13 resultados para Fe chlorosis

em Université de Lausanne, Switzerland


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Eukaryotic cells generate energy in the form of ATP, through a network of mitochondrial complexes and electron carriers known as the oxidative phosphorylation system. In mammals, mitochondrial complex I (CI) is the largest component of this system, comprising 45 different subunits encoded by mitochondrial and nuclear DNA. Humans diagnosed with mutations in the gene NDUFS4, encoding a nuclear DNA-encoded subunit of CI (NADH dehydrogenase ubiquinone Fe-S protein 4), typically suffer from Leigh syndrome, a neurodegenerative disease with onset in infancy or early childhood. Mitochondria from NDUFS4 patients usually lack detectable NDUFS4 protein and show a CI stability/assembly defect. Here, we describe a recessive mouse phenotype caused by the insertion of a transposable element into Ndufs4, identified by a novel combined linkage and expression analysis. Designated Ndufs4(fky), the mutation leads to aberrant transcript splicing and absence of NDUFS4 protein in all tissues tested of homozygous mice. Physical and behavioral symptoms displayed by Ndufs4(fky/fky) mice include temporary fur loss, growth retardation, unsteady gait, and abnormal body posture when suspended by the tail. Analysis of CI in Ndufs4(fky/fky) mice using blue native PAGE revealed the presence of a faster migrating crippled complex. This crippled CI was shown to lack subunits of the "N assembly module", which contains the NADH binding site, but contained two assembly factors not present in intact CI. Metabolomic analysis of the blood by tandem mass spectrometry showed increased hydroxyacylcarnitine species, implying that the CI defect leads to an imbalanced NADH/NAD(+) ratio that inhibits mitochondrial fatty acid β-oxidation.

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Pizgrischite, (Cu,Fe)Cu14PbBi17S35, is a new mineral species named after the type locality, Piz Grisch Mountain, Val Ferrera, Graubunden, Switzerland. This sulfosalt occurs as thin, striated, metallic lead-grey blades measuring up to I cm in length, embedded in quartz and associated with tetrahedrite, chalcopyrite, pyrite, sphalerite, emplectite and derivatives of the aikinite-bismuthinite series. In plane-polarized light, the new species is brownish grey with no perceptible pleochroism; under crossed nicols in oil immersion, it presents a weak anisotropy with dark brown tints. Minimum and maximum reflectance values (in %) in air are: 40.7-42.15 (470 nm), 41.2-43.1 (546 nm), 41.2-43.35 (589 nm) and 40.7-43.3 (650 nm). Cleavage is perfect along 001 I and well developed on {010}. Abundant polysynthetic twinning is observed on (010). The mean micro-indentation hardness is 190 kg/mm(2) (Mohs hardness 3.3), and the calculated density is 6.58 g/cm(3). Electron-microprobe analyses yield (wt%; mean result of seven analyses): Cu 16.48, Pb 2.10, Fe 0.77, Bi 60.70, Sb 0.35, S 19.16, Se 0.04, total 99.60. The resulting empirical chemical formula is (Cu15.24Fe0.80Pb0.60)(Sigma 16.64)(Bi17.07Sb0.17)(Sigma 17.24)(S35.09Se0.03)(Sigma 35.12), in accordance with the formula derived from the single-crystal refinement of the structure, (Cu,Fe)Cu14PbBi17S35. Pizgrischite is monoclinic, space group C2/m, with the following unit-cell parameters: a 35.054(2), b3.91123(I), c43.192(2) angstrom, beta 96.713(4)degrees, V5881.24 angstrom(3), Z=4. The strongest seven X-ray powder-diffraction lines [d in angstrom (I)(hkl)] are: 5.364(40)((6) over bar 04), 4.080(50)((8) over bar 05), 3.120(40)(118), 3.104(68)((3) over bar 18), 2.759(53) ((9) over bar 11),2.752(44)(910) and 1.956(100)(020). The crystal structure is an expanded monoclinic derivative of kupcikite. Pizgrischite belongs to the cuprobismutite series of bismuth sulfosalts but, sensu stricto, it is not a homologue of cuprobismutite. At the type locality. pizarischite is the result of the Alpine metamorphism under greenschist-facies conditions of pre-Tertiary hydrothermal Cu-Bi mineralization.

