1 2 3 Journal of Radioanalytical and Nuclear Chemistry An International Journal Dealing with All Aspects and Applications of Nuclear Chemistry Volume

Abstract We carried out time-series observations of 210 Po and 210 Pb radioactivity in the western North Pacific Ocean. The sinking fluxes of particulate organic carbon (POC) in the mesopelagic zone were estimated from 210 Po radioactivity during several seasons in the subarctic and subtropical regions of the western North Pacific. The seasonal changes of POC fluxes at a depth of 400 m were larger in the subarctic region than in the subtropical region. The annual mean POC flux at a depth of 400 m was larger in the subarctic region (57 mgC m -2 day -1 ) than in the subtropical region (36 mgC m -2 day -1 ). The annual mean of the e-ratio (the ratio of POC flux to primary productivity) in the subarctic region (18 %) was about twice the e-ratio in the subtropical region (10 %). These results imply that the efficiency of the biological pump is larger in the subarctic region than in the subtropical region of the western North Pacific

Western North Pacific Integrated Physical-Biogeochemical Ocean Observation Experiment (INBOX): Part 2. Biogeochemical responses to eddies and typhoons revealed from the S1 mooring and shipboard measurements

An interdisciplinary project called S1-INBOX (Western North Pacific Integrated PhysicalBiogeochemical Ocean Observation Experiment conducted around the S1 biogeochemical mooring site) was carried out during the summer of 2011 in the oligotrophic, subtropical North Pacific Ocean near biogeochemical mooring S1 (30° N, 145° E). Results from the S1 mooring during S1-INBOX revealed a large export flux at a depth of 200 m, a high chlorophyll a concentration in the deep chlorophyll maximum layer, and a high potential photochemical efficiency of photosystem II. These phenomena were associated with vertical uplift of isopycnal surfaces at the edge of a cyclonic eddy and a transition from the cyclonic eddy to an anticyclonic eddy. Shipboard biogeochemical surveys conducted during oligotrophic conditions in July 2011 revealed that the phytoplankton community in these waters was dominated by small species that are responsive to intermittent supplies of nutrients. Surface wind forcing because of Typhoons MA-ON and SONCA may have generated near-inertial oscillations. Diapycnal mixing associated with near-inertial waves was also related to high export fluxes, the indication being that propagation of near-inertial internal waves and subsequent mixing may have been important to biogeochemical phenomena during S1-INBOX

Orientation of point nodes and nonunitary triplet pairing tuned by the easy-axis magnetization in UTe2

The gap structure of a novel uranium-based superconductor UTe$_2$, situated in the vicinity of ferromagnetic quantum criticality, has been investigated via specific-heat $C(T,H,\Omega)$ measurements in various field orientations. Its angular $\Omega(\phi,\theta)$ variation shows a characteristic shoulder anomaly with a local minimum in $H \parallel a$ at moderate fields rotated within the $ab$ and $ac$ planes. Based on the theoretical calculations, these features can be attributed to the presence of point nodes in the superconducting gap along the $a$ direction. Under the field orientation along the easy-magnetization $a$ axis, an unusual temperature dependence of the upper critical field at low fields together with a convex downward curvature in $C(H)$ were observed. These anomalous behaviors can be explained on the basis of a nonunitary triplet state model with equal-spin pairing whose $T_{\rm c}$ is tuned by the magnetization along the $a$ axis. From these results, the gap symmetry of UTe$_2$ is most likely described by a vector order parameter of $d(k)=(b + ic)(k_b + ik_c)$.Comment: 6 pages, 4 figures (main text) + 7 pages, 5 figures (Supplementary Material), accepted for publication in Phys. Rev. Researc

Reappraisal of meridional differences of factors controlling phytoplankton biomass and initial increase preceding seasonal bloom in the northwestern Pacific Ocean

