Myoblast proliferation and myotube formation are critical early events in skeletal muscle regeneration. The attending inflammation and cytokine signaling are involved in regulation of skeletal muscle ...cell proliferation and differentiation. Secretion of muscle-derived cytokines upon exposure to inflammatory factors may depend on the differentiation stage of regenerating muscle cells. Cultured human myoblasts and myotubes were exposed to 24-hour treatment with tumor necrosis factor (TNF)-α or lipopolysaccharide (LPS). Secretion of interleukin 6 (IL-6), a major muscle-derived cytokine, and interleukin 1 (IL-1), an important regulator of inflammatory response, was measured 24 hours after termination of TNF-α or LPS treatment. Myoblasts pretreated with TNF-α or LPS displayed robustly increased IL-6 secretion during the 24-hour period after removal of treatments, while IL-1 secretion remained unaltered. IL-6 secretion was also increased in myotubes, but the response was less pronounced compared with myoblasts. In contrast to myoblasts, IL-1 secretion was markedly stimulated in LPS-pretreated myotubes. We demonstrate that preceding exposure to inflammatory factors stimulates a prolonged upregulation of muscle-derived IL-6 and/or IL-1 in cultured skeletal muscle cells. Our findings also indicate that cytokine response to inflammatory factors in regenerating skeletal muscle partially depends on the differentiation stage of myogenic cells.
Belle experiment discovered two hadrons with exotic quark content
$Z_b^+\simeq \bar bb \bar du$. We present a lattice study of the $\bar bb\bar
du$ systems with various quantum numbers using static ...bottom quarks. Only one
set of quantum numbers that couples to $Z_b$ and $\Upsilon\;\pi$ was explored
on the lattice before: these studies found an attractive potential between $B$
and $\bar B^*$ which leads to a bound state below the threshold. In the present
study, we consider the other three sets of quantum numbers. Eigen-energies of
the $\bar bb \bar du$ system are extracted as a function of separation between
$b$ and $\bar b$. The resulting eigen-energies do not show any sizable
deviation from non-interacting energies of the systems $\bar bb+\bar du$ and
$\bar bu+\bar db$, so no significant attraction or repulsion is found. A slight
exception is a small attraction between $B$ and $\bar B^*$ at small distance
for the quantum number that couples to $Z_b$ and $\eta_b\;\rho$.
Phys. Rev. D 104 (2021) 114503 Two hadrons with exotic quark content $Z_b^+\simeq \bar bb \bar du$ were
discovered by Belle. We present a lattice study of the $\bar bb\bar du$ systems
with various ...quantum numbers using static bottom quarks. Only one set of
quantum numbers that couples to $Z_b$ and $\Upsilon\;\pi$ was explored on the
lattice before; these studies found an attractive potential between $B$ and
$\bar B^*$ resulting in a bound state below the threshold. The present study
considers the other three sets of quantum numbers. Eigenenergies of the $\bar
bb \bar du$ system are extracted as a function of separation between $b$ and
$\bar b$. The resulting eigenenergies do not show any sizable deviation from
noninteracting energies of the systems $\bar bb+\bar du$ and $\bar bu+\bar db$,
so no significant attraction or repulsion is found. A slight exception is a
small attraction between $B$ and $\bar B^*$ at small distance for the quantum
number that couples to $Z_b$ and $\eta_b\;\rho$.
Many mesons with properties incompatible with a $\bar cc$ structure have
already been discovered, e.g. the $Z_c$ mesons with isospin 1. We investigate
the spectrum of exotic charmonium-like mesons ...using lattice QCD. The focus is
on $\bar cc \bar qq$ states with $J^{PC}=1^{+\pm}$ and isospin 1. This is the
first study of four-quark states with these quantum numbers, a non-zero total
momentum and two different lattice volumes. We extract the energy levels and
determine the scattering length for $D\bar D^*$ scattering close to the
threshold using L\"uscher's formalism. Our preliminary results show that the
energy shifts for eigenstates dominated by $D\bar{D}^*$ are very small in the
$1^{++}$ channel and consistent with zero in the $1^{+-}$ channel.
Two hadrons with exotic quark content \(Z_b^+\simeq \bar bb \bar du\) were discovered by Belle. We present a lattice study of the \(\bar bb\bar du\) systems with various quantum numbers using static ...bottom quarks. Only one set of quantum numbers that couples to \(Z_b\) and \(\Upsilon\;\pi\) was explored on the lattice before; these studies found an attractive potential between \(B\) and \(\bar B^*\) resulting in a bound state below the threshold. The present study considers the other three sets of quantum numbers. Eigenenergies of the \(\bar bb \bar du\) system are extracted as a function of separation between \(b\) and \(\bar b\). The resulting eigenenergies do not show any sizable deviation from noninteracting energies of the systems \(\bar bb+\bar du\) and \(\bar bu+\bar db\), so no significant attraction or repulsion is found. A slight exception is a small attraction between \(B\) and \(\bar B^*\) at small distance for the quantum number that couples to \(Z_b\) and \(\eta_b\;\rho\).
