598 research outputs found
CFD simulations of turbulent flows in a twin swirl combustor by RANS and hybrid RANS/LES methods
A confined isothermal flow in a Twin Swirl Combustor (TSC) was studied under both steady and transient conditions. The Reynolds Averaged Navier-Stokes (RANS) simulation was carried out to investigate the timeaveraged flow features in TSC under different ratios of the primary air flow rate to the secondary air flow rate. The steady-state velocity profiles inside the combustion chamber were analyzed using both Renormalized Group (RNG) k-Ξ΅ model and Shear Stress Transport (SST) turbulence model. For the transient conditions, the Scale Adaptive Simulation (SAS) method based on the SST model was used to probe the instantaneous three dimensional (3D) vortex structures to better understand the formation of the internal recirculation zone (IRZ). The existence of a pressing vortex cores (PVC) and a hurricane-shaped vortical structure in the TSC were captured by the SAS model. The SAS model can yield vortex-level results similar to large eddy simulation (LES) prediction while saves much more computational resource. This paper briefly reports some preliminary results of this study.Yinli Liu, Hao Tang, Zhaofeng Tian, Haifei Zhen
Expression of anion exchanger 2 in human gastric cancer
Anion exchanger 2 (AE2), which mediates exchange of Cl-/HCO3- across the plasma membrane, is widely expressed in body tissues. It is most abundantly expressed in stomach and is responsible for the uptake of Cl- ions that are destined to become HCl molecules. Aim: To determine whether AE2 expression was altered in gastric tumors. Methods: We have studied AE2 expression in normal human gastric tissues (n =16) and in gastric tumors (n = 33) using immunohistochemistry and immunofluorescent labeling. Results: In normal gastric tissue positive staining was observed in gastric fundus gland, suggesting parietal cell-related expression of AE2, and AE2 expression was localized in the nuclear membrane and even in cell nuclei. For assay of cancerous gastric tissues, specimens of human gastric cancer arising from the region of the fundus (2 cases), the body (14 cases) and the antrum (17 cases) were randomly selected. Immunohistochemical staining has showed that AE2 was down-regulated in all 14 cancerous gastric body specimens, whereas staining for AE2 in cancerous antrum was less intense and had a diffuse profile. Conclusions: The data suggest that AE2 might be associated with gastric carcinogenesis and the achlorhydria experienced by gastric cancer patients.ΠΠ½ΠΈΠΎΠ½Π½ΡΠΉ ΠΎΠ±ΠΌΠ΅Π½Π½ΠΈΠΊ 2 (ΠΠ2), ΠΊΠΎΡΠΎΡΡΠΉ ΠΎΠΏΠΎΡΡΠ΅Π΄ΡΠ΅Ρ ΠΏΠ΅ΡΠ΅Π½ΠΎΡ Cl-
/HCO3
-
ΡΠ΅ΡΠ΅Π· ΠΏΠ»Π°Π·ΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΡΡ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½Ρ, ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΡΡΠ΅ΡΡΡ
ΠΊΠ»Π΅ΡΠΊΠ°ΠΌΠΈ ΡΠ°Π·Π½ΡΡ
ΡΠΊΠ°Π½Π΅ΠΉ. Π‘Π°ΠΌΡΠΉ Π²ΡΡΠΎΠΊΠΈΠΉ ΡΡΠΎΠ²Π΅Π½Ρ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ ΠΠ2 Π² ΠΆΠ΅Π»ΡΠ΄ΠΊΠ΅, ΠΏΠΎΡΠΊΠΎΠ»ΡΠΊΡ ΡΡΠΎΡ Π±Π΅Π»ΠΎΠΊ ΠΎΡΠ²Π΅ΡΠ°Π΅Ρ Π·Π° ΠΏΠΎΠ³Π»ΠΎΡΠ΅Π½ΠΈΠ΅
ΠΈΠΎΠ½ΠΎΠ² Cl-
, ΠΊΠΎΡΠΎΡΡΠ΅ Π²ΠΏΠΎΡΠ»Π΅Π΄ΡΡΠ²ΠΈΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡΡΡ Π΄Π»Ρ ΡΠ΅ΠΊΡΠ΅ΡΠΈΠΈ HCl. Π¦Π΅Π»Ρ: ΠΠ·ΡΡΠΈΡΡ ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΡ Π² ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ ΠΠ2 ΠΏΡΠΈ ΡΠ°ΠΊΠ΅
ΠΆΠ΅Π»ΡΠ΄ΠΊΠ°. ΠΠ΅ΡΠΎΠ΄Ρ: ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½Π° ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΡ ΠΠ2 Π² Π½ΠΎΡΠΌΠ°Π»ΡΠ½ΡΡ
ΡΠΊΠ°Π½ΡΡ
(n = 16) ΠΈ ΠΎΠΏΡΡ
ΠΎΠ»ΡΡ
