(2)). There was no difference between the numbers of surviving RGCs in the uninjured retinas of the two strains (3708 +/- 231.3 cells/mm(2) and 3904 +/- 120 cells/mm(2), respectively). Systemic injections of brimonidine significantly reduced cell death in the Tg-SOD mice, but not in the wild type.
Overexpression of CuZnSOD accelerates RGC death after optic nerve injury in mice. Activation of the alpha2-adrenoreceptor pathway by brimonidine enhances survival of RGCs in an in vivo transgenic model of excessive oxidative stress.
A 3.7MeV He+ ion beam was simultaneously used for Polyethylene Terephtalate (PET) film degradation and characterization. To enhance the potentialities of the characterization method, a multi-detector ...Ion Beam Analysis (IBA) technique was used. The stoichiometry change of the PET target following the irradiation is quantified at a beam fluence varying between 7A-1013 and 1.8A-1016 He+ cma degree 2. The damage induced in PET films by He+ bombarding was analyzed in-situ simultaneously through Rutherford Backscattering Spectrometry (RBS), Particle Elastic scattering Spectrometry (PES) and Hydrogen Elastic Recoil Detection (ERD). Appropriate experimental conditions for the observation of absolute changes in composition and thickness during irradiation were determined. The oxygen and carbon content evolution as a function of the ion fluence was monitored by He+ backscattering whereas the hydrogen content was measured by H( alpha ,H) alpha collisions in which both the scattered He+ ions and the recoiling H could be observed. The present study reveals that, at the highest fluence 1.8A-1016 He+ cma degree 2, the PET films have lost approximately 15% of the carbon, more than 45% of the hydrogen and 85% of the oxygen of the amount contained in the pristine sample. The energy shift of recoiling H+ ions at a forward angle 45A degree was followed in order to study the mass loss effect. The experimental results are consistent with the bulk molecular recombination model. Based on the results, hydrogen, oxygen and carbon release cross sections are determined. For hydrogen, comparison with deuteron irradiation indicates a cross section linear dependence on the stopping power.
In this study, the production of sulphuric acid in bioreactors with
Thiobacillus ferrooxidans attached on elemental sulphur was investigated. These bioreactors reached a maximum H
+ productivity of ...80 mmol kg
−1 d
−1 of support. This medium was used for the indirect dissolution of spent nickel–cadmium batteries recovering after 93 days 100% of cadmium, 96.5% of nickel and 95.0% of iron. Moreover, recoveries higher than 90.0% were reached when anodic and cathodic materials were directly added to
Thiobacillus ferrooxidans cultures with sulphur as the sole energy source. The results presented show an economic and effective method which could be considered the first step to recycle spent and discarded batteries preventing one of the many problems of environmental pollution.
Elongated Co nanoparticles induced by swift heavy ion irradiations D’Orléans, C.; Stoquert, J.P.; Estournès, C. ...
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms,
02/2004, Letnik:
216
Journal Article, Conference Proceeding
Recenzirano
Spherical nanoparticles have been formed in SiO
2 layers by 160 keV Co
+ ion implantation. Different particle sizes have been obtained depending on implantation fluence (2
×
10
16, 5
×
10
16 and 1
×
...10
17 Co
+
cm
−2) and substrate temperature (77, 295 and 873 K). These spherical particles have been subsequently irradiated with 200 MeV
127I ions at fluences from 10
11 to 10
14 cm
−2 at 300 K. Modifications of magnetic properties of the irradiated samples, studied by a SQUID magnetometer at 5 and 295 K in a magnetic field applied perpendicular or parallel to the incident beams, have been related to the modifications of the particle size and shape observed by transmission electron microscopy (TEM). The results are in good agreement with calculations based on a model describing two different regimes: a spherical growth at low irradiation fluences and a prolate deformation along the beam direction for the high fluences.
Irradiations of implanted cobalt nanoparticles in silica layers D’Orléans, C.; Cerruti, C.; Estournès, C. ...
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms,
08/2003, Letnik:
209
Journal Article, Conference Proceeding
Recenzirano
Cobalt ions have been implanted at an energy of 160 keV at fluences of 2×10
16, 5×10
16 and 10
17 Co
+
cm
−2 in silica layers and at temperatures of 77, 295 and 873 K. The nanocomposites formed have ...further been irradiated with electrons and swift heavy ions. Magnetic properties of the nanoparticles studied by a SQUID magnetometer at 295 and 5 K have been related to the modification of particle size and size distribution, which have been observed by transmission electron microscopy.
The RUNX transcription factors are important regulators of linage‐specific gene expression in major developmental pathways. Recently, we demonstrated that Runx3 is highly expressed in developing ...cranial and dorsal root ganglia (DRGs). Here we report that within the DRGs, Runx3 is specifically expressed in a subset of neurons, the tyrosine kinase receptor C (TrkC) proprioceptive neurons. We show that Runx3‐deficient mice develop severe limb ataxia due to disruption of monosynaptic connectivity between intra spinal afferents and motoneurons. We demonstrate that the underlying cause of the defect is a loss of DRG proprioceptive neurons, reflected by a decreased number of TrkC‐, parvalbumin‐ and β‐galactosidase‐positive cells. Thus, Runx3 is a neurogenic TrkC neuron‐specific transcription factor. In its absence, TrkC neurons in the DRG do not survive long enough to extend their axons toward target cells, resulting in lack of connectivity and ataxia. The data provide new genetic insights into the neurogenesis of DRGs and may help elucidate the molecular mechanisms underlying somatosensory‐related ataxia in humans.
The distribution of 5-HT1, 5-HT1A, 5-HT1B and 5-HT2 receptors in the rat spinal cord was investigated with quantitative autoradiography. Receptors were labeled respectively with 3Hserotonin ...(5-3HHT),8- hydroxy-2-N-dipropylamino-3Htetralin (8-OH-3HDPAT), 125Iiodocyanopindolol and 3Hketanserin. It is shown that 5-HT1, 5-HT1A and 5-HT1B receptors are distributed within the spinal cord according to a rostro-caudal gradient. Both 5-HT1 and 5-HT1A receptors are mainly present in the dorsal horn and 5-HT1B is present throughout the spinal cord, exhibiting high densities in the caudal-most part of the dorsal horn in lamina X and in the sacral parasympathetic area. On the other hand, 5-HT2 receptors are shown mostly in the thoracic sympathetic area and in the thoracic ventral horn; the dorsal horn exhibits few 5-HT2 receptors. The differential involvement of 5-HT through different receptors in nociception, autonomous nervous system control and motility are discussed.
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