The invariant spectra of
π
− mesons produced in (
π
+/K
+)p interactions at 250 GeV/
c are analysed in the framework of the hydrodynamical model of three-dimensionally expanding cylindrically ...symmetric finite systems. A satisfactory description of experimental data is achieved. The data favour the pattern according to which the hadron matter undergoes predominantly longitudinal expansion and non-relativistic transverse expansion with mean transverse velocity 〈
u
t〉=0.20±0.07, and is characterized by a large temperature inhomogeneity in the transverse direction: the extracted freeze-out temperature at the center of the tube and at the transverse rms radius are 140±3 MeV and 82±7 MeV, respectively. The width of the (longitudinal) space-time rapidity distribution of the pion source is found to be
Δη=1.36±0.02. Combining this estimate with results of the Bose-Einstein correlation analysis in the same experiment, one extracts a mean freeze-out time of the source of 〈
τ
f〉=1.4±0.1 fm/
c and its transverse geometrical rms radius,
R
G(rms)=1.2±0.2 fm.
Taking into account the anisotropy of phase space in multiparticle production, a self-affine analysis of factorial moments was carried out on the NA22 data for
π
+p and K
+p collisions at 250 GeV/
c. ...Within the transverse plane, the Hurst exponents measuring the anisotropy are consitent with unit value (i.e. no anisotropy). They are, however, only half that value when the longitudinal direction is compared to the transverse ones. Fractality, indeed, turns out to be self-affine rather than self-similar in multiparticle production. In three-dimensional phase space, power-law scaling is observed to be better realized in self-affine than in self-similar analysis.
Recently, we discovered a novel non-angiotensin type 1 (non-AT1), non-AT2 angiotensin binding site in rodent and human brain membranes, which is distinctly different from angiotensin receptors and ...key proteases processing angiotensins. It is hypothesized to be a new member of the renin-angiotensin system. This study was designed to isolate and identify this novel angiotensin binding site. An angiotensin analog, photoaffinity probe 125I-SBpa-Ang II, was used to specifically label the non-AT1, non-AT2 angiotensin binding site in mouse forebrain membranes, followed by a two-step purification procedure based on the molecular size and isoelectric point of the photoradiolabeled binding protein. Purified samples were subjected to two-dimensional gel electrophoresis followed by mass spectrometry identification of proteins in the two-dimensional gel sections containing radioactivity. LC-MS/MS analysis revealed eight protein candidates, of which the four most abundant were immunoprecipitated after photoradiolabeling. Immunoprecipitation studies indicated that the angiotensin binding site might be the membrane-bound variant of metalloendopeptidase neurolysin (EC 3.4.24.16). To verify these observations, radioligand binding and photoradiolabeling experiments were conducted in membrane preparations of HEK293 cells overexpressing mouse neurolysin or thimet oligopeptidase (EC 3.4.24.15), a closely related metalloendopeptidase of the same family. These experiments also identified neurolysin as the non-AT1, non-AT2 angiotensin binding site. Finally, brain membranes of mice lacking neurolysin were nearly devoid of the non-AT1, non-AT2 angiotensin binding site, further establishing membrane-bound neurolysin as the binding site. Future studies will focus on the functional significance of this highly specific, high affinity interaction between neurolysin and angiotensins.
Background: Angiotensin II, the renin-angiotensin system effector peptide, interacts with a recently discovered binding site that is distinctly different from its classic receptors.
Results: A radioiodinated angiotensin II photoprobe bound to a ∼75-kDa membrane protein, enabling its isolation and identification.
Conclusion: Membrane-bound metalloendopeptidase neurolysin (EC 3.4.24.16) is the novel angiotensin-binding protein.
Significance: This metalloendopeptidase may be a crucial component of the renin-angiotensin system.
The transverse energy carried by charged hadrons and by \({\pi}^-\) mesons is studied in interactions of \({\pi}^+\) and K\(^+\) mesons with protons and nuclei at 250 GeV/c. The data obtained on ...transverse energy flow at mid-rapidity can be described by the FRITIOF7.0 model with tuned parameters.
The recently discovered non‐AT1, non‐AT2 angiotensin binding site is hypothesized to be a new member of the renin‐angiotensin system. However, its identity remains unknown. To isolate and identify ...this protein, neonatal (P10) mouse forebrain homogenates were incubated with AT1 (ZD7155) & AT2 (PD123319) receptor antagonists, p‐chloromercuribenzoate and photoreactive ligand 125I‐SBpa Ang II (± Ang II to specifically identify the binding site). After exposure to UV light, membrane suspensions were pelleted and subjected to SDS/PAGE. Gel lanes were cut into 3mm segments and assayed for 125I. Specific binding of photolyzed radioligand was seen at 75kDa. Proteins extracted from this region were focused on an immobilized pH gradient strip. Migration of 125I was monitored in the strip. The radioactive segment (pI ≈ pH 5.5–6.5) was cut out and proteins were extracted. The protein extract was resolved by 2D gel electrophoresis and revealed by autoradiography. The region corresponding to the photolabeled protein was excised and analyzed by mass spectroscopy. LC‐MS/MS analysis identified ~10 candidate proteins with 9 – 27 peptide matches per protein identification. The ability of these candidate proteins to interact with angiotensins is being evaluated to identify this novel binding site. Supported by NHLBI HL‐096357, American Radiolabeled Chemicals & TTUHSC SOP start up funds.
Spike production is studied in pp and π
+p/K
+p collisions in the beam-momentum range of 205–360 GeV/c. The pseudorapidity distribution of spike centers exhibits two narrow peaks in pp interactions, ...while having one wide bump in πp and Kp interactions. The position of the peaks is consistent with the expectation from a model of coherent gluon radiation at finite length. The interference between the quark color amplitudes obtained within this model causes two off-center peaks in pp data, but only one central peak in πp and Kp data.
PDF
