Na(+) doping induced changes in the reduction and charge transport characteristics of Al2O3-stabilized, CuO-based materials for CO2 capture.

Chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) are emerging CO2 capture technologies that could reduce appreciably the costs associated with the capture of CO2. In CLC and CLOU, the oxygen required to combust a hydrocarbon is provided by a solid oxygen carrier. Among the transition metal oxides typically considered for CLC and CLOU, copper oxide (CuO) stands out owing to its high oxygen carrying capacity, exothermic reduction reactions and fast reduction kinetics. However, the low Tammann (sintering) temperature of CuO is a serious drawback. In this context, it has been proposed to support CuO on high Tammann temperature and low cost alumina (Al2O3), thus, reducing the morphological changes occurring over multiple CLC or CLOU redox cycles and stabilizing, in turn, the high activity of CuO. However, in CuO-Al2O3 systems, phase stabilization and avoiding the formation of the CuAl2O4 spinel is key to obtaining a material with a high redox stability and activity. Here, we report a Na(+) doping strategy to phase stabilize Al2O3-supported CuO, yielding in turn an inexpensive material with a high redox stability and CO2 capture efficiency. We also demonstrate that doping CuO-Al2O3 with Na(+) improves the oxygen uncoupling characteristics and coke resistance of the oxygen carriers. Utilizing in situ and ex situ X-ray absorption spectroscopy (XAS), the local structure of Cu and the reduction pathways of CuO were determined as a function of the Na(+) content and cycle number. Finally, using 4-point conductivity measurements, we confirm that doping of Al2O3-supported CuO with Na(+) lowers the activation energy for charge transport explaining conclusively the improved redox characteristics of the new oxygen carriers developed.

[Neuroanatomical eponyms in Revista de Neurología on-line]. / Epónimos neuroanatómicos en Revista de Neurología en línea.

INTRODUCTION: Anatomical eponyms are terms that have been proscribed in anatomical terminology, but are widely used in medicine and neurology. Their persistence is due to the fact that they are used in textbooks and scientific papers. AIMS: To determine which neuroanatomical eponyms are used in neurology in Spanish, and how often they are utilised. MATERIALS AND METHODS: We conducted a descriptive, longitudinal, retrospective study of the neuroanatomical eponyms that appeared in papers published in the online version of Revista de Neurología between 1998 and 2006. RESULTS: In all, 46 papers with 193 eponyms were reviewed. The main eponyms used were the following: vein of Galen (14%), circle or polygon of Willis (11.9%) and cerebral or Sylvian aqueduct (11.4%). Other eponyms that do not appear in the Anatomical terminology were: Broca's area (15.5%) and Wernicke's area (7.2%). Most of the eponyms were found in clinical notes (43.4%) and reviews (28.2%), and there was an increase in the number of eponyms published in more recent years, that is, 2003-2006. CONCLUSIONS: No studies on the frequency of eponym usage were found and the first data on the subject are those included here. In order to prevent the dissemination of eponyms, they should not appear in the title or the keywords used in articles. Eponyms referring to blood vessels and the ventricular system of the brain were the most commonly used and were found in the clinical notes or reviews dealing with magnetic resonance, computed tomography and ultrasound imaging of the vascular system of the brain.

¿Nódulos axonales? / Axonal nodes?

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Epónimos neuroanatómicos en Revista de Neurología en línea / Neuroanatomical eponyms in revista de neurología on-line

Introducción. Los epónimos anatómicos son términos proscritos en la terminología anatómica, pero tienen un amplio uso en medicina y neurología. Su persistencia se debe a su utilización en libros de texto y artículos científicos. Objetivo. Conocer los epónimos neuroanatómicos y con qué frecuencia se utilizan en neurología, en lengua castellana. Materiales y métodos. Se efectuó un estudio descriptivo, longitudinal y retrospectivo de los epónimos neuroanatómicos aparecidos en los artículos de Revista de Neurología en línea desde 1998 hasta 2006. Resultados. Se revisaron 46 artículos con 193 epónimos en total. Los principales epónimos fueron: vena de Galeno (14%), polígono o círculo de Willis (11,9%) y acueducto o conducto de Silvio (11,4%). Otros epónimos que no aparecen en la Terminología anatómica fueron: área de Broca (15,5%) y área de Wernicke (7,2%). La mayoría de los epónimos se encontró en notas clínicas (43,4%) y revisiones (28,2%), y se aprecia un aumento de los epónimos publicados en los últimos años: 2003-2006. Conclusiones. No se han encontrado estudios sobre la frecuencia de los epónimos y se aportan los primeros datos. Para evitar la difusión de los epónimos, éstos no deberían aparecer en el título o las palabras claves del artículo. Los epónimos de los vasos sanguíneos y del sistema ventricular del encéfalo eran los más frecuentes y se encontraron en las notas clínicas o las revisiones sobre resonancia magnética, tomografía computarizada y ecografía del sistema vascular del encéfalo

