Remote impacts of 2009 and 2015 El Niño on oceanic and biological processes in a marginal sea of the Northwestern Pacific.

The significance of long-term teleconnections derived from the anomalous climatic conditions of El Niño has been a highly debated topic, where the remote response of coastal hydrodynamics and marine ecosystems to El Niño conditions is not completely understood. The 14-year long data from a ship-borne acoustic Doppler current profiler was used to examine the El Niño's impact, in particular, 2009 and 2015 El Niño events, on oceanic and biological processes in coastal regions across the Korea/Tsushima Strait. Here, it was revealed that the summer volume transport could be decreased by 8.7% (from 2.46 ± 0.39 to 2.24 ± 0.26 Sv) due to the anomalous northerly winds in the developing year of El Niño. Furthermore, the fall mean volume backscattering strength could be decreased by 1.8% (from - 97.09 ± 2.14 to - 98.84 ± 2.10 dB) due to the decreased surface solar radiation after the El Niño events. Overall, 2009 and 2015 El Niño events remotely affected volume transport and zooplankton abundance across the Korea/Tsushima Strait through climatic teleconnections.

Tempo-spatial variations of the Ryukyu Current southeast of Miyakojima Island determined from mooring observations.

The origin, structure, and variability of the Ryukyu Current (RC) have long been debated, mostly due to limited observations. A mooring array, deployed for two years southeast of Miyakojima in the southern portion of the Ryukyu Island chain, has provided, for the first time, data confirming the existence and revealing the characteristics of the RC in that upstream region, including its velocity structure and variability. The observations show a shoreward-intensified current flowing northeastward, with a subsurface core located near the 1,000 m isobath and having a record-long mean speed of up to 19.4 cm s-1 at 500 m depth. Estimated volume transport across the observation section had mean 9.0 Sv (1 Sv = 106 m3 s-1) and standard deviation 8.7 Sv. The RC shows significant barotropic character compared with other similar mid-latitude currents.

Poleward-propagating near-inertial waves enabled by the western boundary current.

Near-inertial waves (NIWs), which have clockwise (anticlockwise) rotational motion in the Northern (Southern) Hemisphere, exist everywhere in the ocean except at the equator; their frequencies are largely determined by the local inertial frequency, f. It is thought that they supply about 25% of the energy for global ocean mixing through turbulence resulting from their strong current shear and breaking; this contributes mainly to upper-ocean mixing which is related to air-sea interaction, typhoon genesis, marine ecosystem, carbon cycle, and climate change. Observations and numerical simulations have shown that the low-mode NIWs can travel many hundreds of kilometres from a source region toward the equator because the lower inertial frequency at lower latitudes allows their free propagation. Here, using observations and a numerical simulation, we demonstrate poleward propagation of typhoon-induced NIWs by a western boundary current, the Kuroshio. Negative relative vorticity, meaning anticyclonic rotational tendency opposite to the Earth's spin, existing along the right-hand side of the Kuroshio path, makes the local inertial frequency shift to a lower value, thereby trapping the waves. This negative vorticity region works like a waveguide for NIW propagation, and the strong Kuroshio current advects the waves poleward with a speed ~85% of the local current. This finding emphasizes that background currents such as the Kuroshio and the Gulf Stream play a significant role in redistribution of the NIW energy available for global ocean mixing.

Prosthetic Valve Endocarditis caused by HACEK Organisms: a Case Reports and Systematic Review of the Literature.

HACEK is a rare cause of prosthetic valve endocarditis (PVE). We describe 42-year-old male patient who presented with Aggregatibacter aphrophilus PVE and cerebral infarct. A. aphrophilus was isolated from his blood cultures as the sole pathogen, which was confirmed by subsequent 16S rRNA sequencing. He was treated with valve replacement surgery and an 8 week course of pathogen-directed antibiotic therapy and followed for 20 months without recurrence.

Layer-specific analysis of dobutamine stress echocardiography for the evaluation of coronary artery disease.

