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Träfflista för sökning "WFRF:(Ibrahim M.) srt2:(2005-2009)"

Sökning: WFRF:(Ibrahim M.) > (2005-2009)

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1.
  • Aaron, F. D., et al. (författare)
  • Multi-leptons with high transverse momentum at HERA
  • 2009
  • Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :10
  • Tidskriftsartikel (refereegranskat)abstract
    • Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb(-1). The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e(+)p collision data with a scalar sum of the lepton transverse momenta above 100 GeV while 1.94 +/- 0.17 events are expected. Such events are not observed in e(-)p collisions for which 1.19 +/- 0.12 are predicted. Total visible and differential di-electron and di-muon photoproduction cross sections are extracted in a restricted phase space dominated by photon-photon collisions.
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3.
  • de Walle, J. V., et al. (författare)
  • Coulomb excitation of the N=50 nucleus Zn-80
  • 2008
  • Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1012, s. 291-295 453
  • Konferensbidrag (refereegranskat)abstract
    • Neutron rich Zinc isotopes, including the N=50 nucleus Zn-80, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2(+) states. For the first time, an excited state in Zn-80 was observed and the 2(1)(+) state in Zn-78 was established. The measured B(E2,2(1)(+) -> 0(1)(+)) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus Ni-78.
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4.
  • Kelly, J. J., et al. (författare)
  • Recoil polarization measurements for neutral pion electroproduction at Q(2)=1(GeV/c)(2) near the Delta resonance
  • 2007
  • Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:2
  • Tidskriftsartikel (refereegranskat)abstract
    • We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q(2)=1.0 (GeV/c)(2) in 10 bins of 1.17 <= W <= 1.35 GeV across the Delta resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near the physical mass, W=M-Delta approximate to 1.232 GeV, but the variation among models is large for response functions governed by imaginary parts, and for both types of response functions, the variation increases rapidly with W > M-Delta. We performed a multipole analysis that adjusts suitable subsets of center dot(pi)<= 2 amplitudes with higher partial waves constrained by baseline models. This analysis provides both real and imaginary parts. The fitted multipole amplitudes are nearly model independent-there is very little sensitivity to the choice of baseline model or truncation scheme. By contrast, truncation errors in the traditional Legendre analysis of N ->Delta quadrupole ratios are not negligible. Parabolic fits to the W dependence around M-Delta for the multiple analysis gives values for Re(S1+/M1+)=(-6.61 +/- 0.18)% and Re(E1+/M1+)=(-2.87 +/- 0.19)% for the p pi(0) channel at W=1.232 GeV and Q(2)=1.0 (GeV/c)(2) that are distinctly larger than those from the Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+)=(+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe.
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5.
  • Van de Walle, J., et al. (författare)
  • Coulomb excitation of neutron-rich Zn isotopes: First observation of the 2(1)(+) state in Zn-80
  • 2007
  • Ingår i: Physical Review Letters. - 1079-7114. ; 99:14
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron-rich, radioactive Zn isotopes were investigated at the Radioactive Ion Beam facility REX-ISOLDE (CERN) using low-energy Coulomb excitation. The energy of the 2(1)(+) state in Zn-78 could be firmly established and for the first time the 2(+)-> 0(1)(+) transition in Zn-80 was observed at 1492(1) keV. B(E2,2(1)(+)-> 0(1)(+)) values were extracted for Zn-74,Zn-76,Zn-78,Zn-80 and compared to large scale shell model calculations. With only two protons outside the Z=28 proton core, Zn-80 is the lightest N=50 isotone for which spectroscopic information has been obtained to date. Two sets of advanced shell model calculations reproduce the observed B(E2) systematics. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus Ni-78.
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6.
  • Van de Walle, J., et al. (författare)
  • Low-energy Coulomb excitation of neutron-rich zinc isotopes
  • 2009
  • Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 79:1
  • Tidskriftsartikel (refereegranskat)abstract
    • At the radioactive ion beam facility REX-ISOLDE, neutron-rich zinc isotopes were investigated using low-energy Coulomb excitation. These experiments have resulted in B(E2, 2(1)(+)-> 0(1)(+)) values in Zn74-80, B(E2, 4(1)(+)-> 2(1)(+)) values in Zn-74,Zn-76 and the determination of the energy of the first excited 2(1)(+) states in Zn-78,Zn-80. The zinc isotopes were produced by high-energy proton- (A = 74, 76, 80) and neutron-(A = 78) induced fission of U-238, combined with selective laser ionization and mass separation. The isobaric beam was postaccelerated by the REX linear accelerator and Coulomb excitation was induced on a thin secondary target, which was surrounded by the MINIBALL germanium detector array. In this work, it is shown how the selective laser ionization can be used to deal with the considerable isobaric beam contamination and how a reliable normalization of the experiment can be achieved. The results for zinc isotopes and the N = 50 isotones are compared to collective model predictions and state-of-the-art large-scale shell-model calculations, including a recent empirical residual interaction constructed to describe the present experimental data up to 2004 in this region of the nuclear chart.
