The Role of Kinaesthetic Motor Imagery in Promoting Activation of the Lumbrical Muscles in the Hemiparetic Hand: a Randomised Controlled Study

The objective of the investigation who gave as result this work was to investigate the effectiveness of kinaesthetic motor imagery in the activation of the hemiplegic hand muscles following stroke. The experiment consisted of two random groups. Movements were measured after treatment. The participants were ten patients with hemiplegic hands (men who mean age was 74.4 years; mean time since stroke 3.05 months). All patients received three sessions of physical treatment based on an identical treatment protocol. Five patients were randomly assigned to an experimental group practising kinaesthetic motor imagery of a grasp using the 'lumbrical action' (experimental group). The others five (control group) followed a relaxation script. All the patients were then asked to grasp an object using the 'lumbrical action'. The grasps were recorded using an optoelectronic motion capture system. The magnitude of the extension of the index finger and the correlation of the angular displacement of the proximal phalangeal joints and the metacarpophalangeal joints were calculated. The movement time for the whole grip was calculated. The experimental group demonstrated higher extension in the index finger (p = < 0.01) and they had a higher correlation coefficient (0.99) than the control group (0.77) for the displacement of the proximal interphalangeal joint and the metacarpophalangeal joints. The movement time for the experimental group was faster, although the difference was not significant.

O2 activation at bioinspired complexes: dinuclear copper systems and mononuclear non-heme iron compounds. Mechanisms and catalytic applications in oxidative transformations

L'activació d'oxigen que té lloc en els éssers vius constitueix una font d'inspiració pel desenvolupament d'alternatives als oxidants tradicionals, considerats altament tòxics i nocius. En aquesta treball s'utilitzen compostos sintètics com a models del centre actiu de proteïnes dinuclears de coure i mononuclears de ferro de tipus no-hemo que participen en l'activació d'oxigen en els éssers vius. Els sistemes dinuclears de coure mostren un centre de tipus coure(III) bis(oxo) que és capaç de dur a terme l'ortho-hidroxilació de fenols de manera similar a la reacció que catalitza la proteïna tirosinasa. Per altra banda, els sistemes de ferro desenvolupats en aquest treball actuen com a models de les dioxigenases de Rieske i poden dur a terme l'hidroxilació estereoespecífica d'alcans i l'epoxidació i cis-dihidroxilació d'olefines utilitzant peròxid d'hidrogen com a agent oxidant. Tot plegat demostra que el desenvolupament de sistemes model constitueix una bona estratègia per l'estudi dels sistemes naturals.

Isomerism and C-H, C-C, O-O, C-O bond activation studies by transition metals

Aquesta tesi és el reflex que de la cooperació entre grups experimentals i grups teòrics s'aconsegueix l'assoliment d'objectius inassolibles de forma individual. A partir de la DFT s'expliquen processos inorgànics i organometàl·lics de gran valor biològic i/o industrial. La tesi està enfocada especialment a l'estudi de complexos mononuclears i binuclears de coure, on té lloc l'activació d'enllaços C-H, C-C, i O-O. L'estudi de complexos octaèdrics de ruteni ha permès dur a terme extensos estudis isomèrics i racionalitzar les propietats espectroscòpiques dels mateixos. A més a més, estudis més puntuals respecte clusters de coure, l'estudi de la reacció de Pawson-Khand, l'estudi d'enllaços Pt-Pt en complexos trimèrics de platí, a més a més de l'estudi de la isomeria de complexos de Ni i Pt.

Characterization of mineral surfaces using FIB and TEM: a case study of naturally weathered alkali feldspars

Using a focused ion beam (FIB) instrument, electron-transparent samples (termed foils) have been cut from the naturally weathered surfaces of perthitic alkali feldspars recovered from soils overlying the Shap granite, northwest England. Characterization of these foils by transmission electron microscopy (TEM) has enabled determination of the crystallinity and chemical composition of near-surface regions of the feldspar and an assessment of the influence of intragranular microtextures on the microtopography of grain surfaces and development of etch pits. Damage accompanying implantation of the 30 kV Ga+ ions used for imaging and deposition of protective platinum prior to ion milling creates amorphous layers beneath outer grain surfaces, but can be overcome by coating grains with > 85 nm of gold before FIB work. The sidewalls of the foil and feldspar surrounding original voids are also partially amorphized during later stages of ion milling. No evidence was found for the presence of amorphous or crystalline weathering products or amorphous "leached layers" immediately beneath outer grain surfaces. The absence of a leached layer indicates that chemical weathering of feldspar in the Shap soils is stoichiometric, or if non-stoichiometric, either the layer is too thin to resolve by the TEM techniques used (i.e., <=similar to 2.5 nm) or an insufficient proportion of ions have been leached from near-surface regions so that feldspar crystallinity is maintained. No evidence was found for any difference in the mechanisms of weathering where a microbial filament rests on the feldspar surface. Sub-micrometer-sized steps on the grain surface have formed where subgrains and exsolution lamellae have influenced the propagation of fractures during physical weathering, whereas finer scale corrugations form due to compositional or strain-related differences in dissolution rates of albite platelets and enclosing tweed orthoclase. With progressive weathering, etch pits that initiated at the grain surface extend into grain interiors as etch tubes by exploiting preexisting networks of nanopores that formed during the igneous history of the grain. The combination of FIB and TEM techniques is an especially powerful way of exploring mechanisms of weathering within the "internal zone" beneath outer grain surfaces, but results must be interpreted with caution owing to the ease with which artifacts can be created by the high-energy ion and electron beams used in the preparation and characterization of the foils.

