Sub-100-as timing jitter optical pulse trains from mode-locked Er-fiber lasers

We demonstrate sub-100-attosecond timing jitter optical pulse trains generated from free-running, 77.6-MHz repetition-rate, mode-locked Er-fiber lasers. At -0.002(\pm0.001) ps2 net cavity dispersion, the rms timing jitter is 70 as (224 as) integrated from 10 kHz (1 kHz) to 38.8 MHz offset frequency, when measured by a 24-as-resolution balanced optical cross-correlator. To our knowledge, this result corresponds to the lowest rms timing jitter measured from any mode-locked fiber lasers so far. The measured result also agrees fairly well with the Namiki-Haus analytic model of quantum-limited timing jitter in stretched-pulse fiber lasers.Comment: 4 pages, 2 figures, to appear in Optics Letter

Quantitative agreement of Dzyaloshinskii-Moriya interactions for domain-wall motion and spin-wave propagation

The magnetic exchange interaction is the one of the key factors governing the basic characteristics of magnetic systems. Unlike the symmetric nature of the Heisenberg exchange interaction, the interfacial Dzyaloshinskii-Moriya interaction (DMI) generates an antisymmetric exchange interaction which offers challenging opportunities in spintronics with intriguing antisymmetric phenomena. The role of the DMI, however, is still being debated, largely because distinct strengths of DMI have been measured for different magnetic objects, particularly chiral magnetic domain walls (DWs) and non-reciprocal spin waves (SWs). In this paper, we show that, after careful data analysis, both the DWs and SWs experience the same strength of DMI. This was confirmed by spin-torque efficiency measurement for the DWs, and Brillouin light scattering measurement for the SWs. This observation, therefore, indicates the unique role of the DMI on the magnetic DW and SW dynamics and also guarantees the compatibility of several DMI-measurement schemes recently proposed.Comment: 24 pages, 5 figure

Influence of HEMA content on the mechanical and bonding properties of experimental HEMA-added glass ionomer cements

The purpose of this study was to determine the influence of incrementally added uncured HEMA in experimental HEMA-added glass ionomer cement (HAGICs) on the mechanical and shear bond strength (SBS) of these materials. Increasing contents of uncured HEMA (10-50 wt.%) were added to a commercial glass ionomer cement liquid (Fuji II, GC, Japan), and the compressive and diametral tensile strengths of the resulting HAGICs were measured. The SBS to non-precious alloy, precious alloy, enamel and dentin was also determined after these surfaces were subjected to either airborne-particle abrasion (Aa) or SiC abrasive paper grinding (Sp). Both strength properties of the HAGICs first increased and then decreased as the HEMA content increased, with a maximum value obtained when the HEMA content was 20% for the compressive strength and 40% for the tensile strength. The SBS was influenced by the HEMA content, the surface treatment, and the type of bonding surface (

Resonant two-photon ionization and laser induced fluorescence spectroscopy of jet-cooled adenine

Resonant two-photon ionization (R2PI) and laser induced fluorescence (LIF) techniques were used to obtain the electronic spectra of the jet-cooled DNA base adenine. The spectrum consisted of two bands of the n??* and ????* characters. The vibronic mixing between the two states resulted in the broad absorption whose onset was located 1100 cm -1 above the n??* origin. The presence of these electronically states revealed the presence of vibronic mixing.open12813

miTarget: microRNA target gene prediction using a support vector machine

BACKGROUND: MicroRNAs (miRNAs) are small noncoding RNAs, which play significant roles as posttranscriptional regulators. The functions of animal miRNAs are generally based on complementarity for their 5' components. Although several computational miRNA target-gene prediction methods have been proposed, they still have limitations in revealing actual target genes. RESULTS: We implemented miTarget, a support vector machine (SVM) classifier for miRNA target gene prediction. It uses a radial basis function kernel as a similarity measure for SVM features, categorized by structural, thermodynamic, and position-based features. The latter features are introduced in this study for the first time and reflect the mechanism of miRNA binding. The SVM classifier produces high performance with a biologically relevant data set obtained from the literature, compared with previous tools. We predicted significant functions for human miR-1, miR-124a, and miR-373 using Gene Ontology (GO) analysis and revealed the importance of pairing at positions 4, 5, and 6 in the 5' region of a miRNA from a feature selection experiment. We also provide a web interface for the program. CONCLUSION: miTarget is a reliable miRNA target gene prediction tool and is a successful application of an SVM classifier. Compared with previous tools, its predictions are meaningful by GO analysis and its performance can be improved given more training examples

Elevated intracellular cAMP exacerbates vulnerability to oxidative stress in optic nerve head astrocytes.

Glaucoma is characterized by a progressive loss of retinal ganglion cells and their axons, but the underlying biological basis for the accompanying neurodegeneration is not known. Accumulating evidence indicates that structural and functional abnormalities of astrocytes within the optic nerve head (ONH) have a role. However, whether the activation of cyclic adenosine 3',5'-monophosphate (cAMP) signaling pathway is associated with astrocyte dysfunction in the ONH remains unknown. We report here that the cAMP/protein kinase A (PKA) pathway is critical to ONH astrocyte dysfunction, leading to caspase-3 activation and cell death via the AKT/Bim/Bax signaling pathway. Furthermore, elevated intracellular cAMP exacerbates vulnerability to oxidative stress in ONH astrocytes, and this may contribute to axonal damage in glaucomatous neurodegeneration. Inhibition of intracellular cAMP/PKA signaling activation protects ONH astrocytes by increasing AKT phosphorylation against oxidative stress. These results strongly indicate that activation of cAMP/PKA pathway has an important role in astrocyte dysfunction, and suggest that modulating cAMP/PKA pathway has therapeutic potential for glaucomatous ONH degeneration

Comparison of total body irradiation-based or non-total body irradiation-based conditioning regimens for allogeneic stem cell transplantation in pediatric leukemia patients

Purpose : This study aims to compare the outcome of total body irradiation (TBI)- or non-TBI-containing conditioning regimens for leukemia in children. Methods : We retrospectively evaluated 77 children conditioned with TBI (n=40) or non-TBI (n=37) regimens, transplanted at Chonnam National University Hospital between January 1996 and December 2007. The type of transplantation, disease status at the time of transplant, conditioning regimen, engraftment kinetics, development of graft-versus-host disease (GVHD), complications, cause of deaths, overall survival (OS), and event-free survival (EFS) were compared between the 2 groups. Results : Among 34 patients with acute lymphoblastic leukemia (ALL), 28 (82.4%) were in the TBI group, while 72.7% (24/33) of patients with myeloid leukemia were in the non-TBI group. Although the 5-year EFS of the 2 groups was similar for all patients (62% vs 63%), the TBI group showed a better 5-year EFS than the non-TBI group when only ALL patients were analyzed (65% vs 17%&#59; P =0.005). In acute myelogenous leukemia patients, the non-TBI group had better survival tendency (73% vs 38%&#59; P=0.089). The incidence of GVHD, engraftment, survival, cause of death, and late complications was not different between the 2 groups. Conclusion : The TBI and non-TBI groups showed comparable results, but the TBI group showed a significantly higher 5-year EFS than the non-TBI group in ALL patients. Further prospective, randomized controlled studies involving larger number of patients are needed to assess the late-onset complications and to compare the socioeconomic quality of life