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Broadband ferromagnetic resonance is measured in single crystalline Fe films of varying thickness sandwiched between MgO layers. An exhaustive magnetic characterization of the films (exchange constant, cubic, uniaxial and surface anisotropies) is enabled by the study of the uniform and the first perpendicular standing spin wave modes as a function of applied magnetic field and film thickness. Additional measurements of non-reciprocal spin wave propagation allow us to separate each of the two interface contributions to the total surface anisotropy. The results are consistent with the model of a quasi-bulk film interior and two magnetically different top and bottom interfaces, a difference ascribed to different oxidation states.

Single molecule force spectroscopy is a powerful approach to probe the structure, conformational changes, and kinetic properties of biological and synthetic macromolecules. However, common approaches to apply forces to biomolecules require expensive and cumbersome equipment and relatively large probes such as beads or cantilevers, which limits their use for many environments and makes integrating with other methods challenging. Furthermore, existing methods have key limitations such as an inability to apply compressive forces on single molecules. We report a nanoscale DNA force spectrometer (nDFS), which is based on a DNA origami hinge with tunable mechanical and dynamic properties. The angular free energy landscape of the nDFS can be engineered across a wide range through substitution of less than 5% of the strand components. We further incorporate a removable strut that enables reversible toggling of the nDFS between open and closed states to allow for actuated application of tensile and compressive forces. We demonstrate the ability to apply compressive forces by inducing a large bend in a 249bp DNA molecule, and tensile forces by inducing DNA unwrapping of a nucleosome sample. These results establish a versatile tool for force spectroscopy and robust methods for designing nanoscale mechanical devices with tunable force application.

Despite demonstrating exciting potential for applications such as drug delivery and biosensing, the development of nanodevices for practical applications and broader use in research and education are still hindered by the time, effort, and cost associated with DNA origami fabrication. Simple and robust methods to perform and scale the DNA origami self-assembly process are critical to facilitate broader use and translation to industrial or clinical applications. We report a simple approach to fold DNA origami nanostructures that is fast, robust, and scalable. We demonstrate fabrication at scales approximately 100–1,500-fold higher than typical scales. We further demonstrate an approach we termed low-cost efficient annealing (LEAN) self-assembly involving initial heating at 65 °C for 10 min, then annealing at 51 °C for 2 h, followed by brief quenching at 4 °C that leads to effective assembly of a range of DNA origami structures tested. In contrast to other methods for scaling DNA origami assembly, this approach can be carried out using cheap and widely available equipment (e.g., hot plates, water baths, and laboratory burners) and uses standard recipes and materials so is readily applied to any existing or new DNA origami designs. We envision these methods can facilitate device development for commercial applications and facilitate broader use of DNA origami in research and education.

International audience; The metal-insulator transition and the original magnetic phase that appear in vanadium oxide nanoclusters epitaxially embedded in an MgO matrix are studied via electron transport, magneto-resistance, and X-ray circular dichroism measurements. The metal-insulator transition temperature is observed to be in the range of 1.5-27 K. We observe, from 0.3 K to at least 125 K, a superparamagnetic behavior, whereas vanadium oxide, in its bulk phase, is reported to be anti-ferromagnetic (AF) at low temperatures. This striking feature is consistent with either ferromagnetic spin pairing or spin canting in the AF spin order along the 1D vanadium ion chains of the Magn eli phase or for the VO 2 (A)-like phase. Finally, the observed magneto-resistive effect, which reached up to 8% at low temperatures, indicates ferromagnetic behavior for some of the nanoparticles. This enables their integration in spintronic devices that could be combined with metal-insulator switching and magneto-resistive effects.

What is effective listening? This question intrigues both scholars and the general public. Theoretical explorations provide insight into the listening process as well as pragmatic guidelines for how to be a good listener. But even the most learned listening scholar will often fall back on the observation that they know effective listening best when they experience it.Five renowned listening experts were asked to respond to the question, “What is listening from the perspective of your lived experience?” Each was asked to work from an auto-ethnographic methodology. The five lifeworlds described in this study represent their responses to this question and offer unique, individual ethnographic contexts describing the listening experience of each of the participants.

