Possible S-wave Dibaryons in SU(3) Chiral Quark Model

In the framework of the SU(3) chiral quark model, the $S-$wave baryon-baryon bound states are investigated. It is found that according to the symmetry character of the system and the contributions from chiral fields, there are three types of bound states. The states of the first type, such as $[\Omega\Omega]_{(0,0)}$ and $[\Xi^{*}\Omega]_{(0,1/2)}$ are deeply bound dibaryon with narrow widths. The second type states, $[\Sigma^{*} \Delta]_{(0,5/2)}$,$[\Sigma^{*} \Delta]_{(3,1/2)}$, $[\Delta\Delta]_{(0,3)}$ and $[\Delta\Delta]_{(3,0)}$ are also bound states, but with broad widths. $[\Xi\Omega - \Xi^{*}\Omega]_{(1,1/2)}$, $[\Xi\Xi]_{(0,1)}$, and $[N \Omega]_{(2,1/2)}$ are third type states. They, like {\em d}, are weakly bound only if the chiral fields can provide attraction between baryons.Comment: Latex files, 1 figur

Deltaron Dibaryon Structure in Chiral SU(3) Quark Model

We discuss the structure of Deltaron dibaryon in the chiral SU(3) quark model. The energy of Deltaron is obtained by considering the coupling of the $\Delta\Delta$ and $CC$ (hidden color) channels. The effects of various parameters on the Deltaron mass are also studied. It is shown that the mass of Deltaron is lower than the mass of $\Delta\Delta$ but higher than the mass of $\Delta N \pi$.Comment: 15 pages, Late

N-N Interactions in the Extended Chiral SU(3) Quark Model

The chiral SU(3) quark model is extended to include coupling between vector chiral field and quarks. By using this model, the phase shifts of NN scattering for different partial waves are studied. The results are very similar to those of the chiral SU(3) quark model calculation, in which one gluon exchange (OGE) plays dominate role in the short range part of the quark-quark interactions. Only in the $^1S_0$ case, the one channel phase shifts of the extended chiral SU(3) quark model are obviously improved.Comment: 15 pages, 6 figure

A study of pentaquark Θ\Theta state in the chiral SU(3) quark model

The structure of the pentaquark state uudd-sbar is studied in the chiral SU(3) quark model as well as in the extended chiral SU(3) quark model, in which the vector meson exchanges are included. Four configurations of JP=1/2- and four of JP=1/2+ are considered. The results show that the isospin T=0 state is always the lowest one for both JP=1/2- and JP=1/2+ cases in various models. But the theoretical value of the lowest one is still about 200-300 MeV higher than the experimental mass of $\Theta$. It seems that a dynamical calculation should be done for the further study.Comment: 9 page

Possible Dibaryons with Strangeness s=-5

In the framework of $RGM$, the binding energy of the six quark system with strangeness s=-5 is systematically investigated under the SU(3) chiral constituent quark model. The single $\Xi^*\Omega$ channel calculation with spins S=0 and 3 and the coupled $\Xi\Omega$ and $\Xi^*\Omega$ channel calculation with spins S=1 and 2 are considered, respectively. The results show following observations: In the spin=0 case, $\Xi^* \Omega$ is a bound dibaryon with the binding energy being $80.0 \sim 92.4 MeV$. In the S=1 case, $\Xi\Omega$ is also a bound dibaryon. Its binding energy is ranged from $26.2 MeV$ to $32.9 MeV$. In the S=2 and S=3 cases, no evidence of bound dibaryons are found. The phase shifts and scattering lengths in the S=0 and S=1 cases are also given.Comment: 10 pages, late

Comparative Analysis of Crack Resistance of Fiber Metal Laminates with HS2 Glass/T700 Carbon Layers for Various Stress Ratios

Because of good crack growth resistance owe to the fibers between the aluminum layers, fiber metal laminates (FML) offer significant improvements compared to currently applied materials for aircraft structures. The crack resistance of different reinforced fibers, glass fiber, and carbon fiber, under stress ratio R = -1, 0.1, and 0.5, respectively, are analyzed through test data. The results showed significant scatter in the positive stress ratio and obvious difference between two outer aluminum layers. So, the failure criterions of metal materials specified in the test standard are unsuitable for the FMLs fatigue test, and it is a problem to determine the failure criterion according to the engineering applications. This study is an experimental investigations with respect to the FMLs crack resistance and a qualitative conclusions have been drawn from the data analysis

Correlation between chemical composition, EHGE and TME of corn for ducks

Correlations between chemical composition, enzymatic hydrolysate gross energy (EHGE), and true metabolizable energy (TME) of corn for ducks were investigated. Twenty-two corn samples were collected from various regions in 11 provinces of China. The crude protein (CP), ether extract (EE), neutral detergent fibre (NDF), Ash, gross energy (GE), dry matter (DM), amylopectin (AP), amylose (AM), total starch (TS), and AP/AM were determined for each sample. Five of the samples of corn were chosen at the mean, mean ± 1 standard deviation (SD), and mean ± 2 SD based on AP/AM. The EHGE of these samples was analysed using the pepsin-artificial small intestinal fluid enzymatic method. These five samples were also force-fed to male Cherry Valley ducks to assay their TME. Finally, correlation analyses were performed, and regression equations were established. Ash content, GE, and TS were highly related to EHGE. Univariate prediction equations were EHGE = 11.8566Ash-0.0421 (P <0.05), EHGE = 0.1535GE1.5642 (P <0.05), and EHGE = 0.1020TS1.1561 (P <0.05). The total starch, AP/AM, and ash of the chemical compositions were highly related to TME. The corresponding univariate regression equations were TME = 21.9355TS-0.0910 (P <0.05), TME = 15.6590AP/AM-0.0559 (P <0.05), and TME = 15.0778Ash0.0442 (P <0.05). The mean EHGE was equivalent to 78.5% of TME, but their correlation coefficient was low. In conclusion, chemical composition was predictive of EHGE and TME of corn samples for ducks, but the correlation of EHGE and TME was low Keywords: Cherry Valley duck, amylopectin, amylose, true metabolizable energ

