4,900 research outputs found

    Bimodality in low-luminosity E and S0 galaxies

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    Stellar population characteristics are presented for a sample of low-luminosity early-type galaxies (LLEs) in order to compare them with their more luminous counterparts. Long-slit spectra of a sample of 10 LLEs were taken with the ESO New Technology Telescope, selected for their low luminosities. Line strengths were measured on the Lick standard system. Lick indices for these LLEs were correlated with velocity dispersion (σ), alongside published data for a variety of Hubble types. The LLEs were found to fall below an extrapolation of the correlation for luminous ellipticals and were consistent with the locations of spiral bulges in plots of line strengths versus σ. Luminosity weighted average ages, metallicities and abundance ratios were estimated from χ2 fitting of 19 Lick indices to predictions from simple stellar population models. The LLEs appear younger than luminous ellipticals and of comparable ages to spiral bulges. These LLEs show a bimodal metallicity distribution, consisting of a low-metallicity group (possibly misclassified dwarf spheroidal galaxies) and a high-metallicity group (similar to spiral bulges). Finally, they have low α-element to iron peak abundance ratios indicative of slow, extended star formation

    Genetic variations between two ecotypes of Egyptian clover by inter-simple sequence repeat (ISSR) techniques

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    The inter-simple sequence repeat (ISSR) markers have been used in order to determine genetic variation and relationship between two clover ecotypes. Ten (10) primers for ISSR were used in this study but only six were successful in generating reproducible and reliable amplicons for different types of the Egyptian clover. The results reveal the polymorphism level by ISSR primers. HB10 ISSR-primer was higher than the rest of the ISSR primers in polymorphic 100%. The Fahl monocut ecotype had 29 present bands, 3 absent bands in total of 32 bands; among those there were two unique bands. The multicut ecotype were given different pattern of bands, Gemmiza1 (21 present and 11 absent), Giza6 (21 present and 11 absent) and Serw1; (23 present and 9 absent). There were three unique bands appearance in the two ecotypes. Fahl was given two with HB11 and HB13; the Serw1 multicut cultivar had one unique bands with HB08. Similarity indices among the four Egyptian clover cultivars based on ISSR analysis was estimated and the highest value appeared between Fahl and Gemmiza1 as well as Giza6 and Serw1 followed by Fahl and Serw1. The lowest similarity value appeared between Gemmiza1 and Serw1 followed by Gemmiza1 and Giza6.Key words: Egyptian clover, molecular marker, Fahl, Gemmiza1, Giza6, Serw1

    Evaluation of in vitro and in vivo Cytotoxic Activities and Kinase Inhibition of Newly Synthesized Cyclo (Nα-Dinicotinoyl)-Bis-[(L-Valinyl)-L-Lysine Methyl Ester]

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    222-225Cancer is a major risk disease affecting human survival. The pharmaceutical companies are continuing searching for new drug candidates with promising anticancer activities, and reduced side effects. The current work aimed at synthesized a new tripeptide with potential pharmacological properties. L-Valine methyl ester was used to prepare cyclo (Nα-dinicotinoyl)-bis-[(L-valinyl)-L-lysine methyl ester. The new compound revealed promising in vitro cytotoxic activities against different neuroblastoma, cervical carcinoma, fibrosarcoma as well as hepatocellular carcinomas. Furthermore, we also found that the obtained IC50 of the compound decreased by about 50% during its in vivo anti-prostate cancer evaluation. Furthermore, the mechanism of action studies proposes that the new prepared derivative affects cancer cells trough the inhibition of VEGFR-2 kinase enzyme

    Plasma and intracellular (platelet) zinc levels in chronic renal failure (CRF) patients under different treatment modalities

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    The causes and degree of zinc (Zn) deficiency in uraemia are still controversial. The effect of different treatment modalities are still unsettled. Plasma Zn represents only a small part of the total body Zn (about 0.5%). Thus determination of intracellular Zn in the peripheral blood cells might be more reliable. The present study was designed to assess the actual Zn status in uraemia and to find whether the treatment modalities of CRF (conservative and dialytic) could influence Zn status. Also to determine the elfeet of single dialysis session, type of dialysis and dialysate buffer on the Zn status.This study included ten healthy controls and fourty CRF patients divided in three subgroups on different treatment modalities (10 conservative treatment, 15 on intermittent perioneal dialysis ((IPD) and 15 on haemedialysis (HD). Zinc was measured by atomic absorption spectrophotometry in plasma and platelets. Statistically significant decrease of plasma Zn and significant increase of platelet Zn were found in CRF patients on different treatment modalities as compared to controls (P<0.01), but there was no significant difference in this respect hetween the three uraemic subgroups. There was no difference as regard serum protein and albunun levels in uraemic subgroups compared to controls. Moreover plasma Zn was significantly increased (still less than control) and platelet Zn was significantly decreased (P<0.01) after a single dialysis session in both IPD and HD subgroups, but the changes of both parameters (before and after dialysis) were insignificant in IPD patients compared to HD patients.Significant negative correlation was found between platelet Zn and creatinine clearance in the three uraemic subgroups (r = -0.81 P<0.01 in conservative patients, r= -0.72 P<0.01 in IPD and r= -0.76 P<0.01 in HD) while no correlation could be detected between the duration of dialysis and each of platelet & plasma Zn and between plasma Zn and each of platelet Zn, serum creatinine and clearance. Plasma Zn showed transient significant rise in HD patients using bicarbonate (11.6 ± 1.1 umol/L) as compared to those using acetate buffer (9.1 ± 1.3 umol/L), P<0.01. We can conclude that intracellular measurements of Zn (platelet) is of value in diagnosis and monitoring of Zn status in uraemics. Different treatment modalities does not influence Zn haernostasis. with no superiority of particular type of dialysis in this respect. The effect of a single dialysis session and the use of bicarbonate versus acetate buffer was just a transient rise of plasma Zn due to haemoconcentration and better correction of acidosis during dialysis

