Suppression of Conductance in a Topological Insulator Nanostep Junction

We investigate quantum transport via surface states in a nanostep junction on the surface of a 3D topological insulator that involves two different side surfaces. We calculate the conductance across the junction within the scattering matrix formalism and find that as the bias voltage is increased, the conductance of the nanostep junction is suppressed by a universal factor of 1/3 compared to the conductance of a similar planar junction based on a single surface of a topological insulator. We also calculate and analyze the Fano factor of the nanostep junction and predict that the Fano factor saturates at 1/5, five times smaller than for a Poisson process

Adiabatic quantum pumping through surface states in 3D topological insulators

We investigate adiabatic quantum pumping of Dirac fermions on the surface of a strong 3D topological insulator. Two different geometries are studied in detail, a normal metal -- ferromagnetic -- normal metal (NFN) junction and a ferromagnetic -- normal metal -- ferromagnetic (FNF) junction. Using a scattering matrix approach, we first calculate the tunneling conductance and then the adiabatically pumped current using different pumping mechanisms for both types of junctions. We explain the oscillatory behavior of the conductance by studying the condition for resonant transmission in the junctions and find that each time a new resonant mode appears in the transport window, the pumped current diverges. We also predict an experimentally distinguishable difference between the pumped current and the rectified current

When nanoemulsified, d-limonene reduces Listeria monocytogenes heat resistance about one hundred times

AbstractThe application of oily antimicrobials in form of nanoemulsion has been proved to solve the problem of their immiscibility in aqueous media, still preventing microbial growth and even improving the antimicrobial effect observed when applied directly. At present, only a few documented studies have evaluated the combined effect of nanoemulsions with other factors of stress for the microorganism. The present research shows very promising results on the combination of nanoemulsified d-limonene with thermal treatments on the inactivation of Listeria monocytogenes. The thermal resistance of L. monocytogenes was reduced two to five times when 0.5 mM d-limonene was added directly to the heating medium. However, when the same concentration of d-limonene was present in the heating medium in form of nanoemulsion, the heat resistance was reduced by one hundred times at all heating temperatures tested. The addition of nanoemulsified antimicrobials would allow to reduce greatly the intensity of the thermal treatments currently applied in the food processing industry

Adiabatic quantum pumping in graphene NIS junctions

We investigate adiabatic quantum pumping through a normal metal-insulator-superconductor (NIS) junction in a monolayer of graphene. The pumped current is generated by periodic modulation of two gate voltages, applied to the insulating and superconducting regions respectively. In the bilinear response regime and in the limit of a thin high insulating barrier, we find that the presence of the superconductor enhances the pumped current per mode by a factor of 4 at resonance. Compared to the pumped current in an analogous semiconductor NIS junction, the resonances have a $\pi/2$ phase difference. We also predict experimentally distinguishable differences between the pumped current and the tunneling conductance in graphene NIS junctions.Comment: 4 pages, 3 figure

Acrylic resins in wet white

Content: The purpose of this paper is to study the influence of acrylic resins on the properties of the hide when added in the pickling-tanning stage of a wet white process. Among retanning products, acrylic resins are very frequently used because they lend very good properties to the hide on account of their high affinity for chromium. When applied during chrome tanning, these resins provide the hides with high fullness, due to the strong interaction of the carboxylate groups with chromium. Extensive bibliography is available on the application of acrylic resins in wet blue, where it is observed that the properties they provide to the hides depend basically on the type of monomers and molecular weight. However, less information is found when these products are applied in wet white tanning. In this study, 9 resins with different molecular weights and different monomer compositions were selected. Resins were applied to pelt leathers of Spanish origin split at 3.5 mm. Hides were cut along the backbone. A standard process was applied to the left halves and the same process adding the resin was applied to the right halves. The resin was added after adjusting the salt of the bath and before adding the pickling acids. The COD was measured before and after adding formic and sulfuric acid, and the shrinkage temperature and the degree of whiteness of the tanned hide were assessed. Hides were retanned and fatliquored with a standard process, and degree of softness, thickness, color intensity and organoleptic properties (fluffiness, compactness and grain tightness) were assessed. Leather shrinkage under temperature was also assessed, and images of leather sections were obtained by scanning electron microscopy (SEM). While acrylic resins did not increase shrinkage temperature, they did fix and/or deposit themselves in the interfibrillary spaces of the hide; indeed, highly reduced COD values after acidification in the pickling stage were observed. This study shows that homopolymeric acrylic resins provided fuller and fluffier hides, while the rest of resins practically did not improve the physical and organoleptic properties of the hides. Take-Away: Homopolymeric acrylic resins provided full er and fluffier hides, while the rest of resins practically did not improve the physical and organoleptic properties of the hides Wet white tanning improvemen

