Two-dimensional heterogeneous photonic bandedge laser

We proposed and realized a two-dimensional (2D) photonic bandedge laser surrounded by the photonic bandgap. The heterogeneous photonic crystal structure consists of two triangular lattices of the same lattice constant with different air hole radii. The photonic crystal laser was realized by room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells emitting at 1.55 micrometer. The lasing mode was identified from its spectral positions and polarization directions. A low threshold incident pump power of 0.24mW was achieved. The measured characteristics of the photonic crystal lasers closely agree with the results of real space and Fourier space calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure

Spontaneous emission enhancement in strain-induced WSe2 monolayer based quantum light sources on metallic surfaces

Atomic monolayers of transition metal dichalcogenides represent an emerging material platform for the implementation of ultra compact quantum light emitters via strain engineering. In this framework, we discuss experimental results on creation of strain induced single photon sources using a WSe2 monolayer on a silver substrate, coated with a very thin dielectric layer. We identify quantum emitters which are formed at various locations in the sample. The emission is highly linearly polarized, stable in linewidth and decay times down to 300 ps are observed. We provide numerical calculations of our monolayer-metal device platform to assess the strength of the radiative decay rate enhancement by the presence of the plasmonic structure. We believe, that our results represent a crucial step towards the ultra-compact integration of high performance single photon sources in nanoplasmonic devices and circuits

Purcell-enhanced and indistinguishable single-photon generation from quantum dots coupled to on-chip integrated ring resonators

Funding: Ł.D.acknowledges the financial support from the Alexander von Humboldt Foundation. S.-H. K. acknowledges the financial support from the National Research Foundation of Korea through the Korean Government Grant NRF-2019R1A2C4069587. We are furthermore grateful for the support by the State of Bavaria.Integrated photonic circuits provide a versatile toolbox of functionalities for advanced quantum optics applications. Here, we demonstrate an essential component of such a system in the form of a Purcell-enhanced single-photon source based on a quantum dot coupled to a robust on-chip integrated resonator. For that, we develop GaAs monolithic ring cavities based on distributed Bragg reflector ridge waveguides. Under resonant excitation conditions, we observe an over 2-fold spontaneous emission rate enhancement using Purcell effect and gain a full coherent optical control of a QD-two-level system via Rabi oscillations. Furthermore, we demonstrate an on-demand single-photon generation with strongly suppressed multiphoton emission probability as low as 1% and two-photon interference with visibility up to 95%. This integrated single-photon source can be readily scaled up, promising a realistic pathway for scalable on-chip linear optical quantum simulation, quantum computation, and quantum networks.PostprintPeer reviewe

Properties of oriented strand board made from Betung bamboo (Dendrocalamus asper (Schultes.f) Backer ex Heyne)

Bamboo has gained increasing attention as an alternative raw material for use in the manufacture of composite boards. Three-layer OSBs were made using Betung bamboo (Dendrocalamus asper (Schultes.f) Backer ex Heyne) strands to evaluate the effects of strand length and pre-treatment techniques on the physical, mechanical, and durability properties. Three different strand lengths, namely 50, 60, and 70 mm, were prepared. Prior to the manufacture into OSB, the strands were immersed in cold water for 24 h and in 6% acetic anhydrides solution for 48 h. The OSBs were fabricated using 5% MDI resin based on the strand dry weight. The results indicated that MOR and MOE values in perpendicular to the grain direction were much influenced by strand length. The dimensional stability of OSB was slightly improved by immersing the strands in acetic anhydride solution. Immersing strands in cold water and acetic anhydride solution improved the resistance of OSB against subterranean termite (Macrotermes gylvus) attack under the adopted experimental condition. All OSB parameters manufactured in this experiment were better than the minimum requirement of CSA 0437.0 (Grade O–2) standard

Rim 2/Hipa CACTA transposon display ; A new genetic marker technique in Oryza species

BACKGROUND: Transposons constitute the major fractions of repetitive sequences in eukaryotes, and have been crucial in the shaping of current genomes. Transposons are generally divided into two classes according to the mechanism underlying their transposition: RNA intermediate class 1 and DNA intermediate class 2. CACTA is a class 2 transposon superfamily, which is found exclusively in plants. As some transposons, including the CACTA superfamily, are highly abundant in plant species, and their nucleotide sequences are highly conserved within a family, they can be utilized as genetic markers, using a slightly modified version of the conventional AFLP protocol. Rim2 /Hipa is a CACTA transposon family having 16 bp consensus TIR sequences to be present in high copy numbers in rice genome. This research was carried out in order to develop a Rim2/Hipa CACTA-AFLP or Rim2/Hipa CACTA-TD (transposon display, hereafter Rim2/Hipa-TD) protocol for the study of genetic markers in map construction and the study of genetic diversity in rice. RESULTS: Rim2/Hipa-TD generated ample polymorphic profiles among the different rice accessions, and the amplification profiles were highly reproducible between different thermocyclers and Taq polymerases. These amplification profiles allowed for clear distinction between two different ecotypes, Japonica and Indica, of Oryza sativa. In the analysis of RIL populations, the Rim2/Hipa-TD markers were found to be segregated largely in a dominant manner, although in a few cases, non-parental bands were observed in the segregating populations. Upon linkage analysis, the Rim2/Hipa-TD markers were found to be distributed in the regions proximal to the centromeres of the chromosomes. The distribution of the Rim2/Hipa CACTA elements was surveyed in 15 different Oryza species via Rim2/Hipa-TD. While Rim2/Hipa-TD yielded ample amplification profiles between 100 to 700 bp in the AA diploid Oryza species, other species having BB, CC, EE, BBCC and CCDD, profiles demonstrated that most of the amplified fragments were larger than 400 bp, and that our methods were insufficient to clearly distinguish between these fragments. However, the overall amplification profiles between species in the Oryza genus were fully distinct. Phenetic relationships among the AA diploid Oryza species, as evidenced by the Rim2/Hipa-TD markers, were matched with their geographical distributions. CONCLUSION: The abundance of the Rim2/Hipa TIR sequences is very informative since the Rim2/Hipa-TD produced high polymorphic profiles with ample reproducibility within a species as well as between species in the Oryza genus. Therefore, Rim2/Hipa-TD markers can be useful in the development of high-density of genetic map around the centromeric regions. Rim2/Hipa-TD may also prove useful in evaluations of genetic variation and species relationships in the Oryza species