Introduction. Anatomical eponyms are terms that have been proscribed in anatomical terminology, but are widely used in medicine and neurology. Their persistence is due to the fact that they are used in textbooks and scientific papers. Aims. To determine which neuroanatomical eponyms are used in neurology in Spanish, and how often they are utilised. Materials and methods. We conducted a descriptive, longitudinal, retrospective study of the neuroanatomical eponyms that appeared in papers published in the online version of Revista de Neurología between 1998 and 2006. Results. In all, 46 papers with 193 eponyms were reviewed. The main eponyms used were the following: vein of Galen (14%), circle or polygon of Willis (11.9%) and cerebral or Sylvian aqueduct (11.4%). Other eponyms that do not appear in the Anatomical terminology were: Broca's area (15.5%) and Wernicke’s area (7.2%). Most of the eponyms were found in clinical notes (43.4%) and reviews (28.2%), and there was an increase in the number of eponyms published in more recent years, that is, 2003-2006. Conclusions. No studies on the frequency of eponym usage were found and the first data on the subject are those included here. In order to prevent the dissemination of eponyms, they should not appear in the title or the keywords used in articles. Eponyms referring to blood vessels and the ventricular system of the brain were the most commonly used and were found in the clinical notes or reviews dealing with magnetic resonance, computed tomography and ultrasound imaging of the vascular system of the brain

Neuronal activity in the substantia nigra in the anaesthetized rat has fractal characteristics. Evidence for firing-code patterns in the basal ganglia.

Current models of the basal ganglia assume a firing-rate code for information processing. We have applied five complementary computing methods to assess firing patterns in 188 cells of the substantia nigra in the anaesthetized rat. Fractal firing activity was found in 100% of nigral cells projecting to the superior colliculus, in 51% of cells projecting to the thalamus and in 33% of cells projecting to the pedunculopontine nucleus, but was practically absent in dopaminergic nigrostriatal neurons (3%). The finding of fractal firing patterns may lead to a better understanding of the normal operational mode and pathological manifestations of the basal ganglia.

The deep mesencephalic nucleus as an output center of basal ganglia: morphological and electrophysiological similarities with the substantia nigra.

The deep mesencephalic nucleus (DMN) is a large midbrain reticular region between the superior colliculus, the substantia nigra compacta, the periaqueductal gray, and the medial geniculate body. Although some data suggest that it is involved in nociception and visceral control, its functions remain unclear. In the present study, by using morphological (combination of anterograde and retrograde tracers with immunocytochemistry and in situ hibrydization) and electrophysiological (firing activity and transynaptic response to striatal stimulation) methods, we show that a subpopulation of DMN cells shares many morphological and electrophysiological characteristics with those of the substantia nigra reticulata (SNR). These similarities include the following: 1) firing rate, firing pattern, and conduction velocity; 2) expression of GAD65, GAD67, and PV; 3) excitatory and inhibitory inputs from the striatum; and 4) projections to the ventral thalamus, superior colliculus, and pedunculopontine tegmental nucleus. Some differences were also found. In comparison with SN, DMN cells and striatal afferents are more sparsely distributed and they show conspicuous contralateral projections to the thalamus and superior colliculus. This suggests that, similarly to the SNR, the DMN acts as an output center of basal ganglia and probably facilitates the inter-hemispheric regulation of these centers.

Dopamine cell degeneration induced by intraventricular administration of 6-hydroxydopamine in the rat: similarities with cell loss in parkinson's disease.

In an attempt to find a convenient rat model to study cell vulnerability in Parkinson's disease, we have investigated the cell-loss profile in different midbrain dopaminergic nuclei and subnuclei of rats injected with 6-hydroxydopamine (6-OHDA) in the third ventricle. Following administration of different doses (5-1000 microgram) of 6-OHDA, motor behavior was evaluated and tyrosine hydroxylase-immunostained neurons were counted in the A8 group and different subdivisions of A9 and A10 groups. Animals developed hypokinesia, repetitive chewing movements, and catalepsia. Signs of cell degeneration were evident from the first day after injection, reaching the definitive pattern at the end of the first week. There was a similar degeneration in both brain sides, the A9 group showing the highest degree of cell-loss, followed by A8 and A10 groups. In the A9 group, the degeneration mostly affected those subgroups located in its ventral, lateral, and posterior regions. In the A10 group the degeneration mainly affected the parabrachial pigmented nucleus, the paranigral nucleus and the ventral tegmental area. This topographic pattern of degeneration is very similar to that previously described in Parkinson's disease, suggesting that this model may be a useful tool in the study of the cell vulnerability mechanisms in this neurodegenerative disorder. In addition, our results also showed that small dopaminergic neurons are more resistant to degeneration than the large ones. In some DA subgroups, the cells that contained calbindin but not calretinin were less vulnerable to the neurotoxic effect of 6-OHDA.

Motor behavioural changes after intracerebroventricular injection of 6-hydroxydopamine in the rat: an animal model of Parkinson's disease.