This paper presents an electromagnetic analysis based on an innovative simulation environment and a spherical near field facility well suited to evaluate the near field generated by wireless BAN communication technologies close to an anthropomorphic human mannequin. The interest is to demonstrate the main advantages of these new electromagnetic tools in the theoretical and experimental domains.

We investigate the second harmonic generation (SHG) signal in strained Cr

The technique of propagating spin wave spectroscopy is applied to a 20 nm thick Fe/MgO (001) film. The magnetic parameters extracted from the position of the resonance peaks are very close to those tabulated for bulk iron. From the propagating waveforms, a group velocity of 4 km/s and an attenuation length of about 6 micrometers are extracted for 1.6 micrometers-wavelength spin-wave at 18 GHz. From the measured current-induced spin-wave Doppler shift, we also extract a surprisingly high degree of spin-polarization of the current of 83%. This set of results makes single-crystalline iron a promising candidate for building devices utilizing high frequency spin-waves and spin-polarized currents., 5 figures, submitted to Phys. Rev. B

We study electron transport in an assembly of epitaxial Cr2O3 nanoparticles embedded in a MgO tunnel barrier: an unusual variation in the Coulomb blockade charging energy is observed as a function of the size of the clusters. In striking contrast to the expected increase in charging energy when decreasing the cluster size, an almost constant behavior is observed. We argue here that the spontaneous superparaelectric moment carried by the cluster core is the origin of this unusual behavior since it drives the dielectric constant in this cluster assembly. This phenomenon could be exploited to fabricate devices with single valued Coulomb blockade energy despite a statistical dispersion in the cluster size.We study electron transport in an assembly of epitaxial Cr2O3 nanoparticles embedded in a MgO tunnel barrier: an unusual variation in the Coulomb blockade charging energy is observed as a function of the size of the clusters. In striking contrast to the expected increase in charging energy when decreasing the cluster size, an almost constant behavior is observed. We argue here that the spontaneous superparaelectric moment carried by the cluster core is the origin of this unusual behavior since it drives the dielectric constant in this cluster assembly. This phenomenon could be exploited to fabricate devices with single valued Coulomb blockade energy despite a statistical dispersion in the cluster size.

The conservation of an electron’s spin and symmetry as it undergoes solid-state tunnelling within magnetic tunnel junctions (MTJs) is thought to be best understood using MgO-based MTJs1. Yet the very large experimental values of tunnelling magnetoresistance (TMR) that justify this perception are often associated with tunnelling barrier heights well below those suggested by the MgO optical band gap. This combination of high TMR and low RA-product, while spawning spin-transfer/spin-orbit torque experiments and considerable industrial interest, cannot be explained by standard theory. Noting the impact of a tunnel barrier’s altered stoichiometry on TMR2, we reconcile this 10+year-old contradiction between theory and experiment by considering the impact of the MgO barrier’s structural defects3–5. We find that the ground and excited states of oxygen vacancies can promote localized states within the band gap with differing electronic character. By setting symmetry- and temperature-dependent tunnelling barrier heights, they alter symmetry-polarized tunnelling and thus TMR. We will examine how annealing, depending on MgO growth conditions, can alter the nature of these localized states. This oxygen vacancy paradigm of inorganic tunnelling spintronics opens interesting perspectives into endowing the MTJ with additional functionalities, such as optically manipulating the MTJ’s spintronic response.

Large assemblies of self-organized aluminum nanoclusters embedded in an oxide layer are formed on graphene templates and used to build tunnel-junction devices. Unexpectedly, single-electron-transport behavior with well-defined Coulomb oscillations is observed for a record junction area of up to 100 mu m(2) containing millions of metal islands. Such graphene-metal nanocluster hybrid materials offer new prospects for single-electron electronics.

