| 1. |
- Adcox, K, et al.
(författare)
-
PHENIX detector overview
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 3. |
- Wijesooriya, K, et al.
(författare)
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Polarization measurements in high-energy deuteron photodisintegration
- 2001
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 86:14, s. 2975-2979
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the recoil proton polarization for the d(γ⃗,p⃗)n reaction at θc.m. = 90° for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization py vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(γ,p)ncross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.
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| 4. |
- Schlegel, C, et al.
(författare)
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K-isomers in very neutron-rich nuclei around mass 180
- 2000
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Ingår i: Physica Scripta. Topical Issues. - 0281-1847. ; T88, s. 72-76
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Tidskriftsartikel (refereegranskat)abstract
- gamma-spectroscopy methods have been used to search for microsecond isomers among the fragmentation products of a 1 GeV/nucleon Pb-208 beam. In particular the population of the known K-pi = 35/2(-) isomer in W-179 has been investigated and several new isomeric decays have been found for neutron rich nuclei in the A approximate to 180-200 mass region. The ground state band of the neutron rich N = 116 system of W-190 has been identified for the first time and we discuss its structure in comparison to neighboring systems.
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| 5. |
- Schulte, EC, et al.
(författare)
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High energy angular distribution measurements of the exclusive deuteron photodisintegration reaction
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - : American Physical Society. - 0556-2813 .- 1089-490X. ; 66:4
-
Tidskriftsartikel (refereegranskat)abstract
- The first complete measurements of the angular distributions of the two-body deuteron photodisintegration differential cross section at photon energies above 1.6 GeV were performed at the Thomas Jefferson National Accelerator Facility. The results show a persistent forward-backward asymmetry up to E-gamma=2.4 GeV, the highest-energy measured in this experiment. The Hard Rescattering and the Quark-Gluon string models are in fair agreement with the results.
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| 6. |
- Wijesooriya, K, et al.
(författare)
-
Polarization measurements in neutral pion photoproduction
- 2002
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:3
-
Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the recoil proton polarization for the H-1((γ) over right arrow,(p) over right arrow)pi(0) reaction for theta(c.m.)(pi) = 60degrees-135degrees and for photon energies up to 4.1 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. Various theoretical models are compared with the results. No evidence for hadron helicity conservation is observed. Models that employ factorization are not favored. It appears from the strong angular dependence of the induced polarization at photon energies of 2.5 and 3.1 GeV that a relatively high spin resonance or background amplitude might exist in this energy region.
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| 7. |
- Zhu, LY, et al.
(författare)
-
Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium
- 2003
-
Ingår i: Physical Review Letters. - 1079-7114. ; 91:2: 022003
-
Tidskriftsartikel (refereegranskat)abstract
- We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma)greater than or similar to3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.
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| 8. |
- Bearden, IG, et al.
(författare)
-
Deuteron and triton production with high energy sulphur and lead beams
- 2002
-
Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 23:2, s. 237-247
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Tidskriftsartikel (refereegranskat)abstract
- Proton and deuteron production has been observed in S+S and S+Pb collisions at 200 A-GeV and in Pb+Pb reactions at 158 A-GeV at the CERN SPS accelerator. For Pb+Pb triton production was also measured. The p and d spectra as well as the p and t spectra were observed in similar rapidity ranges and over similar ranges of transverse momenta per nucleon, making it possible to interpret the cross sections of the composite particles in terms of coalescence mechanisms. Volumes of homogeneity were extracted and compared to pion-pair HBT interferometry results. Special attention is given to the dependence on transverse mass, centrality and rapidity.
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| 9. |
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| 10. |
- Bearden, IG, et al.
(författare)
-
Particle production in central Pb+Pb collisions at 158A GeV/c
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:4
-
Tidskriftsartikel (refereegranskat)abstract
- The NA44 experiment has measured single-particle inclusive spectra for charged pions, kaons, and protons as a function of transverse mass near midrapidity in 158A GeV/c Pb+Pb collisions. From the particle mass dependence of the observed m(T) distributions, we are able to deduce a value of about 120 MeV for the temperature at thermal freeze-out. From the observed ratios of the rapidity densities, we find values of the chemical potentials for light and strange quarks and a chemical freeze-out temperature of approximately 140 MeV.
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| 11. |
- Dutta, D, et al.
