177 research outputs found
Synthetic Efforts for Stereo Structure Determination of Cytotoxic Marine Natural Product Pericosines as Metabolites of Periconia sp. from Sea Hare
Pericosines are unique C7 cyclohexenoid metabolites of Periconia byssoides OUPS-N133 fungus that was originally isolated from the sea hare, Aplysia kurodai. Pericosines show significant in vitro cytotoxicity against P388 lymphocytic leukemia cells. Pericosine A, in particular, shows the most potent activity and significant in vivo antitumor activity against P388 cells. Thus, pericosines are promising candidates for seed compounds of anticancer drugs. However, before the total syntheses of pericosines were accomplished, their stereo structures could not be determined by spectral analyses because they have multi-functionalized cyclohexenoid structures with torsional strain. In this review, synthetic efforts for pericosines in this decade are surveyed
Patterns of burns and scalds in Mongolian children: a hospital-based prospective study
ObjectiveTo describe the circumstances of burn injury occurrence among Mongolian children and the products involved.MethodsStudy participants were children aged 15 years and younger who were admitted to the Burn Unit of the National Trauma Orthopedic Research Center from August 2015 to July 2016. We collected data on participant demographics and the aetiology and clinical features of their burn injuries, and we analysed the data based on the NOMESCO Classification model.FindingsOf 906 children, 83% were aged 0–3 years, 66% were injured around the cooking area in the traditional tent‐like dwelling called a ger or a detached house where no specified kitchen exists, and 28% were injured in a kitchen. Burn injuries resulted mostly from exposure to overflowing hot liquids (93%). Electric pots and electric kettles were the products most frequently involved in causing burn injuries (41% and 14%, respectively). Of 601 major burn injuries, 52% were due to electric pots. Moreover, burn injuries inflicted by electric pots were most likely to be major burn injuries (83%). Children typically fell into electric pots, while electric kettles were often pulled down by children.ConclusionBurn injuries among Mongolian children mainly occurred in cooking area of a ger involving electric pots. The current practice of cooking on the floor should be reconsidered for child burn prevention
Star Formation in the Extreme Outer Galaxy: Digel Cloud 2 Clusters
As a first step for studying star formation in the extreme outer Galaxy
(EOG), we obtained deep near-infrared images of two embedded clusters at the
northern and southern CO peaks of Cloud 2, which is one of the most distant
star forming regions in the outer Galaxy (galactic radius R_g ~ 19 kpc). With
high spatial resolution (FWHM ~ 0".35) and deep imaging (K ~ 21 mag) with the
IRCS imager at the Subaru telescope, we detected cluster members with a mass
detection limit of < 0.1 M_{sun}, which is well into the substellar regime.
These high quality data enables a comparison of EOG to those in the solar
neighborhood on the same basis for the first time. Before interpreting the
photometric result, we have first constructed the NIR color-color diagram
(dwarf star track, classical T Tauri star (CTTS) locus, reddening law) in the
Mauna Kea Observatory filter system and also for the low metallicity
environment since the metallicity in EOG is much lower than those in the solar
neighborhood. The estimated stellar density suggests that an ``isolated type''
star formation is ongoing in Cloud 2-N, while a ``cluster type'' star formation
is ongoing in Cloud 2-S. Despite the difference of the star formation mode,
other characteristics of the two clusters are found to be almost identical: (1)
K-band luminosity function (KLF) of the two clusters are quite similar, as is
the estimated IMF and ages (~ 0.5--1 Myr) from the KLF fitting, (2) the
estimated star formation efficiencies (SFEs) for both clusters are typical
compared to those of embedded clusters in the solar neighborhood (~ 10 %). The
similarity of two independent clusters with a large separation (~ 25 pc)
strongly suggest that their star formation activities were triggered by the
same mechanism, probably the supernova remnant (GSH 138-01-94).Comment: 14pages, 11 figures; Accepted for publication in Ap
Factors responsible for elevated plasma B-type natriuretic peptide levels in severe aortic stenosis: Comparison between elderly and younger patients
