Nanostructured Bulk Copper Fabricated by Accumulative Roll Bonding

Takata, Naoki,Lee, Seong-Hee,Lim, Cha-Yong,Kim, Sang-Shik,Tsuji, Nobuhiro American Scientific Publishers 2007 Journal of nanoscience and nanotechnology Vol.7 No.11

<P>In this study, we tried to fabricate the nanostructured bulk copper alloys by a severe plastic deformation process. The sheets of copper alloys (OFC, PMC90, and DLP) were heavily deformed to an equivalent strain of 6.4 by the accumulative roll-bonding (ARB) process. The microstructure and the mechanical property of the fabricated specimens were systematically investigated. The microstructure was finely subdivided with increasing the equivalent strain by the ARB process. The severely deformed copper alloys exhibited the ultrafine lamellar boundary structure where the mean lamella spacing was about 200 nm. The strength significantly increased with decreasing the lamella spacing in the ARB processed copper alloys. Especially, the tensile strength of the DLP alloys ARB processed by 8 cycles (the equivalent strain of 6.4) reached to 520 MPa, which was about three times higher than that of same materials with conventional grain size of 10-100 <I>μ</I>m. On the other hand, the total elongation greatly dropped only by 1 ARB cycle corresponding to an equivalent strain of 0.8, which was around 3%. However, the total elongation increased again with increasing the number of the ARB cycle, and it reached to 10% after 8 cycles. The recovery of the total elongation could be recognized in all studied copper alloys. The obtained stress-strain curves showed that the improvement of the total elongation was caused by the increase in the post-uniform elongation. It can be concluded that the nanostructured copper alloys sheets having high strength without a large loss of ductility could be fabricated by the ARB process.</P>

INTEGRATION OF HUMANISTIC THERAPEUTIC APPROACH(ATA) WITH SOCIAL SKILLS TRAINING(SST) SIGNIFICANTLY IMPROVES SATISFACTORY QUALITY OF LIFE(QOL) AND INCREASES EFFECTIVENESS OF REHABILITATION TREATMENT FOR CHRONIC SCHIZOPHRENIC IN-PATIENTS

Takata Yamamoto 용인정신의학연구소 1994 용인정신의학보 Vol.1 No.2

Delayed differentiation of potent effector CD8⁺ T cells reducing viremia and reservoir seeding in acute HIV infection

Takata, Hiroshi,Buranapraditkun, Supranee,Kessing, Cari,Fletcher, James L. K.,Muir, Roshell,Tardif, Virginie,Cartwright, Pearline,Vandergeeten, Claire,Bakeman, Wendy,Nichols, Carmen N.,Pinyakorn, Sute American Association for the Advancement of Scienc 2017 Science Translational Medicine Vol.9 No.377

<P>CD8(+) T cells play a critical role in controlling HIV viremia and could be important in reducing HIV-infected cells in approaches to eradicate HIV. The simian immunodeficiency virus model provided the proof of concept for a CD8(+) T cell-mediated reservoir clearance but showed conflicting evidence on the role of these cells to eliminate HIV-infected cells. In humans, HIV-specific CD8(+) T cell responses have not been associated with a reduction of the HIV-infected cell pool in vivo. We studied HIV-specific CD8(+) T cells in the RV254 cohort of individuals initiating ART in the earliest stages of acute HIV infection (AHI). We showed that the HIV-specific CD8(+) T cells generated as early as AHI stages 1 and 2 before peak viremia are delayed in expanding and acquiring effector functions but are endowed with higher memory potential. In contrast, the fully differentiated HIV-specific CD8(+) T cells at peak viremia in AHI stage 3 were more prone to apoptosis but were associated with a steeper viral load decrease after ART initiation. Their capacity to persist in vivo after ART initiation correlated with a lower HIV DNA reservoir. These findings demonstrate that HIV-specific CD8(+) T cell magnitude and differentiation are delayed in the earliest stages of infection. These results also demonstrate that potent HIV-specific CD8(+) T cells contribute to the reduction of the pool of HIV-producing cells and the HIV reservoir seeding in vivo and provide the rationale to design interventions aiming at inducing these potent responses to cure HIV infection.</P>

Mid-Holocene forcing of the Tsushima Warm Current to the coastal environments in southwestern Japan with a view to foraminiferal faunas

Takata, Hiroyuki,Nishida, Naohisa,Ikehara, Ken,Katsuki, Kota,Khim, Boo-Keun Elsevier 2018 QUATERNARY INTERNATIONAL Vol.482 No.-

