Phenomenological analysis of the double-pion production in nucleon-nucleon collisions up to 2.2 GeV

With an effective Lagrangian approach, we analyze several NN -> NN pi pi channels by including various resonances with mass up to 1.72 GeV. For the channels with the pion pair of isospin zero, we confirm the dominance of N*(1440) -> N sigma in the near-threshold region. At higher energies and for channels with the final pion pair of isospin one, we find large contributions from N*(1440) -> Delta pi, double-Delta, Delta(1600) -> N*(1440)pi, Delta(1600) -> Delta pi and Delta(1620) -> Delta pi. There are also sizable contributions from Delta -> Delta pi, Delta -> N pi, N -> Delta pi, and nucleon pole at energies close to the threshold. We give a good reproduction to the total cross sections up to beam energies of 2.2 GeV except for the pp -> pp pi(0)pi(0) channel at energies around 1.1 GeV and our results agree with the existing data of differential cross sections of pp -> pp pi(+)p pi(-), pp -> nn pi(+)pi(+), and pp -> pp pi(0)pi(0) which are measured at CELSIUS and COSY.

MEASUREMENT OF TWO-PROTON CORRELATION FROM THE BREAK-UP OF Al-23

Experiments of Al-23 and Mg-22 radioactive beams bombarding a C-12 target at an energy of 60 similar to 70 A MeV have been performed at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility to study the two-proton emission from Al-23 and Mg-22 excited states, respectively. The trajectorie of the decay products, namely Na-21 + p + p from Al-23 and Ne-20 + p + p from Mg-22, are clean identified. The relative momentum and opening angle between two protons in the rest frame of three body decay channels are obtained by relativistic-kinematics reconstruction. The results demonstrate that there are some di-proton emission components from He-2 cluster for the excited Al-23 and Mg-22.

MEASUREMENT OF THE PROTON-PROTON CORRELATION FUNCTION FROM THE BREAK-UP OF Mg-22 AND Ne-20

An experiment of Mg-22 and Ne-20 beams bombarding on a C-12 target at an energy of 60 similar to 70 A MeV has been performed at the RIKEN projectile fragment separator (RIPS)in the RIKEN Ring Cyclotron Facility to study the two-proton correlated emission from Mg-22 and Ne-20 excited states. The two-protons momentum correlation functions have been obtained for Mg-22 and Ne-20, respectively. The trajectories of the Mg-22 decayed products (Ne-20 + p + p) were also measured to get the angular correlations between the two protons in Center of Mass of decaying system by relativistic-kinematics reconstruction. The results exhibit that Mg-22 has the features of He-2 cluster decay mechanism.

Pyrazine-containing Acene-Type Molecular Ribbons with up to 16 Rectilinearly Arranged Fused Aromatic Rings

A series of acene-type conjugated molecules(1-5) containing 2-6 pyrazine units and up to 16 rectilinearly arranged fused aromatic rings were synthesized by condensation coupling of 1,2-diamines and 1,2-diketones. The energy gap of the molecules estimated from absorption edge decreases with an increase in molecular length, indicating the well-delocalized nature of the molecules. The cyclic voltarnmetry measurements suggest that the n-type properties of these ribbonlike pyrazine derivatives are dependent on the molecular length and the number of the pyrazine units.

Avidin conjugation to up-conversion phosphor NaYF4:Yb3+, Er3+ by the oxidation of the oligosaccharide chains

NaYF4:Yb3+, Er3+ nanoparticles were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. After being functionalized with SiO2-NH2 layer, these NaYF4:Yb3+, Er3+ nanoparticles can conjugate with activated avidin molecules (activated by the oxidation of the oligosaccharide chain). The as-formed NaYF4:Yb3+, Er3+ nanoparticles, NaYF4:Yb3+, Er3+ nanoparticles functionalized with amino groups, avidin conjugated amino-functionalized NaYF4:Yb3+, Er3+ nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FT-IR), UV/Vis absorption spectra, and up-conversion luminescence spectra, respectively.

Avidin conjugation to up-conversion phosphor NaYF4:Yb3+, Er3+ by the oxidation of the oligosaccharide chains

NaYF4:Yb3+, Er3+ nanoparticles were successfully prepared by a polyol process using diethyleneglycol (DEG) as solvent. After being functionalized with SiO2-NH2 layer, these NaYF4:Yb3+, Er3+ nanoparticles can conjugate with activated avidin molecules (activated by the oxidation of the oligosaccharide chain). The as-formed NaYF4:Yb3+, Er3+ nanoparticles, NaYF4:Yb3+, Er3+ nanoparticles functionalized with amino groups, avidin conjugated amino-functionalized NaYF4:Yb3+, Er3+ nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FT-IR), UV/Vis absorption spectra, and up-conversion luminescence spectra, respectively. The biofunctionalization of the NaYF4:Yb3+, Er3+ nanoparticles has less effect on their luminescence properties, i.e., they still show the up-conversion emission (from Er3+, with S-4(3/2) -> I-4(15/2) at similar to 540 nm and F-4(9/2) -> I-4(15/2) at similar to 653 nm), indicative of the great potential for these NaYF4:Yb3+, Er3+ nanoparticles to be used as fluorescence probes for biological system.

Up-conversion spectrum properties of the oxy-fluoride glass co-doped with Er3+ and Yb3+

Up-conversion of 45PbF(2)-45GeO(2)-10WO(3) oxy-fluoride glasses co-doped with Yb3+ and Er3+ ions were prepared by fusion method through melting at 1223 K and then annealing at 653 K for 4 h. Transmittance of the undoped host glass was beyond 73% in a range of 0.6-2.5 mu m and the co-doped glasses still provided good transmittance beyond 50%. Refractive indices of the host and co-doped glasses were 1.517 and 1.650, respectively. Blue, green and red fluorescence spectra were observed in a range of 400-700 nm under 980 nm diode laser excitation. Up-conversion spectra at about 410, 518, 530and 650 nm were assigned to the 4f electron transitions of H-2(9/2) -> I-4(15)/(2), H-2(15/2) -> I-4(15/2) S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2) of Er3+ ion, respectively. The mechanism of energy transfer between Yb3+ and Er3+ ions in the glass was analyzed. Raman shift shows the non-radiative relaxation of the glass sample is low.

Scale-up of fermentation and purification of recombinant allophycocyanin over-expressed in Escherichia coli

Phycobiliprotein is a photosynthetic antenna pigment found in cyanobacteria, rhodophytes, cryptophytes and certain dinoflagellates, which has been found to have anti-oxidative and anti-tumour activities. In this paper, a recombinant allophycocyanin (rAPC) had been expressed in Escherichia coli for anti-tumour effect. E. coli cells were cultured using glucose fed-batch method to achieve high cell densities. The biomass of rAPC was up to 3.52 g/L broth. The rAPC was purified from soluble E. coli cell lysate employing hydrophobic interaction chromatographic (HIC) method developed at the bench scale using 20 mL column. The process was performed at the pilot scale using 500 mL column for evaluation of scale-up. An amylose affinity column was used to improve the purity of final product in pilot scale purification. The purification process resulted in greater than 98% pure product and yielded up to 2.0 g/kg wet cells at the bench scale and 1.2 g/kg wet cells at the pilot scale. Peptide mapping was used to prove the identity of rAPC purified from bench scale and pilot scale process. Purified rAPC at the pilot scale was found to have remarkable inhibition on S-180 carcinoma in mice. (c) 2005 Elsevier Ltd. All rights reserved.