Evolution of the Magnetic Excitations in Electron-Doped La_{2-x}Ce_{x}CuO_{4}.

We investigated the high energy spin excitations in electron-doped La_{2-x}Ce_{x}CuO_{4}, a cuprate superconductor, by resonant inelastic x-ray scattering (RIXS) measurements. Efforts were paid to disentangle the paramagnon signal from non-spin-flip spectral weight mixing in the RIXS spectrum at Q_{∥}=(0.6π,0) and (0.9π,0) along the (1 0) direction. Our results show that, for doping level x from 0.07 to 0.185, the variation of the paramagnon excitation energy is marginal. We discuss the implication of our results in connection with the evolution of the electron correlation strength in this system.

Three-dimensional collective charge excitations in electron-doped copper oxide superconductors.

High-temperature copper oxide superconductors consist of stacked CuO2 planes, with electronic band structures and magnetic excitations that are primarily two-dimensional1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides5-7 reveals their charge origin, that is, without mixing with magnetic components5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO2 planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems8-12 and argued to play a substantial part in mediating high-temperature superconductivity10-12.

Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser.

The interactions that lead to the emergence of superconductivity in iron-based materials remain a subject of debate. It has been suggested that electron-electron correlations enhance electron-phonon coupling in iron selenide (FeSe) and related pnictides, but direct experimental verification has been lacking. Here we show that the electron-phonon coupling strength in FeSe can be quantified by combining two time-domain experiments into a "coherent lock-in" measurement in the terahertz regime. X-ray diffraction tracks the light-induced femtosecond coherent lattice motion at a single phonon frequency, and photoemission monitors the subsequent coherent changes in the electronic band structure. Comparison with theory reveals a strong enhancement of the coupling strength in FeSe owing to correlation effects. Given that the electron-phonon coupling affects superconductivity exponentially, this enhancement highlights the importance of the cooperative interplay between electron-electron and electron-phonon interactions.

Magneto- to electroactive transmutation of spin waves in ErMnO3.

The low-energy dynamical properties of the multiferroic hexagonal perovskite ErMnO3 have been studied by inelastic neutron scattering as well as terahertz and far infrared spectroscopies on a synchrotron source. From these complementary techniques, we have determined the magnon and crystal field spectra and identified a zone center magnon excitable only by the electric field of an electromagnetic wave. Using a comparison with the isostructural YMnO3 compound and crystal field calculations, we propose that this dynamical magnetoelectric process is due to the hybridization of a magnon with an electroactive crystal field transition.

THz magnetoelectric atomic rotations in the chiral compound Ba3NbFe3Si2O14.

We have determined the terahertz spectrum of the chiral langasite Ba3NbFe3Si2O14 by means of synchrotron-radiation measurements. Two excitations are revealed that are shown to have a different nature. The first one, purely magnetic, is observed at low temperature in the magnetically ordered phase and is assigned to a magnon. The second one persists far into the paramagnetic phase and exhibits both an electric and a magnetic activity at slightly different energies. This magnetoelectric excitation is interpreted in terms of atomic rotations and requires a helical electric polarization.

Experience of multidisciplinary assessment of elderly patients with cancer in a French general hospital during 1 year: a new model care study.

OBJECTIVES: Our main aim was to describe and explore a multidisciplinary approach to the management of elderly patients with cancer, who constitute a heterogeneous population. MATERIALS AND METHODS: This descriptive study was performed between October 2009 and September 2010. Patients with cancer ≥ 70 years of age were included. Some underwent a simplified multidimensional geriatric assessment with a Charlson score administered by an oncologist, and the evaluation was submitted to a geriatrician who decided whether or not a complete a comprehensive geriatric assessment (CGA) (n=54) should be done. Another group of patients directly underwent a CGA (n=49), and a few patients included in a specific trial underwent a geriatric assessment (n=8). Each patient was classified as fit, vulnerable, or frail by a multidisciplinary team. RESULTS: 111 patients were included (median age: 81 years [range: 65-96]; 60 males). The most frequent types of cancer were lung (n=29), gastrointestinal (n=20) and head and neck (n=14). Median Charlson score was 2.1 [range: 0-9]. Standard therapy was given to 37/41 (90%) fit, 19/41 (42%) vulnerable, and 6/29 (21%) frail patients. Thirteen frail patients received best supportive care. A social worker was mobilized for 2/41 (5%) fit, 14/41 (34%) vulnerable, and 11/29 (38%) frail patients. CONCLUSIONS: Our study outlines the possibilities of cooperation between geriatricians and oncologists in a general hospital. This collaboration could modify therapeutic schedules especially in frail and vulnerable patients.