Many exotic charmoniumlike mesons have already been discovered
experimentally, of which the $Z_c$ mesons with isospin 1 are prominent
examples. We investigate $J^{PC}=1^{+\pm}$ states with flavor ...$\bar cc \bar qq$
($q=u,d$) in isospin 1 using lattice QCD. This is the first study of these
mesons employing more than one volume and involving frames with nonzero total
momentum. We utilize two $N_f=2+1$ CLS ensembles with $m_{\pi}\simeq 280\,$MeV.
As the simulations are performed with unphysical quark masses and at a single
lattice spacing of $a=0.086\,$fm, our results provide only qualitative
insights. Resulting eigenenergies are compatible or just slightly shifted down
with respect to noninteracting energies, where the most significant shifts
occur for certain $D\bar D^*$ states. Both channels $1^{+\pm}$ have a virtual
pole slightly below the threshold if $D\bar D^*$ is assumed to be decoupled
from other channels. In addition, we perform a coupled channel analysis of
$J/\psi \pi$ and $D\bar D^*$ scattering with $J^{PC}=1^{+-}$ within an
effective field theory framework. The $J/\psi \pi$ and $D\bar D^*$
invariant-mass distributions from BESIII and finite-volume energies from
several lattice QCD simulations, including this work, are fitted
simultaneously. All fits yield two poles relatively close to the $D\bar D^*$
threshold and reasonably reproduce the experimental $Z_c$ peaks. They also
reproduce lattice energies up to slightly above the $D\bar{D}^*$ threshold,
while reproduction at even higher energies is better for fits that put more
weight on the lattice data. Our findings suggest that the employed effective
field theory can reasonably reconcile the peaks in the experimental line shapes
and the lattice energies, although those lie close to noninteracting energies.
We also study $J/\psi \pi$ scattering in s-wave and place upper bounds on the
phase shift.
Belle experiment discovered two hadrons with exotic quark content \(Z_b^+\simeq \bar bb \bar du\). We present a lattice study of the \(\bar bb\bar du\) systems with various quantum numbers using ...static bottom quarks. Only one set of quantum numbers that couples to \(Z_b\) and \(\Upsilon\;\pi\) was explored on the lattice before: these studies found an attractive potential between \(B\) and \(\bar B^*\) which leads to a bound state below the threshold. In the present study, we consider the other three sets of quantum numbers. Eigen-energies of the \(\bar bb \bar du\) system are extracted as a function of separation between \(b\) and \(\bar b\). The resulting eigen-energies do not show any sizable deviation from non-interacting energies of the systems \(\bar bb+\bar du\) and \(\bar bu+\bar db\), so no significant attraction or repulsion is found. A slight exception is a small attraction between \(B\) and \(\bar B^*\) at small distance for the quantum number that couples to \(Z_b\) and \(\eta_b\;\rho\).
Many mesons with properties incompatible with a \(\bar cc\) structure have already been discovered, e.g. the \(Z_c\) mesons with isospin 1. We investigate the spectrum of exotic charmonium-like ...mesons using lattice QCD. The focus is on \(\bar cc \bar qq\) states with \(J^{PC}=1^{+\pm}\) and isospin 1. This is the first study of four-quark states with these quantum numbers, a non-zero total momentum and two different lattice volumes. We extract the energy levels and determine the scattering length for \(D\bar D^*\) scattering close to the threshold using L\"uscher's formalism. Our preliminary results show that the energy shifts for eigenstates dominated by \(D\bar{D}^*\) are very small in the \(1^{++}\) channel and consistent with zero in the \(1^{+-}\) channel.
Many exotic charmoniumlike mesons have already been discovered experimentally, of which the \(Z_c\) mesons with isospin 1 are prominent examples. We investigate \(J^{PC}=1^{+\pm}\) states with flavor ...\(\bar cc \bar qq\) (\(q=u,d\)) in isospin 1 using lattice QCD. This is the first study of these mesons employing more than one volume and involving frames with nonzero total momentum. We utilize two \(N_f=2+1\) CLS ensembles with \(m_{\pi}\simeq 280\,\)MeV. As the simulations are performed with unphysical quark masses and at a single lattice spacing of \(a=0.086\,\)fm, our results provide only qualitative insights. Resulting eigenenergies are compatible or just slightly shifted down with respect to noninteracting energies, where the most significant shifts occur for certain \(D\bar D^*\) states. Both channels \(1^{+\pm}\) have a virtual pole slightly below the threshold if \(D\bar D^*\) is assumed to be decoupled from other channels. In addition, we perform a coupled channel analysis of \(J/\psi \pi\) and \(D\bar D^*\) scattering with \(J^{PC}=1^{+-}\) within an effective field theory framework. The \(J/\psi \pi\) and \(D\bar D^*\) invariant-mass distributions from BESIII and finite-volume energies from several lattice QCD simulations, including this work, are fitted simultaneously. All fits yield two poles relatively close to the \(D\bar D^*\) threshold and reasonably reproduce the experimental \(Z_c\) peaks. They also reproduce lattice energies up to slightly above the \(D\bar{D}^*\) threshold, while reproduction at even higher energies is better for fits that put more weight on the lattice data. Our findings suggest that the employed effective field theory can reasonably reconcile the peaks in the experimental line shapes and the lattice energies, although those lie close to noninteracting energies. We also study \(J/\psi \pi\) scattering in s-wave and place upper bounds on the phase shift.
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