(författare)
-
Nuclear transparency with the gamma n ->pi(-)p process in He-4
- 2003
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 68:2: 021001
-
Tidskriftsartikel (refereegranskat)abstract
- We have measured the nuclear transparency of the fundamental process gamman-->pi(-)p in He-4. These measurements were performed at Jefferson Lab in the photon energy range of 1.6-4.5 GeV and at theta(cm)(pi)=70degrees and 90degrees. These measurements are the first of their kind in the study of nuclear transparency in photoreactions. They also provide a benchmark test of Glauber calculations based on traditional models of nuclear physics. The transparency results suggest deviations from the traditional nuclear physics picture. The momentum transfer dependence of the measured nuclear transparency is consistent with Glauber calculations that include the quantum chromodynamics phenomenon of color transparency.
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| 12. |
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| 13. |
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| 14. |
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| 15. |
- Spolaore, P., et al.
(författare)
-
Identification and study of the very neutron deficient nuclide I-111 : search for octupole correlations in the region of N approximate to Z approximate to 56
- 2001
-
Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 682, s. 387C-393C
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the neutron-deficient nuclide I-111 have been populated with the fusion reaction Ni-58 + Ni-58 at a beam energy of 210 MeV, in an experiment performed at the Tandem Accelerator of the Laboratori Nazionali di Legnaro. The gamma spectrometer GASP was used in time coincidence with the ISIS Si-ball and the CAMEL recoil mass spectrometer for the positive identification of the nuclide. Gamma transitions and structure details previously attributed to I-111 by Other authors are only partially confirmed. The obtained level scheme includes new rotational bands and a new low lying structure which suggests the presence of octupole correlations at predicted rotational frequency values.
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| 16. |
- Ameye, L, et al.
(författare)
-
Abnormal collagen fibrils in tendons of biglycan/fibromodulin-deficient mice lead to gait impairment, ectopic ossification, and osteoarthritis
- 2002
-
Ingår i: FASEB Journal. - : Wiley. - 1530-6860 .- 0892-6638. ; 16:7, s. 673-680
-
Tidskriftsartikel (refereegranskat)abstract
- Small leucine-rich proteoglycans (SLRPs) regulate extracellular matrix organization, a process essential in development, tissue repair, and metastasis. In vivo interactions of biglycan and fibromodulin, two SLRPs highly expressed in tendons and bones, were investigated by generating biglycan/fibromodulin double-deficient mice. Here we show that collagen fibrils in tendons from mice deficient in biglycan and/or fibromodulin are structurally and mechanically altered resulting in unstable joints. As a result, the mice develop successively and progressively 1) gait impairment, 2) ectopic tendon ossification, and 3) severe premature osteoarthritis. Forced use of the joints increases ectopic ossification and osteoarthritis in the double-deficient mice, further indicating that structurally weak tendons cause the phenotype. The study shows that mutations in SLRPs may predispose to osteoarthritis and offers a valuable and unique animal model for spontaneous osteoarthritis characterized by early onset and a rapid progression of the disease.
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| 17. |
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| 18. |
- Enfors, Sven-Olof, et al.
(författare)
-
Physiological responses to mixing in large scale bioreactors
- 2001
-
Ingår i: Journal of Biotechnology. - 0168-1656 .- 1873-4863. ; 85:2, s. 175-185
-
Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli fed-batch cultivations at 22 m(3) scale were compared to corresponding laboratory scale processes and cultivations using a scale-down reactor furnished with a high-glucose concentration zone to mimic the conditions in a feed zone of the large bioreactor. Formate accumulated in the large reactor, indicating the existence of oxygen limitation zones. It is suggested that the reduced biomass yield at large scale partly is due to repeated production/reassimilation of acetate from overflow metabolism and mixed acid fermentation products due to local moving zones with oxygen limitation. The conditions that generated mixed-acid fermentation in the scale-down reactor also induced a number of stress responses, monitored by analysis of mRNA of selected stress induced genes. The stress responses were relaxed when the cells returned to the substrate limited and oxygen sufficient compartment of the reactor. Corresponding analysis in the large reactor showed that the concentration of mRNA of four stress induced genes was lowest at the sampling port most distant from the feed zone. It is assumed that repeated induction/relaxation of stress responses in a large bioreactor may contribute to altered physiological properties of the cells grown in large-scale bioreactor. Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.