Development of cDNA-derived SSR markers and their efficiency in diversity assessment of Cymbidium accessions

Abstract Cymbidium spp. are popular flowering plants. Assessment of the genetic diversity in cultivated Cymbidium facilitates conservation of germplasm and subsequent cultivar improvement. Thus, it is important to develop more efficient polymorphic DNA markers. Although more motifs (403) were identified and more primers (206) were designed in the genomic library compared to the cDNA library, a larger number of successful primers were obtained from the cDNA library (59.9%) than from genomic DNA library (51.1%). However, higher PIC and gene diversity were identified in genomic SSRs. The average allele number per locus was also higher in genomic SSRs (7.3) than EST-SSRs (5.2), among the 24 evaluated Cymbidium accessions. AT/TA was comparatively high in EST-SSRs, while this motif was not as common in genomic SSRs. The CTT/AAG/TCT/AGA/TTC/GAA and TGC/GCA/GCT/AGC/CTG/CAG motifs were the most abundant tri-nucleotide sequences in EST-SSRs, while GTT/AAC/TGT/ACA/TTG/CAA was the most frequent in genomic SSRs. The number of repeats ranged from 3 to 12 in EST-SSRs. Currently, 52 novel polymorphic SSR markers have been evaluated, which will be useful for germplasm assessments, core set construction, evaluation of genetic diversity, and marker assisted selection (MAS) based Cymbidium breeding

N-(3,4-Difluoro­phen­yl)-2-(3,4-dimethoxy­phen­yl)acetamide

In the title amide, C16H15F2NO3, the dihedral angle between the benzene rings is 53.7 (1)°. Mol­ecules are linked in the crystal structure by an inter­molecular N—H⋯O hydrogen bond involving N—H and C=O functionalities of the amide group. A one-dimensional network is thus formed along the [001] direction. No significant inter­chain contacts are observed

Spontaneous Tonsillar Hemorrhage and Post-Tonsillectomy Hemorrhage

Spontaneous tonsillar hemorrhage from infectious causes is extremely rare and post-tonsillectomy hemorrhage, although also relatively rare, is an unavoidable complication of the procedure. Hemorrhage in association with tonsillitis or tonsillectomy is potentially dangerous and can be life threatening. We report here the presentation and management of a 42-yr-old man with severe spontaneous hemorrhage from infected tonsils and post-tonsillectomy hemorrhage. We suggest that if attempts to control the bleeding are not successful or if severe spontaneous tonsillar hemorrhage occurs repeatedly or a malignancy is suspected, tonsillectomy and close postoperative follow up is recommended

Lamivudine plus adefovir combination therapy for lamivudine resistance in hepatitis-B-related hepatocellular carcinoma patients

Background/AimsLamivudine (LAM) plus adefovir (ADV) combination therapy has been accepted as one of the best treatments for LAM-resistant chronic hepatitis B (CHB). The aim of this study was to determine the efficacy of this combination therapy in hepatocellular carcinoma (HCC) patients.MethodsThe medical records of CHB patients who developed LAM resistance and were treated with LAM plus ADV combination therapy for more than 6 months were reviewed. Their virological response (VR; undetectable HBV DNA) and biochemical response (BR; alanine aminotransferase normalization) were evaluated, and the findings of HCC and non-HCC patients were compared.ResultsThe data from 104 patients (19 with HCC and 85 without HCC) were analyzed. The VR rates did not differ significantly between the HCC and non-HCC groups: 33.3% vs. 55.6% at 12 months (P=0.119), 58.3% vs. 67.2% at 24 months (P=0.742), 50% vs. 69.8% at 36 months (P=0.280), and 66.7% vs. 71.0% at 48 months (P=1.000). The BR rates also did not differ significantly between the groups: 55.6% vs. 84.0% at 12 months (P=0.021), 58.3% vs. 83.8% at 24 months (P=0.057), 70.0% vs. 77.8% at 36 months (P=0.687), and 66.7% vs. 80.6% at 48 months (P=0.591).ConclusionsThe efficacy of LAM plus ADV combination therapy is comparable in HCC and non-HCC patients