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91.
Alexopoulos T Arenton M Barbosa RF Barker AR Bellantoni L Bellavance A Blucher E Bock GJ Cheu E Childress S Coleman R Corcoran MD Cox B Erwin AR Ford R Glazov A Golossanov A Graham J Hamm J Hanagaki K Hsiung YB Huang H Jejer V Jensen DA Kessler R Kobrak HG Kotera K LaDue J Ledovskoy A McBride PL Monnier E Nelson KS Nguyen H Niclasen R Prasad V Qi XR Ramberg EJ Ray RE Ronquest M Santos E Shanahan P Shields J Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Wah YW Wang J White HB 《Physical review letters》2004,93(18):181802
We present a determination of the Cabibbo-Kobayashi-Maskawa parameter |V(us)| based on new measurements of the six largest K(L) branching fractions and semileptonic form factors by the KTeV (E832) experiment at Fermilab. We find |V(us)|=0.2252+/-0.0008(KTeV)+/-0.0021(ext), where the errors are from KTeV measurements and from external sources. We also use the measured branching fractions to determine the CP violation parameter |eta(+-)|=(2.228+/-0.005(KTeV)+/-0.009(ext))x10(-3). 相似文献
92.
Battaglieri M Brunoldi M De Vita R Laget JM Osipenko M Ripani M Taiuti M Adams G Amaryan MJ Anciant E Anghinolfi M Armstrong DS Asavapibhop B Asryan G Audit G Auger T Avakian H Barrow S Beard K Bektasoglu M Berman BL Bersani A Bianchi N Biselli AS Boiarinov S Bouchigny S Bradford R Branford D Briscoe WJ Brooks WK Burkert VD Calarco JR Capitani GP Carman DS Carnahan B Cazes A Cetina C Cole PL Coleman A Cords D Corvisiero P Crabb D Crannell H Cummings JP DeSanctis E Degtyarenko PV Demirchyan R 《Physical review letters》2003,90(2):022002
The differential cross section, dsigma/dt, for omega meson exclusive photoproduction on the proton above the resonance region (2.6相似文献
93.
Alavi-Harati A Alexopoulos T Arenton M Arisaka K Barbosa RF Barker AR Barrio M Bellantoni L Bellavance A Blucher E Bock GJ Bown C Bright S Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Ford R Glazov A Golossanov A Gouffon P Graham J Hamm J Hanagaki K Hsiung YB Huang H Jejer V Jensen DA Kessler R Kobrak HG Kotera K LaDue J Lai N Ledovskoy A McBride PL Monnier E Nelson KS Nguyen H Prasad V Qi XR Quinn B Ramberg EJ Ray RE Santos E Senyo K Shanahan P Shields J Slater W Solomey N Swallow EC 《Physical review letters》2003,90(14):141801
The KTeV experiment at Fermilab has isolated a total of 132 events from the rare decay K(L)-->e+ e- mu+ mu-, with an estimated background of 0.8 events. The branching ratio of this mode is determined to be [2.69+/-0.24(stat)+/-0.12(syst)]x10(-9), with a radiative cutoff of M(2)(ee mu mu)/M(2)(K)>0.95. The first measurement using this mode of the parameter alpha from the D'Ambrosio-Isidori-Portolès (DIP) model of the K(L)gamma*gamma* vertex yields a result of -1.59+/-0.37, consistent with values obtained from other decay modes. Because of the limited statistics, no sensitivity is found to the DIP parameter beta. We use this decay mode to set limits on CP and lepton violation. 相似文献
94.
Fatemi R Skabelin AV Burkert VD Crabb D De Vita R Kuhn SE Minehart R Adams G Anciant E Anghinolfi M Asavapibhop B Audit G Auger T Avakian H Bagdasaryan H Ball JP Barrow S Battaglieri M Beard K Bektasoglu M Bellis M Bertozzi W Bianchi N Biselli AS Boiarinov S Bonner BE Bosted PE Bouchigny S Bradford R Branford D Brooks WK Butuceanu C Calarco JR Carman DS Carnahan B Cetina C Ciciani L Clark R Cole PL Coleman A Connelly J Cords D Corvisiero P Crannell H Cummings JP De Sanctis E Degtyarenko PV 《Physical review letters》2003,91(22):222002
Double-polarization asymmetries for inclusive ep scattering were measured at Jefferson Lab using 2.6 and 4.3 GeV longitudinally polarized electrons incident on a longitudinally polarized NH3 target in the CLAS detector. The polarized structure function g(1)(x,Q2) was extracted throughout the nucleon resonance region and into the deep inelastic regime, for Q(2)=0.15-1.64 GeV2. The contributions to the first moment Gamma(1)(Q2)= integral g(1)(x,Q2) dx were determined up to Q(2)=1.2 GeV2. Using a parametrization for g(1) in the unmeasured low x regions, the complete first moment was estimated over this Q2 region. A rapid change in Gamma(1) is observed for Q2<1 GeV2, with a sign change near Q(2)=0.3 GeV2, indicating dominant contributions from the resonance region. At Q(2)=1.2 GeV2 our data are below the perturbative QCD evolved scaling value. 相似文献
95.
