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S Magnier

Publications and source records attributed to S Magnier.

At least 19 recordsLinked to original sources
PubMed2006

The K2 2(3)Pi(g) state: new observations and analysis.

Totally 3045 transitions into the 2(3)Pi(g) v = 0-42, J = 0-103, Omega = 0, 1, 2 rovibrational levels have been observed by infrared-infrared double resonance fluorescence excitation and two-photon spectroscopy. Molecular constants including the spin-orbit interaction parameters are obtained. Although the K2 2(3)Pi(g) state dissociates to the 4s + 3d atomic limit, it is strongly mixed with the 3P ionic states in the range of the potential well. This mixing results in a relatively large equilibrium internuclear distance Re = 5.254 A and a larger spin-orbit constant A0 approximately 14.17 cm(-1) than that of the atomic limit -2.33 cm(-1). Strong perturbations of the 2(3)Pi(g) levels observed are attributed to the spin-orbit coupling with the 4(1)Sigma(g)+ state.

Journal Article↗
PubMed2006

Measurement of the electronic transition dipole moment by Autler-Townes splitting: Comparison of three- and four-level excitation schemes for the Na2 A 1Sigma(u)+ - X 1Sigma(g)+ system.

We present a fundamentally new approach for measuring the transition dipole moment of molecular transitions, which combines the benefits of quantum interference effects, such as the Autler-Townes splitting, with the familiar R-centroid approximation. This method is superior to other experimental methods for determining the absolute value of the R-dependent electronic transition dipole moment function mu(e)(R), since it requires only an accurate measurement of the coupling laser electric field amplitude and the determination of the Rabi frequency from an Autler-Townes split fluorescence spectral line. We illustrate this method by measuring the transition dipole moment matrix element for the Na2 A 1Sigma(u)+ (v' = 25, J' = 20e)-X 1Sigma(g)+ (v" = 38, J" = 21e) rovibronic transition and compare our experimental results with our ab initio calculations. We have compared the three-level (cascade) and four-level (extended Lambda) excitation schemes and found that the latter is preferable in this case for two reasons. First, this excitation scheme takes advantage of the fact that the coupling field lower level is outside the thermal population range. As a result vibrational levels with larger wave function amplitudes at the outer turning point of vibration lead to larger transition dipole moment matrix elements and Rabi frequencies than those accessible from the equilibrium internuclear distance of the thermal population distribution. Second, the coupling laser can be "tuned" to different rovibronic transitions in order to determine the internuclear distance dependence of the electronic transition dipole moment function in the region of the R-centroid of each coupling laser transition. Thus the internuclear distance dependence of the transition moment function mu(e)(R) can be determined at several very different values of the R centroid. The measured transition dipole moment matrix element for the Na2 A 1Sigma(u)+ (v' = 25, J' = 20e)-X 1Sigma(g)+ (v" = 38, J" = 21e) transition is 5.5+/-0.2 D compared to our ab initio value of 5.9 D. By using the R-centroid approximation for this transition the corresponding experimental electronic transition dipole moment is 9.72 D at Rc = 4.81 A, in good agreement with our ab initio value of 10.55 D.

Journal Article↗
PubMed2004

Theoretical determination of highly excited states of K2 correlated adiabatically above K4p + K4p.

The electronic structure of the K(2) molecule is revisited to describe the 36 highly excited states dissociating into the three limits K(4s) + K(4f), K(4s) + K(6p), and K(4s) + K(5d), which have not yet been investigated theoretically. Potential energy curves and spectroscopic constants are (re)displayed for the 98(1,3)Lambda(g,u) ((+,-)) molecular states correlated adiabatically to the limits up to K(4s) + K(5d). For the 10 states dissociating adiabatically into K(4p) + K(4p) and limits above for which experimental data are available, averaged errors of present results are found to be Delta R(e) = 0.07a(0), Delta T(e) = 50 cm(-1), Delta omega(e) = 0.8 cm(-1) and Delta D(e) = 60 cm(-1). Full energy data are available at the following address http://lasim.univ-lyon1.fr/allouche/k2.html

Journal Article↗
PubMed2003

[Antenatal diagnosis of congenital left ventricular aneurysm].