The composition and crystallinity of the near-surface regions of weathered alkali feldspars

Our ability to identify thin non-stoichiometric and amorphous layers beneath mineral surfaces has been tested by undertaking X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) work on alkali feldspars from pH 1 dissolution experiments. The outcomes of this work were used to help interpret XPS and TEM results from alkali feldspars weathered for <10,000 years in soils overlying the Shap Granite (north-west England). The chemistry of effluent solutions indicates that silica-rich layers a few nanometers in thickness formed during the pH I experiments. These layers can be successfully identified by XPS and have lower Al/Si, Na/Si, K/Si and Ca/Si values than the outermost similar to 9 nm of unweathered controls. Development of Al-Si non-stoichiometry is coupled with loss of crystal structure to produce amorphous layers that are identifiable by TEM where >similar to 2.5 nm thick, whereas the crystallinity of albite is retained despite leaching of Na to depths of tens to hundreds on nanometers. Integration of XPS data over the outermost 6-9 nm of naturally weathered Shap feldspars shows that they have stoichiometric Al/Si and K/Si ratios, which is consistent with findings of previous TEM work on the same material that they lack amorphous layers. There is some XPS evidence for loss of K from the outermost couple of nanometers of Shap orthoclase, and the possibility of leaching of Na from albite to greater depths cannot be excluded using the XPS or TEM results. This study demonstrates that the leached layer model, as formulated from laboratory experiments, is inapplicable to the weathering of alkali feldspars within acidic soils, which is an essentially stoichiometric reaction. (C) 2008 Elsevier Ltd. All rights reserved.

Gaze fixations predict brain activation during the voluntary regulation of picture-induced negative affect

Recent studies have identified a distributed network of brain regions thought to support cognitive reappraisal processes underlying emotion regulation in response to affective images, including parieto-temporal regions and lateral/medial regions of prefrontal cortex (PFC). A number of these commonly activated regions are also known to underlie visuospatial attention and oculomotor control, which raises the possibility that people use attentional redeployment rather than, or in addition to, reappraisal as a strategy to regulate emotion. We predicted that a significant portion of the observed variance in brain activation during emotion regulation tasks would be associated with differences in how participants visually scan the images while regulating their emotions. We recorded brain activation using fMRI and quantified patterns of gaze fixation while participants increased or decreased their affective response to a set of affective images. fMRI results replicated previous findings on emotion regulation with regulation differences reflected in regions of PFC and the amygdala. In addition, our gaze fixation data revealed that when regulating, individuals changed their gaze patterns relative to a control condition. Furthermore, this variation in gaze fixation accounted for substantial amounts of variance in brain activation. These data point to the importance of controlling for gaze fixation in studies of emotion regulation that use visual stimuli.

Sex-dependent age modulation of frontostriatal and temporo-parietal activation during cognitive control

Developmental functional imaging studies of cognitive control show progressive age-related increase in task-relevant fronto-striatal activation in male development from childhood to adulthood. Little is known, however, about how gender affects this functional development. In this study, we used event related functional magnetic resonance imaging to examine effects of sex, age, and their interaction on brain activation during attentional switching and interference inhibition, in 63 male and female adolescents and adults, aged 13 to 38. Linear age correlations were observed across all subjects in task-specific frontal, striatal and temporo-parietal activation. Gender analysis revealed increased activation in females relative to males in fronto-striatal areas during the Switch task, and laterality effects in the Simon task, with females showing increased left inferior prefrontal and temporal activation, and males showing increased right inferior prefrontal and parietal activation. Increased prefrontal activation clusters in females and increased parietal activation clusters in males furthermore overlapped with clusters that were age-correlated across the whole group, potentially reflecting more mature prefrontal brain activation patterns for females, and more mature parietal activation patterns for males. Gender by age interactions further supported this dissociation, revealing exclusive female-specific age correlations in inferior and medial prefrontal brain regions during both tasks, and exclusive male-specific age correlations in superior parietal (Switch task) and temporal regions (Simon task). These findings show increased recruitment of age-correlated prefrontal activation in females, and of age-correlated parietal activation in males, during tasks of cognitive control. Gender differences in frontal and parietal recruitment may thus be related to gender differences in the neurofunctional maturation of these brain regions.

