Chemical stability of caesium iodide deposits in air/steam atmosphere.

Iodine compounds that may be released in case of severe nuclear accident will have important radiotoxicity if they are disseminated in air. One of the most important iodine species is CsI that is deposited on the surfaces of the reactor coolant system. However, depending on the conditions, CsI can volatilize or react with oxidants to produce I2(g). Theoretical and experimental studies demonstrate that the oxidation of iodide depends on the temperature and in the presence of oxidants in the gas. It is also slightly influenced by the crystallinity of the CsI particles and the nature of the support. In case of a high temperature deposition, the iodine release started at temperature lower than 300 °C. For the CsI vapour and aerosol depositions, the iodine is detected only at temperature above 450 °C and become very important above 550 °C.

[Assessment of intracardiac flows by Magnetic Resonance Imaging: The 4D Flow imaging]. / Évaluation des flux en imagerie par résonnance magnétique cardiaque : l'imagerie de flux 4D.

2D flow cardiac MRI is a well-established technique but has some current limitations in routine practice. New 4D flow MRI may overcome these limitations, providing dramatic dynamic imaging, easily understandable, allowing robust quantification of flows. 4D flow imaging should become soon the reference technic for valvular regurgitations and congenital heart disease.

Factors Affecting Growth Kinetics and Spontaneous Metastasis in the B16F10 Syngeneic Murine Melanoma Model.

Melanoma is an immunogenic tumor that can metastasize quickly to proximal and distal sites, thus complicating the application of therapeutic modalities. Numerous mouse model systems have been used to gain understanding of the immunobiology and metastatic potential of melanoma. Here, we report the optimization of a syngeneic mouse melanoma model protocol using the mouse B16-derived melanoma cell line B16F10 that ensures the production of tumors on mice pinnae that are similar in size between animals and that enlarge in a time-dependent manner. In this model, B16F10 cells are first allowed to develop tumors after injection in the interscapular area or flank of C57BL/6J mice. Subsequently, the tumors are harvested, cells dissociated and injected into mouse pinnae. Dose-dependent studies revealed that injection of 2 × 105 cells allowed for slow tumor enlargement, producing tumors averaging 100 mm³ within 2 to 3 wk with a metastatic frequency of 100%. This experimental protocol will be useful in dissecting the immunobiology of melanoma tumor development and metastasis and the evaluation of immunotherapeutic antimelanoma therapies.

[Role of MSCT and MRI in the diagnosis of congenital heart disease]. / Place du scanner multicoupes (SMC) et de l'IRM dans la stratégie diagnostique des cardiopathies congénitales.

Initial diagnosis of congenital heart disease traditionally relies upon clinical examination and ultrasound. Development of non-invasive imaging, multislice CT (MSCT) and magnetic resonance imaging (MRI) has changed the way those patients are evaluated for diagnosis or follow-up. Cardiac catheterization is no longer the step two and in many clinical situations, non-invasive imaging is the method of choice, either before or instead of invasive angiography examination. Cross-sectional cardiovascular imaging brings thorough examination of the thorax, heart and great vessels, leading to three-dimensional volumes imaging, allowing diagnosis of the cardiopathy, evaluation of the anatomy and associated abnormalities. For each imaging technique advantages and drawbacks are discussed. X-ray use is the main disadvantage of MSCT, although it is a fast, easy and efficient technique, especially in babies because of its high spatial and temporal resolutions. Beside a precise 3D evaluation of the heart and great vessels, MSCT allows evaluation of small structures, like coronary arteries in routine, including in neonates and infants, at a fast cardiac rhythm, and in a short examination time. The air-filled structures are well-depicted with MSCT, and 3D imaging is helpful in evaluation of tracheal and bronchi compression as compared to MRI. MR imaging brings, aside from the morphologic evaluation, helpful functional information for the left and right ventricles, and evaluation of valvular disease (stenosis and regurgitation). Those are critical data in the follow-up of patients treated for tetralogy of fallot or after atrial switch for transposition of the great vessels. The technique is also very powerful in evaluating aortic disease, e.g. aortic coarctation and restenosis, and Marfan's disease. Disadvantages are mainly the accessibility and the examination time, which in young patients may require sedation or general anaesthesia. Cross-sectional cardiovascular imaging, MSCT and MRI, have considerably changed the diagnosis and follow-up of patients suffering of congenital cardiopathy. The techniques are complementary, and the choice will depend on the age, the clinical condition and the diagnosis of the patient.

[Computed tomography for imaging of pediatric congenital heart disease]. / Die Computertomographie bei der Bildgebung von Kindern mit kongenitalen Herzvitien.

Congenital heart diseases are the most common congenital abnormalities of development. In general, echocardiography and cardiac catheter angiography are considered the gold standard for the evaluation of congenital heart disease. Cardiac magnetic resonance imaging has become an important supplementary imaging modality because of its ability to provide an accurate morphological and functional evaluation. The role of cardiac computed tomography in the imaging of patients with congenital heart disease is becoming increasingly more important due to the development of low radiation dose protocols and improvements in the spatial and temporal resolution. In the preoperative depiction and follow-up after surgical repair of congenital heart diseases, cardiac computed tomography provides detailed information of the heart, the venous and arterial pulmonary circulation as well as systemic arteries. This article reviews the technical aspects of cardiac CT and the modification of examination protocols according to the expected pathology and patient age. The potentials and limitations of the various radiation dose reduction strategies are outlined.

[Technological advances in cardiac CT]. / Evolutions technologiques en tomodensitométrie cardiaque.

The SFR-SFC presents guidelines dedicated to cardiac and coronary imaging using CT in the area of indications, technological requirement including both hardware and software, patient conditioning, CT protocols and related results concerning radiation dose, image quality and diagnostic value. These guidelines are based either on up-dated medical literature proofs and/or on expert consensus.

