► Facility scaled from ‘typical’ BWR fuel bundle. ► New data for local flow quantities in an 8×8 rod bundle. ► Data includes axial development of flow parameters. ► Data shows interfacial area ...concentration higher than in pipes and strong effect of length scales. ► Spacer grid effects require further study.
In order to accurately predict nuclear reactor behavior, the ability to predict the transfer of mass, momentum and energy between the phases in two-phase flows, whether in the Reactor Pressure Vessel (RPV) or steam generator, is essential. A significant component of this prediction is the area available for transfer per unit volume, called the interfacial area concentration. Current thermal-hydraulic system analysis code predictions use empirical models to predict the interfacial area concentration; however accuracy and reliability can be improved through the use of an Interfacial Area Transport Equation (IATE). The IATE requires rigorously developed models for sources and sinks due to bubble interactions or phase change and an extensive database to validate those models. To provide this database, experiments using electrical conductivity probes to measure the interfacial area concentration at several axial positions have been performed in an 8×8 rod bundle which was carefully scaled from an actual BWR rod bundle.
Transitional circumstellar disks around young stellar objects have a distinctive infrared deficit around 10 mu m in their spectral energy distributions, recently measured by the Spitzer Infrared ...Spectrograph (IRS), suggesting dust depletion in the inner regions. These disks have been confirmed to have giant central cavities by imaging of the submillimeter continuum emission using the Submillimeter Array (SMA). However, the polarized near-infrared scattered light images for most objects in a systematic IRS/SMA cross sample, obtained by HiCIAO on the Subaru telescope, show no evidence for the cavity, in clear contrast with SMA and Spitzer observations. Radiative transfer modeling indicates that many of these scattered light images are consistent with a smooth spatial distribution for mu m-sized grains, with little discontinuity in the surface density of the mu m-sized grains at the cavity edge. Here we present a generic disk model that can simultaneously account for the general features in IRS, SMA, and Subaru observations. Particularly, the scattered light images for this model are computed, which agree with the general trend seen in Subaru data. Decoupling between the spatial distributions of the mu m-sized dust and mm-sized dust inside the cavity is suggested by the model, which, if confirmed, necessitates a mechanism, such as dust filtration, for differentiating the small and big dust in the cavity clearing process. Our model also suggests an inwardly increasing gas-to-dust ratio in the inner disk, and different spatial distributions for the small dust inside and outside the cavity, echoing the predictions in grain coagulation and growth models.
In relation to the development of the interfacial area transport equation, the sink and source terms in an adiabatic bubbly flow system were modeled based on the mechanisms of bubble–bubble and ...bubble–turbulent eddy random collisions, respectively. The interfacial area transport mechanism was discussed based on the derived model. One-dimensional interfacial area transport equation with the derived sink and source terms was evaluated by using the area averaged flow parameters of adiabatic air–water bubbly flows measured in 25.4 mm and 50.8 mm diameter tubes. The flow conditions of the data set covered most of the bubbly flow regime, including finely dispersed bubbly flow (inlet superficial gas velocity: 0.0414–3.90 m/s, superficial liquid velocity: 0.262–5.00 m/s, void fraction: 1.27–46.8%). Excellent agreement was obtained between modeled and measured interfacial area concentrations within the average relative deviation of 11.6%. It was recognized that the present model would be promising for the interfacial area transport of the examined bubbly flows.
A major polyphenol of green tea, epigallocatechin-3-gallate (EGCG), has previously been shown to induce cell-cycle arrest and apoptosis in various cancers. However, little is known about its effects ...on hepatocellular carcinomas (HCCs).
Four HCC cell lines, HLE, HepG2, HuH-7 and PLC/PRF/5, were treated with EGCG or vehicle. Cell viability was assessed by trypan blue staining and WST-8 assay. Cell-cycle, apoptosis and apoptosis-related proteins in HLE cells were evaluated by flow cytometry and Western blotting. The effect of EGCG was also studied in vivo using a xenograft model. The effect of co-treatment with EGCG and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was also assessed.
