Mn-induced Fermi-surface reconstruction in the SmFeAsO parent compound.

The electronic ground state of iron-based materials is unusually sensitive to electronic correlations. Among others, its delicate balance is profoundly affected by the insertion of magnetic impurities in the FeAs layers. Here, we address the effects of Fe-to-Mn substitution in the non-superconducting Sm-1111 pnictide parent compound via a comparative study of SmFe[Formula: see text]Mn[Formula: see text]AsO samples with [Formula: see text] 0.05 and 0.10. Magnetization, Hall effect, and muon-spin spectroscopy data provide a coherent picture, indicating a weakening of the commensurate Fe spin-density-wave (SDW) order, as shown by the lowering of the SDW transition temperature [Formula: see text] with increasing Mn content, and the unexpected appearance of another magnetic order, occurring at [Formula: see text] and 20 K for [Formula: see text] and 0.10, respectively. We attribute the new magnetic transition at [Formula: see text], occurring well inside the SDW phase, to a reorganization of the Fermi surface due to Fe-to-Mn substitutions. These give rise to enhanced magnetic fluctuations along the incommensurate wavevector [Formula: see text], further increased by the RKKY interactions among Mn impurities.

Structural and magnetic properties of the Yb2Pd2(In1-x Sn x ) system: a synchrotron x-ray and neutron powder diffraction investigation.

The structural properties of the Yb2Pd2(In1-x Sn x ) system were investigated at room temperature by synchrotron x-ray powder diffraction. All the inspected compositions (x = 0.0, 0.3, 0.4, 0.5, 0.6, 0.8, 0.9) crystallize in the tetragonal space group P4/mbm; the cell parameters exhibit a non-linear dependence on composition, whereas cell volume changes more regularly, with a minimum at x = 0.8. Samples with Sn content x = 0.5, 0.6, 0.9 were also analysed by neutron diffraction down to 0.5 K. No evidence for a structural transition can be detected at low temperature, whereas an antiferromagnetic ordering is observed, characterized by a propagation vectors k = (0,0,½). Magnetic moments order in the tetragonal ab-plane and the magnetic structure belongs to the Shubnikov magnetic space group P4/mbm.

In-plane and out-of-plane properties of a BaFe2As2 single crystal.

Anisotropy of transport and magnetic properties of parent compounds of iron based superconductors is a key ingredient of superconductivity. In this work, we investigate in-plane and out-of-plane properties, namely thermal, electric, thermoelectric transport and magnetic susceptibility in a high quality BaFe2As2 single crystal of the 122 parent compound, using a combined experimental and theoretical approach. Combining the ab initio calculation of the band structure and the measured in-plane and out-of-plane resistivity, we evaluate the scattering rates which turn out to be strongly anisotropic and determined by spin excitations in the antiferromagnetic state. The observed anisotropy of thermal conductivity is discussed in terms of anisotropy of sound velocities which we estimate to be [Formula: see text]. Remarkably, we find that thermal conductivity is characterized by a sizeable electronic contribution at low temperature, which is ascribed to the high purity of our crystal.

Experimental Evidence for Static Charge Density Waves in Iron Oxypnictides.

In this Letter we report high-resolution synchrotron x-ray powder diffraction and transmission electron microscope analysis of Mn-substituted LaFeAsO samples, demonstrating that a static incommensurate modulated structure develops across the low-temperature orthorhombic phase, whose modulation wave vector depends on the Mn content. The incommensurate structural distortion is likely originating from a charge-density-wave instability, a periodic modulation of the density of conduction electrons associated with a modulation of the atomic positions. Our results add a new component in the physics of Fe-based superconductors, indicating that the density wave ordering is charge driven.

Thermoelectric behavior of Ruddlesden-Popper series iridates.

The goal of this work is to study the evolution of thermoelectric transport across the members of the Ruddlesden-Popper series iridates [Formula: see text], where a metal-insulator transition driven by bandwidth change occurs, from the strongly insulating Sr2IrO4 to the metallic non Fermi liquid behavior of SrIrO3. Sr2IrO4 ([Formula: see text]), Sr3Ir2O7 ([Formula: see text]) and SrIrO3 ([Formula: see text]) polycrystals are synthesized at high pressure and characterized by structural, magnetic, electric and thermoelectric transport analyses. We find a complex thermoelectric phenomenology in the three compounds. Thermal diffusion of charge carriers accounts for the Seebeck behavior of Sr2IrO4, whereas additional drag mechanisms come into play in determining the Seebeck temperature dependence of Sr3Ir2O7 and SrIrO3. These findings reveal a close relationship between magnetic, electronic and thermoelectric properties, strong coupling of charge carriers with phonons and spin fluctuations as well as the relevance of multiband description in these compounds.

