191 research outputs found
Combined sizing and layout optimization of truss structures via update Monte Carlo tree search (UMCTS) algorithm
The main concern of this study is to find the optimal design of truss
structures considering sizing and layout variables simultaneously. As compared
to purely sizing optimization problems, this problem is more challenging since
the two types of variables involved are fundamentally different in nature. In
this paper, a reinforcement learning method combining the update process and
Monte Carlo tree search called the update Monte Carlo tree search (UMCTS) for
sizing optimization problems is applied to solve combined sizing and layout
optimization for truss structures. This study proposes a novel update process
for nodal coordinates with two features. (1) The allowed range of each
coordinate varies in each round. (2) Accelerators for the number of entries in
the allowed range and iteration numbers are introduced to reduce the
computation time. Furthermore, nodal coordinates and member areas are
determined at the same time with only one search tree in each round. The
validation and efficiency of the UMCTS are tested on benchmark problems of
planar and spatial trusses with discrete sizing variables and continuous layout
variables. It is shown that the CPU time of the UMCTS is two times faster than
the branch and bound method. The numerical results demonstrate that the
proposed method stably achieves a better solution than other traditional
methods.Comment: 25 pages, 19 figures, 7 tables. arXiv admin note: text overlap with
arXiv:2309.0604
Phenotype Conversion of Salivary Gland Cells
Four major kallikreins (mK1, mK22, mK9, and mK13) were identified in the mouse submandibular gland (SMG). mK1, a true tissue kallikrein, was used as a protein marker to identify different types of SMG granular convoluted tubule (GCT) cells along with epidermal growth factor (EGF), nerve growth factor (NGF), and renin. Kallikrein mK1 was localized in a very small number (~5%) of GCT cells, which were scattered throughout the GCT, indicating that the majority of GCT cells are mK1-negative. Among mK1-positive cells, particularly strong signals were observed in a small number of narrow cells, recognized as slender granular cells (SG cells, Type IV), in the GCT. After postnatal development of the SMG, GCT cells are no longer uniform based on the bioactive substances (mK1, EGF, NGF, and renin) that they produce and secrete. GCT cells were classified into four subtypes, Types I–IV, and it became clear that these subtypes are complicatedly and reversibly converted by the endocrine hormones 5α-dihydrotestosterone (DHT) and triiodothyronine (T3). Duct segments with similar morphology or hormone dependency were recognized in the sublingual and parotid glands. The presence of duct cells with such characteristics is therefore a common feature of the three major salivary glands of rodents
Dynamics of Salivary Gland AQP5 under Normal and Pathologic Conditions
Aquaporin 5 (AQP5) plays an important role in the salivary gland function. The mRNA and protein for AQP5 are expressed in the acini from embryonic days E13-16 and E17-18, respectively and for entire postnatal days. Ligation-reopening of main excretory duct induces changes in the AQP5 level which would give an insight for mechanism of regeneration/self-duplication of acinar cells. The AQP5 level in the submandibular gland (SMG) decreases by chorda tympani denervation (CTD) via activation autophagosome, suggesting that its level in the SMG under normal condition is maintained by parasympathetic nerve. Isoproterenol (IPR), a β-adrenergic agonist, raised the levels of membrane AQP5 protein and its mRNA in the parotid gland (PG), suggesting coupling of the AQP5 dynamic and amylase secretion-restoration cycle. In the PG, lipopolysaccharide (LPS) is shown to activate mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signalings and potentially downregulate AQP5 expression via cross coupling of activator protein-1 (AP-1) and NF-κB. In most species, Ser-156 and Thr-259 of AQP5 are experimentally phosphorylated, which is enhanced by cAMP analogues and forskolin. cAMP-dependent phosphorylation of AQP5 does not seem to be markedly involved in regulation of its intracellular traffcking but seems to play a role in its constitutive expression and lateral diffusion in the cell membrane. Additionally, Ser-156 phosphorylation may be important for cancer development
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