EGCG inhibited the growth of all HCC cell lines at concentrations of 50–100
μg/ml. In HLE cells, EGCG induced apoptosis but not cell-cycle arrest and appears to have down-regulated Bcl-2α and Bcl-xl by inactivation of NF-κB. Oral administration of EGCG showed similar effects in HLE xenograft tumors. Co-treatment with EGCG and TRAIL synergistically induced apoptosis in HLE cells.
EGCG induced apoptosis in HLE cells, both in vitro and in vivo. Moreover, it enhanced TRAIL-induced apoptosis. Therefore, EGCG treatment may be useful for improving the prognosis of HCCs.
The formation scenario of a gapped disk, i.e., transitional disk, and its asymmetry is still under debate. Proposed scenarios such as disk-planet interaction, photoevaporation, grain growth, ...anticyclonic vortex, eccentricity, and their combinations would result in different radial distributions of the gas and the small (sub-μm size) and large (millimeter size) dust grains as well as asymmetric structures in a disk. Optical/near-infrared (NIR) imaging observations and (sub-)millimeter interferometry can trace small and large dust grains, respectively; therefore multi-wavelength observations could help elucidate the origin of complicated structures of a disk. Here we report Submillimeter Array observations of the dust continuum at 1.3 mm and {sup 12}CO J = 2 → 1 line emission of the pre-transitional protoplanetary disk around the solar-mass star PDS 70. PDS 70, a weak-lined T Tauri star, exhibits a gap in the scattered light from its disk with a radius of ∼65 AU at NIR wavelengths. However, we found a larger gap in the disk with a radius of ∼80 AU at 1.3 mm. Emission from all three disk components (the gas and the small and large dust grains) in images exhibits a deficit in brightness in the central region of the disk, in particular, the dust disk in small and large dust grains has asymmetric brightness. The contrast ratio of the flux density in the dust continuum between the peak position to the opposite side of the disk reaches 1.4. We suggest the asymmetries and different gap radii of the disk around PDS 70 are potentially formed by several (unseen) accreting planets inducing dust filtration.
Measurements of two-phase flow parameters such as void-fraction, bubble velocities, and interfacial area density have been performed in an upwards air–water flow at atmospheric pressure by means of a ...four-tip needle-probe and a wire-mesh sensor. For the first time, a direct comparison between the two measuring techniques has been carried out. Both techniques are based on the measurement of the fluid conductivity. For void-fraction and velocity measurements, similarity exists between the two methodologies for signal analysis. A significantly different approach is followed, instead, for the estimation of the interfacial area concentration: while the evaluation based on the needle-probe signal is carried out by using projections of the gas–liquid interface velocity, the evaluation based on the wire-mesh signals consist in a full reconstruction of the bubbles interfaces. The comparison between the two techniques shows a good agreement.
► Models developed to predict interfacial area change in large diameter pipes. ► Mechanistic models based on bubble breakup and coalescence mechanisms. ► These models have been benchmarked against ...data from pipes of various diameters. ► Models perform very well for bubbly and cap-bubbly flows.
Flow in large pipes is important in a wide variety of applications. In the nuclear industry in particular, understanding of flow in large diameter pipes is essential in predicting the behavior of reactor systems. This is especially true of natural circulation Boiling Water Reactor (BWR) designs, where a large-diameter chimney above the core provides the gravity head to drive circulation of the coolant through the reactor. The behavior of such reactors during transients and during normal operation will be predicted using advanced thermal-hydraulics analysis codes utilizing the two-fluid model. Essential to accurate two-fluid model calculations is reliable and accurate computation of the interfacial transfer terms. These interfacial transfer terms can be expressed as the product of one term describing the potential driving the transfer and a second term describing the available surface area for transfer, or interfacial area concentration. Currently, the interfacial area is predicted using flow regime-dependent semi-empirical correlations; however the interfacial area concentration is best computed through the use of the one-dimensional interfacial area transport equation (IATE). To be useful in practical applications the IATE requires mechanistic models for the change in interfacial area concentration due to interactions between bubbles. Therefore using previously collected data and proper scaling methods, current models for bubble interactions for the IATE are briefly discussed and new models applicable to large pipes are developed and compared with the existing data.