<P><B>Abstract</B></P> <P>We investigated fossil benthic and planktonic foraminifera in sediment cores FV10-05 and FV10-06-2, off Fukuoka, southwestern Japan to evaluate the impact of the Tsushima Warm Current on coastal environments around the strait between southeastern Korea and southwestern Japan during the early to middle Holocene. A cluster analysis of benthic foraminifera in these cores established four sample clusters (A, B, C, and D), which are interpreted as indicators of relatively high energy condition due to wave/current processes. Clusters A and C, characterized by attached taxa, became dominant at ∼6.6 ka. Such faunal changes are consistent with the current-influenced sedimentation, confirming that the Tsushima Warm Current reached its present-day distribution at that time. A hiatus at ∼8–7 ka has been reported in cores from deeper water off Fukuoka, whereas our shallow core shows deposition under high energy conditions was continuous even at ∼8–7 ka near the coast off river mouth. Across the strait, the maximum landward extent of benthic foraminifera occurred in the Nakdong River delta (southeastern Korea) in ∼8–7 ka, and an outer bay fauna of benthic foraminifera with seagrass beds occurred transiently in the restricted bay of the San-in district (southwestern Japan) at that time. The evolution of the Tsushima Warm Current during the early to middle Holocene thus appears to play an important role in coastal environments not only in the strait areas between southeastern Korea and southwestern Japan, but also in the San-in district.</P>

Biotic response of benthic foraminifera in Aso-kai lagoon, central Japan, to changes in terrestrial climate and ocean conditions (~AD 700–1600)

Takata, Hiroyuki,Tanaka, Satoshi,Seto, Koji,Sakai, Saburo,Takayasu, Katsumi,Khim, Boo-Keun Springer-Verlag 2014 Journal of paleolimnology Vol.51 No.3

Latitudinal Change in Benthic Foraminiferal Fauna by ITCZ Movement along the ~131°W Transect in the Equatorial Pacific Ocean

Takata, Hiroyuki,Yoo, Chan Min,Kim, Hyung Jeek,Khim, Boo-Keun Korean Ocean Research & Development Institute and 2016 OCEAN SCIENCE JOURNAL Vol.51 No.4

Modern and fossil benthic foraminifera were examined from nine surface sediments and two piston cores along the <TEX>${\sim}131^{\circ}W$</TEX> transect in the equatorial Pacific Ocean. This study was conducted to clarify the biotic response of abyssal benthic foraminifera during the last 220 ka to changes in the seasonal extent of the Intertropical Convergence Zone (ITCZ). The abundance of modern benthic foraminifera was high at stations between the equator and <TEX>$6^{\circ}N$</TEX>, whereas it was low at stations north of <TEX>$6^{\circ}N$</TEX>, which is generally consistent with the latitudinal <TEX>$CaCO_3$</TEX> distribution of surface sediments. The northward increase of Epistominella exigua from the equator to <TEX>${\sim}6^{\circ}N$</TEX> is similar to the seasonal variations in chlorophyll-a concentrations in the surface water and ITCZ position along <TEX>${\sim}131^{\circ}W$</TEX>. This species was more common at core PC5103 (<TEX>${\sim}6^{\circ}N$</TEX>) than at core PC5101 (<TEX>${\sim}2^{\circ}N$</TEX>) after ~130 ka, when the Shannon-Wiener diversity (H') between the two cores started to diverge. Hence, the presentday latitudinal difference in benthic foraminifera (E. exigua and species diversity) between <TEX>${\sim}2^{\circ}N$</TEX> and <TEX>${\sim}6^{\circ}N$</TEX> along <TEX>${\sim}131^{\circ}W$</TEX> has been generally established since ~130 ka. According to the modern relationship between the seasonality of primary production and seasonal ITCZ variations in the northern margin of the ITCZ, the latitudinal divergence of benthic foraminiferal fauna between <TEX>${\sim}2^{\circ}N$</TEX> and <TEX>${\sim}6^{\circ}N$</TEX> since ~130 ka appear to have been induced by more distinct variations in the seasonal movement of ITCZ.

Central Equatorial Pacific benthic foraminifera during the mid-Brunhes dissolution interval: Ballasting of particulate organic matter by biogenic silica and carbonate

Takata, Hiroyuki,Kim, Hyung Jeek,Asahi, Hirofumi,Thomas, Ellen,Yoo, Chan Min,Chi, Sang Bum,Khim, Boo-Keun Elsevier 2019 Quaternary science reviews Vol.210 No.-