    Necessary and sufficient condition for longitudinal magnetoresistance

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    Since the Lorentz force is perpendicular to the magnetic field, it should not affect the motion of a charge along the field. This argument seems to imply absence of longitudinal magnetoresistance (LMR) which is, however, observed in many materials and reproduced by standard semiclassical transport theory applied to particular metals. We derive a necessary and sufficient condition on the shape of the Fermi surface for non-zero LMR. Although an anisotropic spectrum is a pre-requisite for LMR, not all types of anisotropy can give rise to the effect: a spectrum should not be separable in any sense. More precisely, the combination kρvϕ/vρk_{\rho}v_{\phi}/v_{\rho}, where kρk_\rho is the radial component of the momentum in a cylindrical system with the z-axis along the magnetic field and vρ(vϕv_{\rho} (v_{\phi}) is the radial (tangential) component of the velocity, should depend on the momentum along the field. For some lattice types, this condition is satisfied already at the level of nearest-neighbor hopping; for others, the required non-separabality occurs only if next-to-nearest-neighbor hopping is taken into account.Comment: 7 pages, 2 figure

    Investigation of Growth Inhibitory Effects of cyclo (Nα-pyrido)-bis-[(L-valinyl)-L-ornthenyl acid hydrazide] on Various Cancer Cells as well as in vitro VEGFR-2 Kinase Inhibition

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    328–332During the current work, we synthesized a new peptide derivative; 4,13-diisopropyl-2,5,12,15-tetraoxo-3,6,11,14-tetraaza-1(3,5)-pyridinacyclopentadecaphane-7-carbohydrazide. The prepared hydrazide was investigated for its in vivo as well as in vitro anticancer effects. Results revealed that this derivative has a great potential against 6 cancerous cell lines. Furthermore, the highest effect was obtained against HT1080 and HeLa cells, where the compound showed 7.4- and 15.1-folds increased activity against them, respectively. Additionally, the compound seems to exert its potential anticancer effect by affecting the kinase enzyme VEGFR-2. Finally, the compound showed promising results when tested in in vivo against prostate cancer developed animal models

    Anti-VEGFR-2 Kinase Effects of Cyclo (Nα-dinicotinoyl)-bis-[(L-valinyl)- L-lysine] and its Anticancer Activities Against Different Cancer Cell Lines

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    The current work aimed at preparing a cyclo (Nα-dinicotinoyl)-bis-[(L-valinyl)-L-lysine] from previously established synthetic routs. The derivative was investigated for its potential anticancer activities as well as its possible mechanism of action. The prepared compound showed variable anticancer activities against all tested cell lines. Furthermore, it showed very promising activities in terms of obtained IC50 values compared to known used drugs. The mechanism of action studies showed that the prepared tripeptide may act on cancerous cells through its inhibitory action on tyrosine kinase pathway. Animal model experiments proved the potential of the synthesized tripeptide as an anticancer agent against PC3 cancer cells

    Two-dimensional wind-tunnel tests of a NASA supercritical airfoil with various high-lift systems. Volume 2: Test data

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    Three high lift systems for a 9.3 percent blunt based, supercritical airfoil were designed, fabricated, and wind tunnel tested. A method for calculating the viscous flow about two dimensional multicomponent airfoils was evaluated by comparing its predictions with test data. A comparison of high lift systems derived from supercritical airfoils with high lift systems derived from conventional airfoils is presented. The high lift systems for the supercritical airfoil were designed to achieve maximum lift and consisted of: (1) a single slotted flap, (2) a double slotted flap and a leading edge slat, and (3) a triple slotted flap and a leading edge slat. Aerodynamic force and moment data and surface pressure data are presented for all configurations and boundary layer and wake profiles for the single slotted flap configuration. The wind-tunnel models, test facilities and instrumentation, and data reduction are described

    On the correlation functions of the domain wall six vertex model

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    We propose an (essentially combinatorial) approach to the correlation functions of the domain wall six vertex model. We reproduce the boundary 1-point function determinant expression of Bogoliubov, Pronko and Zvonarev, then use that as a building block to obtain analogous expressions for boundary 2-point functions. The latter can be used, at least in principle, to express more general boundary (and bulk) correlation functions as sums over (products of) determinants.Comment: LaTeX2e, requires eepic, 25 pages, including 29 figure
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