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| 19. |
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| 20. |
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| 21. |
- Li, K., et al.
(författare)
-
MBE-based SiGe/Si heterojunction multilayer structures
- 2001
-
Ingår i: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 227-228, s. 744-748
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, SiGe/Si multilayer heterostructures prepared by molecular beam epitaxy (MBE) are described with the aim of manufacturing SiGe heterojunction bipolar transistors (HBTs). Based on the simulations made by Medici, device structures have been designed and grown. The quality of the MBE layered structures has been characterized by reflection high-energy electron diffraction, X-ray diffraction, secondary ion mass spectrometry and spreading resistance. Furthermore, SiGe-HBTs have been fabricated. Promising DC and RF results of processed HBT devices have been obtained. © 2001 Elsevier Science B.V.
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| 22. |
- Lindmark, F, et al.
(författare)
-
H6D polymorphism in macrophage-inhibitory cytokine-1 gene associated with prostate cancer
- 2004
-
Ingår i: Journal of the National Cancer Institute. - Umea Univ, Dept Radiat Sci Oncol, S-90187 Umea, Sweden. Karolinska Inst, Dept Med Epidemiol & Biostat, Stockholm, Sweden. Umea Univ Hosp, Dept Urol & Androl, S-90185 Umea, Sweden. Wake Forest Univ, Sch Med, Ctr Human Genomics, Winston Salem, NC 27109 USA. Johns Hopkins Med Inst, Dept Urol, Baltimore, MD 21205 USA. : OXFORD UNIV PRESS INC. - 0027-8874 .- 1460-2105. ; 96:16, s. 1248-1254
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Accumulating epidemiologic and molecular evidence suggest that inflammation is an important component in the etiology of prostate cancer. Macrophage-inhibitory cytokine-1 (MIC-1), a member of the transforming growth factor beta superfamily, is thought to play an important role in inflammation by regulating macrophage activity. We examined whether sequence variants in the MIC-1 gene are associated with the risk of prostate cancer. Methods: The study population, a population-based case-control study in Sweden, consisted of 1383 prostate cancer case patients and 780 control subjects. From 94 of the control subjects, we constructed gene-specific haplotypes of MIC-1 and identified four haplotype-tagging single-nucleotide polymorphisms (SNPs): Exon1+25 (V9L), Exon1+142 (S48T), IVS1+1809, and Exon2+2423 (H6D). All study subjects were genotyped for the four SNPs, and conditional logistic regression analysis was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs). Results: A statistically significant difference (P = .006) in genotype frequency was observed for the nonsynonymous change H6D) (histidine to aspartic acid at position 6) between prostate cancer patients and control subjects. Carriers of the GC genotype, which results in the H6D change, experienced a lower risk of sporadic prostate cancer (OR = 0.80, 95% CI = 0.66 to 0.97) and of familial prostate cancer (OR = 0.61, 95% CI = 0.42 to 0.89) than the CC genotype carriers. In the study population, the proportion of prostate cancer cases attributable to the CC genotype was 7.2% for sporadic cancer and 19.2% for familial cancer. None of the other SNPs or haplotypes was associated with prostate cancer. Conclusion: This study shows an association between a nonsynonymous change (H6D) in the MIC-1 gene and prostate cancer. This finding supports the hypothesis that genetic variation in the inflammatory process contributes to prostate cancer susceptibility.
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| 23. |
- Liu, C, et al.
(författare)
-
Inhibition of histone deacetylases
- 2004
-
Ingår i: Methods in molecular biology (Clifton, N.J.). - New Jersey : Humana Press. - 1064-3745. ; 287, s. 87-97
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Tidskriftsartikel (refereegranskat)
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| 24. |
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| 25. |
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| 26. |
- Shorubalko, Ivan, et al.
(författare)
-
A novel frequency-doubling device based on three-terminal ballistic junction
- 2002
-
Ingår i: Device Research Conference (Cat. No.02TH8606). - 0780373170 ; , s. 159-160
-
Konferensbidrag (refereegranskat)abstract
- Summary form only given. Ballistic devices have received increasing attention for their nonlinear electrical properties, which are interesting from both physics and application points of view. Recently, novel nonlinear electrical properties of three-terminal ballistic junctions (TBJs) have been discovered theoretically and experimentally. In this work we propose and demonstrate functionality of a novel frequency-doubling device based on a three-terminal ballistic junction. The novel devices are fabricated by integrating a T-shaped TBJ and a one-dimensional (1D) lateral-field-effect transistor (lateral-FET) with trench gate-channel insulation on high-electron-mobility GaInAs/InP quantum well structures The results of the measurements show frequency doubling and gain in these novel devices at room temperature
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| 27. |
- Shorubalko, Ivan, et al.