Congenital aneurysm of the left ventricle is a rare condition of unknown origin, the main differential diagnosis of which is the diverticulum. The natural history of this pathology is well known in adults and adolescents, contrary to those forms diagnosed by foetal echocardiography. Based on a case of congenital left ventricular aneurysm diagnosed ante-natally and a review of the literature, the authors propose echocardiographic prognostic factors useful for prenatal management. Thus, early antenatal diagnosis, size and progression of the aneurysm, signs of antenatal cardiac failure, are poor prognostic factors and should be discussed during parent counselling.

Adult↗
PubMed2002

[A case of atrial flutter after umbilical venous catheterization].

UNLABELLED: Isolated atrial flutter is an extremely rare form of supraventricular tachycardia in the neonatal period. It may be initiated by central venous catheterization. CASE REPORT: A male infant was born at 35 weeks by cesarean section for placenta praevia. He was eutrophic. Apgar score was 10 at 1 and 5 minutes. He secondary developed a respiratory distress syndrome. He was then ventilated by nasal CPAP. Immediately after an umbilical venous catheterization, a tachycardia appeared without preexistent cardiac dysfunction. An intravenous dose of adenosine (Striadyne) showed a characteristic sawtooth pattern of P waves on inferior leads. The cardiac-US examination was normal. This atrial flutter was converted to normal sinus rhythm by transoesophageal pacing, without adjunction of antiarrhythmic drugs. The newborn was weaned from mechanical ventilation 48 hours later and discharged from hospital at seven days post natal age. His development and clinical examination were normal two months later. CONCLUSION: The isolated atrial flutter is rare in the neonate. It may be triggered by a venous catheterization. Transoesophageal atrial pacing is safe and effective for conversion.

Adenosine↗
PubMed2001

[Antenatal atrial tachycardia. Two case reports].

The authors report two cases of foetal supraventricular tachycardia in healthy hearts with 1/1 atrioventricular conduction which turned out to be atrial tachycardias in the postnatal period. The first foetus had permanent tachycardia at 190/minute at 34 weeks' amenorrhea with left ventricular dysfunction at 36 weeks. In the postnatal period, treatment with digoxine and amiodarone restored sinus rhythm and normal left ventricular function. Permanent foetal tachycardia, even at a rate of less than 200 beats/minute, should suggest an arrhythmia and may lead to left ventricular dysfunction in utero. The other foetus had an aneurysm of the foramen ovale with paroxysmal tachycardias at 220/minute without cardiac dysfunction. A Holter at 1 month showed paroxysmalatrial tachycardia. Postnatal rhythm monitoring is necessary in paroxysmal foetus tachycardia, especially with prenatal aneurysm of the foramen ovale.

Adult↗
PubMed2001

[Cardiogenic shock in an infant due to rupture of an aneurysm of the sinus of Valsalva into the left ventricle].

The authors report the case of a 15 month-old infant admitted to the intensive care unit for cardiogenic shock due to rupture of an aneurysm of the right anterior sinus of Valsalva into the left ventricle, associated with massive aortic regurgitation. The patient underwent a Ross procedure with resection of the aneurysm. This is a very rare condition because rupture of the aneurysm into the left ventricle has not been previously reported in a young girl to the best of the authors' knowledge. Moreover, a Ross procedure has not been previously described in this indication. The case illustrates the diagnostic difficulty associated with this pathology and underlines the necessity of thinking of this diagnosis in infants with appearances of dilated cardiomyopathy and aortic regurgitation.

Aortic Aneurysm↗
PubMed2000

Transcatheter closure of apical ventricular muscular septal defect combined with arterial switch operation in a newborn infant.

This report describes a case of transposition of the great arteries and apical muscular ventricular septal defect in a newborn infant successfully treated by transcatheter closure of the septal defect with the Amplatzer duct occluder device followed by an arterial-switch operation within the first 2 weeks of life. Cathet. Cardiovasc. Intervent. 49:173-176, 2000.

Angiography↗
PubMed2000

Potential Energies, Permanent and Transition Dipole Moments for Numerous Electronic Excited States of NaK.