The spring-type near isogenic line (NIL) of the winter-type barley (Hordeum vulgare ssp. vulgare) var. Hayakiso 2 (HK2) was developed by introducing VERNALIZATION-H1 (Vrn-H1) for spring growth habit ...from the spring-type var. Indo Omugi. Contrary to expectations, the spring-type NIL flowered later than winter-type HK2. This phenotypic difference was controlled by a single gene, which cosegregated only with phytochrome C (HvPhyC) among three candidates around the Vrn-H1 region (Vrn-H1, HvPhyC, and CASEIN KINASE IIα), indicating that HvPhyC was the most likely candidate gene. Compared with the late-flowering allele HvPhyC-l from the NIL, the early-flowering allele HvPhyC-e from HK2 had a single nucleotide polymorphism T1139C in exon 1, which caused a nonsynonymous amino acid substitution of phenylalanine at position 380 by serine in the functionally essential GAF (3′, 5′-cyclic-GMP phosphodiesterase, adenylate cyclase, formate hydrogen lyase activator protein) domain. Functional assay using a rice (Oryza sativa) phyA phyC double mutant line showed that both of the HvPhyC alleles are functional, but HvPhyC-e may have a hyperfunction. Expression analysis using NILs carrying HvPhyC-e and HvPhyC-l (NIL HvPhyC-e and NIL HvPhyC-l, respectively) showed that HvPhyC-e up-regulated only the flowering promoter FLOWERING LOCUS T1 by bypassing the circadian clock genes and flowering integrator CONSTANS1 under a long photoperiod. Consistent with the up-regulation, NIL (HvPhyC-e) flowered earlier than NIL (HvPhyC-l) under long photoperiods. These results implied that HvPhyC is a key factor to control long-day flowering directly.
Chromosome 5p partial monosomy (5p-syndrome) and chromosome 6p partial trisomy are chromosomal abnormalities that result in a variety of symptoms, but liver dysfunction is not normally one of them. ...Alagille syndrome (OMIM #118450) is a multisystem disorder that is defined clinically by hepatic bile duct paucity and cholestasis, in association with cardiac, skeletal, and ophthalmologic manifestations, and characteristic facial features. Alagille syndrome is caused by mutations in JAG1 on chromosome 20 or NOTCH2 on chromosome 1. Here, we report a preterm infant with karyotype 46,XX,der(5)t(5,6)(p15.2;p22.3) and hepatic dysfunction, who was diagnosed as having incomplete Alagille syndrome.
The Japanese infant was diagnosed based on the cardiac abnormalities, ocular abnormalities, characteristic facial features, and liver pathological findings. Analysis of the JAG1 and NOTCH sequences failed to detect any mutations in these genes.
These results suggest that, besides the genes that are known to be responsible for Alagille syndrome, other genetic mutations also may cause Alagille syndrome.
The properties of the T8.5p dwarf Ross 458C Burningham, Ben; Leggett, S. K.; Homeier, D. ...
Monthly notices of the Royal Astronomical Society,
07/2011, Letnik:
414, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We present near-infrared photometry and spectroscopy, and warm-Spitzer IRAC photometry of the young very cool T dwarf Ross 458C, which we have typed as T8.5p. By applying the fiducial age constraints ...(≤1 Gyr) imposed by the properties of the active M dwarf Ross 458A, we have used these data to determine that Ross 458C has T
eff= 695 ± 60 K, log g= 4.0-4.7 and an inferred mass of 5-20M
J. We have compared fits of the near-infrared spectrum and IRAC photometry to the BT Settl and Saumon & Marley model grids, and have found that both sets provide best fits that are consistent with our derived properties, whilst the former provide a marginally closer match to the data for all scenarios explored here. The main difference between the model grids arises in the 4.5-μm region, where the BT Settl models are able to better predict the flux through the IRAC filter, suggesting that non-equilibrium effects on the CO-CO2 ratio are important for shaping the mid-infrared spectra of very cool T dwarfs. We have also revisited the issue of the dust opacity in the spectra of Ross 458C that was raised by Burgasser et al. We have found that the BT Settl models which also incorporate a condensate cloud model provide a better match to the near-infrared spectrum of this target than the Saumon & Marley model with f
sed= 2 and we briefly discuss the influence of condensate clouds on T dwarf spectra.
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