596 research outputs found
Proto-clusters in the Lambda CDM Universe
We compare the highly clustered populations of very high redshift galaxies
with proto-clusters identified numerically in a standard CDM universe
() simulation. We evolve 256^3 dark matter
particles in a comoving box of side 150h^{-1}Mpc. By the present day there are
63 cluster sized objects of mass in excess of 10^{14}h^{-1}Mo in this box. We
trace these clusters back to higher redshift finding that their progenitors at
z=4--5 are extended regions of typically 20--40 Mpc (comoving) in size, with
dark halos of mass in excess of 10^{12}h^{-1}Mo and are overdense by typically
1.3--13 times the cosmological mean density. Comparison with the observation of
Lyman alpha emitting (LAEs) galaxies at z=4.86 and at z=4.1 indicates that the
observed excess clustering is consistent with that expected for a proto-cluster
region if LAEs typically correspond to massive dark halos of more than
10^{12}h^{-1}Mo. We give a brief discussion on the relation between high
redshift concentration of massive dark halos and present day rich clusters of
galaxies.Comment: 4 pages, 5 figures, Accepted for publication in ApJ Letter
Structure based development of novel specific inhibitors for cathepsin L and cathepsin S in vitro and in vivo
AbstractSpecific inhibitors for cathepsin L and cathepsin S have been developed with the help of computer-graphic modeling based on the stereo-structure. The common fragment, N-(L-trans-carbamoyloxyrane-2-carbonyl)-phenylalanine-dimethylamide, is required for specific inhibition of cathepsin L. Seven novel inhibitors of the cathepsin L inhibitor Katunuma (CLIK) specifically inhibited cathepsin L at a concentration of 10−7 M in vitro, while almost no inhibition of cathepsins B, C, S and K was observed. Four of the CLIKs are stable, and showed highly selective inhibition for hepatic cathepsin L in vivo. One of the CLIK inhibitors contains an aldehyde group, and specifically inhibits cathepsin S at 10−7 M in vitro
Dust Destruction in the High-Velocity Shocks Driven by Supernovae in the Early Universe
We investigate the destruction of dust grains by sputtering in the
high-velocity interstellar shocks driven by supernovae (SNe) in the early
universe to reveal the dependence of the time-scale of dust destruction on the
gas density in the interstellar medium (ISM) as well as on the
progenitor mass and explosion energy of SN. The
sputtering yields for the combinations of dust and ion species of interest to
us are evaluated by applying the so-called universal relation with a slight
modification. The dynamics of dust grains and their destruction by sputtering
in shock are calculated by taking into account the size distribution of each
dust species, together with the time evolution of temperature and density of
gas in spherically symmetric shocks. The results of calculations show that the
efficiency of dust destruction depends not only on the sputtering yield but
also on the initial size distribution of each grain species. The efficiency of
dust destruction increases with increasing and/or increasing
, but is almost independent of as long as is the same. The mass of gas swept up by shock is the increasing function
of and the decreasing function of . Combining
these results, we present the approximation formula for the time-scale of
destruction for each grain species in the early universe as a function of
and . This formula is applicable for investigating
the evolution of dust grains at the early epoch of the universe with the
metallicity of Z \la 10^{-3} . The effects of the cooling processes
of gas on the destruction of dust are briefly discussed.Comment: 49 pages including 7 tables and 25 figures, accepted for publication
in Ap
The amphioxus genome and the evolution of the chordate karyotype
Lancelets ('amphioxus') are the modern survivors of an ancient chordate lineage, with a fossil record dating back to the Cambrian period. Here we describe the structure and gene content of the highly polymorphic approx520-megabase genome of the Florida lancelet Branchiostoma floridae, and analyse it in the context of chordate evolution. Whole-genome comparisons illuminate the murky relationships among the three chordate groups (tunicates, lancelets and vertebrates), and allow not only reconstruction of the gene complement of the last common chordate ancestor but also partial reconstruction of its genomic organization, as well as a description of two genome-wide duplications and subsequent reorganizations in the vertebrate lineage. These genome-scale events shaped the vertebrate genome and provided additional genetic variation for exploitation during vertebrate evolution