Recent experimental works have been devoted to the spectroscopy of highly excited states of NaK, confirming the accuracy of our previous calculations [S. Magnier and Ph. Millié, Phys. Rev. A: Gen. Phys. 54, 204 (1996)] of spectroscopic constants and potential curves. Among them, [E. Laub, I. Mazsa, S. C. Webb, J. La Civita, I. Prodan, Z. J. Zabbour, R. K. Namiotka, and J. Huennekens, J. Mol. Spectrosc. 193, 376 (1999)] have deduced from their measurements the variation of the transition dipole moment with the interatomic distance for the transition X(1)Sigma+ --> (3)(1)Pi. They have shown that a large discrepancy was observed with the previous ab initio calculations currently used as a guide for spectroscopic experiments. Upon request of several experimentalists, we have computed again potential curves for electronic states correlated up to Na(4p) + K(4s) as well as relevant permanent and transition dipole moments. We present extensive predictions for the electronic structure of NaK (potential energies, dipole moments) for which numerical data have been listed in a data base available as supplementary data. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Thoracic pheochromocytoma revealed by ventricular tachycardia. Clinical case and review of the literature.

A case of thoracic extra-adrenal pheochromocytoma was observed in a 13-year-old girl. The initial clinical symptoms consisted of her being unwell after effort over a period of 3 years. The diagnosis was suggested after a recorded episode of paroxysmal ventricular tachycardia with concomitant hypertension, which reproduced the characteristic symptoms. Biochemical analysis confirmed hypersecretion of catecholamines and morphological examinations showed the presence of an isolated left median thoracic tumor. One year after surgical excision, the patient remained completely asymptomatic, in spite of resuming intense sporting activity. The diagnosis of ectopic pheochromocytoma should be considered as a possible etiology of cardiac rhythm disturbances or hypertension in children. Thorough biochemical and radiological examination including MIBG radioisotope scanning should be carried out systematically before surgical excision; pheochromocytomas in children are frequently extra-adrenal (30%), multifocal (50%) or associated with multiple endocrine neoplasms (NEM).

Adolescent↗
PubMed2000

[Bundle of His tachycardia and chronic reciprocating rhythm: rare forms of prenatal tachycardia].

In cases of permanent tachycardia, ante-natal diagnosis of chronic reciprocating rhythms with long RP' intervals or His bundle tachycardias is difficult. The authors report two cases of permanent foetal tachycardia with 1/1 atrioventricular conduction. In one case, the tachycardia rate was 170/min with anasarca treated by amiodarone in view of a family history of His bundle tachycardia. In the other case, the tachycardia rate was 200/min but with no signs of cardiac failure and was, therefore, not treated. The ECG at birth confirmed the diagnosis of His bundle tachycardia in the first case and identified a chronic reciprocating rhythm in the other.

Adult↗
PubMed1999

Prenatal diagnosis of a familial form of junctional ectopic tachycardia.

Junctional ectopic tachycardia (JET) is a rare cardiac arrhythmia characterized by atrio-ventricular dissociation, a high rate junctional escape rhythm and poor clinical tolerance in neonates and infants. Sudden infant death has been reported. The intra-uterine presentation of this arrhythmia is unknown. We report a familial form of JET with antenatal diagnosis. A sustained tachycardia at a rate of 170 beats/min with a 1:1 conduction was diagnosed in a hydropic fetus at a gestational age of 32 weeks. The older brother had presented with prenatal hydrops and junctional ectopic tachycardia was diagnosed at birth. Assuming that this arrhythmia was a JET, amiodarone was given to the mother in order to control the fetal tachycardia. The arrhythmia persisted with a 1/1 pattern but at a slower ventricular rate (140 beats/min). The ECG performed at birth revealed a narrow QRS tachycardia with a ventricular rate of 180 beats/min and a 1/1 retrograde conduction. Amiodarone therapy was continued with the addition of propanolol. Postnatal echocardiography revealed normal chambers and left ventricular dysfunction with a left ventricular shortening fraction of 17 per cent. Subsequent ECGs and Holter monitoring demonstrated typical electrocardiographic features of JET. Both parents had a normal ECG and Holter monitoring. A fetal tachycardia of moderately high rate with a 1/1 retrograde conduction and poor cardiac tolerance can be due to JET. In such cases, the use of amiodarone can be considered as a first line drug.

Adult↗
PubMed1999

[Role of right-to-left atrial shunt in exercise tolerance of patients with Ebstein anomaly].