Benefits of vibration training in the neuromuscular system of the elderly

Introducción: El entrenamiento vibratorio puede ser una opción de intervención óptima para prevenir la pérdida de masa muscular en adultos mayores. Objetivo: Comprobar la efectividad del entrenamiento vibratorio en el sistema neuromuscular de los adultos mayores. Material y método: Revisión bibliográfica en las bases de datos Medline, CINAHL, WOS y PEDro, mediante la combinación de los descriptores del Medical Subjects Headings referentes a entrenamiento vibratorio, fuerza muscular, masa muscular y personas mayores. Resultados: Los estudios localizados sobre el entrenamiento vibratorio en personas mayores se realizaron, bien como única intervención, o en combinación con otro tipo de ejercicios de fuerza, aeróbicos, de equilibrio o de flexibilidad. La diversidad de protocolos empleados dificulta una comparación entre estudios. Conclusión: El entrenamiento con plataformas vibratorias demuestra ser un método de entrenamiento de la fuerza seguro, adecuado y eficaz para la población de mayor edad, pero con resultados similares al ejercicio de resistencia convencional

Universal Reconfiguration of Facet-Connected Modular Robots by Pivots: The O(1) Musketeers

We present the first universal reconfiguration algorithm for transforming a modular robot between any two facet-connected square-grid configurations using pivot moves. More precisely, we show that five extra "helper" modules ("musketeers") suffice to reconfigure the remaining n modules between any two given configurations. Our algorithm uses O(n^2) pivot moves, which is worst-case optimal. Previous reconfiguration algorithms either require less restrictive "sliding" moves, do not preserve facet-connectivity, or for the setting we consider, could only handle a small subset of configurations defined by a local forbidden pattern. Configurations with the forbidden pattern do have disconnected reconfiguration graphs (discrete configuration spaces), and indeed we show that they can have an exponential number of connected components. But forbidding the local pattern throughout the configuration is far from necessary, as we show that just a constant number of added modules (placed to be freely reconfigurable) suffice for universal reconfigurability. We also classify three different models of natural pivot moves that preserve facet-connectivity, and show separations between these models

Use of Frequency Distribution Functions to Establish Safe Conditions in Relation to the Foodborne Pathogen Bacillus cereus

Minimal processing implementation greatly depends on a detailed knowledge of the effects of preservation factors and their combinations on the spoilage and foodborne pathogenic microorganisms. The effectiveness of mild preservation conditions will become increasingly dependent on a more stochastic approach linking microbial physiological factors with product preservation factors. In this study, the validity of frequency distributions to efficiently describe the inactivation and growth of Bacillus cereus in the presence of natural antimicrobials (essential oils) has been studied. For this purpose, vegetative cells were exposed to 0.6 mM of thymol or cymene, obtaining survival curves that were best described by the distribution of Weibull, since a tailing effect was observed. B. cereus was also exposed in a growth medium to a low concentration (0.1 mM) of both antimicrobials, separately or combined, and the lag times obtained were fitted to a normal distribution, which allowed a description of dispersion of the start of growth. This allowed a more efficient evaluation of the experimental data to establish safe processing conditions according to accurate parameters and their implementation in risk assessment