Development of the MICROMEGAS Detector for Measuring the Energy Spectrum of Alpha Particles by using a 241-Am Source

We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting {\alpha} particles emitted from an 241-Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room temperature and atmospheric pressure. The energy of {\alpha} particles from the 241-Am source can be varied by changing the flight path of the {\alpha} particle from the 241 Am source. The channel numbers of the experimentally-measured pulse peak positions for different energies of the {\alpha} particles are associated with the energies deposited by the alpha particles in the ionization region of the detector as calculated by using GEANT4 simulations; thus, the energy calibration of the MICROMEGAS detector for {\alpha} particles is done. For the energy calibration, the thickness of the ionization region is adjusted so that {\alpha} particles may completely stop in the ionization region and their kinetic energies are fully deposited in the region. The efficiency of our MICROMEGAS detector for {\alpha} particles under the present conditions is found to be ~ 97.3 %

Prognostic Value of Metastatic Tumoral Caveolin-1 Expression in Patients with Resected Gastric Cancer

Objective. Caveolin-1 (Cav-1), as the main component of caveolae, has complex roles in tumourigenesis in human malignancies. We investigated Cav-1 in primary and metastatic tumor cells of gastric cancer (GC) and its association with clinical outcomes. Methods. We retrieved 145 cases of GC who had undergone curative gastrectomy. The expression levels of Cav-1 was evaluated by immunohistochemistry, and its association with clinicopathological parameters and patient survival was analyzed. Results. High expression of Cav-1 protein of the GC in the stomach and metastatic lymph node was 12.4% (18/145) and 16.5% (15/91). In the multivariate analysis, tumoral Cav-1 protein in metastatic lymph node showed prognostic significance for relapse-free survival (RFS, HR, 3.934; 95% CI, 1.882–8.224; P=0.001) and cancer-specific survival outcome (CSS, HR, 2.681; 95% CI, 1.613–8.623; P=0.002). Among the GCs with metastatic lymph node, it remained as a strong indicator of poor prognosis for RFS (HR, 3.136; 95% CI, 1.444–6.810; P=0.004) and CSS (HR, 2.509; 95% CI, 1.078–5.837; P=0.032). Conclusion. High expression of tumoral Cav-1 protein in metastatic lymph node is associated with unfavorable prognosis of curative resected GC, indicating the potential of novel prognostic markers

Osteogenic Effect of Inducible Nitric Oxide Synthase (iNOS)-Loaded Mineralized Nanoparticles on Embryonic Stem Cells

Background/Aims: This study investigated the effect of inducible nitric oxide synthase-loaded mineralized nanoparticles (iNOS-MNPs) on the osteogenic differentiation of mouse embryonic stem cells (ESCs). Methods: We prepared iNOS-MNPs using an anionic block copolymer template-mediated calcium carbonate (CaCO3) mineralization process in the presence of iNOS. iNOS-MNPs were spherical and had a narrow size distribution. iNOS was stably loaded within MNPs without denaturation. In order to confirm the successful introduction of iNOS-MNPs into the cytosol of ESCs, intracellular levels of nitric oxide (NO) was determined with a fluorometric analysis. A NO effector molecule, cyclic guanosine 3’,5’ monophosphate (cGMP) was also quantified with a competitive enzyme immunoassay. Cell viability in response to iNOS-MNP treatment was determined using the cell counting kit-8 (CCK-8) assay. Alkaline phosphatase (ALP) activity assay, intracellular calcium quantification assay, and Alizarin red S staining for matrix mineralization were performed to investigate osteogenic differentiation of ESCs. The protein levels of Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osterix (OSX) as osteogenic-related factors were also assessed by immunofluorescence staining and Western blot analysis. The complex pathways associated with iNOS-MNP-derived osteogenic differentiation of ESCs were evaluated by network-based analysis. Results: Cells with iNOS-MNPs displayed a significant increase in NO and cGMP concentration compared with the control group. When cells were exposed to iNOS-MNPs, there were no adverse effects on cell viability. Importantly, iNOS-MNP uptake promoted the osteogenic differentiation of ESCs. Using transcriptome profiling, we obtained 1,836 differentially-induced genes and performed functional enrichment analysis with ClueGO and KEGG. These analyses identified significantly enriched and interconnected molecular pathways such as protein kinase activity, estrogen receptor activity, bone morphogenetic protein (BMP) receptor binding, ligand-gated ion channel activity, and phosphatidylinositol 3-phosphate binding. Conclusion: These findings suggest that iNOS-MNPs can induce osteogenic differentiation in ESCs by integrating complex signaling pathways