Activation of angiotensin type 2 receptors prevents diabetic complications in female db/db mice by nitric oxide‐mediated mechanisms

Background and Purpose: The AT2 receptor plays a role in metabolism by opposing the actions triggered by the AT1 receptors. Activation of AT2 receptors has been shown to enhance insulin sensitivity in both normal and insulin resistance animal models. In this study, we investigated the mechanism by which AT2 receptors activation improves metabolism in diabetic mice. Experimental Approach: Female diabetic (db/db) and non-diabetic (db/+) mice were treated for 1 month with the selective AT2 agonist, compound 21 (C21, 0.3 mg·kg−1·day−1, s.c.). To evaluate whether the effects of C21 depend on NO production, a subgroup of mice was treated with C21 plus a sub-pressor dose of the NOS inhibitor l-NAME (0.1 mg·ml−1, drinking water). Key Results: C21-treated db/db mice displayed improved glucose and pyruvate tolerance compared with saline-treated db/db mice. Also, C21-treated db/db mice showed reduced liver weight and decreased hepatic lipid accumulation compared with saline-treated db/db mice. Insulin signalling analysis showed increased phosphorylation of the insulin receptor, Akt and FOXO1 in the livers of C21-treated db/db mice compared with saline-treated counterparts. These findings were associated with increased adiponectin levels in plasma and adipose tissue and reduced adipocyte size in inguinal fat. The beneficial effects of AT2 receptors activation were associated with increased eNOS phosphorylation and higher levels of NO metabolites and were abolished by l-NAME. Conclusion and Implications: Chronic C21 infusion exerts beneficial metabolic effects in female diabetic db/db mice, alleviating type 2 diabetes complications, through a mechanism that involves NO production.Fil: Dominici, Fernando Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Veiras, Luciana Cecilia. Cedars Sinai Medical Center; Estados UnidosFil: Shen, Justin Z.Y.. Cedars Sinai Medical Center; Estados UnidosFil: Bernstein, Ellen A.. Cedars Sinai Medical Center; Estados UnidosFil: Quiroga, Diego Tomás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Steckelings, Ulrike M.. University of Southern Denmark; DinamarcaFil: Bernstein, Kenneth E.. Cedars Sinai Medical Center; Estados UnidosFil: Giani, Jorge F.. Cedars Sinai Medical Center; Estados Unido

Further study on 5q configuration states in the chiral SU(3) quark model

The structure of the $5q$ configuration states with strangeness ${\cal{S}}=+1$ is further studied in the chiral SU(3) quark model based on our previous work. We calculate the energies of fifteen low configurations of the $5q$ system, four lowest configurations of $J^{\pi}={1/2}^-$ with $4q$ partition $[4]_{orb}(0s^4)[31]^{\sigma f}$, four of $J^{\pi}={1/2}^+$ with $4q$ partition $[31]_{orb}(0s^30p)[4]^{\sigma f}$ and seven of $J^{\pi}={1/2}^+$ with $4q$ partition $[4]_{orb}(0s^30p)[31]^{\sigma f}$. Some modifications are made in this further study, i.e., the orbital wave function is extended as an expansion of 4 different size harmonic oscillator forms; three various forms (quadratic, linear and error function form) of the color confinement potential are considered; the states with $4q$ partition $[4]_{orb}(0s^30p)[31]^{\sigma f}$ are added, which are unnegligible in the $J^{\pi}={1/2}^+$ case and were not considered in our previous paper, further the mixing between configurations $[31]_{orb}(0s^30p)[4]^{\sigma f}$ and $[4]_{orb}(0s^30p)[31]^{\sigma f}$ is also investigated. The results show that the T=0 state is still always the lowest one for both $J^{\pi}={1/2}^-$ and $J^{\pi}={1/2}^+$ states, and $J^{\pi}={1/2}^-, T=0$ state is always lower than that of $J^{\pi}={1/2}^+$. All of these modifications can only offer several tens to hundred MeV effect, and the theoretical value of the lowest state is still about 245 MeV higher than the experimental mass of $\Theta^+$. It seems to be difficult to get the calculated mass close to the observed one with the reasonable parameters in the framework of the chiral SU(3) quark model when the model space is chosen as a $5q$ cluster.Comment: 16 page

Discovery of New Natural Products by Intact-Cell Mass Spectrometry and LC-SPE-NMR: Malbranpyrroles, Novel Polyketides from Thermophilic Fungus Malbranchea sulfurea

Six photosensitive polyketides, malbranpyrroles A-F, were discovered from the thermophilic fungus Malbranchea sulfurea by using intact-cell desorption/ionization on silicon mass (ICD-MS) and LC-SPE-NMR. These two strategies facilitate the searching and structural determination of unstable natural products. The ICD-MS indicated that only brown hyphae of M. sulfurea can produce malbranpyrroles. The biosynthetic pathway of malbranpyrroles was evidenced by (13)C isotope precursors and amino acid feeding experiments. The cytotoxicity data revealed that the conformation of the conjugated system in malbranpyrroles does not affect cytotoxic potency against cancer cell lines. In addition, the chlorine atom was shown to be the pharmacophore for cytotoxicity