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The determination of characteristic cardiac parameters, such as displacement, stress and strain distribution are essential for an understanding of the mechanics of the heart. The calculation of these parameters has been limited until recently by the use of idealised mathematical representations of biventricular geometries and by applying simple material laws. On the basis of 20 short axis heart slices and in consideration of linear and nonlinear material behaviour we have developed a FE model with about 100,000 degrees of freedom. Marching Cubes and Phong's incremental shading technique were used to visualise the three dimensional geometry. In a quasistatic FE analysis continuous distribution of regional stress and strain corresponding to the endsystolic state were calculated. Substantial regional variation of the Von Mises stress and the total strain energy were observed at all levels of the heart model. The results of both the linear elastic model and the model with a nonlinear material description (Mooney-Rivlin) were compared. While the stress distribution and peak stress values were found to be comparable, the displacement vectors obtained with the nonlinear model were generally higher in comparison with the linear elastic case indicating the need to include nonlinear effects.

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The Guelb Moghrein Fe oxide-Cu-Au-Co deposit is located at the western boundary of the West African craton in NW Mauritania. The wall rocks to the mineralization represent a meta-volcanosedimentary succession typical of Archaean greenstone belts. Two types of meta-volcanic rocks are distinguished: (1) volcanoclastic rocks of rhyodacite-dacite composition (Sainte Barbe volcanic unit), which form the stratigraphic base; (2) tholeiitic andesites-basalts (Akjoujt meta-basalt unit). The trace element signature of both types is characteristic of a volcanic arc setting. A small meta-pelitic division belongs to the Sainte Barbe volcanic unit. A meta-carbonate body, which contains the mineralization, forms a tectonic lens in the Akjoujt meta-basalt unit. It can be defined by the high X(mg) (=36) of Fe-Mg carbonate, the REE pattern and the delta(13)C values of -18 to -17 parts per thousand as a marine precipitate similar to Archaean banded iron formation (BIF). Additionally, small slices of Fe-Mg clinoamphibole-chlorite schist in the meta-carbonate show characteristics of marine shale. This assemblage, therefore, does not represent an alteration product, but represents an iron formation unit deposited on a continental shelf, which probably belongs to the Lembeitih Formation. The hydrothermal mineralization at 2492 Ma was contemporaneous with regional D(2) thrusting of the Sainte Barbe volcanic unit and imbrications of the meta-carbonate in the upper greenschist facies. This resulted in the formation of an ore breccia in the meta-carbonate, which is enriched in Fe, Ni, Co, Cu, Bi, Mo, As and Au. Massive sulphide ore breccia contains up to 20 wt% Cu. The ore fluid was aqueous-carbonic in nature and either changed its composition from a Mg-rich oxidizing to an Fe-rich reducing fluid or the two fluid types mixed at the trap site. All lithologies at Guelb Moghrein were deformed by D(3) thrusting to the east in the lower greenschist facies. The mobility of REE in the retrogressed rocks explains the formation of a second generation of hydrothermal monazite, which was dated at c. 1742 Ma. Archaean rocks of the West African craton extend to the west to Guelb Moghrein. The active continental margin was deformed and mineralized in the Late Archaean-Early Proterozoic and again reactivated in the Mid-Proterozoic and Westphalian, showing that the western boundary of the craton was reactivated several times.

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Molar heat capacities of the binary compounds NiAl, NiIn, NiSi, NiGe, NiBi, NiSb, CoSb and FeSb were determined every 10 K by differential scanning calorimetry in the temperature range 310-1080 K. The experimental results have been fitted versus temperature according to C-p = a + b . T + c . T-2 + d . T-2. Results are given, discussed and compared to estimations found in the literature. Two compounds, NiBi and FeSb, are subject to transformations between 460 and 500 K. (C) 1999 Elsevier Science Ltd. All rights reserved.

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The present study discusses the effect of iron doping in TiO2 thin films deposited by rf sputtering. Iron doping induces a structural transformation from anatase to rutile and electrical measurements indicate that iron acts as an acceptor impurity. Thermoelectric power measurement shows a transition between n-type and p-type electrical conduction for an iron concentration around 0.13 at.%. The highest p-type conductivity at room temperature achieved by iron doping was 10(-6) S m(-1).

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Stable isotope compositions of a suite of magmatic amphiboles from alkaline basalts and andesitic rocks were examined to constrain the effects of degassing processes on the hydrogen isotope compositions. The Fe3+ (as Fe3+/Fe-total) and H2O contents, as well as the H isotope compositions of the amphiboles, differ markedly (27-58%, 0.5-2.2 wt%, -107 to -15 parts per thousand, respectively) but indicate systematic variations. The observed trends can be explained either as dehydrogenation or dehydration processes, both of which are coupled to oxidation processes, the latter most probably related to O2- substitution within amphiboles. The dehydrogenation-dehydration models can be used to assess the primary compositions of the magmas. As an important example, delta D values of amphiboles of Martian meteorites are discussed in a similar context. Copyright (c) 2006 John Wiley & Sons, Ltd.