ΠΆΠ΅Π»ΡΠ΄ΠΊΠ° (n = 33) Ρ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ΠΌ
ΠΌΠ΅ΡΠΎΠ΄ΠΎΠ² ΠΈΠΌΠΌΡΠ½ΠΎΠ³ΠΈΡΡΠΎΡ
ΠΈΠΌΠΈΠΈ ΠΈ ΠΈΠΌΠΌΡΠ½ΠΎΡΠ»ΡΠΎΡΠ΅ΡΡΠ΅Π½ΡΠΈΠΈ. Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ: Π² Π½Π΅ΡΡΠ°Π½ΡΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ ΠΆΠ΅Π»ΡΠ΄ΠΊΠ° Π² ΡΡΠ½Π΄Π°Π»ΡΠ½ΠΎΠΉ
ΠΆΠ΅Π»Π΅Π·Π΅ Π²ΡΡΠ²Π»ΡΠ»ΠΈ ΡΠΈΠ»ΡΠ½ΡΡ ΠΏΠΎΠ»ΠΎΠΆΠΈΡΠ΅Π»ΡΠ½ΡΡ ΡΠ΅Π°ΠΊΡΠΈΡ, ΡΡΠΎ ΡΠ²ΠΈΠ΄Π΅ΡΠ΅Π»ΡΡΡΠ²ΡΠ΅Ρ ΠΎΠ± ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ ΠΠ2 ΠΏΠ°ΡΠΈΠ΅ΡΠ°Π»ΡΠ½ΡΠΌΠΈ ΠΊΠ»Π΅ΡΠΊΠ°ΠΌΠΈ,
ΠΏΡΠΈΡΠ΅ΠΌ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΡ ΠΠ2 Π±ΡΠ»Π° Π»ΠΎΠΊΠ°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π° Π² ΡΠ΄Π΅ΡΠ½ΠΎΠΉ ΠΌΠ΅ΠΌΠ±ΡΠ°Π½Π΅ ΠΈ Π² ΡΠ΄ΡΠ΅. Π ΠΎΠΏΡΡ
ΠΎΠ»ΡΡ
ΠΆΠ΅Π»ΡΠ΄ΠΊΠ° (ΡΡΠ½Π΄Π°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΎΡΠ΄Π΅Π»Π° (n =
2), ΡΠ΅Π»Π° (n = 14) ΠΈ Π°Π½ΡΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΎΡΠ΄Π΅Π»Π° (n = 17)), ΠΎΡΠΎΠ±ΡΠ°Π½Π½ΡΡ
ΡΠ»ΡΡΠ°ΠΉΠ½ΡΠΌ ΠΎΠ±ΡΠ°Π·ΠΎΠΌ, Π±ΡΠ» ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ Π°Π½Π°Π»ΠΈΠ· ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ ΠΠ2.
ΠΠΌΠΌΡΠ½ΠΎΠ³ΠΈΡΡΠΎΡ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΎ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΠ΅ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠΈ ΠΠ2 Π²ΠΎ Π²ΡΠ΅Ρ
14 ΡΠ»ΡΡΠ°ΡΡ
ΡΠ°ΠΊΠ° ΡΠ΅Π»Π° ΠΆΠ΅Π»ΡΠ΄ΠΊΠ°. ΠΠΊΡΠ°ΡΠΈΠ²Π°Π½ΠΈΠ΅
ΠΠ2 Π² ΠΎΠ±ΡΠ°Π·ΡΠ°Ρ
ΡΠ°ΠΊΠ° Π°Π½ΡΡΠ°Π»ΡΠ½ΠΎΠ³ΠΎ ΠΎΡΠ΄Π΅Π»Π° ΠΆΠ΅Π»ΡΠ΄ΠΊΠ° Π±ΡΠ»ΠΎ ΠΌΠ΅Π½Π΅Π΅ ΠΈΠ½ΡΠ΅Π½ΡΠΈΠ²Π½ΡΠΌ ΠΈ Π΄ΠΈΡΡΡΠ·Π½ΡΠΌ. ΠΡΠ²ΠΎΠ΄Ρ: ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅
Π΄Π°Π½Π½ΡΠ΅ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΡΡ ΠΏΡΠ΅Π΄ΠΏΠΎΠ»ΠΎΠΆΠΈΡΡ Π½Π°Π»ΠΈΡΠΈΠ΅ ΡΠ²ΡΠ·ΠΈ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠΊΡΠΏΡΠ΅ΡΡΠΈΠ΅ΠΉ ΠΠ2 ΠΈ ΡΠ°Π·Π²ΠΈΡΠΈΠ΅ΠΌ ΡΠ°ΠΊΠ° ΠΆΠ΅Π»ΡΠ΄ΠΊΠ°, Π° ΡΠ°ΠΊΠΆΠ΅ Π°Ρ
Π»ΠΎΡΠ³ΠΈΠ΄ΡΠΈΠ΅ΠΉ,
ΠΎΡΠΌΠ΅ΡΠ°Π΅ΠΌΠΎΠΉ Ρ Π±ΠΎΠ»ΡΠ½ΡΡ
ΡΠ°ΠΊΠΎΠΌ ΠΆΠ΅Π»ΡΠ΄ΠΊΠ°
Two-Hole and Four-Hole Bound States in a t-J Ladder at half-filling
The two-hole excitation spectrum of the t-J ladder at half-filling is studied
using linked-cluster series expansion methods. A rich spectrum of bound states
emerges, particularly at small . Their dispersion relations and coherence
lengths are computed, along with the threshold behaviour as the bound states
merge into the continuum. A class of 4-hole bound states is also studied,
leading to the conclusion that phase separation occurs for ,
in agreement with other studies.Comment: revtex
TEM Study on the Evolution of Ge Nanocrystals in Si Oxide Matrix as a Function of Ge Concentration and the Si Reduction Process
Growth and evolution of germanium (Ge) nanocrystals embedded into a silicon oxide (SiOβ) system have been studied based on the Ge content of co-sputtered Ge-SiOβ films using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy. It was found that when the proportion of Ge relative to Ge oxide is 20%, TEM showed that annealing the samples at 800Β°C for 60 min resulted in the formation of a denuded region between the silicon/silicon oxide (Si/SiOβ) interface and a band of Ge nanocrystals towards the surface of the film. By introducing a 20nm thick thermal oxide barrier on top of the silicon (Si) substrate on which the film is deposited, no denuded region in the bulk of this sample is observed. It is proposed that this barrier is effective in reducing both Ge diffusion into the Si substrate and Si diffusion from the substrate into the film. Si diffusing from the Si substrate reduces the Ge oxide into Ge which can subsequently diffuse into the Si substrate. However, the oxide barrier is able to confine the Ge within the oxide matrix so that the denuded