AbstractBackgroundElevated plasma B-type natriuretic peptide (BNP) is a predictor of outcome and helpful for risk stratification in aortic stenosis (AS). However, left ventricular (LV) diastolic dysfunction progresses with aging and may also influence plasma BNP levels in elderly patients. We hypothesized that plasma BNP levels may be influenced by age in severe AS, and that factors that affect the elevation of plasma BNP levels may be different between elderly and younger patients with AS.MethodsWe performed echocardiography in 341 patients with severe AS [aortic valve area (AVA)<1.0cm2] and classified them into two groups by age (elderly ≥75 years old, n=201; younger patients <75 years old, n=140). We used multivariate linear regression analysis to assess the factors that determine plasma BNP levels in both groups.ResultsAge was found to be one of the independent determinants of plasma BNP levels in all patients (β=0.135, p=0.005). Although AVA was similar in the two groups, plasma BNP levels and E/e′ were significantly higher in elderly than younger patients [133.0 (IQR, 73.3–329.7)pg/dl vs 92.8 (IQR, 40.6–171.8)pg/dl, p<0.01; 20±8 vs 16±6, p<0.01, respectively). In multivariate stepwise linear regression analysis, AVA index, LV ejection fraction, mass index, E/e′, estimated systolic pulmonary artery pressure (eSPAS), and the presence of atrial fibrillation were independent determinants of plasma BNP levels in younger patients. In contrast, the independent determinants of plasma BNP levels in elderly patients were LV ejection fraction, mass index, E/e′, eSPAS, the presence of atrial fibrillation, age, and hemoglobin levels, but not AVA index.ConclusionsThere may be differences in the factors that influence plasma BNP levels between elderly and younger patients with severe AS. In elderly patients, plasma BNP levels may be influenced more by these factors than AS severity compared with younger patients
Association of IL28B gene polymorphism with development of hepatocellular carcinoma in Japanese patients with chronic hepatitis C virus infection
IL28B single nucleotide polymorphisms (SNPs) are associated with spontaneous and treatment-induced elimination of hepatitis C virus (HCV). To assess whether the IL28B rs8099917 SNP also affects the progression of chronic HCV infection, we genotyped 511 Japanese HCV patients, including 69 with hepatocellular carcinoma (HCC). The T/T genotype of rs8099917 was not associated with the development of HCC (p = 0.623), although stepwise logistic regression analysis showed that liver cirrhosis, age greater than 68 years, and serum albumin <4.2 mg/dl were associated with HCC onset. It appears that the IL28B SNP does not directly influence hepatocarcinogenesis in chronic HCV infection.ArticleHUMAN IMMUNOLOGY. 73(3):298-300 (2012)journal articl
Star Formation Rates and Metallicities of K-selected Star Forming Galaxies at z~2
We present spectroscopy of 15 star-forming BzK galaxies (sBzKs) with K(AB)<23
in the Subaru Deep Field, for which Halpha and some other emission lines are
detected in 0.9 to 2.3 micron spectra with a resolution of R=500. Using Halpha
luminosities, we obtain star formation rates (SFRs), and then specific SFRs
(SSFRs) dividing SFRs by stellar masses, which are derived from SED fitting to
BVRi'z'K photometry. It is found that sBzKs with higher stellar masses have
larger SFRs. A negative correlation is seen between stellar mass and SSFR,
which is consistent with the previous results for z~2 galaxies. This implies
that a larger growth of stellar mass occurs in less massive galaxies. In
addition, gas-phase oxygen abundances, 12+log(O/H), are derived from the ratio
of NII(lambda 6584) to Halpha using the N2 index method. We have found a
correlation between stellar mass and oxygen abundance in the sense that more
massive sBzKs tend to be more metal rich, which is qualitatively consistent
with the relation for UV-selected z~2 galaxies. However, the metallicity of the
sBzKs is ~0.2 dex higher than that of UV-selected galaxies with similar stellar
masses, which is significant considering the small uncertainties. The sBzKs in
our sample have redder R-K colors than the UV-selected galaxies. This galaxy
color-dependence in the oxygen abundance may be caused by older or dustier
galaxies having higher metallicities at z~2.Comment: 20 pages, 13 figures, 2 tables, accepted for publication in The
Astrophysical Journa
High star formation activity in the central region of a distant cluster at z=1.46
We present an unbiased deep [OII] emission survey of a cluster XMMXCS
J2215.9-1738 at z=1.46, the most distant cluster to date with a detection of
extended X-ray emission. With wide-field optical and near-infrared cameras
(Suprime-Cam and MOIRCS, respectively) on Subaru telescope, we performed deep
imaging with a narrow-band filter NB912 (lambda_c=9139A, Delta_lambda=134A) as
well as broad-band filters (B, z', J and Ks). From the photometric catalogues,
we have identified 44 [OII] emitters in the cluster central region of 6'x6'
down to a dust-free star formation rate of 2.6 Msun/yr (3 sigma).