We present an optically induced remanent photostriction in BiFeO3, resulting from the photovoltaic effect, which is used to modify the ferromagnetism of Ni film in a hybrid BiFeO3/Ni structure. The 75% change in coercivity in the Ni film is achieved via optical and nonvolatile control. This photoferromagnetic effect can be reversed by static or ac electric depolarization of BiFeO3. Hence, the strain dependent changes in magnetic properties are written optically, and erased electrically. Light-mediated straintronics is therefore a possible approach for low-power multistate control of magnetic elements relevant for memory and spintronic applications., Report on photopolarization effect in BiFeO3 used to write magnetic properties via the remanent photostriction

Pluripotency is a cellular state of multiple options. Here, we highlight the potential for self-organization to contribute to stem cell fate computation. A new way of considering regulatory circuitry is presented that describes the expression of each transcription factor (TF) as a branching process that propagates through time, interacting and competing with others. In a single cell, the interactions between multiple branching processes generate a collective process called ‘critical-like self-organization’. We explain how this phenomenon provides a valid description of whole genome regulatory circuit dynamics. The hypothesis of exploratory stem cell decision-making proposes that critical-like self-organization (also called rapid self-organized criticality) provides the backbone for cell fate computation in regulative embryos and pluripotent stem cells. Unspecific amplification of TF expression is predicted to initiate this self-organizing circuitry, where cascades of gene expression propagate and may interact either synergistically or antagonistically. The emergent and highly dynamic circuitry is affected by various sources of selection pressure, such as the expression of TFs with disproportionate influence over other genes, and extrinsic biological and physical stimuli that differentially modulate particular gene expression cascades. Extrinsic conditions continuously trigger waves of transcription that ripple throughout regulatory networks on multiple spatiotemporal scales, providing the context within which circuitry self-organizes. In this framework, a distinction between instructive and selective mechanisms of fate determination is misleading because it is the 'interference pattern', rather than any single instructing or selecting factor, that is ultimately responsible for computing and directing cell fate. Using this framework, we consider whether the idea of a naïve ground state of pluripotency and that of a fluctuating transcriptome are compatible, and whether a ground state like that captured in vitro could exist in vivo.

We review literature relating to three types of factors known to influence stem cell behavior. These factors are stochastic gene expression, regulatory network architecture, and the influence of external signals, such as those emanating from the niche. Although these factors are considered separately, their shared evolutionary history necessitates integration. Stochastic gene expression pervades network components; network architecture controls, modulates, or exploits this noise while performing additional computation; and such complexity also interplays with factors external to cells. Adequate understanding of each of these components, and how they interact, will lead to a conceptual model of the stem cell regulatory system that can be used to drive hypothesis-driven research and facilitate interpretation of experimental data.

For building and maintaining a primary care workforce to staff an integrated care delivery strategy, considerations include:Geographic presencePatient care modelingProfessional staffing.

Many cancers show primary or acquired drug resistance due to the overexpression of efflux pumps. A novel mechanism to circumvent this is to integrate drugs, such as anthracycline antibiotics, with nanoparticle delivery vehicles that can bypass intrinsic tumor drug-resistance mechanisms. DNA nanoparticles serve as an efficient binding platform for intercalating drugs (e.g., anthracyclines doxorubicin and daunorubicin, which are widely used to treat acute leukemias) and enable precise structure design and chemical modifications, for example, for incorporating targeting capabilities. Here, DNA nanostructures are utilized to circumvent daunorubicin drug resistance at clinically relevant doses in a leukemia cell line model. The fabrication of a rod-like DNA origami drug carrier is reported that can be controllably loaded with daunorubicin. It is further directly verified that nanostructure-mediated daunorubicin delivery leads to increased drug entry and retention in cells relative to free daunorubicin at equal concentrations, which yields significantly enhanced drug efficacy. Our results indicate that DNA origami nanostructures can circumvent efflux-pump-mediated drug resistance in leukemia cells at clinically relevant drug concentrations and provide a robust DNA nanostructure design that could be implemented in a wide range of cellular applications due to its remarkably fast self-assembly (≈5 min) and excellent stability in cell culture conditions.