Crossover between magnetism and superconductivity in LaFeAsO with low H-doping level.

By making a systematic study of the hydrogen-doped LaFeAsO system by means of dc resistivity, dc magnetometry, and muon-spin spectroscopy, we addressed the question of universality of the phase diagram of rare-earth-1111 pnictides. In many respects, the behaviour of LaFeAsO(1-x)H(x) resembles that of its widely studied F-doped counterpart, with H(-) realizing a similar (or better) electron doping in the LaO planes. In an x = 0.01 sample we found a long-range spin-density wave (SDW) order with TN = 119 K, while at x = 0.05 the SDW establishes only at 38 K and, below Tc = 10 K, it coexists at a nanoscopic scale with bulk superconductivity. Unlike the abrupt magnetic-superconducting transition found in the La-1111 compound, the presence of a crossover region makes the H-doped system qualitatively similar to other Sm-1111, Ce-1111, and Nd-1111 families.

A magnetic glassy phase in Fe(1+y)Se(x)Te(1-x) single crystals.

The evolution of magnetic order in Fe1+ySexTe1-x crystals as a function of Se content was investigated by means of ac/dc magnetometry and muon-spin spectroscopy. Experimental results and self-consistent density functional theory calculations both indicate that muons are implanted in vacant iron-excess sites, where they probe a local field mainly of dipolar origin, resulting from an antiferromagnetic (AFM) bicollinear arrangement of iron spins. This long-range AFM phase becomes progressively disordered with increasing Se content. At the same time all the tested samples manifest a marked glassy character that vanishes for high Se contents. The presence of local electronic/compositional inhomogeneities most likely favours the growth of clusters whose magnetic moment 'freezes' at low temperature. This glassy magnetic phase justifies both the coherent muon precession seen at short times in the asymmetry data, as well as the glassy behaviour evidenced by both dc and ac magnetometry.

Correlated trends of coexisting magnetism and superconductivity in optimally electron-doped oxypnictides.

We report on the recovery of the short-range static magnetic order and on the concomitant degradation of the superconducting state in optimally F-doped SmFe(1-x)Ru(x)AsO(0.85)F(0.15) for 0.1≤x≲0.5. The two reduced order parameters coexist within nanometer-size domains in the FeAs layers and eventually disappear around a common critical threshold x(c)~0.6. Superconductivity and magnetism are shown to be closely related to two distinct well-defined local electronic environments of the FeAs layers. The two transition temperatures, controlled by the isoelectronic and diamagnetic Ru substitution, scale with the volume fraction of the corresponding environments. This fact indicates that superconductivity is assisted by magnetic fluctuations, which are frozen whenever a short-range static order appears, and totally vanish above the magnetic dilution threshold x(c).

Measuring case-mix and outcome for older people in acute hospital care across Europe: the development and potential of the ACMEplus instrument.

AIM: To identify case-mix variables measured shortly after admission to be included in a patient classification system (ACMEplus) that best explains hospital outcome for older people in different health care systems. DESIGN: Observational prospective cohort study collecting patient factors (sociodemographics, functional, mental, clinical, administrative and perceived health) at different time assessments. METHODS: Multicentre study involving eight hospitals in six European countries (United Kingdom, Spain, Italy, Finland, Greece and Poland). It included consecutive patients aged 65 years or older admitted to hospital for acute medical problems. MAIN OUTCOME MEASURES: discharge status, hospital readmission, mortality and length of stay. RESULTS: Of the 1667 included patients (mean age = 78.1 years; male gender = 43.5%) two-third had at least one 'Geriatric Giant' (immobility, confusion, incontinence or falls) on admission or shortly after. The most frequently affected system was cardiovascular (29.2%) and 31% of patients declared poor or very poor health. Mean length of stay was 17.9 days, 79% of patients were discharged to their usual residence; in-hospital and 1-month follow up mortality were 7.4% and 11.6%, respectively. Physical function explained the highest variation (between 8% and 21%), followed by cognitive status and number of Geriatric Giants, for almost all outcomes except readmission. CONCLUSION: Factors other than diagnosis (physical function, cognition and presenting problems) are important in predicting key outcomes of acute hospital care for older people and are consistent across countries. Their inclusion in a standardized system of measurement may be a way of improving quality and equity of medical care in older people.

[The experience of family carers of older people in the use of support services in Europe: selected findings from the EUROFAMCARE project]. / Erfahrungen von pflegenden Angehörigen älterer Menschen in Europa bei der Inanspruchnahme von Unterstützungsleistungen: Ausgewählte Ergebnisse des Projektes EUROFAMCARE.