region in the bulk of the film cannot form. However the reduction in diffusion should be more significant for Ge as its diffusion coefficient is lower than Si due to its larger size. It is suggested that the denuded region consists of amorphous Ge diffusing towards the Si/SiOβ interface. When the Ge content is increased to slightly more than 70%, TEM showed that Ge nanocrysyals formed after annealing at 800Β°C for only 30 min for samples with and without the oxide barrier. There is no denuded region between the Ge nanocrystals band and the Si/SiOβ interface for both samples but it was observed that coarsening effects were more prominent in the film deposited on top of the oxide barrier. The reduction effect of Si on Ge oxide should not play a significant role in these samples as the Ge content is high.Singapore-MIT Alliance (SMA
Zn and Fe concentration variations of grain and flag leaf and the Relationship with NAM-G1 Gene in Triticum timopheevii (Zhuk.) Zhuk. ssp. timopheevii
Grains of 12 accessions of Triticum timopheevii (Zhuk.) Zhuk. ssp. timopheevii (AAGG, 2n = 4x = 28) and one bread wheat cultivar Chinese Spring (CS) and one durum wheat cultivar Langdon (LDN) grown across two years were analyzed for grain iron (Fe) and zinc (Zn) concentrations. All the 12 tested T. timopheevii ssp. timopheevii genotypes showed significantly higher concentration of grain Fe and Zn than CS and LDN. Aboundant genetic variability of both the Fe and Zn concentrations was observed among the T. timopheevii ssp. timopheevii accessions, averagely varied from 47.06 to 90.26 mg kgβ1 and from 30.05 to 65.91 mg kgβ1, respectively. Their grain Fe and Zn concentrations between years exhibited a significantly positive correlation with the correlation coefficients r = 0.895 and r = 0.891, respectively, indicating the highly genetic stability. Flag leaf possessed twice or three times higher concentrations for both Fe and Zn than grain, and a significantly high positive correlation appeared between the two organs with r = 0.648 for Fe and r = 0.957 for Zn concentrations, respectively, suggesting flag leaves might be indirectly used for evaluating grain Zn and Fe contents. Significant correlations occurred between grain Fe and Zn concentrations, and between grain Zn concentration and the two agronomic traits of plant height and number of spikelets per spike. Both the concentrations were not related to seed size or weight as well as NAM-G1 gene, implying the higher grain Fe and Zn concentrations of T. timopheevii ssp. timopheevii species are not ascribed to concentration effects of seed and the genetic control of NAM-G1 gene. There might be some other biological factors impacting the grainβs Zn and Fe concentrations. These results indicated T. timopheevii ssp. timopheevii species might be a promising genetic resource with high Fe and Zn concentrations for the biofortification of current wheat cultivars
Characterization of starch synthetic genes and starch granule during seeds development between synthetic hexaploid wheat and its parents
To study the development of starch granules in polyploid wheats, we investigated the expression of starch synthetic genes between the synthetic hexaploid wheat SHW-L1, its parents T. turgidum AS2255 and diploid Ae. tauschii AS60. The synthetic hexaploid wheat SHW-L1 showed significantly higher starch content and grain weight than its parents. Scanning electron microscopy (SEM) showed that SHW-L1 rapidly developed starch granules than AS2255 and AS60. The amount of B-type granule in AS60 was less than that in SHW-L1 and AS2255. RT-qPCR result