[Long-term treatment of Alzheimer's disease: followup of a cohort of 255 patients treated with lacrine for four years]. / Traitement de la maladie d'Alzheimer au long cours: à propos d'une cohorte de 255 patients traités quatre ans par tacrine.

We describe the follow-up of a cohort of 255 Alzheimer's disease (AD) patients (81 males, 174 females) treated by tacrine during 4 years. We performed the survey of hepatic, cholinergic and general tolérance. Drug efficacy was measured by MMS examination on weeks 0, 18, 30, 52, 104, 156 and 208. A total of 190 patients (74.5 percent) were dropped out of this study, 75 (29 percent) for adverse events. We found 85 hepatic (33 percent), 79 cholinergic (31 percent), 31 (12 percent) neuropsychiatric and 72 general (28 percent) side effects. In term of drug efficacy we observed a global decline of 2.5 MMS points during the first year and 2 MMS points between W52 and W156. Tacrine's symptomatic efficacy, defined as the number of patients improved or stabilized at W30, was present in 50 patients (46 percent) among the 109 patients reaching W30. The intensity of symptomatic efficacy was expressed by a 2.7 MMS points increase in 37 patients improved on W30. The long term effects of Tacrine, measured by the MMS score at one year, showed a positive impact as the MMS was 2.5 points above the expected score in non treated AD patients. This study raises the practical problem of optimal cholinesterase inhibitors use in AD and the theoretical question of long term action of cholinesterase inhibitors on cerebral lesions of AD.

Reanalysis and New Measurements of N(2) and CH(4) Adsorption on Ice and Snow.

Numerous literature data indicate that the mean heat of adsorption of a monolayer of N(2) (DeltaQ(N(2))) on ice or snow at 77.15 K, determined by volumetric methods, is highly variable, suggesting that ice surface properties strongly depend on its mode of formation and its thermal history. Less numerous data on CH(4) adsorption show smaller variations of DeltaQ(CH(4)). If such variations are real, the extrapolation to atmospheric chemistry models of adsorption parameters measured on laboratory-made ice may be unwarranted. We have measured CH(4) adsorption on variable amounts of a crushed ice sample, to show that when the total surface area of the sample is below a threshold value, DeltaQ(CH(4)) decreases. We identify the cause of this artifact as an error in the molar budget, because the temperature gradient in the tube connecting the introduction and expansion volumes is not taken into account. Performing an adequate molar budget suppresses this artifact, except for ice samples with very small total surface areas, where the resolution of the manometer becomes a limiting factor and a further decrease in DeltaQ(CH(4)) is observed. Error in DeltaQ(gas) results in large errors in surface area, and we suggest that the value of DeltaQ(gas) obtained can be used to test the reliability of the surface area measurement. Copyright 2000 Academic Press.

mtDNA analysis of Nile River Valley populations: A genetic corridor or a barrier to migration?

To assess the extent to which the Nile River Valley has been a corridor for human migrations between Egypt and sub-Saharan Africa, we analyzed mtDNA variation in 224 individuals from various locations along the river. Sequences of the first hypervariable segment (HV1) of the mtDNA control region and a polymorphic HpaI site at position 3592 allowed us to designate each mtDNA as being of "northern" or "southern" affiliation. Proportions of northern and southern mtDNA differed significantly between Egypt, Nubia, and the southern Sudan. At slowly evolving sites within HV1, northern-mtDNA diversity was highest in Egypt and lowest in the southern Sudan, and southern-mtDNA diversity was highest in the southern Sudan and lowest in Egypt, indicating that migrations had occurred bidirectionally along the Nile River Valley. Egypt and Nubia have low and similar amounts of divergence for both mtDNA types, which is consistent with historical evidence for long-term interactions between Egypt and Nubia. Spatial autocorrelation analysis demonstrates a smooth gradient of decreasing genetic similarity of mtDNA types as geographic distance between sampling localities increases, strongly suggesting gene flow along the Nile, with no evident barriers. We conclude that these migrations probably occurred within the past few hundred to few thousand years and that the migration from north to south was either earlier or lesser in the extent of gene flow than the migration from south to north.

[Rotablator and endoprosthesis on the left main coronary trunk]. / Rotablator et endoprothèse sur tronc commun de la coronaire gauche.

