Unexpected Magnetism of Small Silver Clusters

The ground-state electronic, structural, and magnetic properties of small silver clusters, Ag$_n$ (2$\le$n$\le$22), have been studied using a linear combination of atomic Gaussian-type orbitals within the density functional theory. The results show that the silver atoms, which are diamagnetic in bulk environment, can be magnetic when they are grouped together in clusters. The Ag$_{13}$ cluster with icosahedral symmetry has the highest magnetic moment per atom among the studied silver clusters. The cluster symmetry and the reduced coordination number specific of small clusters reveal as a fundamental factor for the onset of the magnetism.Comment: 4 pages, 4 figure

The Search for Higher TcT_c in Houston

It is a great pleasure to be invited to join the chorus on this auspicious occasion to celebrate Professor K. Alex Mueller's 90th birthday by Professors Annette Bussman-Holder, Hugo Keller, and Antonio Bianconi. As a student in high temperature superconductivity, I am forever grateful to Professor Alex Mueller and Dr. Georg Bednorz "for their important breakthrough in the discovery of superconductivity in the ceramic materials" in 1986 as described in the citation of their 1987 Nobel Prize in Physics. It is this breakthrough discovery that has ushered in the explosion of research activities in high temperature superconductivity (HTS) and has provided immense excitement in HTS science and technology in the ensuing decades till now. Alex has not been resting on his laurels and has continued to search for the origin of the unusual high temperature superconductivity in cuprates.Comment: Dedicated to Alex Mueller, whose "important breakthrough in the discovery of superconductivity in ceramic materials" in 1986 has changed the world of superconductivit

Integrated luminometer for the determination of trace metals in seawater using fluorescence, phosphorescence and chemiluminescence detection

The paper describes an integrated luminometer able to perform fluorescence (FL), room temperature phosphorescence (RTP) and chemiluminescence (CL) measurements on seawater samples. The technical details of the instrumentation are presented together with flow injection (FI) manifolds for the determination of cadmium and zinc (by FL), lead (RTP) and cobalt (CL). The analytical figures of merit are given for each manifold and results are presented for the determination of the four trace metals in seawater reference materials (NASS-5, SLEW-2) and Scheldt estuarine water samples

Fluorination effects on the thermodynamic, thermophysical and surface properties of ionic liquids

Fundacao para a Ciencia e a Tecnologia (FCT/MCTES) - SFRH/BD/100563/2014 ; SFRH/BPD/82264/2011 ; PTDC/EQU-FTT/118800/2010 ; PTDC/CTM-NAN/121274/2010 ; IF/00210/2014/CP1244/CT0003 ; UID/Multi/04551/2013 ; UID/CTM/50011/2013 European Research Council (ERC) - ERC-2013-StG-337753 FCT/MEC - RECI/BBB-BQB/0230/2012This paper reports the thermal, thermodynamic, thermophysical and surface properties of eight ionic liquids with fluorinated alkyl side chain lengths equal or greater than four carbon atoms. Melting and decomposition temperatures were determined together with experimental densities, surface tensions, refractive indices, dynamic viscosities and ionic conductivities in a temperature interval ranging from (293.15 to 353.15) K. The surface properties of these fluorinated ionic liquids were discussed and several thermodynamic functions, as well as critical temperatures, were estimated. Coefficients of isobaric thermal expansion, molecular volumes and free volume effects were calculated from experimental values of density and refractive index and compared with previous data. Finally, Walden plots were used to evaluate the ionicity of the investigated ionic liquids.publishersversionpublishe

A thermophysical and structural characterization of ionic liquids with alkyl and perfluoroalkyl side chains