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The 2014 Santa Fe Bone Symposium provided a setting for the presentation and discussion of the clinical relevance of recent advances in the fields of osteoporosis and metabolic bone disease. The format included oral presentations of abstracts by endocrinology fellows, plenary lectures, panel discussions and breakout sessions, with ample opportunities for informal discussions before and after scheduled events. Topics addressed in these proceedings included a review of the important scientific publications in the past year, fracture prevention in patients with dysmobility and immobility, fracture liaison services for secondary fracture prevention, management of pre-menopausal osteoporosis, the role of bone microarchitecture in determining bone strength, measurement of microarchitecture in clinical practice and methods to improve the quality of bone density testing. This is a report of the proceedings of the 2014 Santa Fe Bone Symposium.

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Introduction La stratégie de reperfusion coronarienne par voie percutanée (PCI: percutaneous coronary intervention) est considérée comme étant la méthode de choix dans la prise en charge urgente des STEMI(H). Actuellement, les deux accès artériels principaux pour les PCI sont l'artère fémorale et l'artère radiale. La voie radiale est préconisée en première intention par les guidelines actuelles car elle serait associée à moins de complications hémorragiques. Objectif L'objectif de cette étude était de comparer la voie d'abord radiale à la voie fémorale, chez les patients admis pour un STEMI, en analysant le succès de la procédure de revascularisation, l'évolution clinique et les complications. Méthode Il s'agit d'une étude observationnelle, comprenant 268 patients admis au CHUV entre le 1er janvier et le 31 décembre 2013, avec le diagnostic de STEMI. Le choix de la voie d'accès artériel (fémorale ou radiale) était laissé au cardiologue interventionnel, sans randomisation. Les patients ont été séparés en 2 groupes, selon la voie d'abord vasculaire choisie au début de la procédure de revascularisation (intention to treat). Les endpoints primaires étaient les saignements majeurs (≥ 3 selon BARC)(A), et le door to balloon time(B). Les endpoints secondaires étaient les MACE(C), les saignements mineurs(A), le taux succès des procédures(D), le temps de fluoroscopie, la quantité de produit de contraste, et le taux de crossover(E) Résultats 268 patients en STEMI ont été inclus dans cette étude, pour un geste de revascularisation en urgence. La moyenne d'âge était de 64.3 ans, avec 73.1% d'hommes. 3 cas de saignements majeurs(A) ont lieu avec la voie radiale (3.4%), et 10 avec la voie fémorale (5.6%), p=0.44. Le door to balloon time ne diffère pas de manière significative selon la voie d'accès employée : 42 min (34-57) pour le groupe radial, et 48 min (31-61) pour le groupe fémoral, p=0.09. Les taux de MACE étaient de 8.0% avec la voie radiale, et de 6.7% avec la voie fémorale, p=0.7. Le taux de crossover était de 4.5% avec la voie radiale, et 0.6% avec la voie fémorale, p=0.02. Le temps de fluoroscopie était de 7min 28sec (5min 9 sec - 12min 25) pour la voie fémorale, contre 12min 22sec (9min 30 sec - 16min 19sec) pour la voie radiale, p < 0.05. La quantité de produit de contraste nécessaire était de 120 ml (100-160) pour le groupe fémoral, et de 170 ml (140-210) pour le groupe radial, p < 0.05. Le taux de succès était comparable entres les 2 groupes : 97.7% pour le groupe radial et 96.0% pour le groupe fémoral, p=0.47. 5.7% des patients du groupe radial sont décédés, contre 5.7% du groupe fémoral, p=0.97. Conclusion Notre étude démontre que la prise en charge d'un STEMI par voie radiale est possible, puisqu'elle n'allonge pas le « door to balloon time », qu'elle n'augmente pas le taux de MACE ni les saignements majeurs, que soit au point de ponction ou non. Par contre la voie radiale augmente la quantité de produit de contraste nécessaire, et allonge le temps de fluoroscopie de manière non négligeable. De futures études permettront peut-être de mieux définir les groupes de patients qui pourraient bénéficier le plus d'une approche radiale.