Reconfigurable Boolean Logic Using Magnetic Single-Electron Transistors

We propose a novel hybrid single-electron device for reprogrammable low-power logic operations, the magnetic single-electron transistor (MSET). The device consists of an aluminium single-electron transistor with a GaMnAs magnetic back-gate. Changing between different logic gate functions is realized by reorienting the magnetic moments of the magnetic layer, which induces a voltage shift on the Coulomb blockade oscillations of the MSET. We show that we can arbitrarily reprogram the function of the device from an n-type SET for in-plane magnetization of the GaMnAs layer to p-type SET for out-of-plane magnetization orientation. Moreover, we demonstrate a set of reprogrammable Boolean gates and its logical complement at the single device level. Finally, we propose two sets of reconfigurable binary gates using combinations of two MSETs in a pull-down network.     

An efficient transformation system for Bifidobacterium spp.

This study describes a broad host transformation protocol that enables the uptake of plasmid DNA into 10 different species of Bifidobacterium , some of which have never been transformed before. The vector pNC7 (4·9 kb) was used to optimize the electroporation protocol. Transformation efficiencies ranged from 3·6×10⁻¹ to 1·2×10⁵ transformations per μg DNA. The impact of growth medium composition and electric field strength on transformation efficiency were independently optimized. Electrocompetent cells were grown in Iwata medium broth enriched with Actilight^RP 16%, harvested during the early exponential growth phase, and pulsed at 12·5 kV cm⁻¹, 100 Ω and 25 μF.     

Graphical modeling for gene set analysis: A critical appraisal

Current demand for understanding the behavior of groups of related genes, combined with the greater availability of data, has led to an increased focus on statistical methods in gene set analysis. In this paper, we aim to perform a critical appraisal of the methodology based on graphical models developed in Massa et al. ( 2010 ) that uses pathway signaling networks as a starting point to develop statistically sound procedures for gene set analysis. We pay attention to the potential of the methodology with respect to the organizational aspects of dealing with such complex but highly informative starting structures, that is pathways. We focus on three themes: the translation of a biological pathway into a graph suitable for modeling, the role of shrinkage when more genes than samples are obtained, the evaluation of respondence of the statistical models to the biological expectations. To study the impact of shrinkage, two simulation studies will be run. To evaluate the biological expectation we will use data from a network with known behavior that offer the possibility of carrying out a realistic check of respondence of the model to changes in the experimental conditions.     

Partitioning of respiratory mechanics in mechanically ventilated patients.

In ten mechanically ventilated patients, six with chronic obstructive pulmonary disease (COPD) and four with pulmonary edema, we have partitioned the total respiratory system mechanics into the lung (l) and chest wall (w) mechanics using the esophageal balloon technique together with the airway occlusion technique during constant-flow inflation (J. Appl. Physiol. 58: 1840-1848, 1985). Intrinsic positive end-expiratory pressure (PEEPi) was present in eight patients (range 1.1-9.8 cmH2O) and was due mainly to PEEPi,L (80%), with a minor contribution from PEEPi,w (20%), on the average. The increase in respiratory elastance and resistance was determined mainly by abnormalities in lung elastance and resistance. Chest wall elastance was slightly abnormal (7.3 +/- 2.2 cmH2O/l), and chest wall resistance contributed only 10%, on the average, to the total. The work performed by the ventilator to inflate the lung (WL) averaged 2.04 +/- 0.59 and 1.25 +/- 0.21 J/l in COPD and pulmonary edema patients, respectively, whereas Ww was approximately 0.4 J/l in both groups, i.e., close to normal values. We conclude that, in mechanically ventilated patients, abnormalities in total respiratory system mechanics essentially reflect alterations in lung mechanics. However, abnormalities in chest wall mechanics can be relevant in some COPD patients with a high degree of pulmonary hyperinflation.     

The influence of a line with fast diffusion on Fisher-KPP propagation

We propose here a new model to describe biological invasions in the plane when a strong diffusion takes place on a line. We establish the main properties of the system, and also derive the asymptotic speed of spreading in the direction of the line. For low diffusion, the line has no effect, whereas, past a threshold, the line enhances global diffusion in the plane and the propagation is directed by diffusion on the line. It is shown here that the global asymptotic speed of spreading in the plane, in the direction of the line, grows as the square root of the diffusion on the line. The model is much relevant to account for the effects of fast diffusion lines such as roads on spreading of invasive species.