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7.
  • Walle, J. Van de, et al. (författare)
  • Coulomb Excitation of Neutron-Rich Zn Isotopes: First Observation of the 2[sub 1][sup +] State in [sup 80]Zn
  • 2007
  • Ingår i: Physical Review Letters. ; 99:14, s. 142501-
  • Tidskriftsartikel (refereegranskat)abstract
    • Neutron-rich, radioactive Zn isotopes were investigated at the Radioactive Ion Beam facility REX-ISOLDE (CERN) using low-energy Coulomb excitation. The energy of the 21+ state in 78Zn could be firmly established and for the first time the 2+-->01+ transition in 80Zn was observed at 1492(1) keV. B(E2,21+-->01+) values were extracted for 74,76,78,80Zn and compared to large scale shell model calculations. With only two protons outside the Z=28 proton core, 80Zn is the lightest N=50 isotone for which spectroscopic information has been obtained to date. Two sets of advanced shell model calculations reproduce the observed B(E2) systematics. The results for N=50 isotones indicate a good N=50 shell closure and a strong Z=28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus 78Ni.
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8.
  • Stanoiu, M., et al. (författare)
  • Disappearance of the N=14 shell gap in the carbon isotopic chain
  • 2008
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 78:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The structure of C-17-20(6) nuclei was investigated by means of the in-beam gamma-ray spectroscopy technique using fragmentation reactions of radioactive beams. Based on particle-gamma and particle-gamma gamma coincidence data, level schemes are constructed for the neutron-rich C17-20 nuclei. The systematics of the first excited 2(+) states in the carbon isotopes is extended for the first time to A = 20 showing that in contrast to the case of the oxygen isotopes, the N = 14 subshell closure disappears. Experimental results are compared with shell-model calculations. Agreement between them is found only if a reduced neutron-neutron effective interaction is used. Implications of this reduced interaction in some properties of weakly bound neutron-rich Carbon are discussed.
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10.
  • Yu, X., et al. (författare)
  • Association of UCP2 - 866 G/A polymorphism with chronic inflammatory diseases
  • 2009
  • Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 10:6, s. 601-605
  • Tidskriftsartikel (refereegranskat)abstract
    • We reported earlier that two mitochondrial gene polymorphisms, UCP2 -866 G/A (rs659366) and mtDNA nt13708 G/A (rs28359178), are associated with multiple sclerosis (MS). Here we aim to investigate whether these functional polymorphisms contribute to other eight chronic inflammatory diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Wegener' granulomatosis (WG), Churg-Strauss syndrome (CSS), Crohn's disease (CD), ulcerative colitis (UC), primary sclerosing cholangitis (PSC) and psoriasis. Compared with individual control panels, the UCP2 -866 G/A polymorphism was associated with RA and SLE, and the mtDNA nt13708 G/A polymorphism with RA. Compared with combined controls, the UCP2 -866 G/A polymorphism was associated with SLE, WG, CD and UC. When all eight disease panels and the original MS panel were combined in a meta-analysis, the UCP2 was associated with chronic inflammatory diseases in terms of either alleles (odds ratio (OR)=0.91, 95% confidence interval (95% CI): 0.86-0.96), P=0.0003) or genotypes (OR=0.88, (95% CI: 0.82-0.95), P=0.0008), with the -866A allele associated with a decreased risk to diseases. As the -866A allele increases gene expression, our findings suggest a protective role of the UCP2 protein in chronic inflammatory diseases.
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11.
