Threshold temperature of superfluorescence generation in CuCl quantum dots under resonant excitation of excitons and resonant two-photon excitation of biexcitons.

We studied the threshold temperature of superfluorescence (SF) generation with regard to biexcitons in CuCl quantum dots (QDs) under resonant two-photon excitation of biexcitons and resonant excitation of excitons to demonstrate the influence of initial population densities in the QDs on SF generation. As a result, the threshold temperature under the resonant excitation of excitons was higher than that under the two-photon excitation of biexcitons. This indicates that the high density of excited dots facilitates the rapid establishment of coherence among the dots, overcoming disadvantages of incomplete population inversion and formation process of biexcitons. We performed a theoretical calculation of the time profiles of the biexcitonic emission based on semiconductor luminescence equations. The experimentally obtained temperature dependence of the time profiles was qualitatively reproduced by calculating their dependence on the dephasing rate. In addition, we estimated the temperature dependence of the phase relaxation time of the biexcitons in the CuCl QDs by analyzing the temperature dependence of SF.

Imprinting Spatial Helicity Structure of Vector Vortex Beam on Spin Texture in Semiconductors.

We present the transfer of the spatially variant polarization of topologically structured light to the spatial spin texture in a semiconductor quantum well. The electron spin texture, which is a circular pattern with repeating spin-up and spin-down states whose repetition rate is determined by the topological charge, is directly excited by a vector vortex beam with a spatial helicity structure. The generated spin texture efficiently evolves into a helical spin wave pattern owing to the spin-orbit effective magnetic fields in the persistent spin helix state by controlling the spatial wave number of the excited spin mode. By tuning the repetition length and azimuthal angle, we simultaneously generate helical spin waves with opposite phases by a single beam.

Point-of-care molecular diagnosis of Mycoplasma pneumoniae including macrolide sensitivity using quenching probe polymerase chain reaction.

OBJECTIVES: Macrolides are generally considered to be the drugs of choice for treatment of patients with Mycoplasma pneumoniae infection. However, macrolide-resistant M. pneumoniae has been emerging since about 2000. The Smart Gene® system (MIZUHO MEDY Co., Ltd., Tosu, Japan) is a novel fully automated system for detection of pathogens using the method of quantitative polymerase chain reaction (qPCR) with QProbe (QProbe PCR). The entire procedure is completed within 50 min and the size of the instrument is small (15 x 34 x 30 cm). The purpose of this study was to evaluate the usefulness of the Smart Gene® system for detection of M. pneumoniae and detection of a point mutation at domain V of the 23S rRNA gene of M. pneumoniae. MATERIALS: Pharyngeal swab samples were collected from 154 patients who were suspected of having respiratory tract infections associated with M. pneumoniae. RESULTS: Compared with the results of qPCR, the sensitivity and specificity of the Smart Gene® system were 98.7% (78/79) and 100.0% (75/75), respectively. A point mutation at domain V of the 23S rRNA gene was detected from 7 (9.0%) of 78 M. pneumoniae-positive samples by the Smart Gene® system and these results were confirmed by direct sequencing. The minimum inhibitory concentrations of clarithromycin among the 5 isolates of M. pneumoniae with a point mutation at domain V of the 23S rRNA gene were >64 µg/ml and those among the 33 isolates without a mutation in the 23S rRNA gene were <0.0625 µg/ml. CONCLUSION: The Smart Gene® system is a rapid and accurate assay for detection of the existence of M. pneumoniae and a point mutation at domain V of the 23S rRNA gene of M. pneumoniae at the same time. The Smart Gene® system is suitable for point-of-care testing in both hospital and outpatient settings.

Two atypical ANGUSTIFOLIA without a plant-specific C-terminus regulate gametophore and sporophyte shapes in the moss Physcomitrium (Physcomitrella) patens.

ANGUSTIFOLIA (AN) is a plant-specific subfamily of the CtBP/BARS/AN family, characterized by a plant-specific C-terminal domain of approximately 200 amino acids. Previously, we revealed that double knockout (DKO) lines of Physcomitrium (Physcomitrella) patens ANGUSTIFOLIA genes (PpAN1-1 and PpAN1-2) show defects in gametophore height and the lengths of the seta and foot region of sporophytes, by reduced cell elongation. In addition to two canonical ANs, the genome of P. patens has two atypical ANs without a coding region for a plant-specific C-terminus (PpAN2-1 and PpAN2-2); these were investigated in this study. Similar to PpAN1s, both promoters of the PpAN2 genes were highly active in the stems of haploid gametophores and in the middle-to-basal region of young diploid sporophytes that develop into the seta and foot. Analyses of PpAN2-1/2-2 DKO and PpAN quadruple knockout (QKO) lines implied that these four AN genes have partially redundant functions to regulate cell elongation in their expression regions. Transgenic strains harboring P. patens α-tubulin fused to green fluorescent protein, which were generated from a QKO line, showed that the orientation of the microtubules in the gametophore tips in the PpAN QKO lines was unchanged from the wild-type and PpAN1-1/1-2 DKO plants. In addition to both PpAN2-1 and PpAN2-2, short Arabidopsis AN without the C-terminus of 200 amino acids could rescue the Arabidopsis thaliana an-1 phenotypes, implying AN activity is dependent on the N-terminal regions.