Superconductivity in SrNi2As2 Single Crystals

The electrical resistivity \rho(T) and heat capacity C(T) on single crystals of SrNi2As2 and EuNi2As2 are reported. While there is no evidence for a structural transition in either compound, SrNi2As2 is found to be a bulk superconductor at T_c=0.62 K with a Sommerfeld coefficient of \gamma= 8.7 mJ/mol K^2 and a small upper critical field H_{c2} \sim 200 Oe. No superconductivity was found in EuNi2As2 above 0.4 K, but anomalies in \rho and C reveal that magnetic order associated with the Eu^{2+} magnetic moments occurs at T_m = 14 K.Comment: 8 pages, 5 figure

Ohmic contacts to n-type germanium with low specific contact resistivity

A low temperature nickel process has been developed that produces Ohmic contacts to n-type germanium with specific contact resistivities down to (2.3 ± 1.8) x10<sup>-7</sup> Ω-cm<sup>2</sup> for anneal temperatures of 340 degC. The low contact resistivity is attributed to the low resistivity NiGe phase which was identified using electron diffraction in a transmission electron microscope. Electrical results indicate that the linear Ohmic behaviour of the contact is attributed to quantum mechanical tunnelling through the Schottky barrier formed between the NiGe alloy and the heavily doped n-Ge.<p></p&gt

"HAART-Attack" bei junger HIV-Patientin

Zusammenfassung: Seit der Einführung der hochaktiven antiretroviralen Therapie (HAART) hat sich die Prognose von Patienten mit einer HIV-Infektion dramatisch verbessert. Morbidität und Mortalität HIV-assoziierter Infektionen konnten reduziert werden. Als Nebenwirkung dieser Therapie sind metabolische Komplikationen bekannt, die eine akzelerierte Atherosklerose mit Auftreten koronarer und zerebrovaskulärer Ereignisse bewirken können. Dies betrifft auch junge Patienten speziell bei Vorliegen zusätzlicher kardiovaskulärer Risikofaktoren. Wir berichten über eine 30-jährige HIV-Patientin mit einem akutem Myokardinfark

Strong coupling between magnetic and structural order parameters in SrFe2As2

X-ray and Neutron diffraction as well as muon spin relaxation and M\"ossbauer experiments performed on SrFe$_2$As$_2$ polycrystalls confirm a sharp first order transition at $T_0 = 205$,K corresponding to an orthorhombic phase distortion and to a columnar antiferromagnetic Fe ordering with a propagation vector (1,0,1), and a larger distortion and larger size of the ordered moment than reported for BaFe$_2$As$_2$. The structural and the magnetic order parameters present an remarkable similarity in their temperature dependence from $T_0$ down to low temperatures, showing that both phenomena are intimately connected. Accordingly, the size of the ordered Fe moments scale with the lattice distortion when going from SrFe$_2$As$_2$ to BaFe$_2$As$_2$. Full-potential band structure calculations confirm that the columnar magnetic order and the orthorhombic lattice distortion are intrinsically tied to each other.Comment: 10 pages, 4 figure

Transport properties and superconductivity in Ba1−xMxFe2As2Ba_{1-x}M_xFe_2As_2 (M=La and K) with double FeAs layers

We synthesized the samples $Ba_{1-x}M_xFe_2As_2$ (M=La and K) with $ThCr_2Si_2$-type structure. These samples were systematically characterized by resistivity, thermoelectic power (TEP) and Hall coefficient ($R_H$). $BaFe_2As_2$ shows an anomaly in resistivity at about 140 K. Substitution of La for Ba leads to a shift of the anomaly to low temperature, but no superconducting transition is observed. Potassium doping leads to suppression of the anomaly in resistivity and induces superconductivity at 38 K as reported by Rotter et al.\cite{rotter}. The Hall coefficient and TEP measurements indicate that the TEP is negative for $BaFe_2As_2$ and La-doped $BaFe_2As_2$, indicating n-type carrier; while potassium doping leads to change of the sign in $R_H$ and TEP. It definitely indicates p-type carrier in superconducting $Ba_{1-x}K_xFe_2As_2$ with double FeAs layers, being in contrast to the case of $LnO_{1-x}F_xFeAs$ with single FeAs layer. A similar superconductivity is also observed in the sample with nominal composition $Ba_{1-x}K_xOFe_2As_2$.Comment: 4 pages, 4 figure

Effect of 3d-doping on the electronic structure of BaFe2As2

The electronic structure of BaFe2As2 doped with Co, Ni, and Cu has been studied by a variety of experimental and theoretical methods, but a clear picture of the dopant 3d states has not yet emerged. Herein we provide experimental evidence of the distribution of Co, Ni, and Cu 3d states in the valence band. We conclude that the Co and Ni 3d states provide additional free carriers to the Fermi level, while the Cu 3d states are found at the bottom of the valence band in a localized 3d10 shell. These findings help shed light on why superconductivity can occur in BaFe2As2 doped with Co and Ni but not Cu.Comment: 18 pages, 8 figure

Prognostic impact of systemic inflammatory diseases in elderly patients with congestive heart failure