  • Khan, Mohammad A. U., et al. (författare)
  • Endothelial Cell Image Enhancement using Non-subsampled Image Pyramid
  • 2007
  • Ingår i: Information Technology Journal. - : Science Alert. - 1812-5638 .- 1812-5646. ; 6:7, s. 1057-1062
  • Tidskriftsartikel (refereegranskat)abstract
    • A corneal endothelial cell image provides vast amount of information about a human eye. The cell density and cell shape parameters of a given endothelial cell image help opthamologists in making many vital clinical decisions. The acquired endothelial image is poor in contrast where cell boundaries are masked in the background. Previously, most of the work was based on morphological operations in spatial domain. However, if we think of cell structure as texture hidden in noisy background, we can get help from texture segmentation, a well studied area. In this work, we propose a non-subsampled Gaussian pyramid decomposition of lowpass region. At certain level of the pyramid, we start observing cleaner cell boundary structure which greatly facilitates its segmentation. Once segmented automatic cell counting can be used and simulation results have shown improvement in cell density count.
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12.
  • Ellaithi, M, et al. (författare)
  • A del(X)(p11) carrying SRY sequences in an infant with ambiguous genitalia
  • 2006
  • Ingår i: BMC Pediatrics. - : Springer Science and Business Media LLC. - 1471-2431. ; 6:11
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: SRY (sex-determining region, Y) is the gene responsible of gonadal differentiation in the male and it is essential for the regular development of male genitalia. Translocations involving the human sex chromosomes are rarely reported, however here we are reporting a very rare translocation of SRY gene to the q -arm of a deleted X chromosome. This finding was confirmed by cytogenetic, fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR). CASE PRESENTATION: A 7-month infant was clinically diagnosed as an intersex case, with a phallus, labia majora and minora, a blind vagina and a male urethra. Neither uterus nor testes was detected by Ultrasonography. G-banding of his chromosomes showed 46,X,del(X)(p11) and fluorescent in situ hybridization (FISH) analysis showed a very small piece from the Y chromosome translocated to the q-arm of the del(X). Polymerase chain reaction (PCR) analysis revealed the presence of material from the sex-determining region Y (SRY) gene. CONCLUSION: It is suggested that the phenotype of the patient was caused by activation of the deleted X chromosome with SRY translocation, which is responsible for gonadal differentiation.
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13.
  • Ibrahim, N. A., et al. (författare)
  • Constituents and biological activity of the chloroform extract and essential oil of Cupressus sempervirens
  • 2009
  • Ingår i: Chemistry of Natural Compounds. - : Springer Science and Business Media LLC. - 0009-3130 .- 1573-8388. ; 45:3, s. 309-313
  • Tidskriftsartikel (refereegranskat)abstract
    • The essential oil of the leaves of Cupressus sempervirens L. was isolated by hydrodistillation and tested against gram positive and gram negative bacteria, showing remarkable antimicrobial activity against Bacillus subtilis with minimum inhibitory concentration (MIC) 75%. The antiviral activity of the essential oil was tested against Herpes simplex virus type 1 (HSV-1), showing antiviral activity with virucidal percentages of 68.0% and 53.2% at concentrations of 1:32 and 1:64, respectively. We firstly reported the isolation of two epi-betulin esters of fatty acids from the CHCl3 fraction of Cupressus sempervirens L. leaves, which were isolated and purified using HPLC, and identified using PMR and MS. The CHCl3 fraction showed significant cytotoxicity against HeLa cells.
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14.
  • Khayyal, MA, et al. (författare)
  • Towards rational use of drugs in Egypt
  • 2006
  • Ingår i: ACTA PHARMACOLOGICA SINICA. - 1671-4083. ; 27, s. 206-207
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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17.
  • Atalla, E, et al. (författare)
  • An all-digital ΣΔ--frequency discriminator of arbitrary order
  • 2006
  • Ingår i: IEEE International Symposium on Circuits and Systems, ISCAS 2006. Proceedings.. - 0780393899
  • Konferensbidrag (refereegranskat)abstract
    • In this paper, we propose an all-digital frequency synthesizer architecture, based on an all-digital ΣΔ-frequency discriminator. The new all-digital synthesizer is compared to previously published work. The architecture of the ΣΔ-frequency discriminator is verified using behavioral simulation.
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18.
  • Boraschi, Diana, et al. (författare)
  • Immunity against HIV/AIDS, malaria, and tuberculosis during co-infections with neglected infectious diseases: recommendations for the European Union research priorities.