A 78 year old woman with unstable angina due to significant stenosis of the left main coronary artery and occlusion of the right coronary artery was treated medically for 29 months because of a surgical contraindication. Resistance to drug therapy led to referral for complex angioplasty of the left main, left anterior descending and left circumflex arteries, successively by rotablator and balloon angioplasty. An immediate elastic recoil on the left main coronary artery led to implantation of a Palma-Schatz stent. There were no complications and the patient is asymptomatic twenty months later.

[Thromboembolic disease in patients aged 80 and over. Diagnostic and therapeutic strategies]. / La maladie thromboembolique chez la personne âgée de 80 ans et plus. Stratégies diagnostiques et thérpeutiques.

The aim of this retrospective study of 50 deep vein thromboses (DVT) of the lower limbs in patients aged 80 and over (35 women, including 2 with bilateral DVT and 13 men), mean age 83.37 +/- 2.72, hospitalised in a department of cardiology, was to assess the diagnostic value of ultrasound investigations, clinical parameters and results of treatment of thrombo-embolic disease in this age group. High DVT were found in 76 per cent of cases and pulmonary embolism occurred in 52.1 per cent of cases, its incidence increasing with age. One third of DVT were asymptomatic and presented as pulmonary embolism, the predominant clinical feature being edema in the absence of other signs. The existence of atrial fibrillation was associated in 90 per cent of cases with a pulmonary embolism. Venous Echo-Doppler is also the key investigation in the diagnosis of thrombo-embolic disease. Cardiac Echo-Doppler seems particularly useful in the diagnosis of pulmonary embolism when more than 40 per cent of the vascular bed is cut off. Thrombolytic treatment remains possible after the age of 80 in life-threatening situations. Overall hospital mortality remains high (10.4 per cent) and appears to be due chiefly to the onset of a pulmonary embolism which is not thrombolyzed since considered insufficiently serious or occurring in a situation in which fibrinolysis is theoretically contra-indicated.

[Auricular fibrillation in the elderly. Indicators of risk and cerebral prognosis]. / La fibrillation auriculaire chez la personne agée. Indicateurs de risque et pronostic cérébral.

Cardiovascular anomalies contributing to development of atrial fibrillation (AF) and subsequent cerebral repercussion have been studied by analysis of clinical, electrocardiographic and anatomicopathological data for 131 elderly (85.16 +/- 6.7 years) medium- and long-term hospital patients. AF was seen in 22.14% of cases and seems more frequent in the ninth decade than in the eight. Predisposing factors were coronary alterations of repolarization (p less than 0.001), myocardial hypertrophy (less than 0.01), hypertension with cardiac repercussions (p less than 0.01), intraventricular conduction disorders, left anterior hemiblock excepted (p less than 0.05) and mitral valvulopathy. AF developed in 12% of cases without apparent cardiopathy. The risk of cerebral infarct was marginally greater in the presence of AF than in its absence; the risk was clear for paroxysmal forms and nil when AF developed in a healthy heart. In contrast, intellectual deterioration and cerebral hypotrophy were significantly more marked (p less than 0.01) in patients presenting AF. This affirmation is evidence for long-term hemodynamic repercussions of arrhythmia affecting cerebral blood flow and constitutes an argument for re-establishment of sinusal rhythm.

[Risk factors in the combination of myocardial infarction and carotid atheroma]. / Les facteurs de risque dans l'association infarctus du myocarde-athérome carotidien.

This study compares two groups of patients: Group I with 44 patients who suffered recent acute myocardial infarction and Group II: 40 control subjects. In both groups, 2D Doppler echocardiography was performed to detect carotid atheroma, to determine the respective roles of vascular risk factors for two sites of atherosclerosis. Carotid atheroma affected 73 p. 100 of subjects in Group I and 22.5 p. 100 in Group II. Carotid stenosis of more than 40 p. 100 was found mainly in hypertensive patients who presented with acute myocardial infarction, and in patients with left ventricular hypertrophy. Smoking was more frequent in Group I than in Group II (p less than 0.001) irrespective of the frequency of carotid atheroma (p less than 0.05). Hypercholesterolaemia only favoured carotid atherosclerosis after acute myocardial infarction (p = 0.01). We did not find any difference in the incidence of diabetes mellitus in the two groups of patients. Age analysis indicated that carotid atheroma occurred earlier in Group I than in Group II. An association between a dominant risk factor for coronary disease (smoking or hypercholesterolemia) was found in 9 patients, all of whom had severe bipolar atherosclerosis with multivessel coronary lesions and carotid stenosis.