The aim of this study was to assess cardiorespiratory tolerance to exercise in children with non-operated, paucisymptomatic and untreated froms of Ebstein's anomaly. The authors undertook a prospective study in 11 children, mean age 9.6 years, who had lung function tests, cardiorespiratory exercise stress tests (bicycle ergometry N = 8, treadmill N = 3) and contrast echocardiography. All parameters of spirometry were normal. Contrast echocardiography showed a right-to-left interatrial shunt in 7 children (group 1) whereas the remaining 4 children had no shunt (group 2). The resting oxygen saturation was 97.4 +/- 2%, with no difference between the two groups. On the other hand, oxygen saturation at peak VO2 (VO2 max) was 90 +/- 9.5%, significantly lower in group 1 than in group 2 (85.7 +/- 2.2% vs 98.2 +/- 1.2%; p = 0.03). In group 1, the VO2 max was correlated to oxygen saturation (r = 0.98; p < 0.001, N = 6). The oxygen desaturation was correlated with presence of a right-to-left interatrial shunt (p = 0.01). The reduced exercise tolerance of non-operated, paucisymptomatic children with Ebstein's anomaly is due to a right-to-left interatrial shunt. In patients with poor exercise tolerance, contrast echocardiography is advised for the detection of these atrial shunts.

Adolescent↗
PubMed1998

Analytical Formulas for Long-Range Energies of the 16 Omega(+/-)g,u States of Alkali Dimers Dissociating into M(ns) + M(np 2PJ)

Analytical formulas for long-range energies of the 16 Omega(+/-)g,u states of alkali dimers dissociating into M(ns) + M(np 2PJ) are displayed in terms of the long-range Cn coefficients for the 2S+1Lambda(+)g,u corresponding states, and including exchange interaction energy contributions. Corrections due to retardation effects for resonant-dipole interactions are also included. For values of the internuclear distance R large enough so that only Coulombic interactions in R-3 are nonnegligible, the variation with R of the long-range energy is seen to be different from the usually assumed C3/R3 form. Present formulas can be used both to predict accurately long-range energies and to fit experimental energies now available in such long-range of R from photoassociative spectroscopy. As an example, they have been used, together with more accurate values of Cn coefficients than those used some 10 years ago, to predict again the three states of Rb2 displaying structures (well and barrier) at long range, i.e., 0(-)g(3/2), 1u(3/2), and 1u(1/2). Copyright 1998 Academic Press.

Journal Article↗
PubMed1997

[Cardiomyopathy induced by catecholamines in neuroblastoma].

BACKGROUND: Cardiovascular disorders associated with neural crest tumors are congenital malformations rather than cardiomyopathies. CASE REPORT: A 18 month-old girl developed heart failure one week after discovery of an adrenal neuroblastoma with excessive secretion of catecholamines. Investigation showed dilated cardiomyopathy without myocardial hypertrophy. Besides chemotherapy, the patient was given nitrous derivatives, diuretics and converting enzyme inhibitor. His cardiac condition gradually improved so that partial resection of the tumor was possible 2 years later. CONCLUSIONS: The cardiomyopathy presented by this patient is possibly catecholamine-induced even though catecholamines usually results in myocardial hypertrophy rather than dilated cardiomyopathy. The reason why such a cardiomyopathy has never been reported in patients with neuroblastoma remains unclear.

Adrenal Gland Neoplasms↗
PubMed1997

[Hypertrophic cardiomyopathy complicating a prolonged corticotherapy for hemorrhagic rectocolitis].

BACKGROUND: The cardiac side-effects of corticosteroid therapy are very uncommon. CASE REPORT: A girl with ulcerative colitis developed at the age of 8 years an acute digestive episode despite prednisolone and total parenteral nutrition. The patient was then given intravenous methylprednisolone (2 mg/kg/d). Polypnea appeared 25 days later while blood pressure remained normal. Echocardiography revealed a cardiac hypertrophy associated with a systolic anterior motion of the mitral valve. Cardiac symptoms and echography findings returned to normal after reduction of corticosteroid therapy and its administration via the oral route. CONCLUSION: Hypertrophic cardiomyopathy has been described in preterms treated with dexamethasone for bronchopulmonary dysplasia. It is exceptional in older children under corticosteroid therapy and its mechanism remains unknown.

Cardiomyopathy, Hypertrophic↗