The discovery of a low-mass star with such a low metallicity as < or =, slant4.5 x 10 super(-5) Z sub(middot in circle) reveals the critical role of dust in the formation of extremely metal-poor ...stars. In this Letter, we explore the effect of the growth of dust grains through accretion of gaseous refractory elements in very low metallicity pre-stellar cores on cloud fragmentation induced by dust emission cooling. Employing a simple model of grain growth in a gravitationally collapsing gas, we show that Fe and Si grains can grow efficiently at hydrogen densities of Asymptotically = to10 super(10)-10 super(14) cm super(-3) in the clouds with metal abundances of -5 <, ~ Fe, Si/H <, ~ -3. The critical metal number abundances, above which the grain growth could induce the fragmentation of the gas clouds, are estimated to be A sub(crit) Asymptotically = to 10 super(-9)-10 super(-8), unless the initial grain radius is too large (> ~1 mu m) or the sticking probability is too small (<, ~0.01). We find that even if the initial dust-to-gas mass ratio is well below the minimum value required for the dust-induced fragmentation, the grain growth increases the dust mass high enough to cause the gas to fragment into sub-solar mass clumps. We suggest that as long as the critical metal abundance is satisfied, grain growth could play an important role in the formation of low-mass stars with metallicity as low as 10 super(-5) Z sub(middot in circle).
The optimum retreatment strategy for chronic hepatitis C virus (HCV) patients who failed directly-acting antiviral agents (DAA)-based therapy is unknown. We herein report the outcomes of an HCV ...genotype (GT) 2a-infected patient with virologic failure following treatment with sofosbuvir plus ribavirin (SOF+RBV) who was successfully retreated with ombitasvir/paritaprevir/ritonavir plus ribavirin (OBV/PTV/r+RBV).
Sex chromosome dosage compensation (DC) is widely accepted in various organisms. This concept is mostly supported by comparisons of gene expression between chromosomes and between sexes. However, ...genes on the X chromosome and autosomes are mostly not homologous, and the average gene expression level on these chromosomes may not be the same even under DC, which complicates comparisons between chromosomes. Many genes with sex-biased expression also make comparisons between sexes difficult. To overcome these issues, we investigated DC by comparing the expression of neo-X-linked genes in Drosophila pseudoobscura with those of their autosomal orthologs in other Drosophila species. The ratio of the former to the latter in males would be 1 under DC, whereas it becomes 0.5 without DC. We found that the ratio was ∼0.85 for adult whole bodies, indicating that the DC is incomplete on the neo-X chromosome in adults as a whole. The ratio (∼0.90) was also significantly less than 1 for adult bodies without gonads, whereas it was ∼1.0 for adult heads. These results indicate that DC varies among tissues. Our sliding-window analysis of the ratio also revealed that the upregulation of neo-X-linked genes in males occurred chromosome wide in all tissues analyzed, indicating global upregulation mechanisms. However, we found that gene functions also affected the levels of DC. Furthermore, most of the genes recently moved to the X were already under DC at the larval stage but not at the adult stage. These results suggest that DC in Drosophila species operates in a tissue/stage-dependent manner.
Endosymbiosis is an important evolutionary event for organisms, and there is widespread interest in understanding the evolution of endosymbiosis establishment. Hydra is one of the most suitable ...organisms for studying the evolution of endosymbiosis. Within the genus Hydra, H. viridissima and H. vulgaris show endosymbiosis with green algae. Previous studies suggested that the endosymbiosis in H. vulgaris took place much more recently than that in H. viridissima, noting that the establishment of the interaction between H. vulgaris and its algae is not as stable as in H. viridissima. To investigate the on-going process of endosymbiosis, we first compared growth and tolerance to starvation in symbiotic and aposymbiotic polyps of both species. The results revealed that symbiotic H. viridissima had a higher growth rate and greater tolerance to starvation than aposymbiotic polyps. By contrast, growth of symbiotic H. vulgaris was identical to that of aposymbiotic polyps, and symbiotic H. vulgaris was less tolerant to starvation. Moreover, our gene expression analysis showed a pattern of differential gene expression in H. viridissima similar to that in other endosymbiotically established organisms, and contrary to that observed in H. vulgaris We also showed that H. viridissima could cope with oxidative stress that caused damage, such as cell death, in H. vulgaris These observations support the idea that oxidative stress related genes play an important role in the on-going process of endosymbiosis evolution. The different evolutionary stages of endosymbiosis studied here provide a deeper insight into the evolutionary processes occurring toward a stable endosymbiosis.