showed that the starch synthetic genes AGPLSU1, AGPLSU2, AGPSSU1, AGPSSU2, GBSSI, SSIII, PHO1 and PHO2 expressed at earlier stages with larger quantity in SHW-L1 than in its parents during wheat grain development. The expression of the above mentioned genes in AS60 was slower than in SHW-L1 and AS2255. The expression pattern of starch synthase genes was also associated with the grain weight and starch content in all three genotypes. The results suggested that the synthetic hexaploid wheat inherited the pattern of starch granule development and starch synthase gene expression from tetraploid parent. The results suggest that tetraploid wheat could plays more important role for starch quality improvement in hexaploid wheat
Molecular characterization of different Triticum monococcum ssp. monococcum Glu-A1<sup>m</sup>x alleles
High-molecular-weight glutenin subunits (HMW-GSs) are important seed storage proteins associated with bread-making quality in common wheat (Triticum aestivum L., 2n = 6x = 42, AABBDD). Variation in the Glu-A1x locus in common wheat is scare. Diploid Triticum monococcum ssp. monococcum (2n = 2x = 14, AmAm) is the first cultivated wheat. In the present study, allelic variations at the Glu-A1mx locus were systematically investigated in 197 T. monococcum ssp. monococcum accessions. Out of the 8 detected Glu-A1mx alleles, 5 were novel, including Glu-A1m-b, Glu-A1m-c, Glu-A1m-d, Glu-A1m-g, and Glu-A1m-h. This diversity is higher than that of common wheat. Compared with 1Ax1 and 1Ax2*, which are present in common wheat, these alleles contained three deletions/insertions as well as some single nucleotide polymorphism variations that might affect the elastic properties of wheat flour. New variations in T. monococcum probably occurred after the divergence between A and Am and are excluded in common wheat populations. These allelic variations could be used as novel resources to further improve wheat quality
Structure of Schlafen13 reveals a new class of tRNA/rRNA- targeting RNase engaged in translational control
Cleavage of transfer (t)RNA and ribosomal (r)RNA are critical and conserved steps of translational control for cells to overcome varied environmental stresses. However, enzymes that are responsible for this event have not been fully identified in high eukaryotes. Here, we report a mammalian tRNA/rRNA-targeting endoribonuclease: SLFN13, a member of the Schlafen family. Structural study reveals a unique pseudo-dimeric U-pillow-shaped architecture of the SLFN13 N'-domain that may clamp base-paired RNAs. SLFN13 is able to digest tRNAs and rRNAs in vitro, and the endonucleolytic cleavage dissevers 11 nucleotides from the 3'-terminus of tRNA at the acceptor stem. The cytoplasmically localised SLFN13 inhibits protein synthesis in 293T cells. Moreover, SLFN13 restricts HIV replication in a nucleolytic activity-dependent manner. According to these observations, we term SLFN13 RNase S13. Our study provides insights into the modulation of translational machinery in high eukaryotes, and sheds light on the functional mechanisms of the Schlafen family
Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-
We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi -->
D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7
J/Psi events collected with the BESII detector at the BEPC. No excess of signal
above background is observed, and 90% confidence level upper limits on the
branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi
--> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
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