Thrombose veineuse profonde : une thrombolyse est-elle efficace ? : revue cochrane pour le praticien

Scénario: Une patiente de 45 ans vous consulte car sa jambe droite est bleue, cyanosée, avec une tension dans le mollet depuis cinq jours, qui s'est étendue progressivement jusqu'au haut de la cuisse. La circonférence du mollet droit est 4 cm plus grande que celle du mollet gauche. La patiente est en surpoids (IMC à 35 kg/m2) et suit depuis quelques années un traitement oestro-progestatif. Elle n'a pas d'anamnèse familiale ou d'antécédent de maladie thromboembolique. Un ultrason montre une thrombose veineuse profonde (TVP) avec un thrombus s'étendant de la veine poplitée à la veine iliaque externe. Question: La patiente pourrait-elle bénéficier d'une thrombolyse? Contexte: Les complications de la TVP comprennent l'embolie pulmonaire et le syndrome post-thrombotique. Un syndrome post-thrombotique léger à modéré peut survenir chez 30-50% des patients malgré un traitement anticoagulant, qui prévient principalement l'embolie pulmonaire et la récidive de TVP. Cette mise à jour de revue systématique compare l'efficacité du traitement anticoagulant à celui combinant les anticoagulants et la thrombolyse (par streptokinase, urokinase ou activateur tissulaire du plasminogène)

Thrombolyse bei tiefer Venenthrombose? [Thrombolytic therapy in deep venous thrombosis?]

Sie sehen eine 45-jährige Patientin mit einem bläulich-zyanotischen rechten Bein. Vor fünf Tagen habe ein Spannungsschmerz in der Wade begonnen und sich zunehmend in den Oberschenkel hochgezogen. Die rechte Wade misst im Umfang 4 cm mehr als die linke. Die Anamnese ergibt keine familiäre oder persönliche Vorgeschichte einer thromboembolischen Erkrankung. Die Patientin ist übergewichtig ( BMI 35 kg/m2) und nimmt seit einigen Jahren eine Östrogen-Progesteron-Kombination. Der Ultraschall zeigt eine Thrombose der tiefen Beinvenen, die bis in die äussere Beckenvene reicht

Ordered mesoporous metal oxides for electrochemical applications: correlation between structure, electrical properties and device performance

Ordered mesoporous metal oxides with a high specific surface area, tailored porosity and engineered interfaces are promising materials for electrochemical applications. In particular, the method of evaporation-induced self-assembly allows the formation of nanocrystalline films of controlled thickness on polar substrates. In general, mesoporous materials have the advantage of benefiting from a unique combination of structural, chemical and physical properties. This Perspective article addresses the structural characteristics and the electrical (charge-transport) properties of mesoporous metal oxides and how these affect their application in energy storage, catalysis and gas sensing

Transport properties of mixed ionic and electronic conductors - from bulk to nanostructure

Ceria-based materials exhibit mixed ionic and electronic conductivity due to the redox-activity of the cation (Ce4+/Ce3+) and the oxygen ion mobility in the fluorite-type lattice, which intrinsically tends to form a high concentration of Anti-Frenkel defects. Both electrons and ions migrate by an activated hopping mechanism with activation barriers of 0.4 eV for the hopping process of small polarons, 0.8 eV and up to 1.6 eV for the migration and the extrinsic formation and migration of oxygen vacancies, respectively. This leads to a p(O2)-sensitive electrical conductivity, which can be dominated by each process depending on temperature and oxygen activity. Moreover, the material is quite tolerant regarding the substitution of cations. By choosing the type and range of substitution, electrical properties can be adjusted in different ways. Therefore, ceria and its substituted analogues qualify for various applications as solid electrolytes in oxygen membranes, electrode material in solid oxide fuel cells (SOFCs) and in combination with the high oxygen storage capacity for support material in heterogeneous catalysis. The defect chemistry of ceria is already extensively investigated in literature. Thus the material is an ideal model system to study interface effects, in particular the concentration and type of electronic and ionic defects as well as their transport properties in the vicinity of interfaces, complementing the established defect chemical models for bulk material. Within this work we compare the solid solution of ceria and praseodymia (Ce1-xPrxO2-δ) with the solid solution of ceria and zirconia (Ce1-xZrxO2-δ). It is already known, that due to the redox-activity of Pr-ions the combination with praseodymia can lead to an additional transport of polarons, increasing the electronic contribution to electrical conductivity. In contrast, the combination with isovalent zirconia results in an increase of the so-called reducibility of ceria due to the size mismatch of the cations. To gain a deeper understanding of the role of these substitutions on electrochemical transport processes at interfaces, highly ordered mesoporous thin films of Ce1-xPrxO2-δ (CPO) and Ce1-xZrxO2-δ (CZO) have been investigated. The mesoporous samples have been synthesized by a sol-gel process using evaporation induced self-assembly, resulting in a regular pore structure surrounded by a closed packed, interconnected 3D architecture of nanocrystallites. The structural properties were analyzed by SEM, WAXD, XRD, XPS and Raman spectroscopy, confirming the successful synthesis of a mesoporous material of high structural quality, where the surface dominates over the bulk behaviour. The electrical properties were investigated as a function of temperature and oxygen partial pressure using electrochemical impedance spectroscopy. The comparison of the results with previous results of single crystalline samples elucidates the effect of the continuous pore structure on electrical transport properties. The CZO thin films show an unusual p(O2)-dependence at high oxygen partial pressures, which cannot be explained by standard defect chemical models. Furthermore, both mesoporous samples reveal a conductivity plateau under strongly reducing conditions, which is discussed in terms of hopping statistics and defect-defect interaction

