Nonlinear magnetization dynamics of antiferromagnetic spin resonance induced by intense terahertz magnetic field

We report on the nonlinear magnetization dynamics of a HoFeO3 crystal induced by a strong terahertz magnetic field resonantly enhanced with a split ring resonator and measured with magneto-optical Kerr effect microscopy. The terahertz magnetic field induces a large change (~40%) in the spontaneous magnetization. The frequency of the antiferromagnetic resonance decreases in proportion to the square of the magnetization change. A modified Landau-Lifshitz-Gilbert equation with a phenomenological nonlinear damping term quantitatively reproduced the nonlinear dynamics

Large-scale analysis of human alternative protein isoforms: pattern classification and correlation with subcellular localization signals

We investigated human alternative protein isoforms of >2600 genes based on full-length cDNA clones and SwissProt. We classified the isoforms and examined their co-occurrence for each gene. Further, we investigated potential relationships between these changes and differential subcellular localization. The two most abundant patterns were the one with different C-terminal regions and the one with an internal insertion, which together account for 43% of the total. Although changes of the N-terminal region are less common than those of the C-terminal region, extension of the C-terminal region is much less common than that of the N-terminal region, probably because of the difficulty of removing stop codons in one isoform. We also found that there are some frequently used combinations of co-occurrence in alternative isoforms. We interpret this as evidence that there is some structural relationship which produces a repertoire of isoformal patterns. Finally, many terminal changes are predicted to cause differential subcellular localization, especially in targeting either peroxisomes or mitochondria. Our study sheds new light on the enrichment of the human proteome through alternative splicing and related events. Our database of alternative protein isoforms is available through the internet

Surface plasmon enhanced spontaneous emission rate of InGaN/GaN quantum wells probed by time-resolved photoluminescence spectroscopy

We observed a 32-fold increase in the spontaneous emission rate of InGaN/GaN quantum well (QW) at 440 nm by employing surface plasmons (SPs) probed by time-resolved photoluminescence spectroscopy. We explore this remarkable enhancement of the emission rates and intensities resulting from the efficient energy transfer from electron-hole pair recombination in the QW to electron vibrations of SPs at the metal-coated surface of the semiconductor heterostructure. This QW-SP coupling is expected to lead to a new class of super bright and high-speed light-emitting diodes (LEDs) that offer realistic alternatives to conventional fluorescent tubes

Detection of regional scale sea-to-air oxygen emission related to spring bloom near Japan by using in-situ measurements of atmospheric oxygen/nitrogen ratio

International audienceWe have been carrying out in-situ monitoring of atmospheric O2/N2 ratio at Cape Ochi-ishi (COI; 43°10´ N, 145°30´ E) in the northern part of Japan since March 2005 by using a modified gas chromatography/thermal conductivity detector (GC/TCD). The standard deviation of the O2/N2 ratio is estimated to be about ±14 per meg (?3 ppm) with intervals of 10 min. Thus, the in-situ measurement system has a 1? precision of ±6 per meg ((?1.2 ppm) for one-hour mean O2/N2 ratio. Atmospheric potential oxygen (APO ?O2+1.1CO2), which is conserved with respect to terrestrial photosynthesis and respiration but reflects changes in air-sea O2 and CO2 fluxes, shows large variabilities from April to early July 2005. Distribution of satellite-derived marine primary production indicates occurrences of strong bloom in the Japan Sea in April and in the Okhotsk Sea and the western North Pacific near Hokkaido Island in June. Back trajectory analysis of air masses indicates that high values of APO, which last for several hours or several days, can be attributed to the oxygen emission associated with the spring bloom of active primary production