This article presents selected findings of the EUROFAMCARE research project, reporting up-to-date information on the use and accessibility of support services for family carers of older people in six European countries representing different typologies of welfare systems (Germany, Greece, Italy, Poland, Sweden and the UK). Data were collected by means of face-to-face interviews to national samples of about 1000 family carers per country (i.e. 6000 in total), based on a common recruitment and data collection protocol. The reported findings reveal the crossnational usage of different support services - subdivided for comparative reasons in the categories of socio-emotional support, information, respite care, training and assessment services - as well as of available care allowances. The analysis includes the perceived experience of carers in using them, in terms of costs sustained, factors affecting service accessibility - i.e. main obstacles and greatest helps in accessing them - as well as reasons for not using (needed) services or for stopping using (still needed) services. Cross-national differences are relevant, showing a greater availability in Northern European countries, where however higher refusal rates by potential users of available services are recorded, possibly in connection to their lack of flexibility and low customization.

Experimental evidence of s-wave superconductivity in bulk CaC6.

The temperature dependence of the in-plane magnetic penetration depth, lambda(ab)(T), has been measured in a c-axis oriented polycrystalline CaC(6) bulk sample using a high-resolution mutual inductance technique. A clear exponential behavior of lambda(ab)(T) has been observed at low temperatures, strongly suggesting isotropic s-wave pairing. Data fit using the standard BCS theory yields lambda(ab)(0) = (720 +/- 80) A and delta(0) = (1.79 +/- 0.08) meV. The ratio 2delta(0)/k(B)T(c) = (3.6 +/- 0.2) gives indication for a weakly coupled superconductor.

Estudio clinico, histopatológico y ultraestructural del músculo de la lengua en pacientes con carcinoma epidermoide / A clinical, histopathological and ultrastructural study of tongue muscle in patients with squamous cell carcinoma

En el presente trabajo se realizó un estudio mediante microscopÝa de luz y electrónica de transmisión con el fin de estudiar las alteraciones musculares producidas en el músculo de la lengua en pacientes con carcinoma epidermoide. Las anomalÝas estructuras observadas incluyeron, alteraciones tanto en el sistema contrßctil como sarcotubular, por otro lado se observó atrofia y necrosis segmentaria, alteración de mitocondrias y proliferación de organelos, asÝ como vaculolas, lisosomas y grßnulos de lipofucsina. El infiltrado mononuclear estuvo representado principalmente por neutrófilos, macrófagos y mastocitos. Este estudio representa el primer reporte sobre las alteraciones ultraestructurales a nivel del músculo de la lengua producida por esta patologÝa maligna

The COPE index--a first stage assessment of negative impact, positive value and quality of support of caregiving in informal carers of older people.

Data was collected in five countries from informal carers of older people (n = 577) via a common protocol. Carers completed: (1) a 17-item version of the Carers of Older People in Europe (COPE) Index, an assessment of carers' perceptions of their role : (2) a questionnaire on demographic and caregiving circumstances : and (3) three instruments included for the criterion validation of the COPE Index (the General Health Questionnaire, the Hospital Anxiety and Depression Scale, and the World Health Organization Quality of Life-BREF). Principal Component Analysis of the COPE Index was followed by internal consistency analysis of emergent components. Scales derived by summing items loading on the components were analyzed for their association with the criterion measures. Two components, negative impact and positive value, emerged consistently across countries. A third component, quality of support was less consistent across countries. Scales derived from the negative impact and positive value components were internally consistent and significantly associated with the criterion validity measures. These two scales and four items drawn from the quality of support component were retained in the final COPE Index. While further testing is required, the COPE Index has current utility in increasing understanding of the role perceptions of carers of older people.

Improvement of the quality of self assembled bilayer lipid membranes by using a negative potential.

Self-assembled lipid bilayer membranes (s-BLMs) on the tip of Teflon-coated silver electrodes were formed according to the T. Tien method. Their formation process and properties were investigated by capacitance and voltage current cycle measurements. The stability of the membranes was improved and defects were eliminated through the application of a negative dc potential during formation. Cyclic current-voltage measurements were applied to probe membrane integrity, by using an electrolyte interacting with the silver electrode. Oxidation and reduction peaks were observed for non defect-free membranes. These peaks were caused by oxidation of the silver electrode tip and their occurrence was a very sensitive means of measuring membrane integrity. The membrane was a barrier for the ion transport from the electrolyte solution to the electrode surface, and thus defect-free membranes inhibited the appearance of the peaks. With the s-BLMs produced by the described method, binding of ions and proteins to the membrane could be measured repetitively and reproducibly through changes in the system capacitance and the shape of the cyclovoltammogram. The presence of divalent ions lead to a specific increase in total system capacitance of membranes from charged lipids. Protein binding was measured as a decrease of the capacitance, in accordance with the thickness increase of the total membrane after binding. The facility of production and the sensitivity of the aforementioned substances could make the s-BLMs, produced by the described method, a valuable system to be developed in the field of biosensing.