Calnexin (CANX) and calreticulin (CALR) chaperones mediate nascent glycoprotein folding in the endoplasmic reticulum. Here we report that these chaperones have distinct roles in male and female ...fertility. Canx null mice are growth retarded but fertile. Calr null mice die during embryonic development, rendering indeterminate any effect on reproduction. Therefore, we conditionally ablated Calr in male and female germ cells using Stra8 (mcKO) and Zp3 (fcKO) promoter-driven Cre recombinase, respectively. Calr mcKO male mice were fertile, but fcKO female mice were sterile despite normal mating behavior. Strikingly, we found that Calr fcKO female mice had impaired folliculogenesis and decreased ovulatory rates due to defective proliferation of cuboidal granulosa cells. Oocyte-derived, TGF-beta family proteins play a major role in follicular development and molecular analysis revealed that the normal processing of GDF9 and BMP15 was defective in Calr fcKO oocytes. These findings highlight the importance of CALR in female reproduction and demonstrate that compromised CALR function leads to ovarian insufficiency and female infertility.
Dust grains can be efficiently accelerated and shattered in a warm ionized medium (WIM) because of the turbulent motion. This effect is enhanced in starburst galaxies, where gas is ionized and ...turbulence is sustained by massive stars. Moreover, dust production by Type II supernovae (SNe II) can be efficient in starburst galaxies. In this paper, we examine the effect of shattering in a WIM on the dust grains produced by SNe II. We find that, although the grains ejected from SNe II are expected to be biased to large sizes (a≳ 0.1 μ m, where a is the grain radius), because of the shock destruction in supernova remnants the shattering in a WIM is efficient enough in ∼5 Myr to produce small grains if the metallicity is nearly solar or more. The production of small grains by shattering steepens the extinction curve. Thus, the steepening of extinction curves by shattering should always be taken into account for systems in which the metallicity is solar and the starburst age is typically greater than 5 Myr. These conditions may be satisfied not only in nearby starburst galaxies but also in high-redshift (z > 5) quasars.
In this research，examines the possibility of land use control used in conjunction with Location Optimization Plan (LOP) to reduce sprawl in Loose Regulation Area(LRA), based on an understanding of ...the reality of suburbanization in Non Area-divided Cities.The method of this research is to conduct a questionnaire survey of Non Area-divided Cities created and published as of May 2019 to understand their attitudes toward the use of LOP and other factors, and then analyze cities that have land use control in their LRA, (including an analysis of population change from 1995 to 2015 for residential guide area acreage and City Planning Area, Zoning Area, LRA, and DAA using GIS), especially those cities that are considered to have land use control with the intention of discouraging sprawl-like development.As a result, the following points became clear.With the exception of a few cities, the majority of cities have not reviewed their land use planning systems in conjunction with the preparation of LOP, and LRA tended to make little use of land use control methods and had weak recognition, while aiming to maintain the status quo of their living environment.Population trends reveal that suburbanization is still in progress, with the majority of cities in the LRA having higher population ratios, and the lack of control of sprawl through land use control methods in the LRA is thought to be a factor in the progress of suburbanization.On the other hand, in some cities, land use control methods have been developed in conjunction with the LOP, such as the Dwelling Control Area to prevent the conversion of land into residential land in the LRA, strengthening the regulations in the Specific Usage Limitation Area, and clarifying the existing regulatory basis through the city’s own ordinances.Based on the above, we believe that the preparation of a LOP in Non Area-divided Cities is a potential anti-sprawl measure for1.The LOP should be used as an opportunity to clarify the issues of urban change and the direction of guidance, and the corresponding land use control system should be introduced.2.Strengthen the rationality of the traditional method of maintaining land use order by establishing DAA.In Non Area-divided Cities, it is difficult to define the nature of land use in LRA, and there are many cities where the population has become more dispersed.Even though there is a concern about population outflow to LRA and sprawl due to residential development, we have to be cautious about land use control, but we should take the preparation of the LOP as an opportunity to strengthen the regulation and consider the use of land use control methods.
