Proximity-induced superconductivity in epitaxial topological insulator/graphene/gallium heterostructures.

The introduction of superconductivity to the Dirac surface states of a topological insulator leads to a topological superconductor, which may support topological quantum computing through Majorana zero modes1,2. The development of a scalable material platform is key to the realization of topological quantum computing3,4. Here we report on the growth and properties of high-quality (Bi,Sb)2Te3/graphene/gallium heterostructures. Our synthetic approach enables atomically sharp layers at both hetero-interfaces, which in turn promotes proximity-induced superconductivity that originates in the gallium film. A lithography-free, van der Waals tunnel junction is developed to perform transport tunnelling spectroscopy. We find a robust, proximity-induced superconducting gap formed in the Dirac surface states in 5-10 quintuple-layer (Bi,Sb)2Te3/graphene/gallium heterostructures. The presence of a single Abrikosov vortex, where the Majorana zero modes are expected to reside, manifests in discrete conductance changes. The present material platform opens up opportunities for understanding and harnessing the application potential of topological superconductivity.

Enabling Deoxygenative C(sp2)-C(sp3) Cross-Coupling for Parallel Medicinal Chemistry.

Herein we report the development of an automated deoxygenative C(sp2)-C(sp3) coupling of aryl bromide with alcohols to enable parallel medicinal chemistry. Alcohols are among the most diverse and abundant building blocks, but their usage as alkyl precursors has been limited. Although metallaphotoredox deoxygenative coupling is becoming a promising strategy to form C(sp2)-C(sp3) bond, the reaction setup limits its widespread application in library synthesis. To achieve high throughput and consistency, an automated workflow involving solid-dosing and liquid-handling robots has been developed. We have successfully demonstrated this high-throughput protocol is robust and consistent across three automation platforms. Furthermore, guided by cheminformatic analysis, we examined alcohols with comprehensive chemical space coverage and established a meaningful scope for medicinal chemistry applications. By accessing the rich diversity of alcohols, this automated protocol has the potential to substantially increase the impact of C(sp2)-C(sp3) cross-coupling in drug discovery.

Tunable 2D Group-III Metal Alloys.

Chemically stable quantum-confined 2D metals are of interest in next-generation nanoscale quantum devices. Bottom-up design and synthesis of such metals could enable the creation of materials with tailored, on-demand, electronic and optical properties for applications that utilize tunable plasmonic coupling, optical nonlinearity, epsilon-near-zero behavior, or wavelength-specific light trapping. In this work, it is demonstrated that the electronic, superconducting, and optical properties of air-stable 2D metals can be controllably tuned by the formation of alloys. Environmentally robust large-area 2D-Inx Ga1- x alloys are synthesized byConfinement Heteroepitaxy (CHet). Near-complete solid solubility is achieved with no evidence of phase segregation, and the composition is tunable over the full range of x by changing the relative elemental composition of the precursor. The optical and electronic properties directly correlate with alloy composition, wherein the dielectric function, band structure, superconductivity, and charge transfer from the metal to graphene are all controlled by the indium/gallium ratio in the 2D metal layer.

Epitaxial graphene/silicon carbide intercalation: a minireview on graphene modulation and unique 2D materials.

Intercalation of atomic species through epitaxial graphene on silicon carbide began only a few years following its initial report in 2004. The impact of intercalation on the electronic properties of the graphene is well known; however, the intercalant itself can also exhibit intriguing properties not found in nature. This realization has inspired new interest in epitaxial graphene/silicon carbide (EG/SiC) intercalation, where the scope of the technique extends beyond modulation of graphene properties to the creation of new 2D forms of 3D materials. The mission of this minireview is to provide a concise introduction to EG/SiC intercalation and to demonstrate a simplified approach to EG/SiC intercalation. We summarize the primary techniques used to achieve and characterize EG/SiC intercalation, and show that thermal evaporation-based methods can effectively substitute for more complex synthesis techniques, enabling large-scale intercalation of non-refractory metals and compounds including two-dimensional silver (2D-Ag) and gallium nitride (2D-GaNx).

Using Future Employers' Expectations to Inform Global Health Fellowship Curricula.

BACKGROUND: Fellowships in global health are increasingly popular and seek to equip physicians with the skills necessary to be effective global health practitioners. Little objective guidance exists on which skills make graduates competitive applicants from the perspective of potential global health employers. OBJECTIVE: We sought to provide objective evidence for the qualifications that make applicants competitive for global health positions by analyzing the listed qualifications for current job openings in large global health organizations. METHODS: The websites of 48 global health employers were systematically searched for current job postings between May and August 2017. Jobs were included for analysis if a medical degree was listed among the primary degrees accepted, and the job was based primarily in a low- or middle-income country. RESULTS: A total of 5849 employment opportunities were posted during the search period, and 81 (1.4%) of these met inclusion criteria. Twenty-two (27%) jobs required and 35 (43%) preferred a relevant master's degree. Few jobs requested a candidate with a PhD and none mentioned tropical medicine training as a requirement or preference. Twenty-three jobs (28%) required and 19 (23%) preferred candidates to speak another language. Most jobs (69%, 56 of 81) required more than 5 years of relevant experience. Only 11 (13%) jobs were primarily clinical positions. CONCLUSIONS: For physicians pursuing a career in global health, most publicly searchable jobs require substantial previous experience and involvement in global health activities beyond clinical practice. Master's degree and language skills are frequently requested candidate qualifications.

Anti-dsDNA antibodies in systemic lupus erythematosus: A combination of two quantitative methods and the ANA pattern is the most efficient strategy of detection.

Several methods have been used to measure anti-double-stranded DNA auto-antibody (anti-dsDNA). Our aim was to determine the most efficient strategy to test anti-dsDNA in systemic lupus erythematosus (SLE). In this study, anti-dsDNA and anti-nuclear antibody (ANA) tests were requested for 644 patients. Anti-dsDNA was tested by RIA, ELISA and CLIA in all patients. The results indicated that 78 patients had a positive anti-dsDNA test according to at least one of the methods. After a 3-year follow-up period only 26 patients were diagnosed with SLE. We evaluated each method and combination of methods. Specificity and positive predictive value (PPV) increased with the number of assay methods used (p=0.002 for trend), and PPV was 100% in patients whose results were positive by all three anti-dsDNA assay methods. The proportion of anti-dsDNA-positive patients who had SLE was highest (82%; p b 0.001) among those with a homogeneous pattern of ANA staining, followed by those with a speckled pattern. In ANA positive patients, when only RIA was considered, 59% of anti-dsDNA-positive patients had SLE, but when RIA and CLIA were both considered, all patients with positive results on both tests had SLE. The combination of RIA+CLIA in patients with homogeneous and speckled ANA staining showed a similar cost and higher sensitivity than RIA alone in ANA positive patients (p b 0.001). We conclude that the most efficient strategy was to combine simultaneously two quantitative and sensitive methods but only in patients with a homogeneous or speckled pattern of ANA staining. This approach maximized specificity and PPV, and reduced costs.