(författare)
-
A novel frequency-multiplication device based on three-terminal ballistic junction
- 2002
-
Ingår i: IEEE Electron Device Letters. - 0741-3106. ; 23:7, s. 377-379
-
Tidskriftsartikel (refereegranskat)abstract
- In this letter, a novel frequency-multiplication device based on a three-terminal ballistic junction is proposed and demonstrated. A 100 nm-size, three-terminal ballistic junction and a one-dimensional (1-D), lateral-field-effect transistor with trench gate-channel insulation are fabricated from high-electron-mobility GaInAs/InP quantum-well material as a single device. The devices show frequency doubling and gain at room temperature. The performance of these devices up to room temperature originates from the nature of the device functionality and the fact that the three-terminal device extensions are maintained below the carrier mean-free path. Furthermore, it is expected that the device performance can be extended up to THz-range.
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| 28. |
- Soffel, M., et al.
(författare)
-
The IAU 2000 Resolutions for Astrometry, Celestial Mechanics, and Metrology in the Relativistic Framework: Explanatory Supplement
- 2003
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X. ; 126:6, s. 2687-2706
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss the IAU resolutions B1.3, B1.4, B1.5, and B1.9 that wereadopted during the 24th General Assembly in Manchester, 2000, andprovides details on and explanations for these resolutions. It isexplained why they present significant progress over the correspondingIAU 1991 resolutions and why they are necessary in the light of presentaccuracies in astrometry, celestial mechanics, and metrology. In fact,most of these resolutions are consistent with astronomical models andsoftware already in use. The metric tensors and gravitational potentialsof both the Barycentric Celestial Reference System and the GeocentricCelestial Reference System are defined and discussed. The necessity andrelevance of the two celestial reference systems are explained. Thetransformations of coordinates and gravitational potentials arediscussed. Potential coefficients parameterizing the post-Newtoniangravitational potentials are expounded. Simplified versions of the timetransformations suitable for modern clock accuracies are elucidated.Various approximations used in the resolutions are explicated andjustified. Some models (e.g., for higher spin moments) that serve thepurpose of estimating orders of magnitude have actually never beenpublished before.
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| 29. |
- Thormeyer, D, et al.
(författare)
-
Characterization of lacZ complementation deletions using membrane receptor dimerization
- 2003
-
Ingår i: BioTechniques. - : Future Science Ltd. - 0736-6205 .- 1940-9818. ; 34:2, s. 346-
-
Tidskriftsartikel (refereegranskat)abstract
- We describe the screening of lacZ deletions in mammalian cells and the discovery of a novel pair of lacZ deletions that can undergo α-complementation only when they are fused to peptides that interact with each other. The two lacZ deletions, ΔN 11-75 and ΔC 82-1023, were first characterized by fusing to two small interacting peptides and were then further analyzed by fusing to three membrane receptors (G protein-coupled receptors α2cAR and D2DRL and receptor tyrosine kinase insulin receptor) that were known to form homodimers in the membrane. Histochemical and quantitative FACS® assays demonstrated that the novel deletions have much lower level of association with each other, thus offering a much lower background in monitoring membrane protein interactions compared to previously published lacZ deletions. Furthermore, our method has the exciting potential to monitor simultaneously membrane receptor dimerization and localization to the cell surface of living cells.
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| 30. |
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| 31. |
- Wang, XB, et al.
(författare)
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Expression of CTLA-4 by human monocytes
- 2002
-
Ingår i: Scandinavian journal of immunology. - : Wiley. - 0300-9475. ; 55:1, s. 53-60
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Tidskriftsartikel (refereegranskat)
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| 32. |
- Wuu, J., et al.