Background and aims: Inflammation is part of the pathophysiology of congestive heart failure (CHF). However, little is known about the impact of the presence of systemic inflammatory disease (SID), defined as inflammatory syndrome with constitutional symptoms and involvement of at least two organs as co-morbidity on the clinical course and prognosis of patients with CHF. Methods and results: This is an analysis of all 622 patients included in TIME-CHF. After an 18 months follow-up, outcomes of patients with and without SID were compared. Primary endpoint was all-cause hospitalization free survival. Secondary endpoints were overall survival and CHF hospitalization free survival. At baseline, 38 patients had history of SID (6.1%). These patients had higher N-terminal pro brain natriuretic peptide and worse renal function than patients without SID. SID was a risk factor for adverse outcome [primary endpoint: hazard ratio (HR) = 1.73 (95% confidence interval: 1.18-2.55, P = 0.005); survival: HR = 2.60 (1.49-4.55, P = 0.001); CHF hospitalization free survival: HR = 2.3 (1.45-3.65, P < 0.001)]. In multivariate models, SID remained the strongest independent risk factor for survival and CHF hospitalization free survival. Conclusions: In elderly patients with CHF, SID is independently accompanied with adverse outcome. Given the increasing prevalence of SID in the elderly population, these findings are clinically important for both risk stratification and patient managemen

Structure stability in the simple element sodium under pressure

The simple alkali metal Na, that crystallizes in a body-centred cubic structure at ambient pressure, exhibits a wealth of complex phases at extreme conditions as found by experimental studies. The analysis of the mechanism of stabilization of some of these phases, namely, the low-temperature Sm-type phase and the high-pressure cI16 and oP8 phases, shows that they satisfy the criteria for the Hume-Rothery mechanism. These phases appear to be stabilized due to a formation of numerous planes in a Brillouin-Jones zone in the vicinity of the Fermi sphere of Na, which leads to the reduction of the overall electronic energy. For the oP8 phase, this mechanism seems to be working if one assumes that Na becomes divalent metal at this density. The oP8 phase of Na is analysed in comparison with the MnP-type oP8 phases known in binary compounds, as well as in relation to the hP4 structure of the NiAs-type

International variation in invasive care of the elderly with acute coronary syndromes

Aims To explore variations in invasive care of the elderly with acute coronary syndromes across international practice. Methods and results Using combined populations from the SYMPHONY and 2nd SYMPHONY trials, we describe 30-day cardiac catheterization in elderly (≥75 years; n=1794) vs. younger patients (<75 years; n=14 043) after multivariable adjustment and by region of enrolment. The use of cardiac catheterization and revascularization were not protocol-specified. Elderly patients (median age 78 years) were more often female and more frequently had hypertension, diabetes, prior myocardial infarction, and prior coronary bypass surgery. Overall, they underwent less cardiac catheterization than younger patients [53 vs. 63%; adjusted OR 0.53 (0.46, 0.60)]. The absolute rate of cardiac catheterization in the elderly varied from 77% (vs. 91% in younger patients) in the US cohort to 27% (vs. 41% in younger patients) in the non-US cohort. Revascularization of elderly who underwent cardiac catheterization was also higher in US than non-US cohorts (71.3 vs. 53.6%). There was a significant interaction between the patient age and the use of catheterization across US and non-US regions of enrolment, as well as differences in the predictors of catheterization in the elderly. Despite these findings, after adjustment, 90-day rates of death and death or myocardial infarction (MI) were not significantly different in elderly who underwent catheterization compared with those who did not. Conclusion Although older age is universally predictive of lower use of cardiac catheterization, marked variation in catheterization of the elderly exists across international practice. Demonstrated differences in patterns of use suggest a lack of consensus regarding optimal use of an invasive strategy in the elderl

Prognostic relevance of symptoms versus objective evidence of coronary artery disease in diabetic patients

Aim Little is known about the prognostic significance of silent versus symptomatic coronary artery disease (CAD) in diabetic patients. We therefore assessed the incidence of scintigraphic evidence of CAD in diabetic patients without known CAD and the impact of symptoms and scintigraphic findings on prognosis. Methods and results A consecutive series of 1737 diabetic patients without known CAD underwent dual-isotope myocardial perfusion SPECT (MPS) and 1430 were followed-up for a median of 2 (1-8.5) years. Critical events were defined as myocardial infarction or cardiac death. Objective evidence of CAD was found in 39% of 826 asymptomatic diabetic patients, in 51% of 151 diabetic patients with shortness of breath (SOB), and in 44% of 760 diabetic patients with angina. During follow-up, 98 critical events occurred. Annual critical event rates were 2.2% in asymptomatic, 3.2% in angina, and 7.7% in diabetic patients with shortness of breath (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} $p{<}0.001$ \end{document} versus other groups). With MPS evidence of CAD, critical event rates increased to 3.4% (asymptomatic), 5.6% (angina), and 13.2% (SOB) (\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} $p{\leqslant}0.009$ \end{document} versus no evidence of CAD). Age, hypertension, shortness of breath, scarring and ischaemia were independent predictors of critical events. MPS findings added incremental information to prescan information regarding outcome prediction. Conclusions In asymptomatic diabetic patients, the rate of objective evidence of CAD and annual critical events were similar to those found in diabetic patients with angina. The outcome was three times worse in diabetic patients with shortness of breath. MPS findings were strongly predictive of outcome and proved valuable for risk stratificatio