Although dobutamine stress echocardiography (DSE) is a well-defined tool for the diagnosis of coronary artery disease (CAD), false-negative and false-positive results still occur. This study investigated the diagnostic role of layer-specific analysis using 2-dimensional speckle-tracking echocardiography (STE) during DSE.A total of 121 patients who underwent DSE and showed normal wall motion and ejection fraction during baseline echocardiography were enrolled. All patients underwent coronary angiography after DSE within 2 weeks. The patients were divided into the following 4 groups according to DSE results and CAD status: negative DSE with no significant CAD (n = 73), positive DSE with significant CAD (n = 16), negative DSE with significant CAD (n = 17), and positive DSE with no significant CAD (n = 15). Layer-specific global longitudinal strain (GLS) was assessed in the endocardium, mid-myocardium, and epicardium by STE techniques.Patients with significant CAD were older, more male and showed higher glucose level compared to patients without CAD. But coronary risk factors and previous medications were not different between patients with and without CAD. There were no significant differences in whole myocardium or layer-specific GLS found in the baseline echocardiography. During recovery echocardiography, endocardial GLS was significantly different between patients with and without CAD, regardless of the DSE results. A receiver-operating characteristic curve analysis showed that endocardial GLS (>-16%) was superior for identifying significant CAD during the DSE recovery stage. Diagnostic accuracy was improved by applying the results of endocardial GLS compared with visual estimation of DSE.The assessment of layer-specific strain by STE during DSE was feasible, and the evaluation of poststress endocardial function is a more sensitive tool for the detection of CAD.

The formation and fate of internal waves in the South China Sea.

Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis, sediment and pollutant transport and acoustic transmission; they also pose hazards for man-made structures in the ocean. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometres from their sources before breaking, making it challenging to observe them and to include them in numerical climate models, which are sensitive to their effects. For over a decade, studies have targeted the South China Sea, where the oceans' most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variability and energy budget, however, owing to the lack of in situ data from the Luzon Strait, where extreme flow conditions make measurements difficult. Here we use new observations and numerical models to (1) show that the waves begin as sinusoidal disturbances rather than arising from sharp hydraulic phenomena, (2) reveal the existence of >200-metre-high breaking internal waves in the region of generation that give rise to turbulence levels >10,000 times that in the open ocean, (3) determine that the Kuroshio western boundary current noticeably refracts the internal wave field emanating from the Luzon Strait, and (4) demonstrate a factor-of-two agreement between modelled and observed energy fluxes, which allows us to produce an observationally supported energy budget of the region. Together, these findings give a cradle-to-grave picture of internal waves on a basin scale, which will support further improvements of their representation in numerical climate predictions.

Preparation and characterization of biodegradable nanoparticles entrapping immunodominant peptide conjugated with PEG for oral tolerance induction.

PEG-conjugated immunodominant peptides for collagen-induced arthritis (CIA) were prepared for oral tolerance induction instead of whole Type II collagen (CII), because a small peptide can be converted to a macromolecule soluble in methylene chloride by the coupling of poly-ethylene glycol (PEG). PEG-pep1 was synthesized from a peptide and mPEG-NH2 (Mw approximately 5000) using SPDP as a linker, whereas PEG-pep2 was prepared by the direct disulfide coupling between PEG-OD (Mw approximately 10,000) and the peptide. PEG-pep1 and PEG-pep2 were purified by gel permeation chromatography (GPC), and the peak fractions of GPC were identified by GPC and MALDI-TOF mass spectroscopy. The peptide coupling gave much earlier retention times for PEG-pep1 (11.26 min) and PEG-pep2 (10.61 min) than for mPEG-SPDP (15.63 min) and mPEG-OD (14.58 min). The Mw's of mPEG-NH2, mPEG-SPDP, PEG-pep1, mPEG-OD and PEG-pep2 were 5451, 5588, 7035, 10,360 and 11,826, respectively, suggesting that PEG-pep1 and PEG-pep2 of high purity could be obtained. The nanoparticles entrapping PEG-pep1 and PEG-pep2 (NP/PEG-pep1 and NP/PEG-pep2) were prepared by the o/w solvent evaporation method, whereas the peptide-loaded nanoparticles (NP/pep) were prepared by the w/o/w double emulsion method. Although all the nanoparticles had a similar spherical morphology under scanning electron microscopy, NP/pep showed up as having a larger mean size than the others, which was confirmed by dynamic light scattering analysis (NP/pep, 499.7+/-27.2 nm; NP/PEG-pep1, 333.0+/-16.8 nm; NP/PEG-pep2, 342.4+/-15.1 nm). The lower encapsulation efficiency of NP/pep (21.0+/-1.6%) than NP/PEG-pep1 (66.5+/-5.0%) and NP/PEG-pep2 (73.8+/-5.5%) can also be attributed to the preparation method. In in vitro release studies, NP/PEG-pep1 and NP/PEG-pep2 displayed a similar release profile, close to a linear release pattern, whereas NP/pep displayed a tri-phasic release profile. From these results, it was demonstrated that nanoparticles entrapping a PEG-conjugated peptide could be an alternative delivery method for the induction of oral tolerance rather than CII and peptide.