(författare)
-
Correlates of pregnancy oestrogen, progesterone and sex hormone-binding globulin in the USA and China
- 2002
-
Ingår i: European Journal of Cancer Prevention. - : Ovid Technologies (Wolters Kluwer Health). - 0959-8278 .- 1473-5709. ; 11:3, s. 283-293
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study is to examine perinatal correlates of oestradiol (E2), oestriol (E3), progesterone and sex hormone-binding globulin (SHBG) among pregnant women in the USA and China. Three hundred and four Caucasian women in Boston and 335 Chinese women in Shanghai were studied. Levels of E2, E3, progesterone and SHBG were measured in maternal blood at weeks 16 and 27 of gestation, and correlated with maternal, gestational and perinatal characteristics. Height, weight and body mass index (BMI) before pregnancy is inversely associated with E2 and SHBG, whereas E3 is inversely associated with height and progesterone is inversely associated with weight and BMI. A previous live birth is associated with lower E2 and SHBG in the index pregnancy. Total gestation duration is inversely associated with E2, E3 and progesterone, whereas weight gain during pregnancy is inversely associated with progesterone and SHBG. In the US, pregnancies with female fetuses are characterized by significantly reduced progesterone. Pregnancy hormones are associated with several maternal, gestational and neonatal characteristics.
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| 33. |
- Xu, BZ, et al.
(författare)
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Cloning and sequencing of a molluscan endo-beta-1,4-glucanase gene from the blue mussel, Mytilus edulis
- 2001
-
Ingår i: EUROPEAN JOURNAL OF BIOCHEMISTRY. - : BLACKWELL SCIENCE LTD. - 0014-2956. ; 268:13, s. 3718-3727
-
Tidskriftsartikel (refereegranskat)abstract
- Using polymerase chain reaction, cloning and sequencing techniques, a complementary DNA encoding a low molecular mass cellulase (endo-1,4-beta -n-glucanase, EC 3.2.1.4) has been identified in the digestive gland of the marine mussel, Mytilus edulis, It co
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| 34. |
- Xu, B., et al.
(författare)
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Maternal and gestational correlates of pregnancy prolactin and growth hormone in USA and China
- 2003
-
Ingår i: European Journal of Cancer Prevention. - : Ovid Technologies (Wolters Kluwer Health). - 0959-8278 .- 1473-5709. ; 12:1, s. 35-42
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study is to determine correlates of prolactin and growth hormone levels among pregnant women in the USA and China. We studied 304 pregnant Caucasian and 335 pregnant Chinese women. Levels of prolactin and growth hormone were measured at weeks 16 and 27 of gestation, and correlated with maternal, gestational and perinatal characteristics. Both growth hormone and, to a lesser extent, prolactin were inversely associated with pregnancy weight and body mass index, history of a previous live birth and newborn size, whereas educated women had higher levels of both hormones. Growth hormone levels were lower in women who gained more weight, smoked and had nausea and vomiting during pregnancy, whereas prolactin increased with longer total gestation. We found robust associations between maternal and newborn characteristics on the one hand and prolactin and growth hormone during pregnancy on the other.
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| 35. |
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| 36. |
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| 37. |
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| 38. |
- Xu, D, et al.
(författare)
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Telomerase activity in plasma cell dyscrasias
- 2001
-
Ingår i: British journal of cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 84:5, s. 621-625
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Tidskriftsartikel (refereegranskat)
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| 39. |
- Xu, X., et al.
(författare)
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Ordered mesoporous niobium oxide film : A novel matrix for assembling functional proteins for bioelectrochemical applications
- 2003
-
Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 15:22, s. 1932-
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Tidskriftsartikel (refereegranskat)abstract
- The immobilization of cytochrome c (Cyt-c) in ordered mesoporous niobium oxide thin films is investigated for the first time. The direct electrochemical behavior of Cyt-c assembled onto the. inorganic matrix (see Figure) and the electrocatalytic properties of this assembly are studied. The results open a new doorway for the application of niobium oxides as bioanalytical devices.
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| 40. |
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| 41. |
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| 42. |
- Zhang, Shi-Li, et al.