Bleomycin is a clinically used antitumor antibiotic long thought to function therapeutically at the level of DNA cleavage. Recently, it has become clear that bleomycin can also cleave selected members of all major classes of RNA. Using the computer program COMPARE to search the database established by the Anticancer Drug Screening Program of the National Cancer Institute, a possible mechanism-based correlation was found between onconase, an antitumor ribonuclease currently being evaluated in phase III clinical trials, and the chemotherapeutic agent bleomycin. Following these observations, experimentation revealed that bleomycin caused tRNA cleavage and DNA-independent protein synthesis inhibition in rabbit reticulocyte lysate and when microinjected into Xenopus oocytes. The correlation of protein synthesis inhibition to the previously reported site-specific RNA cleavage caused by bleomycin supports the thesis that RNA cleavage may constitute an important element of the mechanism of action of bleomycin. 相似文献
96.
Coleman AW Da Silva E Nouar F Nierlich M Navaza A 《Chemical communications (Cambridge, England)》2003,(7):826-827
The crystal structure of the complex 12.calix-[4]-arene dihydroxyphosphonic acid, 12.propane diammonium, 12.ethanol and 40.water molecules is based on dimeric units of the calix, assembled via trigonal units into a hexameric tube of 15 A radius and 16 A depth, further assemby via spanning propane diammonium cations and ethanol molecules forms a channel (40 A), selectively containing all the water molecules. 相似文献
97.
Tkachenko AG Xie H Coleman D Glomm W Ryan J Anderson MF Franzen S Feldheim DL 《Journal of the American Chemical Society》2003,125(16):4700-4701
The ability of peptide-modified gold nanoparticles to target the nucleus of HepG2 cells was explored. Five peptide/nanoparticle complexes were investigated, particles modified with (1) the nuclear localization signal (NLS) from the SV 40 virus; (2) the adenovirus NLS; (3) the adenovirus receptor-mediated endocytosis (RME) peptide; (4) one long peptide containing the adenovirus RME and NLS; and (5) the adenovirus RME and NLS peptides attached to the nanoparticle as separate pieces. Gold nanoparticles were used because they are easy to identify using video-enhanced color differential interference contrast microscopy, and they are excellent scaffolds from which to build multifunctional nuclear targeting vectors. For example, particles modified solely with NLS peptides were not able to target the nucleus of HepG2 cells from outside the plasma membrane, because they either could not enter the cell or were trapped in endosomes. The combination of NLS/RME particles (4) and (5) did reach the nucleus; however, nuclear targeting was more efficient when the two signals were attached to nanoparticles as separate short pieces versus one long peptide. These studies highlight the challenges associated with nuclear targeting and the potential advantages of designing multifunctional nanostructured materials as tools for intracellular diagnostics and therapeutic delivery. 相似文献
98.
99.
Thompson R Dytman S Kim KY Mueller J Adams GS Amaryan MJ Anciant E Anghinolfi M Asavapibhop B Auger T Audit G Avakian H Barrow S Battaglieri M Beard K Bektasoglu M Bertozzi W Bianchi N Biselli A Boiarinov S Bonner BE Briscoe WJ Brooks W Burkert VD Calarco JR Capitani G Carman DS Carnahan B Cole PL Coleman A Connelly J Cords D Corvisiero P Crabb D Crannell H Cummings J Day D Degtyarenko PV Demirchyan RA Dennis LC Deppman A De Sanctis E De Vita R Dhuga KS Djalali C Dodge GE Doughty D 《Physical review letters》2001,86(9):1702-1706
New cross sections for the reaction e p-->e p eta are reported for total center of mass energy W = 1.5--1.86 GeV and invariant momentum transfer Q2 = 0.25--1.5 (GeV/c)(2). This large kinematic range allows extraction of important new information about response functions, photocouplings, and eta N coupling strengths of baryon resonances. Newly observed structure at W approximately 1.65 GeV is shown to come from interference between S and P waves and can be interpreted with known resonances. Improved values are derived for the photon coupling amplitude for the S11(1535) resonance. 相似文献
100.
Coleman BD Swigon D Tobias I 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》2000,61(1):759-770
Configurations of protein-free DNA miniplasmids are calculated with the effects of impenetrability and self-contact forces taken into account by using exact solutions of Kirchhoff's equations of equilibrium for elastic rods of circular cross section. Bifurcation diagrams are presented as graphs of excess link, DeltaL, versus writhe, W, and the stability criteria derived in paper I of this series are employed in a search for regions of such diagrams that correspond to configurations that are stable, in the sense that they give local minima to elastic energy. Primary bifurcation branches that originate at circular configurations are composed of configurations with D(m) symmetry (m=2,3,...). Among the results obtained are the following. (i) There are configurations with C2 symmetry forming secondary bifurcation branches which emerge from the primary branch with m=3, and bifurcation of such secondary branches gives rise to tertiary branches of configurations without symmetry. (ii) Whether or not self-contact occurs, a noncircular configuration in the primary branch with m=2, called branch alpha, is stable when for it the derivative dDeltaL/dW, computed along that branch, is strictly positive. (iii) For configurations not in alpha, the condition dDeltaL/dW>0 is not sufficient for stability; in fact, each nonplanar contact-free configuration that is in a branch other than alpha is unstable. A rule relating the number of points of self-contact and the occurrence of intervals of such contact to the magnitude of DeltaL, which in paper I was found to hold for segments of DNA subject to strong anchoring end conditions, is here observed to hold for computed configurations of protein-free miniplasmids. 相似文献