Magnetic properties of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ epitaxial clusters inserted in an Fe/MgO/Fe tunnel barrier are revealed by their tunnel magnetoresistance signature. The cluster assembly has been shown in a previous work to behave as a superparamagnet when a magnetic field was applied in the plane of the tunnel junction. We here demonstrate that an external large out-of plane electric field (in the order of 0.5 GV/m) favors in-plane magnetization orientation. This is due to an electric-field-induced magnetic anisotropy along the normal to the plane, corresponding to large anisotropy fields reaching up to 2 T. The assembly of clusters is thus strictly speaking not superparamagnetic and its magnetization cannot be exactly described by a Langevin law. This is attributed either to a strain-induced enhanced magnetoelectric effect or to a voltage-induced change of the magnetic anisotropy at interfaces with MgO.

Performance improvement in hospital-owned practices requires: The organizational will to sponsor change. Decision-making partnerships between physicians and executives. Effective implementers to drive change at the practice level. Relevant performance measures. A culture of accountability for all stakeholders.

The near-field Coulomb interaction between a nano-emitter and a graphene monolayer results in strong F\"orster-type resonant energy transfer and subsequent fluorescence quenching. Here, we investigate the distance dependence of the energy transfer rate from individual, i) zero-dimensional CdSe/CdS nanocrystals and ii) two-dimensional CdSe/CdS/ZnS nanoplatelets to a graphene monolayer. For increasing distances $d$, the energy transfer rate from individual nanocrystals to graphene decays as $1/d^4$. In contrast, the distance dependence of the energy transfer rate from a two-dimensional nanoplatelet to graphene deviates from a simple power law, but is well described by a theoretical model, which considers a thermal distribution of free excitons in a two-dimensional quantum well. Our results show that accurate distance measurements can be performed at the single particle level using graphene-based molecular rulers and that energy transfer allows probing dimensionality effects at the nanoscale., Comment: Main text (+ 5 figures) and Supporting Information (+ 7 figures)

Perovskite SrRuO 3 films are promising candidates as metallic electrodes in high-permittivity (high k ) capacitors and possibly in fully epitaxial CMOS stacks. The thermal stability of SrRuO 3 during forming-gas (FG) anneal is an important requirement and is investigated here by in situ X-ray diffraction (XRD) and electrical resistivity measurements. A weak and smooth increase of the resistivity is observed above 300 °C and is attributed to the effect of hydrogen diffusion. It is followed by a sharp transition at 500 °C into a highly resistive state due to the decomposition of the SrRuO 3 . We found that the addition of about 1% O 2 in the FG prevents both the onset of resistivity at 300 °C and the decomposition of the oxide.

The carrier mobility μ in low-doped silicon-on-insulator wafers is found to be strongly modified by the deposition of a thin ZrO2 or SrZrO3 top layer grown by molecular-beam epitaxy. Pseudo-metal–oxide–semiconductor field-effect-transistor measurements performed on several samples clearly show a correlation between μ and the density of interface traps (Dit) at the Si/buried-oxide interface. The reduction of Dit by a forming gas anneal leads to a corresponding increase in mobility. Moreover, the high-k/Si interface can contribute to the total drain current via the creation of an inversion channel induced by trapped charges in the high-k layer. Using Hall-effect measurements, we took advantage of this additional current to evaluate the carrier mobility at the high-k/Si interface, without the need of a top gate electrode.