<P><B>Abstract</B></P> <P>We evaluated the response of Quaternary abyssal benthic foraminifera in cores PC5101 (2º00.86′N, 131º34.32′W) and PC5103 (6º00.10′N, 131º28.57′W) of the Central Equatorial Pacific Ocean to the environmental changes over the past ∼520 kyrs, focusing on the mid-Brunhes dissolution interval (∼533–191 ka). We used multi-dimensional scaling (MDS) to derive MDS axis 1, reflecting food supply from low (negative scores) to high (positive scores) amounts, and MDS axis 2, reflecting variability in the food supply. From ∼120 ka on, <I>Epistominella exigua</I>, an indicator of variable food supply, was more abundant in core PC5103 (∼6<SUP>o</SUP>N) than in core PC5101 (∼2<SUP>o</SUP>N), but this was reversed from ∼300 to 250 ka.</P> <P>In core PC5101, MDS axis 1 scores are negatively correlated to the biogenic opal mass accumulation rates (MAR) after 249.6 ka, i.e., lower food supply at higher opal-MAR. In contrast, MDS axis 1 scores are positively correlated to the CaCO<SUB>3</SUB>-MAR from 520.8 to 331.2 ka. Both carbonate and opal skeletons might ballast particulate organic matter (POM) to enhance food supply to the benthos, but our data indicate that carbonate is more efficient and that changes in dominant ballasting of POM by different biominerals thus may have significantly affected the biological pump. During the transitional period (∼327.5–257.1 ka), ballasting of POM changed from control by calcareous plankton to control by siliceous plankton, with a transient period during which the latitudinal pattern of the Intertropical Convergence Zone was opposite to its modern pattern, with the more variable food supply at ∼ 6<SUP>o</SUP>N.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Quaternary abyssal benthic foraminifera were compared in terms of multi-dimensional scaling (MDS) in the Central Equatorial Pacific Ocean. </LI> <LI> In core PC5101, located closer to the equator, MDS axis 1 scores are negatively correlated to the biogenic opal mass accumulation rates (MAR) after 249.6 ka. </LI> <LI> In contrast, core PC5101 shows that MDS axis 1 scores are positively correlated to the CaCO<SUB>3</SUB>-MAR from 520.8 to 331.2 ka. </LI> <LI> Ballasting of particulate organic matter changed from control by calcareous plankton to control by siliceous plankton during ∼327.5–257.1 ka. </LI> <LI> During a transient period, the latitudinal pattern of the Intertropical Convergence Zone was opposite to its modern pattern, with the more variable food supply at ∼6°N. </LI> </UL> </P>

High-energy Emissions from the Pulsar/Be Binary System PSR J2032+4127/MT91 213

Takata, J.,Tam, P. H. T.,Ng, C. W.,Li, K. L.,Kong, A. K. H.,Hui, C. Y.,Cheng, K. S. American Astronomical Society 2017 The Astrophysical journal Vol.836 No.2

<P>PSR. J2032+4127 is a radio-loud gamma-ray-emitting pulsar; it is orbiting around a high-mass Be type star with a very long orbital period of 25-50 years, and is approaching periastron, which will occur in late 2017/early 2018. This system comprises a young pulsar and a Be type star, which is similar to the so-called gamma-ray binary PSR. B1259-63/LS2883. It is expected therefore that PSR. J2032+4127 shows an enhancement of high-energy emission caused by the interaction between the pulsar wind and Be wind/disk around periastron. Ho et al. recently reported a rapid increase in the X-ray flux from this system. In this paper, we also confirm a rapid increase in the X-ray flux along the orbit, while the GeV flux shows no significant change. We discuss the high-energy emissions from the shock caused by the pulsar wind and stellar wind interaction and examine the properties of the pulsar wind in this binary system. We argue that the rate of increase of the X-ray flux observed by Swift indicates (1) a variation of the momentum ratio of the two-wind interaction region along the orbit, or (2) an evolution of the magnetization parameter of the pulsar wind with the radial distance from the pulsar. We also discuss the pulsar wind/Be disk interaction at the periastron passage, and propose the possibility of formation of an accretion disk around the pulsar. We model high-energy emissions through the inverse-Compton scattering process of the cold-relativistic pulsar wind off soft photons from the accretion disk.</P>

Correlation between faunal transitions of benthic foraminifera and ballasting of particulate organic carbon by siliceous plankton during the Holocene off San-in district, southwestern Japan

Takata, Hiroyuki,Itaki, Takuya,Ikehara, Ken,Khim, Boo-Keun E. Arnold Distributed in North America by Cambridg 2018 The Holocene Vol.28 No.3

HIGH-ENERGY EMISSIONS FROM THE GAMMA-RAY BINARY LS 5039

Takata, J.,Leung, Gene C. K.,Tam, P. H. T.,Kong, A. K. H.,Hui, C. Y.,Cheng, K. S. IOP Publishing 2014 The Astrophysical journal Vol.790 No.1

<P>We study mechanisms of multi-wavelength emissions (X-ray, GeV, and TeV gamma-rays) from the gamma-ray binary LS 5039. This paper is composed of two parts. In the first part, we report on results of observational analysis using 4 yr data of the Fermi Large Area Telescope. Due to the improvement of instrumental response function and increase of the statistics, the observational uncertainties of the spectrum in the similar to 100-300 MeV bands and > 10 GeV bands are significantly improved. The present data analysis suggests that the 0.1-100 GeV emissions from LS 5039 contain three different components: (1) the first component contributes to <1 GeV emissions around superior conjunction, (2) the second component dominates in the 1-10 GeV energy bands, and (3) the third component is compatible with the lower-energy tail of the TeV emissions. In the second part, we develop an emission model to explain the properties of the phase-resolved emissions in multi-wavelength observations. Assuming that LS 5039 includes a pulsar, we argue that emissions from both the magnetospheric outer gap and the inverse-Compton scattering process of cold-relativistic pulsar wind contribute to the observed GeV emissions. We assume that the pulsar is wrapped by two kinds of termination shock: Shock-I due to the interaction between the pulsar wind and the stellar wind and Shock-II due to the effect of the orbital motion. We propose that the X-rays are produced by the synchrotron radiation at the Shock-I region and the TeV gamma-rays are produced by the inverse-Compton scattering process at the Shock-II region.</P>