The circumstellar (CS) environment is key to understanding progenitors of Type Ia supernovae (SNe Ia), as well as the origin of a peculiar extinction property towards SNe Ia for cosmological ...application. It has been suggested that multiple scatterings of SN photons by CS dust may explain the non-standard reddening law. In this paper, we examine the effect of re-emission of SN photons by CS dust in the infrared (IR) wavelength regime. This effect allows the observed IR light curves to be used as a constraint on the position/size and the amount of CS dust. The method was applied to observed near-infrared (NIR) SN Ia samples; meaningful upper limits on the CS dust mass were derived even under conservative assumptions. We thereby clarify a difficulty associated with the CS dust-scattering model as a general explanation for the peculiar reddening law, while it may still apply to a sub-sample of highly reddened SNe Ia. For SNe Ia in general, the environment at the interstellar scale appears to be responsible for the non-standard extinction law. Furthermore, deeper limits can be obtained using the standard nature of SN Ia NIR light curves. In this application, an upper limit of
$\dot{M} \lesssim 10^{-8}{-}10^{-7} \,\mathrm{M}_{{\odot }}$
yr−1 (for the wind velocity of ∼10 km s−1) is obtained for a mass-loss rate from a progenitor up to ∼0.01 pc, and
$\dot{M} \lesssim 10^{-7}{-}10^{-6} \,\mathrm{M}_{{\odot }}$
yr−1 up to ∼0.1 pc.
Resveratrol (RSV) has recently attracted keen interest because of its pleiotropic effects. It exerts a wide range of health-promoting effects. In addition to health-promoting effects, RSV possesses ...anti-carcinogenic activity. However, a non-physiological concentration is needed to achieve an anti-cancer effect, and its
bioavailability is low. Therefore, the clinical application of phytochemicals requires alternative candidates that induce the desired effects at a lower concentration and with increased bioavailability. We previously reported a low IC
of vaticanol C (VTC), an RSV tetramer, among 12 RSV derivatives (Ito T. et al, 2003). However, the precise mechanism involved remains to be determined. Here, we screened an in-house chemical library bearing RSV building blocks ranging from dimers to octamers for cytotoxic effects in several leukemia and cancer cell lines and their anti-cancer drug-resistant sublines. Among the compounds, VTC exhibited the highest cytotoxicity, which was partially inhibited by a caspase 3 inhibitor, Z-VAD-FMK. VTC decreased the expression of sphingosine kinase 1, sphingosine kinase 2 and glucosylceramide synthase by transcriptional or post-transcriptional mechanisms, and increased cellular ceramides/dihydroceramides and decreased sphingosine 1-phosphate (S1P). VTC-induced sphingolipid rheostat modulation (the ratio of ceramide/S1P) is thought to be involved in cellular apoptosis. Indeed, exogenous S1P addition modulated VTC cytotoxicity significantly. A combination of SPHK1, SPHK2, and GCS chemical inhibitors induced sphingolipid rheostat modulation, cell growth suppression, and cytotoxicity similar to that of VTC. These results suggest the involvement of sphingolipid metabolism in VTC-induced cytotoxicity, and indicate VTC is a promising prototype for translational research.
This article presents a pulse-amplitude modulation (PAM)-4-based 25.6-Gb/s serial interface for high-bandwidth (BW) and large-capacity storage systems consisting of NAND flash memory. A conventional ...interface with multi-drop bus topology between the NAND flash memories and their controller has an inevitable tradeoff between BW and capacity if we assume a reasonable PCB design in which the numbers of pins and wires near the NAND controller is limited. Although a daisy-chain-based interface can resolve this tradeoff, it requires the additional overheads of bridge chips and procedures for distinguishing between bridge chips. In order to address these challenges, this article presents three key techniques: 1) ring topology; 2) PAM-4-based four-channel multiplexing; and 3) cascaded clock and data recovery (CDR) circuits with phase-error-dependent bang-bang phase detector (PED-BBPD). The fabricated transceiver for the proposed interface using a 28-nm CMOS process achieves energy efficiency of 3.69 pJ/b at 25.6-Gb/s PRBS31 with a bit error rate (BER) of less than <inline-formula> <tex-math notation="LaTeX">10^{-15} </tex-math></inline-formula> through a short channel with 1.84-dB loss. The proposed interface mitigates the overhead of the bridge chips with higher data rate than previous works, and it can achieve a state-of-the-art figure of merit of 1.80 PKG Gb/s/mW, defined as "No. of NAND packages (PKGs) <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> data rate/power consumption," with a controller and four bridge chips.
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