13,024 research outputs found
Photoproduction with Nucleon Resonances
We investigate the reaction mechanism of photoproduction off
the neutron target, i.e., , in the range of GeV. We employ an effective Lagrangian method at the tree-level Born
approximation combining with a Regge approach. As a background, the
-Reggeon trajectory is taken into account in the channel and
and hyperons in the -channel Feynman diagram. In addition, the role
of various nucleon resonances listed in the Particle Data Group (PDG) is
carefully scrutinized in the channel where the resonance parameters are
extracted from the experimental data and constituent quark model. We present
our numerical results of the total and differential cross sections and compare
them with the recent CLAS data. The effect of the narrow nucleon resonance
on cross sections is studied in detail and it turns out that
its existence is essential in photoproduction to reproduce the
CLAS data.Comment: 4 pages, 3 figures, Proceedings of "8th International Conference on
Quarks and Nuclear Physics (QNP2018)", November 13-17, 2018, Tsukuba, Japa
Parity-violating coupling constant from the flavor-conserving effective weak chiral Lagrangian
We investigate the parity-violating pion-nucleon-nucleon coupling constant
, based on the chiral quark-soliton model. We employ an effective
weak Hamiltonian that takes into account the next-to-leading order corrections
from QCD to the weak interactions at the quark level. Using the gradient
expansion, we derive the leading-order effective weak chiral Lagrangian with
the low-energy constants determined. The effective weak chiral Lagrangian is
incorporated in the chiral quark-soliton model to calculate the
parity-violating constant . We obtain a value of about
at the leading order. The corrections from the next-to-leading order
reduce the leading order result by about 20~\%.Comment: 12 page
Heavy pentaquark states and in the production induced by pion beams off the nucleon
In this study, we investigate the production induced by pion beams
off the nucleon, particularly the heavy pentaquarks and
in intermediate states, based on a hybridized Regge model. The process
involving and meson exchange in the channel is considered as
background, and the heavy pentaquark exchange is included in the channel.
The coupling constants such as the and vertices are taken
from the potentials, whereas those for the and
vertices are determined by using experimental data based on the
branching ratios. In order to estimate the and coupling
constants, we use the experimental upper limit on the total cross section as a
guide for the reaction. The background total cross section
is the order of nb. In the vicinity of the heavy pentaquark
masses, the total cross section reaches about nb.Comment: 13 pages, 6 figures. To be published in Phys. Lets.
Therapeutic effects of epigallocatechin gallate on streptozotocin-induced diabetic nephropathy in mice.
Diabetic nephropathy is one of the most serious complications in diabetes mellitus and has been the most common cause of end-stage renal disease. Green tea extracts have antioxidant properties, and (-)-epigallocatechin 3-O-gallate (EGCG) is known to be the most abundant in green tea. Osteopontin (OPN) is a large phosphoglycoprotein adhesion molecule, and has emerged as a potentially key pathophysiologic contributor in diabetic nephropathy. We examined whether EGCG could amelliorate the development of diabetic nephropathy and its role of OPN. The mice (n=28) were divided into 3 groups. Control group (n=7) was intraperitoneal (IP) injected 0.9% saline, Streptozotocin (STZ) group (n=7) was IP injected STZ 200mg/Kg and induced diabetic nephropathy. After a 8weeks, EGCG groups (n=7/each group) were received EGCG 50mg/kg and 100mg/kg body weight by subcutaneous injection. Serum glucose, blood urea nitrogen, serum creatinine, urine volume and urine protein amounts were measured. Western blot assay of OPN was compared for the different groups. Histopathologic examination and immunohistochemical staining of mice kidney were performed. Compared with control group, STZ-group showed an increase in blood glucose, blood urea nitrogen, creatinine levels and urine protein amounts, and a decrease in body weight. All the above parameters were significantly reversed with EGCG treatment. After STZ injection, there were an diabetic glomerulosclerosis with increased renal OPN accumulation and its protein expression in the kidney cortex. EGCG-treated mice kidney showed a reduced expression of above parameters and an reserved pathologic findings. These results suggest that EGCG ameliorates STZ-induced diabetic nephropathy by OPN suppression. The potential use of EGCG in the treatment of diabetic nephropathy should be further explored
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