Afin d'augmenter les capacites de stockage des media d'enregistrement magnetique, on cherche a diminuer la taille des domaines magnetiques qui portent l'information. L'elaboration de couches minces d'alliages magnetiques dans des phases ordonnees permet d'envisager des structures a tres forte anisotropie magnetique perpendiculaire, necessaire pour obtenir des domaines stables malgre leur taille reduite. Nous avons etudie, grâce a un dispositif original de diffraction X en temperature, la mise en ordre de couches FePd ou FePt deposees par MBE dans des etats differents d'ordre initial et de contrainte. La mise en ordre se fait selon l'axe de croissance. La structure des couches est tres inhomogene: coexistent des domaines non ordonnes et ordonnes, avec ou sans defaut dans l'empilement de la phase L1 0 , voire d'autres phases. Les petites zones ordonnees lors de la croissance ne semblent pas participer au developpement de l'ordre a grande distance lors du traitement en temperature. L'evolution de la fraction qui s'ordonne est identique quel que soit l'etat de contrainte epitaxiale impose. Des modifications des conditions experimentales permettent desormais d'envisager des mesures plus systematiques avec un historique en temperature plus rigoureux afin de confirmer ces observations.

We investigate the second harmonic generation (SHG) signal in strained Cr2O3 clusters. We show that the SHG signal generated by nanometric Cr2O3 clusters embedded in MgO varies under an applied electric field, at room temperature. The variation of the intensity follows a Langevin law as a function of the electric field, which is consistent with a super-paraelectric clusters assembly. This reveals the presence of a weak spontaneous electric dipole in Cr2O3 when in the shape of highly strained epitaxial clusters, whereas this material does not posses any permanent electric dipole in the bulk phase. These results indicate that the multiferroic state recently observed at low temperature in those clusters, which was associated to a giant magneto-electric effect, might still exist at room temperature: this opens the way to new applications based on chromium oxide strained nanoparticles.

We report on the fabrication and characterization of vertical spin-valve structures using a thick epitaxial MgO barrier as spacer layer and a graphene-passivated Ni film as bottom ferromagnetic electrode. The devices show robust and scalable tunnel magnetoresistance, with several changes of sign upon varying the applied bias voltage. These findings are explained by a model of phonon-assisted transport mechanisms that relies on the peculiarity of the band structure and spin density of states at the hybrid graphene|Ni interface.

Équipe 101 : Nanomagnétisme et électronique de spin; International audience; Research on advanced materials such as multiferroic perovskites underscores promising applications, yet studies on these materials rarely address the impact of defects on the nominally expected materials property. Here, we revisit the comparatively simple oxide MgO as the model material system for spin-polarized solid-state tunnelling studies. We present a defect-mediated tunnelling potential landscape of localized states owing to explicitly identified defect species, against which we examine the bias and temperature dependence of magnetotransport. By mixing symmetry-resolved transport channels, a localized state may alter the effective barrier height for symmetry-resolved charge carriers, such that tunnelling magnetoresistance decreases most with increasing temperature when that state is addressed electrically. Thermal excitation promotes an occupancy switchover from the ground to the excited state of a defect, which impacts these magnetotransport characteristics. We thus resolve contradictions between experiment and theory in this otherwise canonical spintronics system, and propose a new perspective on defects in dielectrics.

Hospitals can correct most of the causes of reduced performance in hospital-owned medical practices by setting appropriate performance expectations and implementing correct operating principles. Engaging employed physicians and executives as partners who provide principle-based direction and support to practice managers encourages performance improvement. A critical determinant of a hospital's ability to successfully own medical practices is understanding and implementing the principles for success in this unique ambulatory business.

Primary care physicians today can be expected to capture between 2,000 and 5,000 active patients who consider that physician to be "my physician." The geographic location of primary care physicians affects the payer mix of the hospital and its affiliated subspecialists. Hospital and health system CFOs would be wise to advocate investment in primary care physicians to secure market share. They should also develop compensation plans with a value-volume balance and establish ways to actively manage referrals.