  • 2008
  • Ingår i: PLoS neglected tropical diseases. - : Public Library of Science (PLoS). - 1935-2735. ; 2:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Infectious diseases remain a major health and socioeconomic problem in many low-income countries, particularly in sub-Saharan Africa. For many years, the three most devastating diseases, HIV/AIDS, malaria, and tuberculosis (TB) have received most of the world's attention. However, in rural and impoverished urban areas, a number of infectious diseases remain neglected and cause massive suffering. It has been calculated that a group of 13 neglected infectious diseases affects over one billion people, corresponding to a sixth of the world's population. These diseases include infections with different types of worms and parasites, cholera, and sleeping sickness, and can cause significant mortality and severe disabilities in low-income countries. For most of these diseases, vaccines are either not available, poorly effective, or too expensive. Moreover, these neglected diseases often occur in individuals who are also affected by HIV/AIDS, malaria, or TB, making the problem even more serious and indicating that co-infections are the rule rather than the exception in many geographical areas. To address the importance of combating co-infections, scientists from 14 different countries in Africa and Europe met in Addis Ababa, Ethiopia, on September 9-11, 2007. The message coming from these scientists is that the only possibility for winning the fight against infections in low-income countries is by studying, in the most global way possible, the complex interaction between different infections and conditions of malnourishment. The new scientific and technical tools of the post-genomic era can allow us to reach this goal. However, a concomitant effort in improving education and social conditions will be needed to make the scientific findings effective.
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  • Jallow, Muminatou, et al. (författare)
  • Genome-wide and fine-resolution association analysis of malaria in West Africa.
  • 2009
  • Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; , s. 657-665
  • Tidskriftsartikel (refereegranskat)abstract
    • We report a genome-wide association (GWA) study of severe malaria in The Gambia. The initial GWA scan included 2,500 children genotyped on the Affymetrix 500K GeneChip, and a replication study included 3,400 children. We used this to examine the performance of GWA methods in Africa. We found considerable population stratification, and also that signals of association at known malaria resistance loci were greatly attenuated owing to weak linkage disequilibrium (LD). To investigate possible solutions to the problem of low LD, we focused on the HbS locus, sequencing this region of the genome in 62 Gambian individuals and then using these data to conduct multipoint imputation in the GWA samples. This increased the signal of association, from P = 4 x 10(-7) to P = 4 x 10(-14), with the peak of the signal located precisely at the HbS causal variant. Our findings provide proof of principle that fine-resolution multipoint imputation, based on population-specific sequencing data, can substantially boost authentic GWA signals and enable fine mapping of causal variants in African populations.
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  • Ma, Li-Jun, et al. (författare)
  • Genomic analysis of the basal lineage fungus Rhizopus oryzae reveals a whole-genome duplication.
  • 2009
  • Ingår i: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 5:7, s. e1000549-
  • Tidskriftsartikel (refereegranskat)abstract
    • Rhizopus oryzae is the primary cause of mucormycosis, an emerging, life-threatening infection characterized by rapid angioinvasive growth with an overall mortality rate that exceeds 50%. As a representative of the paraphyletic basal group of the fungal kingdom called "zygomycetes," R. oryzae is also used as a model to study fungal evolution. Here we report the genome sequence of R. oryzae strain 99-880, isolated from a fatal case of mucormycosis. The highly repetitive 45.3 Mb genome assembly contains abundant transposable elements (TEs), comprising approximately 20% of the genome. We predicted 13,895 protein-coding genes not overlapping TEs, many of which are paralogous gene pairs. The order and genomic arrangement of the duplicated gene pairs and their common phylogenetic origin provide evidence for an ancestral whole-genome duplication (WGD) event. The WGD resulted in the duplication of nearly all subunits of the protein complexes associated with respiratory electron transport chains, the V-ATPase, and the ubiquitin-proteasome systems. The WGD, together with recent gene duplications, resulted in the expansion of multiple gene families related to cell growth and signal transduction, as well as secreted aspartic protease and subtilase protein families, which are known fungal virulence factors. The duplication of the ergosterol biosynthetic pathway, especially the major azole target, lanosterol 14alpha-demethylase (ERG11), could contribute to the variable responses of R. oryzae to different azole drugs, including voriconazole and posaconazole. Expanded families of cell-wall synthesis enzymes, essential for fungal cell integrity but absent in mammalian hosts, reveal potential targets for novel and R. oryzae-specific diagnostic and therapeutic treatments.
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