We present an experimental study of the infrared conductivity, transmission, and reflection of a gated bilayer graphene and their theoretical analysis within the Slonczewski-Weiss-McClure (SWMc) model. The infrared response is shown to be governed by the interplay of the interband and the intraband transitions among the four bands of the bilayer. The position of the main conductivity peak at the charge-neutrality point is determined by the interlayer tunneling frequency. The shift of this peak as a function of the gate voltage gives information about less known parameters of the SWMc model such as those responsible for the electron-hole and sublattice asymmetries. These parameter values are shown to be consistent with recent electronic structure calculations for the bilayer graphene and the SWMc parameters commonly used for the bulk graphite.

An improved three-arm airbridge contacted microdisk diode structure is presented. Continuous-wave lasing from InGaAs quantum dot (QD) in a ~4-micron-diameter microdisks is reported with the threshold current ~40 uA at T = 5 K. With the increase of injection current, the QD's emission blueshifts due to the band-filling effect, while the laser mode peak redshifts by thermal effect. When the QD's gain spectra shift out of alignment with the lasing mode, the next available whispering gallery mode starts lasing from QD wetting layer. The thermal heating effect is discussed by investigating the modes redshift with respect to injection current.

The Mycobacterium smegmatis genome contains many genes encoding putative drug efflux pumps. Yet with the exception of lfrA, it is not clear whether these genes contribute to the intrinsic drug resistance of this organism. We showed first by reverse transcription (RT)-PCR that several of these genes, including lfrA as well as the homologues of Mycobacterium tuberculosis Rv1145, Rv1146, Rv1877, Rv2846c (efpA) and Rv3065 (mmr and emrE), were expressed at detectable levels in the strain mc(2)155. Null mutants each carrying an in-frame deletion of these genes were then constructed in M. smegmatis. The deletions of the lfrA gene or mmr homologue rendered the mutant more susceptible to multiple drugs such as fluoroquinolones, ethidium bromide, and acriflavine (two- to eightfold decrease in MICs). The deletion of the efpA homologue also produced increased susceptibility to these agents but unexpectedly also resulted in decreased susceptibility to rifamycins, isoniazid, and chloramphenicol (two- to fourfold increase in MICs). Deletion of the Rv1877 homologue produced some increased susceptibility to ethidium bromide, acriflavine, and erythromycin. The upstream region of lfrA contained a gene encoding a putative TetR family transcriptional repressor, dubbed LfrR. The deletion of lfrR elevated the expression of lfrA and produced higher resistance to multiple drugs. Multidrug-resistant single-step mutants, independent of LfrA and attributed to a yet-unidentified drug efflux pump (here called LfrX), were selected in vitro and showed decreased accumulation of norfloxacin, ethidium bromide, and acriflavine in intact cells. Finally, use of isogenic beta-lactamase-deficient strains showed the contribution of LfrA and LfrX to resistance to certain beta-lactams in M. smegmatis.

This paper studies the problem of electing a small number of representatives (council) out of a (possible large) group of anonymous candidates. The problem arises in scenarios such as multicast where, to avoid feedback implosion, a small subset of the receivers is chosen to provide feedback on network conditions. We present several algorithms for this problem and analyze the expected number of messages and rounds required for their convergence. In particular, we present an algorithm that almost always converges in one round using a small number of messages (for typical council size) when the number of hosts is known. In the case where the number of hosts is unknown (and too large to be polled), our algorithms converge in a small number of rounds that improves previous results by Bolot et al. (1994).

The Neiguan and Lingdao were stimulated by electroacupuncture in anesthetized Wistar rats. We observed that the value of ventricular fibrillation threshold (VFT) was increased significantly in 30 min of electro-acupuncturing (P less than 0.01) and in 15 min of stopping the acupuncturing (P less than 0.05). Although the value of VFT was increased until 30 min of stopping acupuncture, it was not significantly different compared with its basic value. The control group were dealt with the same way as the experimental group except electroacupuncture. The value of VFT measured in control group were not significantly different compared with its basic value.