Multiplatform observations of ocean biogeochemical data were used to elucidate meridional differences in the factors that limit phytoplankton biomass (Chl-a) and the mechanisms that trigger the seasonal winter or spring phytoplankton bloomin the northwestern Pacific Ocean (NWPO). During the winter, Chl-a north (south) of 30°N is limited by light (nutrients). During the spring and fall, Chl-a in much of the area east of the Japan/Kuril Islands and/or north of 40°N(south of 35°N) is limited by light (nutrients). During the summer, nutrients limit Chl-a over much of the NWPO, except in the areas east of the Japan/Kuril Islands and north of 45°N. In the area south of around 31°N, phytoplankton biomass is nutrient limited throughout the year, and the seasonal bloom emerges in the winter, begins in the fall which is associated with mixed layer deepening. Between 31°N and 40°N, the spring bloom onset is mainly associated with a cessation of mixed layer deepening. In much of the area north of 40°N, including the Oyashio area, the onset of the spring bloom is consistent with Sverdrup’s critical depth hypothesis. The spatial extents of the light- and nutrient-limited areas and the areas associated with a single bloom onset mechanism are by no means constant. They are expected to undergo meridional shifts as a result of large-scale climatic changes and global warming

Changing trends in prognostic factors for patients with multiple myeloma after autologous stem cell transplantation during the immunomodulator drug/proteasome inhibitor era

We evaluated the clinical significance of prognostic factors including the International Staging System (ISS) and modified European Group for Blood and Marrow Transplantation response criteria in 1650 Japanese patients with multiple myeloma (MM) who underwent upfront single autologous stem cell transplantation (ASCT). We categorized patients into two treatment cohorts: pre-novel agent era (1995-2006) and novel agent era (2008-2011). The combined percentage of pre-ASCT complete response and very good partial response cases (463 of 988, 47%) significantly increased during the novel agent era compared with the pre-novel agent era (164 of 527, 31%; P < 0.0001). The 2-year overall survival (OS) rate of 87% during the novel agent era was a significant improvement relative to that of 82% during the pre-novel agent era (P = 0.019). Although significant differences in OS were found among ISS stages during the pre-novel agent era, no significant difference was observed between ISS I and II (P = 0.107) during the novel agent era. The factors independently associated with a superior OS were female gender (P = 0.002), a good performance status (P = 0.024), lower ISS (P < 0.001), pre-ASCT response at least partial response (P < 0.001) and ASCT during the novel agent era (P = 0.017). These results indicate that the response rate and OS were significantly improved, and the ISS could not clearly stratify the prognoses of Japanese patients with MM who underwent upfront single ASCT during the novel agent era. © 2014 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association

An alternative mitophagy pathway mediated by Rab9 protects the heart against ischemia

Energy stress, such as ischemia, induces mitochondrial damage and death in the heart. Degradation of damaged mitochondria by mitophagy is essential for the maintenance of healthy mitochondria and survival. Here, we show that mitophagy during myocardial ischemia was mediated predominantly through autophagy characterized by Rab9-associated autophagosomes, rather than the well-characterized form of autophagy that is dependent on the autophagy-related 7 (Atg) conjugation system and LC3. This form of mitophagy played an essential role in protecting the heart against ischemia and was mediated by a protein complex consisting of unc-51 like kinase 1 (Ulk1), Rab9, receptor-interacting serine/ thronine protein kinase 1 (Rip1), and dynamin-related protein 1 (Drp1). This complex allowed the recruitment of transGolgi membranes associated with Rab9 to damaged mitochondria through S179 phosphorylation of Rab9 by Ulk1 and S616 phosphorylation of Drp1 by Rip1. Knockin of Rab9 (S179A) abolished mitophagy and exacerbated the injury in response to myocardial ischemia, without affecting conventional autophagy. Mitophagy mediated through the Ulk1/Rab9/Rip1/Drp1 pathway protected the heart against ischemia by maintaining healthy mitochondria

Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific

Intensive observations using hydrographical cruises and moored sediment trap deployments during 2010 and 2012 at station K2 in the North Pacific western subarctic gyre (WSG) revealed seasonal changes in δ15N of both suspended and settling particles. Suspended particles (SUS) were collected from depths between the surface and 200 m; settling particles by drifting traps (DST; 100-200 m) and moored traps (MST; 200 and 500 m). All particles showed higher δ15N values in winter and lower in summer, contrary to the expected by isotopic fractionation during phytoplankton nitrate consumption. We suggest that these observed isotopic patterns are due to ammonium consumption via light-controlled nitrification, which could induce variations in δ15N(SUS) of 0.4-3.1 ‰ in the euphotic zone (EZ). The δ15N(SUS) signature was reflected by δ15 N(DST) despite modifications during biogenic transformation from suspended particles in the EZ. δ15 N enrichment (average: 3.6 ‰) and the increase in C:N ratio (by 1.6) in settling particles suggests year-round contributions of metabolites from herbivorous zooplankton as well as TEPs produced by diatoms. Accordingly, seasonal δ15 N(DST) variations of 2.4-7.0 ‰ showed a significant correlation with primary productivity (PP) at K2. By applying the observed δ15 N(DST) vs. PP regression to δ15 N(MST) of 1.9-8.0 ‰, we constructed the first annual time-series of PP changes in the WSG. Moreover, the monthly export ratio at 500 m was calculated using both estimated PP and measured organic carbon fluxes. Results suggest a 1.6 to 1.8 times more efficient transport of photosynthetically-fixed carbon to the intermediate layers occurs in summer/autumn rather than winter/spring

Sixteen-year phytoplankton biomass trends in the northwestern Pacific Ocean observed by the SeaWiFS and MODIS ocean color sensors

Using multisensor/platform biophysical data collected from 1997 to 2013, we investigated trends of the concentrations of phytoplankton biomass (Chl) in the northwestern Pacific Ocean (NWPO) and the probable responsible factors. The trend of rising sea surface temperature (SST) was the main factor maintaining phytoplankton positive net growth and resulted in a trend of increasing Chl at high latitudes in all seasons. At latitudes of 36-46°N, east of 160°E, the trend of rising SST was accompanied by a trend of declining Chl, markedly in spring and fall, which could be ascribed to strengthened stratification. The trends of environmental variables in the Oyashio area have modified conditions in a way detrimental to phytoplankton growth, the result being a trend of declining Chl from spring to fall. Chl south of roughly 36°N exhibited different trends in different seasons because of the different trends of vertical stratification. Whereas the observed 16-year Chl trends were not primarily influenced by interannual climate variability, to some degree they were likely modified by decadal variability associated with a weakened Aleutian Low pressure. This work prompts further comprehensive studies to investigate the probable ecological consequences of the observed Chl trend for high-trophic-level marine organisms in the NWPO

Dispersion of Artificial Caesium-134 and -137 in the Western North Pacific One Month After the Fukushima Accident

In March 2011, an accident at the Fukushima Daiichi nuclear power plant (FNPP) was caused by the Tohoku earthquake and tsunami. Here we show the distribution of artificial caesium-134 and -137 (134Cs and 137Cs) in the western North Pacific one month after the FNPP accident. In surface seawater, 137Cs concentrations were from several times to two orders of magnitude higher than before the FNPP accident. 134Cs was also detected, and in many seawater samples the 134Cs/137Cs ratio was about 1. These findings indicate that radionuclides from the FNPP dispersed quickly in the western North Pacific. 134Cs and 137Cs concentrations in suspended solids and zooplankton at stations K2 and S1 were also one to two orders higher than before the accident. Numerical simulation results show that the higher caesium observed in the western North Pacific one month after the FNPP accident was transported not only by diffusion and advection of seawater but also via the atmosphere as an aerosol.Abstract presented at Ocean Sciences Meeting 2012, the Oceanography Society, ASLO, AGU, Salt Lake City, Utah, Feb. 20-24, 201