The control of the magnetization of a material with an electric field would make the design and the integration of novel electronic devices possible. This explains the renewed interest in multiferroic materials. Progress in this field is currently hampered by the scarcity of the materials available and the smallness of the magnetoelectric effects. Here we present a proof-of-principle experiment showing that engineering large strains through nanoscale size reduction is an efficient route for increasing magnetoelectric coefficients by orders of magnitude. The archetype magnetoelectric material, Cr2O3, in the form of epitaxial clusters, exhibits an unprecedented 600% change in magnetization magnitude under 1V. Furthermore, a multiferroic phase, with both magnetic and electric spontaneous polarizations, is found in the clusters, while absent in the bulk. We gratefully acknowledge A. Carvalho for SEM observations, J. Arabski for technical assistance during MBE growth, STnano staff for technical support during microfabrication, B. Muller for technical support while setting up DEIMOS beamline, DEIMOS beamline staff for help during synchrotron experiments, and M. Bailleul and V. Da Costa for magnetic and structural characterization measurements. N.N. thanks Région Alsace for financial support.

The FePd alloy exhibits an L10 (CuAu-I type) chemically ordered phase which can be grown by molecular beam epitaxy at a low temperature (620 K) on Pd(0 0 1). The surface of the alloy has been observed by scanning tunnelling microscopy to determine the link between the surface morphology and the underlying chemical order. Steps are commonly observed with a bi-atomic height as a result of the surface processes leading to the chemical ordering. Mono-atomic steps are also observed and there is some evidence that they are linked to the antiphase boundaries between ordered domains within the growing layer.

Physician employment is here to stay. The challenge for healthcare finance professionals is to make physician relationships work without the financial losses experienced by hospitals that tried physician employment in the past. Capturing market share should be a key strategy in any physician employment effort. Physicians who are engaged and actively involved in the process make great business partners because they understand the productivity, efficiencies, and cost controls needed to succeed.

Epitaxial growth of electrodes and tunnel barriers on graphene is one of the main technological bottlenecks for graphene spintronics. In this paper, we demonstrate that MgO(111) epitaxial tunnel barriers, one of the prime candidates for spintronic application, can be grown by molecular beam epitaxy on epitaxial graphene on SiC(0001). Ferromagnetic metals (Fe, Co, Fe20Ni80) were epitaxially grown on top of the MgO barrier, thus leading to monocrystalline electrodes on graphene. Structural and magnetic characterizations were performed on these ferromagnetic metals after annealing and dewetting: they form clusters with a 100 nm typical lateral width, which are mostly magnetic monodomains in the case of Fe. This epitaxial stack opens the way to graphene spintronic devices taking benefits from a coherent tunnelling current through the epitaxial MgO/graphene stack.

We observe, as a function of temperature, a second order magnetic phase transition in nanometric Cr2O3 clusters that are epitaxially embedded in an insulating MgO matrix. They are investigated through their tunnel magneto-resistance signature, the MgO layer being used as a tunnel barrier. We infer the small magnetic dipoles carried by the Cr2O3 clusters and provide evidence of a magnetic phase transition at low temperature in those clusters: they evolve from an anti ferromagnetic state, with zero net moment close to 0 K, to a weak ferromagnetic state that saturates above about 10 K. The influence of magneto-electric effects on the weak ferromagnetic phase is also striking: the second order transition temperature turns out to be linearly dependent on the applied electric field.

To work together, physicians, finance leaders, and other executives need: A shared vision that is compelling enough to promote cooperation, A culture of accountability, which helps weed out the disrupters who can stall change, Forums to identify implementation tactics, Leadership skills, which help them come together to solve problems.

As hospitals and health systems grow, they need to focus on the smallest unit of service-the patient visit. Physicians and managers should have the authority and accountability that allows them to work together at the local level to serve patients and solve operational issues. As long as patients and physicians have a choice, the delivery of medical services will be an individual relationship business.

Because of trends that are driving increased consolidation in the healthcare industry, community healthcare systems in the future will have fewer independent medical practices. Hospitals and physician practices can be structurally or functionally integrated, but those that are structurally integrated only, do not function as integrated health systems. For successful integration, leaders from many disciplines need to engage in a partnership and be willing to create conditions for a functional integration.

The "hospital of choice" for independent physicians will have the following characteristics: Adequate capital for investment in human resources, technology, and facilities. A strong and sustainable market position based on affiliated primary care practices. The ability to engage physicians as business partners. The availability of performance management information.