Interestingly, it is found that there are many [OII] emitters even in the
central high density region. In fact, the fraction of [OII] emitters to the
cluster members as well as their star formation rates and equivalent widths
stay almost constant with decreasing cluster-centric distance up to the cluster
core. Unlike clusters at lower redshifts (z<1) where star formation activity is
mostly quenched in their central regions, this higher redshift 2215 cluster
shows its high star formation activity even at its centre, suggesting that we
are beginning to enter the formation epoch of some galaxies in the cluster core
eventually. Moreover, we find a deficit of galaxies on the red sequence at
magnitudes fainter than ~M*+0.5 on the colour-magnitude diagram. This break
magnitude is brighter than that of lower redshift clusters, and it is likely
that we are seeing the formation phase of more massive red galaxies in the
cluster core at z~1. These results may indicate inside-out and down-sizing
propagation of star formation activity in the course of cluster evolution.Comment: 12 pages, 9 figures, 1 table, accepted for publication in MNRA
Isoform-specific potentiation of stem and progenitor cell engraftment by AML1/RUNX1
Background: AML1/RUNX1 is the most frequently mutated gene in leukaemia and is central to the normal biology of hematopoietic stem and progenitor cells. However, the role of different AML1 isoforms within these primitive compartments is unclear. Here we investigate whether altering relative expression of AML1 isoforms impacts the balance between cell self-renewal and differentiation in vitro and in vivo. Methods and Findings: The human AML1a isoform encodes a truncated molecule with DNA-binding but no transactivation capacity. We used a retrovirus-based approach to transduce AML1a into primitive haematopoietic cells isolated from the mouse. We observed that enforced AML1a expression increased the competitive engraftment potential of murine long-term reconstituting stem cells with the proportion of AML1a-expressing cells increasing over time in both primary and secondary recipients. Furthermore, AML1a expression dramatically increased primitive and committed progenitor activity in engrafted animals as assessed by long-term culture, cobblestone formation, and colony assays. In contrast, expression of the full-length isoform AML1b abrogated engraftment potential. In vitro, AML1b promoted differentiation while AML1a promoted proliferation of progenitors capable of short-term lymphomyeloid engraftment. Consistent with these findings, the relative abundance of AML1a was highest in the primitive stem/progenitor compartment of human cord blood, and forced expression of AML1a in these cells enhanced maintenance of primitive potential both in vitro and in vivo. Conclusions: These data demonstrate that the "a" isoform of AML1 has the capacity to potentiate stem and progenitor cell engraftment, both of which are required for successful clinical transplantation. This activity is consistent with its expression pattern in both normal and leukaemic cells. Manipulating the balance of AML1 isoform expression may offer novel therapeutic strategies, exploitable in the contexts of leukaemia and also in cord blood transplantation in adults, in whom stem and progenitor cell numbers are often limiting. © 2007 Tsuzuki et al
Properties of star-forming galaxies in a cluster and its surrounding structure at z=1.46
We conduct a narrow-band imaging survey of [OII] emitters over a 32'x23' area
in and around the XMMXCS J2215.9-1738 cluster at z=1.46 with
Subaru/Suprime-Cam, and select 380 [OII] emitting galaxies down to 1.4E-17
erg/s/cm2. Among them, 16 [OII] emitters in the cluster central region are
confirmed by NIR spectroscopy with Subaru/MOIRCS. We find that [OII] emitters
are distributed along filamentary large-scale structures around the cluster.
The z'-K vs K colour-magnitude diagram shows that a significantly higher
fraction of [OII] emitters is seen on the red sequence in the cluster core than
in other environments we define in this paper. It is likely that these red
galaxies are nearly passively evolving galaxies which host [OII] emitting AGNs,
rather than dust-reddened star-forming galaxies. We argue therefore that AGN
feedback may be one of the critical processes to quench star formation in
massive galaxies in high density regions. We also find that the cluster has
experienced high star formation activities at rates comparable to that in the
field at z=1.46. In addition, a mass-metallicity relation exists in the cluster
at z=1.46, which is similar to that of star-forming galaxies in the field at
z~2. These results all suggest that at z~1.5 star formation activity in the
cluster core becomes as high as those in low density environments and there is
apparently not yet a strong environmental dependence, except for the red
emitters.Comment: 19 pages, 17 figures, 4 tables, accepted for publication in MNRA
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