The authors thank FCT/MEC (Portugal) for financial support through grants SFRH/BD/100563/2014 (N. S. M. V.) and SFRH/BPD/94291/2013 (K. S.), FCT Investigator contracts (A. B. P., J. M. M. A., I. M. M. and J. M. S. S. E) and through projects PTDC/CTM-NAN/121274/2010, FCT-ANR/CTM-NAN/0135/2012, PTDC/EQU-FTT/118800/2010, UID/QUI/00100/2013 and UID/Multi/04551/2013. The NMR spectrometers are part of The National NMR Facility, supported by FCT/MEC (RECI/BBB-BQB/0230/2012).This work represents an essential step towards the understanding of the dynamics and thermodynamic characteristics of a novel family of ionic liquids, namely fluorinated ionic liquids based on the combination of 1-alkyl-3-methylimidazolium cations with perfluoroalkylsulfonates or perfluoroalkylcarboxylates anions. The so far scarce information about these fluids constitutes a limiting factor for their potential applications. In this work, we provide detailed evidence on the influence of hydrogenated and fluorinated alkyl chain lengths in the final characteristics of the fluorinated ionic liquids. Different properties, namely, melting point, decomposition temperature, density, dynamic viscosity, ionic conductivity and refractive index, were determined and the experimental results were discussed taking into account the influence of the length of the hydrogenated and fluorinated alkyl chains. Molecular dynamic simulations were also performed to study the nanoscale structure of these novel compounds.authorsversionpublishe

Impact of house dust mite-driven asthma on children's school performance and activity

Absenteeism; Allergic asthma; Subcutaneous allergen immunotherapyAbsentisme; Asma al·lèrgica; Immunoteràpia subcutània amb al·lèrgensAbsentismo; Asma alérgica; Inmunoterapia subcutánea con alérgenosEvidence regarding asthma's impact on children's daily lives is limited. This prospective and cross-sectional, observational, multicenter study assessed school/work and activity impairment in children and adolescents with allergic asthma and their caregivers and allergen immunotherapy (AIT) effects. Included patients were schooled children and adolescents (5 to 17 years) with allergic asthma due to house dust mites (HDM). Impairment of school/work (i.e., absenteeism and presenteeism) and activity was measured in patients and their caregivers using the Work Productivity Impairment Questionnaire plus Classroom Impairment Questions: Allergy Specific (WPAI + CIQ:AS). HDM allergic patients with school impairment received subcutaneous AIT with a MicroCrystalline Tyrosine-associated allergoid. WPAI + CIQ:AS and effectiveness variables were compared between baseline and 1-year post-AIT. Of the 113 patients included, 59 (52.2%) and 51 (45.1%) showed school and activity impairment, respectively, missing a mean (SD) of 37.6 (24.4) % and 42.6 (25.6) % of school and activity time, respectively. Twenty-six (23%) caregivers reported activity impairment and, of the 79 (69.9%) employed, 30 (38%) reported work impairment. Of the 65 patients with school/activities impairment, 41 (63.1%) received AIT, of which 21 (51.2%) completed 1 year of treatment. Effectiveness variables and WPAI + CIQ:AS significantly improved: Mean (SD) school impairment decreased from 39.7 (26.7) to 2.1 (7.1) % (p < 0.001) and activity impairment from 46.2 (34.6) to 1.4 (3.6) % (p < 0.001). Conclusion: Allergic asthma due to HDMs results in school/work and activity impairment in children and adolescents and their caregivers. One year of AIT provided clinical benefits and reduced school and activity impairment. What is known: • Allergic asthma impairs children's school performance and daily activities. • Allergen immunotherapy modifies allergic disease course and ameliorates its symptoms. What is new: • Asthma symptoms due to allergy to house dust mites impair children's school attendance and productivity and daily activity and their caregivers' work performance and daily lives. • Allergen immunotherapy with a house dust mite MicroCrystalline Tyrosine (MCT)-associated allergoid seems to provide clinical benefits, associated with decreased school and activity impairment, supporting it as an effective treatment option

A survey among dermatologists: diagnostics of superficial fungal infections - what is used and what is needed to initiate therapy and assess efficacy?

