Characterization of polygalacturonases produced by the endophytic fungus Penicillium brevicompactum in solid state fermentation - SSF

Polygalacturonases belong to the family of pectinases, enzymes that are in high demand in industry because of their many different applications. This study therefore sought to examine the production of polygalacturonases using an endophytic fungus, Penicilium brevicompactum, isolated from Baccharis dracunculifolia D.C. (Asteraceae) through semi solid fermentation using orange peels and citric pectin 2% as base substrate, supplemented with different carbon sources. After the fermentation process, the enzyme was characterized. The results showed that the micro-organism was able to use a wide range of carbon sources, but with polygalacturonase activity varying with each source. The highest yield, however, was achieved after 30 hours of incubation in the presence of 4% of galactose and 2% of pectin. Studies on the characterization of the polygalacturonase revealed that the optimal temperature of this enzyme is 72°C and that it maintains 60 and 15% of its maximum activity when incubated for 2 hours at 40 and 90°C, respectively. The optimal pH for the activity of the enzyme was 4.6. The enzyme retained 65 and 30% of its maximum activity when incubated at pH 3.5 and 9.5, respectively, for 24 hours at ambient temperature. The enzyme activity was stimulated by Mg2+ ions. On the other hand, it was inhibited by the ions Cs+2, Hg+2, Li+2 and Sr+2. The ions Zn+2 and Cu+2 inhibited it by 94% and 69%, respectively

Experimental antiproton nuclear stopping power in H2 and D2

Data about antiprotons slowing down in gaseous targets at very low energies (E<1 keV) show that the stopping power in D2 is lower than in H2; the right way to explain this behavior seems to be through a nuclear stopping power derived from the classical Rutherford formula

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

A STUDY OF PONTECORVO REACTIONS IN ANTIPROTON DEUTERIUM ANNIHILATIONS AT REST

The results of the analysis of a new data sample of (p) over bar annihilations at rest on deuterium and hydrogen, taken at the CERN LEAR by the OBELIX spectrometer, are presented. The (p) over bar d --> pi(-)p channel has been measured with a noticeable reduction of both the statistical and the systematic errors with respect to the previous OBELIX measurement and the branching ratio turns out to be (1.29 +/- +/- 0.07(stat) +/- 0.05(syst)).10(-5), in good agreement with the previous result. The (p) over bar d --> rho(-)p --> pi(-) pi(0)p channel has been investigated for the first time and the branching ratio is evaluated to be (2.9 +/- 0.4(stat) +/- 0.5(syst)).10(-5). Finally, as a check of the spectrometer absolute calibration, the (p) over bar p --> pi(+) pi(-) channel was also studied with a measured branching ratio of (4.27 +/- 0.15(stat) +/- 0.17(syst)).10(-3), in good agreement with the ASTERIX result. RI Galli, Domenico/A-1606-2012; Iazzi, Felice/F-4490-2012; Botta, Elena/G-9742-2012; Villa, Mauro/C-9883-2009; Fontana, Andrea/I-4375-2012; Filippi, Alessandra/I-9530-201

NEW RESULTS ON MESON SPECTROSCOPY FROM OBELIX

A preliminary final state analysis of a sample of np in-flight annihilations into three and five charged pions is presented. The partial-wave analysis of three-prong data confirms previous interpretations of the Ax/f2(1520) resonance, from ppBAR annihilations at rest. Concerning five-prong events our analysis favours spin 0 for the already reported zeta(1480) state, but more refined calculations are underway. At high nBAR momenta, the five-prong data show some evidence for a possible spin 2 state at 1640 MeV/c2 decaying in rho(o)rho(o). RI Galli, Domenico/A-1606-2012; Villa, Mauro/C-9883-2009; Filippi, Alessandra/I-9530-201

THE PHI-PI(+) OMEGA-PI(+) RATIO FROM (N)OVER-BAR-P ANNIHILATIONS

A preliminary study of up three-prong annihilations into the channels K- K+ pi(+) and pi(-)pi(+)pi(+)pi(0) is presented for similar to 100-297 MeV/c ($) over bar n momenta. The extracted phi pi(+)/omega pi(+) production ratio shows that also in this channel, never measured before using an ($) over bar n beam, the OZI rule is strongly violated. RI Galli, Domenico/A-1606-2012; Iazzi, Felice/F-4490-2012; Villa, Mauro/C-9883-2009; Filippi, Alessandra/I-9530-201

φπ0 and φη production in antiproton annihilation at rest in a hydrogen gas target at NTP

Data of antiproton annihilation at rest in a hydrogen gas target at NTP have been collected with the Obelix spectrometer exposed to the beam extracted from the LEAR accelerator of CERN. The reactions and have been studied. The analysis of the angular distribution of the kaons emitted by the φ decay has shown that the reaction occurs essentially from 3S1 states with a production rate RNTP = (2.46 ± 0.23 ± 0.07) × 10−4, while the rate from 1P1 states is compatible with zero. Because of acceptance limitations, 3S1 and 1P1 contributions to the reaction could not be resolved and lower and upper limits for the production rate have been measured with the middle value RNTP = (0.87 ± 0.21) × 10−4. Also, for the phase-space K+K−η events the production rate RNTP = (4.67 ± 0.35) × 10−4 has been measured. The φπ0 and φη branching ratios in S- and P-waves (defined in the text) have been estimated in a model dependent way. For the evaluation of the φη rate, a combination of our production rate and of data obtained with a liquid target has been used. The φπ0 production rate, compared to our preliminary value for the ωπ0 production, confirms the strong violation of the OZI rule observed in other experiments. No violation is apparent in the φη production

p̄p annihilation cross section at very low energy

The p̄p total annihilation cross section has been measured, with the Obelix apparatus at LEAR, at ten values of the antiproton incident momentum between 43 and 175 MeV/c. The values of the cross section show that the well known 1/p behaviour of the annihilation cross section is drastically modified at very low momenta, which demonstrates the important role of the Coulomb force in low energy p̄p interaction. Moreover, they do not present any explicit resonant behaviour. Finally, when compared to potential model calculations, the data suggest that the percentage of P-wave in p̄p interaction around 50 MeV/c antiproton incident momentum is less than 5%