Magnetism in 2D BN1−x_{1-x}Ox_x and B1−x_{1-x}Six_xN: polarized itinerant and local electrons

We use density functional theory based first-principles methods to study the magnetism in a 2D hexagonal BN sheet induced by the different concentrations of oxygen and silicon atoms substituting for nitrogen (O$_\mathrm{N}$) and boron (Si$_\mathrm{B}$) respectively. We demonstrate the possible formation of three distinct phases based on the magnetization energy calculated self-consistently for the ferromagnetic (ME$_{\mathrm{FM}}$) and antiferromagnetic (ME$_{\mathrm{AFM}}$) states, i.e. the paramagnetic phase with ME$_{\mathrm{FM}}$=ME$_{\mathrm{AFM}}$, the ferromagnetic phase with ME$_{\mathrm{FM}}$$>$ME$_{\mathrm{AFM}}$ and finally the polarized itinerant electrons with finite ME$_{\mathrm{FM}}$ but zero ME$_{\mathrm{AFM}}$. While the O$_\mathrm{N}$ system was found to exist in all three phases, no tendency towards the formation of the polarized itinerant electrons was observed for the Si$_\mathrm{B}$ system though the existence of the other two phases was ascertained. The different behavior of these two systems is associated with the diverse features in the magnetization energy as a function of the oxygen and silicon concentrations. Finally, the robustness of the polarized itinerant electron phase is also discussed with respect to the O substitute atom distributions and the applied strains to the system.Comment: accepted by RP

Ab initio Studies of the Possible Magnetism in BN Sheet by Non-magnetic Impurities and Vacancies

We performed first-principles calculations to investigate the possible magnetism induced by the different concentrations of non-magnetic impurities and vacancies in BN sheet. The atoms of Be, B, C, N, O, Al and Si are used to replace either B or N in the systems as impurities. We discussed the changes in density of states as well as the extent of the spatial distributions of the defect states, the possible formation of magnetic moments, the magnitude of the magnetization energies and finally the exchange energies due to the presence of these defects. It is shown that the magnetization energies tend to increase as the concentrations of the defects decreases in most of the defect systems which implies a definite preference of finite magnetic moments. The calculated exchange energies are in general tiny but not completely insignificant for two of the studied defect systems, i.e. one with O impurities for N and the other with B vacancies.Comment: 8 pages, 10 figures, submitted to Phys. Rev.

Nanorod Suprastructures from a Ternary Graphene Oxide-Polymer-CsPbX3 Perovskite Nanocrystal Composite That Display High Environmental Stability.

Despite the exceptional optoelectronic characteristics of the emergent perovskite nanocrystals, the ionic nature greatly limits their stability, and thus restricts their potential applications. Here we have adapted a self-assembly strategy to access a rarely reported nanorod suprastructure that provide excellent encapsulation of perovskite nanocrystals by polymer-grafted graphene oxide layers. Polyacrylic acid-grafted graphene oxide (GO-g-PAA) was used as a surface ligand during the synthesis of the CsPbX3 perovskite nanocrystals (NCs), yielding particles (5-12 nm) with tunable halide compositions that were homogeneously embedded in the GO-g-PAA matrix. The resulting NC-GO-g-PAA exhibits a higher photoluminescence quantum yield than previously reported encapsulated NCs while maintaining an easily tunable bandgap, allowing for emission spanning the visible spectrum. The NC-GO-g-PAA hybrid further self-assembles into well-defined nanorods upon solvent treatment. The resulting nanorod morphology imparts extraordinary chemical stability toward protic solvents such as methanol and water and much enhanced thermal stability. The introduction of barrier layers by embedding the perovskite NCs in the GO-g-PAA matrix, together with its unique assembly into nanorods, provides a novel strategy to afford robust perovskite emissive materials with environmental stability that may meet or exceed the requirement for optoelectronic applications

Allosteric p97 inhibitors can overcome resistance to ATP-competitive p97 inhibitors for potential anti-cancer therapy

A major challenge of targeted cancer therapy is the selection for drug‐resistant mutations in tumor cells leading to loss of treatment effectiveness. p97/VCP is a central regulator of protein homeostasis and a promising anti‐cancer target because of its vital role in cell growth and survival. One ATP‐competitive p97 inhibitor, CB‐5083, has entered clinical trials. Selective pressure on HCT116 cells treated with CB‐5083 identified 5 different resistant mutants. Identification of p97 inhibitors with different mechanisms of action would offer the potential to overcome this class of resistance mutations. Our results demonstrate that two CB‐5083 resistant p97 mutants, N660K and T688A, were also resistant to several other ATP‐competitive p97 inhibitors, whereas inhibition by two allosteric p97 inhibitors NMS‐873 and UPCDC‐30245 were unaffected by these mutations. We also established a CB‐5083 resistant cell line that harbors a new p97 double mutation (D649A/T688A). While CB‐5083, NMS‐873, and UPCDC‐30245 all effectively inhibited proliferation of the parental HCT116 cell line, NMS‐873 and UPCDC‐30245 were 30‐fold more potent than CB‐5083 in inhibiting the CB‐5083 resistant D649A/T688A double mutant. Our results suggest that allosteric p97 inhibitors are promising alternatives when resistance to ATP‐competitive p97 inhibitors arises during anti‐cancer treatment