BACKGROUND: Superficial fungal infections are common. It is important to confirm the clinical diagnosis by mycological laboratory methods before initiating systemic antifungal treatment, especially as antifungal sensitivity and in vitro susceptibility may differ between different genera and species. For many years, the gold standard for diagnosis of superficial fungal infections has been direct fungal detection in the clinical specimen (microscopy) supplemented by culturing. Lately, newer molecular based methods for fungal identification have been developed. OBJECTIVE: This study was initiated to focus on the current usage of mycological diagnostics for superficial fungal infections by dermatologists. It was designed to investigate whether it was necessary to differentiate between initial diagnostic tests and those used at treatment follow-up in specific superficial fungal infections. METHODS: An online questionnaire was distributed among members of the EADV mycology Task Force and other dermatologists with a special interest in mycology and nail disease. RESULTS: The survey was distributed to 62 dermatologists of whom 38 (61%) completed the whole survey, 7 (11%) partially completed and 17 (27%) did not respond. Nearly, all respondents (82-100%) said that ideally they would use the result of direct microscopy (or histology) combined with a genus/species directed treatment of onychomycosis, dermatophytosis, Candida- and Malassezia-related infections. The majority of the dermatologists used a combination of clinical assessment and direct microscopy for treatment assessment and the viability of the fungus was considered more important at this visit than when initiating the treatment. Molecular based methods were not available for all responders. CONCLUSION: The available diagnostic methods are heterogeneous and their usage differs between different practices as well as between countries. The survey confirmed that dermatologists find it important to make a mycological diagnosis, particularly prior to starting oral antifungal treatment in order to confirm the diagnose and target the therapy according to genus and species

Strontium hexaferrite platelets: a comprehensive soft X-ray absorption and Mössbauer spectroscopy study

Platelets of strontium hexaferrite (SrFe12O19, SFO), up to several micrometers in width, and tens of nanometers thick have been synthesized by a hydrothermal method. They have been studied by a combination of structural and magnetic techniques, with emphasis on Mössbauer spectroscopy and X-ray absorption based-measurements including spectroscopy and microscopy on the iron-L edges and the oxygen-K edge, allowing us to establish the differences and similarities between our synthesized nanostructures and commercial powders. The Mössbauer spectra reveal a greater contribution of iron tetrahedral sites in platelets in comparison to pure bulk material. For reference, high-resolution absorption and dichroic spectra have also been measured both from the platelets and from pure bulk material. The O-K edge has been reproduced by density functional theory calculations. Out-of-plane domains were observed with 180° domain walls less than 20 nm width, in good agreement with micromagnetic simulationsThis work is supported by the Spanish Ministry of Economy and Competitiveness through Projects MAT2015-64110-C2-1-P, MAT2015-64110-C2-2-P, MAT2015-66888-C3-1-R and by the European Commission through Project H2020 No. 720853 (Amphibian). These experiments were performed at the CIRCE, MISTRAL and BOREAS beamlines of the ALBA Synchrotron Light Facility. G.D.S. acknowledges the European Youth Employement Initiative and the Autonomous Community of Madrid for a one-year fellowship. Slovenian Research Agency is acknowledged for funding the research program Ceramics and complementary materials for advanced engineering and biomedical applications (P2-0087), CEMM, JSI for the use of TE

Theory of noncollinear interactions beyond Heisenberg exchange: Applications to bcc Fe

We show for a simple noncollinear configuration of the atomistic spins (in particular, where one spin is rotated by a finite angle in a ferromagnetic background) that the pairwise energy variation computed in terms of multiple-scattering formalism cannot be fully mapped onto a bilinear Heisenberg spin model even in the absence of spin-orbit coupling. The non-Heisenberg terms induced by the spin-polarized host appear in leading orders in the expansion of the infinitesimal angle variations. However, an E g − T 2 g symmetry analysis based on the orbital decomposition of the exchange parameters in bcc Fe leads to the conclusion that the nearest-neighbor exchange parameters related to the T 2 g orbitals are essentially Heisenberg-like: they do not depend on the spin configuration, and can, in this case, be mapped onto a Heisenberg spin model even in extreme noncollinear cases.Supports from the Swedish Research Council (VR), the KAW foundation (grants 2012.0031 and 2013.0020) and eSSENCE are acknowledged.The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC). A. Bergman acknowledges support from CEA-Enhanced Eurotalents, co-funded by FP7 Marie Sk lodowska-Curie COFUND Programme (Grant Agreement n 600382). P. F. Bessarab acknowledges support from the Icelandic Research Fund (Grant No. 163048-052) and the mega-grant of the Ministry of Education and Science of the Russian Federation (grant no. 14.Y26.31.0015). R. Cardias, D. C. M. Rodrigues, and A. B. Klautau acknowledge financial support from CAPES and CNPq, Brazil.Peer Reviewe