Local Compressibility Measurements of Correlated States in Suspended Bilayer Graphene

Bilayer graphene has attracted considerable interest due to the important role played by many-body effects, particularly at low energies. Here we report local compressibility measurements of a suspended graphene bilayer. We find that the energy gaps at filling factors v = 4 do not vanish at low fields, but instead merge into an incompressible region near the charge neutrality point at zero electric and magnetic field. These results indicate the existence of a zero-field ordered state and are consistent with the formation of either an anomalous quantum Hall state or a nematic phase with broken rotational symmetry. At higher fields, we measure the intrinsic energy gaps of broken-symmetry states at v = 0, 1 and 2, and find that they scale linearly with magnetic field, yet another manifestation of the strong Coulomb interactions in bilayer graphene.Comment: 9 pages, including 4 figures and supplementary material

The scientific merit of Carpobrotus mellei L. based on antimicrobial activity and chemical profiling

Species of the genus Carpobrotus are similar in appearance and have been used for medicinal purposes over many generations. Carpobrotus mellei is endemic to the south-Western Cape of South Africa, and also used for various ailments. To date no scientific validation and information has been reported on C. mellei. This study investigated the antimicrobial potential of C. mellei against Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans and Mycobacterium smegmatis, and determined the minimum inhibitory concentrations (MIC) by two-fold serial dilution. C. mellei showed antimicrobial activity against S. aureus and M. smegmatis in the disc diffusion method. Eight chemical compounds showed clear zones of inhibition in the bioautograms, seven against S. aureus and three compounds were active against M. smegmatis. The ethyl acetate extracts have MIC values of 7.5 mg/ml and 15 mg/ml against S. aureus and M. smegmatis, respectively. Phytochemical tests indicated the presence of flavonoids, hydrolysable tannins, phytosterols and aromatic acids. High performance liquid chromatography (HPLC) showed a species-specific spectrum at a wavelength of 280 nm. The results confirm that C. mellei has scientific merit, and can substitute one of the other Carpobrotus species for antimicrobial usage within the south-Western Cape of South Africa

Mixing characterization inside microdroplets engineered on a microcoalescer

We use a microdevice where microdroplets of reagents are generated and coalesce in a carrier continuous phase. The work focuses on the characterization of the mixing step inside the droplets, in the perspective to use them for chemical kinetic data acquisition. A dye and water are used, and an acid–base instantaneous chemical reaction is monitored thanks to a colored indicator. Acquisitions are done with a high-speed camera coupled to a microscope and a mixing parameter is calculated by image analysis. Different angles of bended channels and different ways of coalescence are compared. It is shown that the homogenization of the droplets can be reached in less than 10 ms after coalescence. This is achieved by forcing the droplets to coalesce in a “shifted” way, and later by adding 45◦ angle bends along the channel

Speckle visibility spectroscopy and variable granular fluidization

We introduce a dynamic light scattering technique capable of resolving motion that changes systematically, and rapidly, with time. It is based on the visibility of a speckle pattern for a given exposure duration. Applying this to a vibrated layer of glass beads, we measure the granular temperature and its variation with phase in the oscillation cycle. We observe several transitions involving jammed states, where the grains are at rest during some portion of the cycle. We also observe a two-step decay of the temperature on approach to jamming.Comment: 4 pages, 4 figures, experimen

Quantum theory of dynamic multiple light scattering

We formulate a quantum theory of dynamic multiple light scattering in fluctuating disordered media and calculate the fluctuation and the autocorrelation function of photon number operator for light transmitted through a disordered slab. The effect of disorder on the information capacity of a quantum communication channel operating in a disordered environment is estimated and the use of squeezed light in diffusing-wave spectroscopy is discussed.Comment: Revised text, additional figur

Increased Biological Activity of Aneurinibacillus migulanus Strains Correlates with the Production of New Gramicidin Secondary Metabolites

Acknowledgments This project was funded by the Government of Kuwait (to FA) and the European Union Seventh Framework Programme under grant agreement 245268 (ISEFOR; to LB and SW). Further support came from the SwissBOL project, financed by the Swiss Federal Office for the Environment (grant holder LB) and the Sciex–Scientific Exchange Programme (http://nms.ch/) (NMS.CH; to LL and LB). LL is indebted to the Ministry of Education, Science, Research and Sport of the Slovak Republic for financial support in the frame of the project “VEGA 1/0061/16” and “VEGA 1/0046/16”. Funding This project was funded by the Government of Kuwait (to FA) and the European Union Seventh Framework Programme under grant agreement 245268 (ISEFOR; to LB and SW). Further support came from the SwissBOL project, financed by the Swiss Federal Office for the Environment (grant holder LB) and the Sciex–Scientific Exchange Programme NMS.CH (to LL and LB). LL is indebted to the Ministry of Education, Science, Research and Sport of the Slovak Republic for financial support in the frame of the project “VEGA 1/0061/16.”Peer reviewedPublisher PD

Binary Colloidal Alloy Test-5: Compete

The Binary Colloidal Alloy Test - 5: Compete (BCAT-5-Compete) investigation will photograph andomized colloidal samples onboard the International Space Station (ISS) to determine their resulting structure over time. The use of EarthKAM software and hardware will allow the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-Compete will utilize samples 6 - 8 in the BCAT-5 hardware to study the competition between phase separation and crystallization, which is important in the manufacture of plastics and other materials