(författare)
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Differences between interfacial and surface molybdenum in the formation Of TiSi2
- 2001
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 89:3, s. 1641-1646
-
Tidskriftsartikel (refereegranskat)abstract
- Backscattering and diffraction results are presented for the effects of an interfacial or a surface Mo layer on the formation of Ti-silicides during solid-state interaction between Ti films and Si substrates. It is shown that the interfacial and surface Mo are fundamentally different in their involvement in the Ti-silicide formation. The interfacial Mo induces the formation of C40 (Mo,Ti)Si-2 at the interface adjacent to the Si substrate already after annealing at 550 degreesC, in agreement with our previous results. Hence, the desired C54 TiSi2 can grow directly on top of the C40 (Mo,Ti)Si-2 at relatively low temperatures as a result of the template effect. The surface Mo is, however, found in a metal-rich silicide presumably (Mo,Ti)(5)Si-3 at 550-600 degreesC, which eventually converts to (Mo,Ti)Si-2 upon annealing at higher temperatures. Underneath this metal-rich silicide lies a fully developed C49 TiSi2 layer. Consequently, the formation of C54 TiSi2 in the presence of surface Mo follows the usual path of the C49-C54 phase transition. This important difference in the participation of Mo in the silicide formation spreads doubts about the validity of using interfacial Mo versus surface Mo to study the dominant mechanism(s) responsible for the enhanced formation of C54 TiSi2.
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| 43. |
- Zhang, Zhibin, et al.
(författare)
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Different routes to the formation of C54TiSi(2) in the presence of surface and interface molybdenum : A transmission electron microscopy study
- 2002
-
Ingår i: Journal of Materials Research. - 0884-2914 .- 2044-5326. ; 17:4, s. 784-789
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Tidskriftsartikel (refereegranskat)abstract
- Direct evidence revealing fundamental differences in sequence of phase formation during the growth of TiSi2 in the presence of an ultrathin surface or interface Mo layer is presented. Results of cross-sectional transmission electron microscopy showed that when the Mo layer was present at the interface between Ti films and Si substrates, C40 (Mo,Ti)Si-2 formed at the interface, and Ti5Si3 grew on top after annealing at 550 degreesC. Additionally, both C54 and C40 TiSi2 were found in the close vicinity of the C40 (Mo,Ti)Si-2 grains. No C49 grains were detected. Raising the annealing temperature to 600 degreesC led to the formation of C54 TiSi2 at the expense of Ti5Si3, and the interfacial C40 (Mo,Ti)Si-2 also began to transform into C54 (Mo,Ti)Si-2 at 600 degreesC. When the Mo was deposited on top of Ti, the silicide film was almost solely composed of C49 TiSi2 at 600 degreesC. However, a small amount of (Mo,Ti)(5)Si-3 was still present in the vicinity of the sample surface. Upon annealing at 650 degreesC, only the C54 phase was found throughout the entire TiSi2 layer with a surface (Mo,Ti)Si, on top of TiSi2 Hence, it was unambiguously shown that in the presence of surface versus interface Mo, different routes were taken to the formation of C54 TiSi2.
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| 44. |
- Zhang, Zhibin, et al.
(författare)
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Formation of C54TiSi(2) on Si(100) using Ti/Mo and Mo/Ti bilayers
- 2002
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Ingår i: International Journal of Modern Physics B. - 0217-9792. ; 16:1-2, s. 205-212
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Tidskriftsartikel (refereegranskat)abstract
- The effect of Mo on the formation of C54 TiSi2 on Si (100) substrates is studied using crosssectional transmission electron microscopy. For a Ti/Mo bilayer on Si, the interfacial Mo film reacts with Ti and Si to form C40 (Mo,Ti)Si-2 at 550 degreesC. Crystal grains of metastable C40 TiSi2 and equilibrium C54 TiSi2 are found in the region near the interfacial (Mo,Ti)Si-2 layer due to the template phenomenon. Increasing the temperature to 600 degreesC leads to the growth of C54 TiSi2 throughout the film. No C49 grains can be detected. The findings confirm that the usual sequence for the formation of C54 TiSi2, i.e. the C49 TiSi2 forms first followed by a phase transition to the C54 TiSi2, is altered by the interposed Mo layer. For a Mo/Ti bilayer on Si, the surface Mo layer is found to be present sequentially in (Mo,Ti)(5)Si-3 at 550 degreesC, C49 (Mo,Ti)Si-2 at 600 degreesC and C54 (Mo,Ti)Si-2 at 650 degreesC. The bulk Ti beneath forms the C54 TiSi2 following the usual route through the C49-C54 phase transition. However, this transition is now enhanced, in comparison with the C54 TiSi2 formation with pure Ti, by the C54 (Mo,Ti)Si-2 atop that plays the role as a template precisely as the interfacial C40 (Mo,Ti)Si-2.
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