At the beginning of the 1970s, different studies reported behavioural disturbances after the intracerebroventricular (icv) administration of 6-hydroxydopamine (6-OHDA) in the rat. Despite the fact that this neurotoxic agent degenerates brain dopaminergic (DA-) cells, its potential utility to produce a rat model of Parkinson's disease (PD) was never systematically studied because the aphagia and adipsia were often observed. In the present study, a procedure that induces a marked DA-cell degeneration that bypasses these and other undesirable complications of icv injection of 6-OHDA is reported. Lesioned animals (50-500 microg of 6-OHDA) showed a persistent motor syndrome composed of hypokinesia, purposeless chewing and catalepsy. The intensity of motor signs was dose-dependent, and recovered partially after administration of DA-receptor agonists, exposure to sensorial stimuli and stress, three procedures that reduce motor dysfunctions in Parkinson's disease (PD). Lesioned animals showed bilateral and symmetrical midbrain DA-cell degeneration with the highest cell-loss in A9 group (substantia nigra), followed by A8 (retrorubral field) and A10 (ventral tegmental area) groups. The similarity between the behavioural syndrome and the topographical profile of cell-loss after icv injection of 6-OHDA in rats and the clinical and neuropathological features of PD indicates that this may be a convenient animal model of PD particularly useful for checking in rats the possible efficacy of new anti-parkinsonian drugs on specific parameters of motor dysfunctions.

Excitatory responses in the 'direct' striatonigral pathway: effect of nigrostriatal lesion.

The existence of a striatonigral GABAergic projection that inhibits substantia nigra reticulata (SNr) cells has been well established. We report on electrophysiological evidence in the rat for a striatonigral excitatory pathway that affects 15% of all SNr cells. Using the antidromic response test to classify SNr cells in relation to their projecting nucleus, an excitatory striatonigral response was found in 57% of cells projecting to the pedunculopontine tegmental nucleus (PPTg) and 11% of cells projecting to the thalamus. SNr cells innervated by inhibitory or excitatory striatonigral inputs had a similar firing rate but a lower variation coefficient (VC) than SNr cells that did not respond to striatonigral inputs. The 6-hydroxydopamine (6-OHDA) degeneration of nigrostriatal dopaminergic cells (A9) induced an increase in the percentage of SNr cells excited from the striatum (52%) and in the VC, but no modification of the firing rate or of the number of spikes induced by each striatal stimulus. This increase in VC was found for the striatonigral inhibitory, but not for the striatonigral excitatory pathway. These data indicate that in addition to its inhibitory action, the direct striatonigral pathway has an excitatory activity that is particularly prominent for SNr cells projecting to the pedunculopontine nucleus. Because the percentage of SNr cells excited by this pathway was markedly increased by DA cell degeneration, our findings suggest that the excitatory striatonigral system could be involved in the pathophysiology of Parkinson's disease.

NOS expression in nigral cells after excitotoxic and non-excitotoxic lesion of the pedunculopontine tegmental nucleus.

The substantia nigra (SN) receives afferents from cholinergic neurons of the pedunculopontine tegmental nucleus (PPTg), a neuronal population that shows high levels of nitric oxide synthase (NOS), the enzyme responsible for the synthesis of nitric oxide. We have investigated the effects of the injection in PPTg of two neurotoxins, kainic acid (an excitotoxic neurotoxin), and ethylcholine mustard azirinium ion (AF64A, a non-excitotoxic neurotoxin), upon the SN cells of the rat, by using choline acetyltransferase (ChAT) immunohistochemistry as a marker of cholinergic neurons, and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry and NOS immunohistochemistry as markers of nitric oxide-producing neurons. Our results show that in normal rats, the SN contains two populations of NOS-positive neurons: large cholinergic neurons of PPTg that invade the caudal region of the SN, and small elongated neurons lying in the SN pars compacta. After ipsilateral PPTg lesion, another population of nigral cells, constituted by medium sized neurons, became NADPHd/NOS-positive. This was much more evident in AF64A-injected rats, in which many medium sized neurons showed enzymatic activity and normal morphological features, at least during the 90 days after injection. Kainic acid-injected rats, in contrast, showed nigral cell degeneration, an effect not found in AF64A material, and only a few NOS-positive neurons. NADPHd/NOS activity was never present in degenerating neurons. These findings suggest that induction of NOS activity is not involved in nigral cell degeneration, and that nitric oxide could have a protective rather than a neurotoxic role. The possible role of nitric oxide in the pathogenesis of Parkinson's disease is discussed.

Hernias abdominais - analise de incidencia em 2000 casos. / Abdominal hernias. Incidence analysis in 2000 cases

Os autores fazem uma analise casuistica dos primeiros 2000 casos operados de hernias abdominais, em sua Clinica de Cirurgia Geral. Nao cuidam da tecnica, das bases anatomicas, nem dos resultados, procuram tao somente a tabulacao dos numeros relativos de ocorrencia. Comparam os seus dados com os de outros autores, observando discrepancia na frequencia entre os tipos crural e umbilical, tendo observado maior incidencia do tipo umbilical sobre o crural. Apos analisarem cada tipo de hernia, concluem mostrando a importancia da doenca herniaria no conjunto das afeccoes cirurgicas, marcando o seu dimensionamento socioeconomico na comunidade