Atomic structure of Mn wires on Si(001) resolved by scanning tunneling microscopy

At submonolayer coverage, Mn forms atomic wires on the Si(001) surface oriented perpendicular to the underlying Si dimer rows. While many other elements form symmetric dimer wires at room temperature, we show that Mn wires have an asymmetric appearance and pin the Si dimers nearby. We find that an atomic configuration with a Mn trimer unit cell can explain these observations due to the interplay between the Si dimer buckling phase near the wire and the orientation of the Mn trimer. We study the resulting four wire configurations in detail using high-resolution scanning tunneling microscopy (STM) imaging and compare our findings with STM images simulated by density functional theory.Comment: 4 pages, 4 figure

Replace Hand Washing with Use of a Waterless Alcohol Hand Rub?

Hand hygiene is one of the basic components of any infection control program and is frequently considered synonymous with hand washing. However, health care workers frequently do not wash their hands, and compliance rarely exceeds 40%. Hand rubbing with a waterless, alcohol-based rub-in cleanser is commonly used in many European countries instead of hand washing. Scientific evidence and ease of use support employment of a hand rub for routine hand hygiene. It is microbiologically more effective in vitro and in vivo, it saves time, and preliminary data demonstrate better compliance than with hand washing. Therefore, a task force comprising experts from the Centers for Disease Control and Prevention and from professional societies is designing guidelines for the use of a hand rub in the United States. Today, most countries of Northern Europe recommend a hand rub for hand hygiene unless the hands are visibly soiled. Side effects are rare and are mainly related to dryness of the skin. This review evaluates the scientific and clinical evidence that support the use of alcohol-based hand rubs in health care facilities as a new option for hand hygien

Serious bacterial infections in patients with rheumatoid arthritis under anti‐TNF‐α therapy

Objective. With rising numbers of anti‐tumour necrosis factor α (TNF‐α) treatments for rheumatoid arthritis (RA), Crohn's disease and other conditions, physicians unaware of potential pitfalls are increasingly likely to encounter associated severe infections. Our purpose was to assess the incidence and nature of severe infections in our RA patients under anti‐TNF‐α therapy. Methods. We reviewed patient charts and records of the Infectious Disease Unit for serious infections in patients with RA in the 2 yr preceding anti‐TNF‐α therapy and during therapy. Results. Serious infections affected 18.3% of patients treated with infliximab or etanercept. The incidence was 0.181 per anti‐TNF‐α treatment year vs 0.008 in the 2 yr preceding anti‐TNF‐α therapy. In several cases, only a few signs or symptoms indicated the severity of developing infections, including sepsis. Conclusions. A high level of suspicion of infection is necessary in patients under anti‐TNF‐α therapy. We suggest additional strategies for the prevention, rapid identification and pre‐emptive therapy of such infection

Fieber und Lymphadenopathie: Bericht über 4Tularämiefälle

Zusammenfassung: Wir berichten über 4Patienten, die in der Schweiz oder dem grenznahen Ausland an unterschiedlichen Formen der Tularämie erkrankten. Als Gemeinsamkeiten zeigten alle Patienten ein febriles Zustandsbild mit mäßiger bis ausgeprägter laborchemischer Entzündungsreaktion und eine lokoregionäre Lymphadenopathie. Zusätzlich führte bei 3Patienten eine empirisch begonnene Therapie mit β-Laktam-Antibiotika zu keiner Verbesserung der Klinik. Als Infektionsquelle konnte bei 2Patienten eine eindeutige, in einem Fall eine mögliche Korrelation mit einem Zeckenstich eruiert werden. Bei der vierten Patientin blieb der Ursprung der Tularämie ungeklärt. Die Diagnose stützte sich auf eine positive Serologie, eine positive Polymerase-Kettenreaktion (PCR) aus einem Gewebeaspirat oder auf positive Blutkulturen. Die Therapie erfolgte bei 3erwachsenen Patienten mit Ciprofloxacin p.o. über 3Wochen, wobei die Dosierung zwischen 500 und 750mg 2-mal täglich variierte. Bei einem pädiatrischen Patienten wurde die Therapie mit Gentamicin 4mg/kgKG i.v. 1-mal täglich für eine Woche und mit Ciprofloxacin 15mg/kgKG p.o. 2-mal täglich für 2weitere Wochen durchgeführt. Unter adäquater Therapie kam es bei allen Patienten zu einem erfreulichen Krankheitsverlauf mit vollständiger Ausheilung. Bei Patienten mit Fieber und Lymphknotenvergrößerung - insbesondere nach Zeckenstich - muss auch in der Schweiz eine Tularämie in die Differenzialdiagnose einbezogen werden. Als Therapie empfehlen wir eine Medikation mit Ciprofloxacin p.o. für 14-21Tag

Correlation between In Vivo and In Vitro Efficacy of Antimicrobial Agents against Foreign Body Infections

Implant-associated infections are often resistant to antibiotic therapy. Routine sensitivity tests fail to predict therapeutic success. Therefore experimental in vitro tests were sought that would better correlate with drug efficacy in device-related infections. The activity of six different antibiotics against methicillin-resistant Staphylococcus epidermidis was investigated. In vivo studies were performed with the guinea pig tissue-cage animal model; in vitro studies with minimum inhibiting and bactericidal concentrations, time-kill studies of growing and stationary-phase microorganisms, the killing of glass-adherent S. epidermidis. Drug efficacy on stationary and adherent microorganisms, but not minimum inhibiting concentrations, predicted the outcome of device-related infections. Rifampin cured 12 of 12 infections and was also the most efficient drug in any experimental in vitro test. Similarly, the failure of ciproftoxacin to eradicate foreign body infections correlated with its low efficacy on stationary-phase and adherent S. epidermidi

Electron acceleration by turbulent plasmoid reconnection

In space and astrophysical plasmas, like in planetary magnetospheres, as that of Mercury,energetic electrons are often found near current sheets (CSs), which hints at electron acceleration by magnetic reconnection. Unfortunately, electron acceleration by reconnection is not well understood, yet. In particular, acceleration by turbulent plasmoid reconnection. We have investigated electron acceleration by turbulent plasmoid reconnection, described by MHD simulations, via test particle calculations. In order to avoid resolving all relevant turbulence scales down to the dissipation scales, a mean-field turbulence model is used to describe the turbulence of sub-grid scales (SGS) and their effects via a turbulent electromotive force (EMF). The mean-field model describes the turbulent EMF as a function of the mean values of current density, vorticity, magnetic field as well as of the energy, cross-helicity and residual helicity of the turbulence. We found that, mainly around X-points of turbulent reconnection, strongly enhanced localized EMFs most efficiently accelerated electrons and caused the formation of power-law spectra. Magnetic-field-aligned EMFs, caused by the turbulence, dominate the electron acceleration process. Scaling the acceleration processes to parameters of the Hermean magnetotail, electron energies up to 60 keV can be reached by turbulent plasmoid reconnection through the thermal plasma.Comment: 2018PhPl...25d2904

Are there localized saddles behind the heterogeneous dynamics of supercooled liquids?

We numerically study the interplay between heterogeneous dynamics and properties of negatively curved regions of the potential energy surface in a model glassy system. We find that the unstable modes of saddles and quasi-saddles undergo a localization transition close to the Mode-Coupling critical temperature. We also find evidence of a positive spatial correlation between clusters of particles having large displacements in the unstable modes and dynamical heterogeneities.Comment: 7 pages, 3 figures, submitted to Europhys. Let