Selective effects of Lactobacillus casei Shirota on T cell activation, natural killer cell activity and cytokine production

Modulation of host immunity is an important potential mechanism by which probiotics confer health benefits. This study was designed to investigate the effects of a probiotic strain, Lactobacillus casei Shirota (LcS), on immune function, using human peripheral blood mononuclear cells (PBMC) in vitro. In addition, the role of monocytes in LcS-induced immunity was also explored. LcS promoted natural killer (NK) cell activity and preferentially induced expression of CD69 and CD25 on CD8+ and CD56+ subsets in the absence of any other stimulus. LcS also induced production of IL-1β, IL-6, TNF-α, IL-12 and IL-10 in the absence of lipopolysaccharide (LPS). In the presence of LPS, LcS enhanced IL-1β production, but inhibited LPS-induced IL-10 and IL-6 production, and had no further effect on TNF-α and IL-12 production. Monocyte-depletion significantly reduced the impact of LcS on lymphocyte activation, cytokine production and NK cell activity. In conclusion, LcS preferentially activated cytotoxic lymphocytes in both the innate and specific immune system, which suggests that LcS could potentiate the destruction of infected cells in the body. LcS also induced both pro-inflammatory and anti-inflammatory cytokine production in the absence of LPS, but inhibited LPS-induced cytokine production in some cases. Monocytes play an important role in LcS-induced immunological responses.

Self-activation and out-group contrast

It has been suggested that higher in-group identifiers primed with an out-group stereotype show contrastive behavioral responses because they activate the in-group, social-self. However, priming the personal-self can lead to contrastive judgments. We investigated whether personal self-activation was also evident for higher identifiers primed with an out-group. An experiment demonstrated that higher identifiers primed with an out-group showed faster responses to self-words than higher identifiers primed with the in-group. This findings suggest that the personal-self is also activated for higher identifiers primed with an out-group, and this self-activation may underlie their contrastive responding.

Reduced capacity to sustain positive emotion in major depression reflects diminished maintenance of fronto-striatal brain activation

Anhedonia, the loss of pleasure or interest in previously rewarding stimuli, is a core feature of major depression. While theorists have argued that anhedonia reflects a reduced capacity to experience pleasure, evidence is mixed as to whether anhedonia is caused by a reduction in hedonic capacity. An alternative explanation is that anhedonia is due to the inability to sustain positive affect across time. Using positive images, we used an emotion regulation task to test whether individuals with depression are unable to sustain activation in neural circuits underlying positive affect and reward. While up-regulating positive affect, depressed individuals failed to sustain nucleus accumbens activity over time compared with controls. This decreased capacity was related to individual differences in self-reported positive affect. Connectivity analyses further implicated the fronto-striatal network in anhedonia. These findings support the hypothesis that anhedonia in depressed patients reflects the inability to sustain engagement of structures involved in positive affect and reward.

Microwave activation of the electro-oxidation of glucose in alkaline media

The oxidation of glucose is a complex process usually requiring catalytically active electrode surfaces or enzyme modified electrodes. In this study the effect of high intensity microwave radiation on the oxidation of glucose in alkaline solution at Au, Cu, and Ni electrodes is reported. Calibration experiments with the Fe(CN)(6)(3-/4-) redox system in aqueous 0.1 M NaOH indicate that strong thermal effects occur at both 50 and 500 mu m diameter electrodes with temperatures reaching 380 K. Extreme mass transport effects with mass transport coefficients of k(mt) > 0.01 m s(-1) (or k(mt) > 1.0 cm s(-1)) are observed at 50 mu m diameter electrodes in the presence of microwaves. The electrocatalytic oxidation of glucose at 500 mu m diameter Au, Cu, or Ni electrodes immersed in 0.1 M NaOH and in the presence of microwave radiation is shown to be dominated by kinetic control. The magnitude of glucose oxidation currents at Cu electrodes is shown to depend on the thickness of a pre-formed oxide layer. At 50 mu m diameter Au, Cu, or Ni electrodes microwave enhanced current densities are generally higher, but only at Au electrodes is a significantly increased rate for the electrocatalytic oxidation of glucose to gluconolactone observed. This rate enhancement appears to be independent of temperature but microwave intensity dependent, and therefore non-thermal in nature. Voltammetric currents observed at Ni electrodes in the presence of microwaves show the best correlation with glucose concentration and are therefore analytically most useful.