Clinical efficacy and safety of monthly oral ibandronate 100 mg versus monthly intravenous ibandronate 1 mg in Japanese patients with primary osteoporosis
Summary: The MOVEST study evaluated the efficacy and safety of monthly oral ibandronate versus licensed monthly IV ibandronate in Japanese osteoporotic patients. Relative BMD gains after 12 months were 5.22 % oral and 5.34 % IV, showing non-inferiority of oral to IV ibandronate (primary endpoint). No new safety concerns were identified. Introduction: The randomized, phase 3, double-blind MOVEST (Monthly Oral VErsus intravenouS ibandronaTe) study evaluated the efficacy and safety of monthly oral ibandronate versus the licensed monthly intravenous (IV) ibandronate regimen in Japanese patients with osteoporosis. Methods: Ambulatory patients aged ?55 years with primary osteoporosis were randomized to receive oral ibandronate 100 mg/month plus monthly IV placebo, or IV ibandronate 1 mg/month plus monthly oral placebo. The primary endpoint was non-inferiority of oral versus IV ibandronate with respect to bone mineral density (BMD) gains at the lumbar spine after 12 months of treatment. Results: Four hundred twenty-two patients were enrolled with 372 patients in the per-protocol set (183 and 189 in the oral and IV ibandronate groups, respectively). The relative change from baseline in lumbar spine BMD values for the oral and IV ibandronate groups, respectively, was 5.22 % (95 % confidence interval [CI] 4.65, 5.80) and 5.34 % (95 % CI 4.78, 5.90). The least squares mean difference between the two groups was ?0.23 % (95 % CI ?0.97, 0.51), showing non-inferiority of oral ibandronate to IV ibandronate (non-inferiority limit = ?1.60). Changes in BMD values at other sites, and bone turnover marker levels in the oral ibandronate group, were comparable with those of the IV group. The safety profile was similar to that previously demonstrated; no new safety concerns were identified. Conclusions: This study demonstrated the non-inferiority of oral ibandronate 100 mg/month to IV ibandronate 1 mg/month (licensed dose in Japan) in increasing lumbar spine BMD in Japanese patients with primary osteoporosis
Genome sequence of an Australian kangaroo, Macropus eugenii, provides insight into the evolution of mammalian reproduction and development.
BACKGROUND: We present the genome sequence of the tammar wallaby, Macropus eugenii, which is a member of the kangaroo family and the first representative of the iconic hopping mammals that symbolize Australia to be sequenced. The tammar has many unusual biological characteristics, including the longest period of embryonic diapause of any mammal, extremely synchronized seasonal breeding and prolonged and sophisticated lactation within a well-defined pouch. Like other marsupials, it gives birth to highly altricial young, and has a small number of very large chromosomes, making it a valuable model for genomics, reproduction and development. RESULTS: The genome has been sequenced to 2 × coverage using Sanger sequencing, enhanced with additional next generation sequencing and the integration of extensive physical and linkage maps to build the genome assembly. We also sequenced the tammar transcriptome across many tissues and developmental time points. Our analyses of these data shed light on mammalian reproduction, development and genome evolution: there is innovation in reproductive and lactational genes, rapid evolution of germ cell genes, and incomplete, locus-specific X inactivation. We also observe novel retrotransposons and a highly rearranged major histocompatibility complex, with many class I genes located outside the complex. Novel microRNAs in the tammar HOX clusters uncover new potential mammalian HOX regulatory elements. CONCLUSIONS: Analyses of these resources enhance our understanding of marsupial gene evolution, identify marsupial-specific conserved non-coding elements and critical genes across a range of biological systems, including reproduction, development and immunity, and provide new insight into marsupial and mammalian biology and genome evolution
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