Extended skyrmion lattice scattering and long-time memory in the chiral magnet Fe1−x_{1-x}Cox_xSi

Small angle neutron scattering measurements on a bulk single crystal of the doped chiral magnet Fe$_{1-x}$Co$_x$Si with $x$=0.3 reveal a pronounced effect of the magnetic history and cooling rates on the magnetic phase diagram. The extracted phase diagrams are qualitatively different for zero and field cooling and reveal a metastable skyrmion lattice phase outside the A-phase for the latter case. These thermodynamically metastable skyrmion lattice correlations coexist with the conical phase and can be enhanced by increasing the cooling rate. They appear in a wide region of the phase diagram at temperatures below the $A$-phase but also at fields considerably smaller or higher than the fields required to stabilize the A-phase

Universality of the helimagnetic transition in cubic chiral magnets: Small angle neutron scattering and neutron spin echo spectroscopy studies of Fe1−x_{1-x}Cox_xSi

We present a comprehensive Small Angle Neutron Scattering (SANS) and Neutron Spin Echo Spectroscopy (NSE) study of the structural and dynamical aspects of the helimagnetic transition in Fe$_{1-x}$Co$_x$Si with $x$ = 0.30. In contrast to the sharp transition observed in the archetype chiral magnet MnSi, the transition in Fe$_{1-x}$Co$_x$Si is gradual and long-range helimagnetic ordering coexists with short-range correlations over a wide temperature range. The dynamics are more complex than in MnSi and involve long relaxation times with a stretched exponential relaxation which persists even under magnetic field. These results in conjunction with an analysis of the hierarchy of the relevant length scales show that the helimagnetic transition in Fe$_{1-x}$Co$_x$Si differs substantially from the transition in MnSi and question the validity of a universal approach to the helimagnetic transition in chiral magnets

Skyrmions and spirals in MnSi under hydrostatic pressure

The archetype cubic chiral magnet MnSi is home to some of the most fascinating states in condensed matter such as skyrmions and a non-Fermi liquid behavior in conjunction with a topological Hall effect under hydrostatic pressure. Using small angle neutron scattering, we study the evolution of the helimagnetic, conical and skyrmionic correlations with increasing hydrostatic pressure. We show that the helical propagation vector smoothly reorients from $\langle 111 \rangle$ to $\langle100\rangle$ at intermediate pressures. At higher pressures, above the critical pressure, the long-range helimagnetic order disappears at zero magnetic field. Nevertheless, skyrmion lattices and conical spirals form under magnetic fields, in a part of the phase diagram where a topological Hall effect and a non-Fermi liquid behavior have been reported. These unexpected results shed light on the puzzling behavior of MnSi at high pressures and the mechanisms that destabilize the helimagnetic long-range order at the critical pressure

Metal Hydrides and Related Materials - Energy Carriers for Novel Hydrogen and Electrochemical Storage

The seventh edition of the International Renewable and Sustainable Energy Conference (IRSEC) was held in Agadir (Sofitel Royal Bay, November 27–30, Morocco) under the Program Chair of Prof. Ahmed Ennaoui (IRESEN). IRSEC, as one of the biggest conferences in north Africa, aims at creating an international forum to facilitate discussions and exchanges in all aspects of renewable and sustainable energy. This Viewpoint will summarize the scientific presentations and stimulated discussions during the Special Session (November 28–29) on Metal Hydrides’ Energy covering topics of metal hydrides and energy related issues for innovative processes and technologies, with a focus on magnesium-based hydrides, intermetallic hydrides, complex and melt hydrides, porous materials, and thin films

Downregulation of Mcl-1 has anti-inflammatory pro-resolution effects and enhances bacterial clearance from the lung

Phagocytes not only coordinate acute inflammation and host defense at mucosal sites, but also contribute to tissue damage. Respiratory infection causes a globally significant disease burden and frequently progresses to acute respiratory distress syndrome, a devastating inflammatory condition characterized by neutrophil recruitment and accumulation of protein-rich edema fluid causing impaired lung function. We hypothesized that targeting the intracellular protein myeloid cell leukemia 1 (Mcl-1) by a cyclin-dependent kinase inhibitor (AT7519) or a flavone (wogonin) would accelerate neutrophil apoptosis and resolution of established inflammation, but without detriment to bacterial clearance. Mcl-1 loss induced human neutrophil apoptosis, but did not induce macrophage apoptosis nor impair phagocytosis of apoptotic neutrophils. Neutrophil-dominant inflammation was modelled in mice by either endotoxin or bacteria (Escherichia coli). Downregulating inflammatory cell Mcl-1 had anti-inflammatory, pro-resolution effects, shortening the resolution interval (R(i)) from 19 to 7 h and improved organ dysfunction with enhanced alveolar–capillary barrier integrity. Conversely, attenuating drug-induced Mcl-1 downregulation inhibited neutrophil apoptosis and delayed resolution of endotoxin-mediated lung inflammation. Importantly, manipulating lung inflammatory cell Mcl-1 also accelerated resolution of bacterial infection (R(i); 50 to 16 h) concurrent with enhanced bacterial clearance. Therefore, manipulating inflammatory cell Mcl-1 accelerates inflammation resolution without detriment to host defense against bacteria, and represents a target for treating infection-associated inflammation

Different effects of deep inspirations on central and peripheral airways in healthy and allergen-challenged mice

<p>Abstract</p> <p>Background</p> <p>Deep inspirations (DI) have bronchodilatory and bronchoprotective effects in healthy human subjects, but these effects appear to be absent in asthmatic lungs. We have characterized the effects of DI on lung mechanics during mechanical ventilation in healthy mice and in a murine model of acute and chronic airway inflammation.</p> <p>Methods</p> <p>Balb/c mice were sensitized to ovalbumin (OVA) and exposed to nebulized OVA for 1 week or 12 weeks. Control mice were challenged with PBS. Mice were randomly selected to receive DI, which were given twice during the minute before assessment of lung mechanics.</p> <p>Results</p> <p>DI protected against bronchoconstriction of central airways in healthy mice and in mice with acute airway inflammation, but not when OVA-induced chronic inflammation was present. DI reduced lung resistance induced by methacholine from 3.8 ± 0.3 to 2.8 ± 0.1 cmH₂O·s·mL^-1in healthy mice and 5.1 ± 0.3 to 3.5 ± 0.3 cmH₂O·s·mL^-1in acute airway inflammation (both <it>P </it>< 0.001). In healthy mice, DI reduced the maximum decrease in lung compliance from 15.9 ± 1.5% to 5.6 ± 0.6% (<it>P </it>< 0.0001). This protective effect was even more pronounced in mice with chronic inflammation where DI attenuated maximum decrease in compliance from 44.1 ± 6.6% to 14.3 ± 1.3% (<it>P </it>< 0.001). DI largely prevented increased peripheral tissue damping (G) and tissue elastance (H) in both healthy (G and H both <it>P </it>< 0.0001) and chronic allergen-treated animals (G and H both <it>P </it>< 0.0001).</p> <p>Conclusion</p> <p>We have tested a mouse model of potential value for defining mechanisms and sites of action of DI in healthy and asthmatic human subjects. Our current results point to potent protective effects of DI on peripheral parts of chronically inflamed murine lungs and that the presence of DI may blunt airway hyperreactivity.</p