Un essai contrôlé randomisé: Effet du port de chaussures à talons hauts sur le squelette appendiculaire inferieur

Introduction: véritable attribut de la féminité, le port de chaussures à talons est devenu une exigence professionnelle dans certaines structuresdes pays en développement comme le Bénin. L'objectif de ce travail est de déterminer les effets spécifiques du port de chaussures à talons hautssur le squelette appendiculaire inférieur. Méthodes: des examens radiographiques de face et de profil de la cheville et du genou ont été effectués sur 122 femmes volontaires, âgées en moyenne de 25,09 ± 1,34 ans et ayant les genu varum qui ont participé à cette étude.Résultats: les résultats ont indiqué une augmentation significative de l'écart inter malléolaire, de l'écart inter condylien, de l'angle antérieur du pied et de l'angle fémoro-patellaire. Une diminution significative de l'angle postérieur du pied a été constatée.Conclusion: le port de chaussures à talons hauts est l'une des causes de la gonarthrose, des troubles des articulations de la cheville et du pied

Tunneling conductance of graphene ferromagnet-insulator-superconductor junctions

We study the transport properties of a graphene ferromagnet-insulator superconductor (FIS) junction within the Blonder-Tinkham-Klapwijk formalism by solving spin-polarized Dirac-Bogoliubov-de-Gennes equation. We find that the retro and specular Andreev reflections in the graphene FIS junction are drastically modified in the presence of exchange interaction and that the spin-polarization ($P_T$) of tunneling current can be tuned from the positive to negative value by bias voltage ($V$). In the thin-barrier limit, the conductance $G$ of a graphene FIS junction oscillates as a function of barrier strength $\chi$. Both the amplitude and phase of the conductance oscillation varies with the exchange energy $E_{ex}$. For $E_{ex}<E_F$ (Fermi energy), the amplitude of oscillation decreases with $E_{ex}$. For $E_{ex}^{c}>E_{ex}>E_F$, the amplitude of oscillation increases with $E_{ex}$, where $E_{ex}^{c}=2E_{F}+U_{0}$ ($U_{0}$ is the applied electrostatic potential on the superconducting segment of the junction). For $E_{ex} > E_{ex}^{c}$, the amplitude of oscillation decreases with $E_{ex}$ again. Interestingly, a universal phase difference of $\pi/2$ in $\chi$ exists between the $G-\chi$ curves for $E_{ex}>E_F$ and $E_{ex}<E_F$. Finally, we find that the transitions between retro and specular Andreev reflections occur at $eV=|E_{F}-E_{ex}|$ and $eV=E_{ex}+E_{F}$, and hence the singular behavior of the conductance near these bias voltages results from the difference in transport properties between specular and retro Andreev reflections.Comment: Accepted for publication in Physical Review

Functional Improvement in Older Adults after a Falls Prevention Pilot Study

Falls are a costly, disabling, and life-threatening risk in the elderly. Improvements in physical function, balance, lower extremity strength, and health-related quality of life are hypothesized to help mitigate fall risk. In this pilot study, six women and men with an average age of 81 years participated in a 6-week exercise and education program created to reduce risk of falls. Evaluations were made at baseline and at 6 weeks on four tests: the Functional Status Questionnaire, the Berg Balance Scale (BBS), the Six-minute Walk Test, and the World Health Organization Quality of Life–BREF 26-question test. Scores indicated significant improvement in functional physical status (activities of daily living), balance, distance walked in 6 min, and quality of life in the physical health domain. The size of this study limits the generalizability of its findings, but its evidence warrants undertaking a larger trial

Tomee — Understanding reader’s choices in books to read

poster abstractToday the amount of information available to individuals is staggering and they often are at a loss when choosing to purchase products. In the case of readers, they have an infinite amount of book available to read. However, they often do not know how to give credibility to the books that are available to them. In this class project we look at “How might we help readers make an informed decision about choosing books.” This research focused on the influences that affect reader’s decisions to purchase literary items. When people buy books there are many things that influence their decision. These influences can be internal perception (wants and needs) or they can take the form of external influences. In the case of influences, the strongest motivation seems to be a communal engagement and a shared experience. As such people place a high value on the perceptions of individuals around them. In our study we look at how people who are interested in books would share information and what outlets would they use to communicate to others. We focus on a qualitative methodology utilizing a co-design process. Our process was to involve readers within the idea generation process to study the effectiveness of working simultaneously to understand people’s needs while utilizing co-design principals to understand how to meet those needs. Our research found, individuals place high value on information from their community members, when making decisions on what books to read. Based on our research, readers would be interested in a way to categories and share their reading choices. We believe there is a need for a platform that allows individuals to share their reading interests with other members of their community