DFT+U studies including spin-orbit coupling - a case study for f-electrons in praseodymium-doped ceria

The mixed ionic electronic conductor Ceria exhibits not only a high concentration of Anti-Frenkel defects with high mobility, resulting in ionic conductivity of oxygen ions, but also enables an additional electronic conduction mechanism in form of small polaron hopping between the f-states of the cations. This promotes the reversible exchange of oxygen with the surrounding atmosphere and thus the oxygen storage capacity of the binary oxide CeO2-δ. The material has been established as a model system to describe both ionic and electronic transport processes in bulk material to gain deeper insights into the characteristics of polaron hopping and defect-defect interactions in mixed conductors. By introducing the redox active lanthanide Praseodymium to the Ceria host lattice, both electronic and ionic conductivities are increased in temperature and oxygen partial pressure regions where pure Ceria lacks of good performance. The redox properties of Pr-ions, shifting the equilibrium from Pr4+ to Pr3+ and forming oxygen vacancies, is key to understand the additional contribution to the total electrical conductivity and the enhanced catalytic activity. So far in literature, only the effect of Pr3+-ions in the Ceria host lattice has been investigated by means of density functional theory. To complement these investigations with the impact of Pr-ions in both oxidation states, density functional theory was applied, including a Hubbard-U correction for electronic correlation in the f-states of both cations in Ce1-xPrxO2-δ. A systematic study of spin polarization, antiferromagnetic coupling and spin-orbit interaction of the unpaired 4f-electrons was performed to investigate the influence of magnetic interactions on the description of localized polarons. The preferred localization of the excess electrons on Pr- rather than Ce-ions as well as the defect formation and configuration is discussed by analyzing the resulting energy levels and densities of states of the investigated ideal and defective super cells

Hepatitis C, diagnosis and management: a survey of practicing physicians in Hawaii.

We surveyed 652 Hawaii physicians who diagnosed hepatitis C (HCV) since 1997. Less than 20% of licensed physicians have diagnosed HCV and initial estimates suggest there are 12,000 to 18,000 undiagnosed HCV cases in Hawaii. Treatment is concentrated among twelve physicians and aggressive case finding may overwhelm present resources. More primary care physicians need to participate in the detection and management of HCV

Grain morphological characterization and protein content of sixty-eight local rice (Oryza sativa L) cultivars from Cameroon

Rice (Oryza sativa L.) cultivated in Cameroon is appreciated by consumers for its nutritive quality and good taste. Diversity of 68 local rice cultivars was investigated via grain morphology and protein content characterization. The size and shape of grains were determined and used with yield parameters to classify the cultivars and perform Principal Component Analysis (PCA). Total protein content and glutelin content of eight selected cultivars (CMRGNd, CMRGDn, CMRGTï, CMRTBa, CMRDWb, CMRDTc3, CMRDTx5 and CMRDTx6) were evaluated by Bradford assay and correlation analysis of all the parameters studied was performed. Long size grains (42) were predominant over extra-long (16), medium (9) and short (1) grains. Slender shaped grains (36) were distinguished as well as medium (28) and bold (4) grains. The 68 cultivars were grouped into four clusters independent of their origins. PCA revealed three principal components accounting for 74.4% of total variation. Highest total protein content was observed in CMRGNd (14.3%) and highest glutelin content in CMRGDn (10.1 mgEqvBSA/g DW). Pearson correlation of the different variables revealed no significant correlation between total protein and glutelin contents with the agro-morphological parameters evaluated in this study. This suggests that none of these parameters could be descriptor for protein content. Positive correlation between grain length and yield (r = 0.7) suggests grain length as yield descriptor

Comparing the electrical and protonic conductivity of mesoporous and nanocrystalline thin films of ceria-zirconia solid solutions

Due to the redox activity of the redox couple Ce3+/Ce4+, ceria-based solid solutions are typical mixed electronic and ionic conductors (MIECs) which are used e.g. as solid electrolytes in oxygen membranes or as electrode material in solid oxide fuel cells. CexZr1-xO2 (CZO) solid solutions not only show an increased thermal and mechanical stability compared to the corresponding binary oxides, but also exhibit an improved oxygen storage capacity making CZO a prominent material system for heterogeneous catalysis. Besides the control over composition, the defect chemistry of CZO may be optimized by nanostructuring. Here we present investigations of the electrical properties of mesoporous C0.8Z0.2O2 thin films prepared by solution phase coassembly of salt precursors with an amphiphilic diblock copolymer using an evaporation-induced self-assembly (EISA) process. The mesoporous thin films exhibit a regular pore network with a high surface to volume ratio making them an ideal model system to study the influence of surface effects on the transport properties. Structural characterization using SEM, WAXD, XRD, XPS and Raman spectroscopy reveal the high structural quality of the thin films with 24 nm diameter pores which are surrounded by a crystalline wall structure consisting of 3 to 15 nm grains. Nanocrystalline thin films were prepared using pulsed laser deposition and characterized by SEM and XRD. Using electrochemical impedance spectroscopy, the electrical properties of the mesoporous and nanocrystalline thin films were investigated in a temperature range from room temperature to 500 °C and under different oxygen partial pressures between 1 and 10-4 bar. Measurements under varying humidity show large differences between the mesoporous and nanocrystalline thin films. While a significant increase in the conductivity is observed for the nanocrystalline thin films at temperatures below 250 °C and high humidity conditions, the mesoporous samples show no contribution of protonic conductivity. As will be discussed, these results indicate that the high surface area of the mesoporous samples has either no or very little effect on the protonic transport properties in CZO. Please click Additional Files below to see the full abstract