[The contribution of computed tomography coronary angiography in Kawasaki disease in adult patients. Report of two cases]. / Apport du scanner coronaire dans la prise en charge de la maladie de Kawasaki chez l'adulte. A propos de deux cas.

OBJECTIVES: During the past few years, multislice computed tomography coronary angiography has made great progress in terms of spatial and temporal resolution. Results on detection and quantification of stenoses are excellent. We found interesting reporting its achievements in aneurismal coronaropathies such as the Kawasaki disease. METHODS: We searched for young adults with Kawasaki disease who had a multislice computed tomography coronary angiography available. Several hospitals in the Paris area have been contacted and only two observations have been kept. RESULTS: Computed tomography provided higher performance than coronarography for the measurement of the real diameter of an aneurism taking into account the mural thrombus, evaluation of its links with the collateral branches and the other aneurisms, assessment of the development of recanalized vessels and the degree of development of collateral vessels, and visualization of non-circulating aneurisms which were not detected with coronary angiography. In addition, the evaluation of the location and the degree of the stenoses by the computed tomography matched the coronary angiography data. It was not possible to conclude with this observations that the computed tomography is better for the diagnostic of Kawasaki disease. CONCLUSION: Multislice computed tomography coronary angiography will be likely more and more used to detect and follow coronary anomalies in case of Kawasaki disease among teenagers and young adults. It is recommended for monitoring medium or large aneurisms in order to evaluate their progression to stenosis.

CO adsorption on CoMo and NiMo sulfide catalysts: a combined IR and DFT study.

Experimental IR spectra of carbon monoxide adsorbed on a series of Mo/Al2O3, CoMo/Al2O3, and NiMo/Al2O3 sulfided catalysts have been compared to ab initio DFT calculations of CO adsorption on CoMo and NiMo model surfaces. This approach allows the main IR features of CO adsorbed on the sulfide phase to be assigned with an uncertainty of 15 cm(-1). On the CoMo system, the band at 2070 cm(-1) is specific of the promotion by Co and is assigned to CO interacting either with a Co atom or with a Mo atom adjacent to a Co atom. On the NiMo system, CO adsorption on Ni centers of the promoted phase leads to a high-wavenumber band at approximately 2120 cm(-1) that strongly overlaps the band at 2110 cm(-1) characteristic of nonpromoted Mo sites. For NiMo and CoMo catalysts, broad shoulders at low wave numbers (below 2060 cm(-1)) are characteristic of Mo centers adjacent to promoter atoms, indicating a partial decoration of the MoS2 edges by the promoter.

[Surgical treatment of chronic thromboembolic pulmonary hypertension]. / Traitement chirurgical de la maladie thromboembolique pulmonaire chronique.

Chronic thromboembolic pulmonary hypertension is a condition that has long remained in the shadows, a kind of orphan disease, because of the lack of any curative treatment. The renewal of interest by pulmonary specialists, cardiologists and thoracic surgeon is due to the development over the past 20 years of major new treatments: lung transplantation, continuous prostacyclin infusion, and pulmonary endarterectomy, in chronological order. Most patients with postembolic pulmonary arterial hypertension (PEPAH) in a sufficiently proximal location can benefit from curative surgical treatment by bilateral endarterectomy of the pulmonary arteries. This complex surgery, performed under deep hypothermic circulatory arrest, clears out the pulmonary vascular bed down through its subsegmental branches and results in a frank reduction in pulmonary vascular resistance and normalization of cardiopulmonary function. It is a curative procedure with a perioperative mortality rate less than 7% and a definitive result, unlike pulmonary and cardiopulmonary transplantation, which have a postoperative mortality rate of 20% and a 5-year survival rate of 50%. It is difficult to recognize the postembolic nature of pulmonary hypertension because there is no known history of venous thrombosis or embolic phenomena in more than 50% of cases. Diagnosis is based on the presence of mismatched segmental defects in the radioisotopic ventilation-perfusion scanning. To be accessible to endarterectomy, lesions must involve the main, lobar, or segmental arteries. When conducted by experienced operators according to specific protocols, pulmonary (frontal and lateral views of each lung) and multislice CT angiography optimize assessment of the lesion site. When the pulmonary vascular resistance evaluated by catheterization is correlated with the anatomical obstruction visible on the images, pulmonary endarterectomy has a mortality rate below 4% and offers the patient a substantial chance to regain normal cardiorespiratory function. In cases of pulmonary arterial hypertension due to older embolisms, major arteriolitis occurs in the nonobstructed areas and aggravates the pulmonary hypertension, which may become suprasystemic. The endarterectomy mortality rate is then higher, and in specific cases justifies preoperative medical treatment. Pulmonary or cardiopulmonary transplantation is indicated in this disease only when the lesions are too distal and thus inaccessible to endarterectomy.

[Multislice CT and MRI of coronary artery disease: current and future role]. / Maladie coronaire: les questions cliniques et les réponses potentielles en scanner multicoupe et en IRM.

If the role of multislice CT and MRI is not clearly defined in ischemic heart disease, these new cardiac imaging techniques are very promising due to recent technological advances. The detection of coronary artery plaque and stenosis, as well as coronary bypass graft and stenting patency, the evaluation of left ventricular remodeling after infarction, are available in routine with a 16-slices multislice CT. MRI is the technique of choice to appreciate the impact of a coronary artery lesion on myocardium: detection of ischemia by first-pass perfusion imaging at rest and under pharmacological stress, detection and extension of infarcted myocardium and assessment of myocardial viability. The potential indications will be discussed for each technique in the light of the main clinical questions asked by the cardiologist in daily practice.