Numerical study on multi-pulse dynamics and shot-to-shot coherence property in quasi-mode-locked regimes of a highly-pumped anomalous dispersion fiber ring cavity.

We numerically investigate quasi-mode-locked (QML) multi-pulse dynamics in a fiber ring laser cavity in the anomalous dispersion regime. We show that the laser cavity can operate in five constitutively different QML regimes, depending on the saturation power of the saturable absorber element and the length of the passive fiber section that parameterize the overall nonlinearity and dispersion characteristic of the laser cavity. We classify them into the incoherent noise-like-pulse, partially-coherent noise-like-pulse, symbiotic, partially-coherent multi-soliton, and coherent multi-soliton regimes, accounting for their coherence and multi-pulse formation features. In particular, we numerically clarify and confirm the symbiotic regime for the first time to the best of our knowledge, in which noise-like pulses and multi-solitons coexist stably in the cavity that has recently been observed experimentally. Furthermore, we analyze the shot-to-shot coherence characteristics of the individual QML regimes relative to the amount of the nonlinear-phase shift per roundtrip, and verify a strong correlation between them. We also show that the net-cavity dispersion plays a critical role in determining the multi-pulse dynamics out of the partially-coherent noise-like-pulse, symbiotic, and partially-coherent multi-soliton regimes, when the cavity bears moderate nonlinearity. We quantify and visualize all those characteristics onto contour maps, which will be very useful and helpful in discussing and clarifying the complex QML dynamics.

Adaptive broadband continuum source at 1200-1400 nm based on an all-fiber dual-wavelength master-oscillator power amplifier and a high-birefringence fiber.

We experimentally analyze the stimulated Raman scattering characteristics of a high-birefringence fiber (HBF), which presents an extraordinary level of spectral broadening incurred by the strong nonlinear interaction between the pump and Stokes pulses via the polarization-mode dispersion and group-velocity dispersion of the fiber. We also investigate the impact of the inter-pulse time-delay on the additional spectra broadening when dual-wavelength pump pulses are used. Exploiting these unique SRS properties of the HBF, we develop a novel Raman continuum source based on an all-fiber dual-wavelength master-oscillator power amplifier that can generate a dip-free spectrum in the 1200-1400-nm spectral range. We finally obtain a broadband continuum having an average power of ~840 mW and a 3-dB bandwidth of ~240 nm centered at 1200-1400 nm, which also represents a good spectral flatness and conversion efficiency. This type of source is very useful and important for optical coherence tomography applications, for example.

Isolation and characterization of a mycovirus in Lentinula edodes.

A mycovirus was isolated from an edible mushroom, Lentinula edodes, that was suffering from a severe epidemic. Fractionation of the diseased cell extract by isopycnic centrifugation with 50% CsCl revealed that the diseased mushroom was infected by Lentinula edodes spherical virus (LeSV), a new spherical virus with a diameter of 55 nm. The particle of LeSV encapsidated the 12 kb RNA genome by a 120 kDa coat protein. BLAST analysis of the partially sequenced LeSV genome showed 95% sequence identity with a putative RNA-dependent RNA polymerase (RdRp) gene of the mycovirus HKB, which was previously reported as being a double-stranded RNA (dsRNA) element. In contrast to HKB, the RNA genome in LeSV is encapsidated by the 120 kDa coat protein. To confirm that the LeSV coat protein is encoded by the viral genome, the N-terminal amino acid sequence of the coat protein was determined. The resulting N-terminal amino acid sequence, N-SALDVAPVVPELYFXXLEV-C, was found to be located in the middle of the HKB ORF1, suggesting that the LeSV coat protein was indeed encoded by the virus. To detect LeSV in L. edodes, a primer set targeting the RdRp gene was designed based on the partial sequence of the LeSV genome. RT-PCR analysis showed that 56 of the 84 commercially available dikaryotic cultivars carry LeSV. The transmission pattern of the virus was determined by analysing basidiospores from LeSV-infected and LeSV-free fruiting bodies. Nine out of 10 basidiospores from the LeSV-infected cultivars contained the virus while the spores from the LeSV-free parent were free of LeSV, suggesting that vertical transmission is the primary mode of LeSV propagation.

Effect of layering methods, composite type, and flowable liner on the polymerization shrinkage stress of light cured composites.

OBJECTIVES: The aim of this study was to investigate the effect of layering methods, flowable composite liner and use of low shrinkage silorane-based composite on the polymerization shrinkage stress of light cured composites. METHODS: Aluminum blocks were used to prepare MOD cavities and divided into four groups. A universal hybrid methacrylate-based composite (Z250), a flowable composite (Z350 flowable), and a silorane-based composite (P90) were used to fill the cavities. Cavities were restored using four different filling protocols. Group 1 was filled in bulk with Z250, group 2 was restored by an increment technique with the same composite, group 3 by an increment technique with Z250 and a Z350 flowable lining, and group 4 was restored by an increment technique with P90. The axial shrinkage strain and flexural modulus of the three composites were determined, and cuspal deflection of each group was measured with LVDT probes and compared among groups using ANOVA and Tukey's post hoc test (α=0.05). RESULTS: The axial shrinkage strains of P90, Z250, and Z350 flowable were 1.09 (0.11), 2.29 (0.06), and 4.12 (0.08)%, respectively. The flexural modulus of P90 was 10.1 (0.9), Z250 was 13.6 (2.0), and that of Z350 flowable was 7.6 (0.9) GPa. The cuspal deflections at 33 min in groups 1-4 were 18.2 (1.54), 14.5 (0.47), 16.2 (1.10), and 6.6 (0.44) µm, respectively. The incremental filling technique yielded significantly lower cuspal deflection than the bulk filling technique. Flowable composite lining under universal composite (Z250) layering showed higher cuspal deflection than that without flowable composite lining. Silorane-based (P90) composite exhibited lower cuspal deflection than metacrylate based (Z250) composite. SIGNIFICANCE: Cuspal deflection resulting from polymerization shrinkage stress may be reduced by an incremental filling technique and by the use of low shrinking composite to obtain optimal clinical outcomes. Flowable composite lining under conventional composite layering did not reduce polymerization shrinkage stress as assessed by cuspal deflection.

Development of a surface plasmon resonance-based immunosensor for the rapid detection of cardiac troponin I.

The concentration of cardiac troponin I (cTnI) in blood is an important marker for heart muscle cell damage. A surface plasmon resonance (SPR)-based immunosensor was devised for the rapid and specific detection of cTnI. It was constructed by crosslinking a monoclonal antibody P-II-13, which was generated against a loop region (aa 84-94) of cTnI protein as an epitope peptide, onto a chemically modified thin gold film. The performance of the sensor was examined with respect to the SPR signal intensity versus cTnI concentration. The signal intensity was directly correlated with the cTnI concentration in the range of 0-160 µg/l. The sensor signal was saturated when the concentration of cTnI approached 660 µg/l with the SPR intensity of 172 RU. The lower detection limit of the sensor was 68 ng/l cTnI, which was comparable to ELISA-based commercial cTnI detection systems.