276 research outputs found
Operad Structure of Poset Matrices
This paper examines operad structures derived from poset matrices by
formulating a set of new construction rules for poset matrices. In this
direction, eleven different partial composition operations will be introduced
as the basis for the construction of poset matrices of any given size by
extending the combinatorial setting of species of structures to poset matrices.
Three of these partial composition operations are shown to define an operad
structure for poset matrices. The structural properties of poset matrices and
their duals are then studied based on their associated operad constructions.Comment: arXiv admin note: substantial text overlap with arXiv:2212.1164
Trib2 regulates the pluripotency of embryonic stem cells and enhances reprogramming efficiency
Embryonic stem (ES) cells are pluripotent cells characterized by self-renewability and differentiation potential. Induced pluripotent stem (iPS) cells are ES cell-equivalent cells derived from somatic cells by the introduction of core reprogramming factors. ES and iPS cells are important sources for understanding basic biology and for generating therapeutic cells for clinical applications. Tribbles homolog 2 (Trib2) functions as a scaffold in signaling pathways. However, the relevance of Trib2 to the pluripotency of ES and iPS cells is unknown. In the present study, we elucidated the importance of Trib2 in maintaining pluripotency in mouse ES cells and in generating iPS cells from somatic cells through the reprogramming process. Trib2 expression decreased as ES cells differentiated, and Trib2 knockdown in ES cells changed their colony morphology while reducing the activity of alkaline phosphatase and the expression of the pluripotency marker genes Oct4, Sox2, Nanog and Klf4. Trib2 directly interacted with Oct4 and elevated Oct4 promoter activity. During the generation of iPS cells, Trib2 knockdown decreased the reprogramming efficiency of mouse embryonic fibroblasts, whereas Trib2 overexpression significantly increased their reprogramming efficiency. In summary, our results suggest that Trib2 is important for maintaining self-renewal in ES cells and for pluripotency induction during the reprogramming process
A Case of Papillary Thyroid Cancer Recurring as an Esophageal Submucosal Tumor
A 75-year-old woman who underwent a total thyroidectomy for papillary thyroid cancer 7 years previously presented with a palpable neck mass. Computed tomography (CT) showed two metastatic masses on the thyroid bed and another mass that looked benign originating from the esophageal wall. Endoscopic ultrasonography (EUS) showed a hypoechoic mass in the esophageal wall that looked similar to a gastrointestinal stromal tumor. The mass on the esophagus had intense fluorodeoxyglucose (FDG) uptake in positron emission tomography-computed tomography (PET-CT), which suggested the possibility of malignancy. Subsequently, after surgery, the mass in the esophagus was confirmed as a metastasis from the thyroid papillary carcinoma. Here we report this unusual case of papillary thyroid cancer that recurred as an esophageal submucosal tumor
Predisposing Factors of Ischemic Colitis: Data from 14 Years of Experience in a Single Center
Background and Aims. While several case reports on ischemic colitis (IC) suggest the presence of predisposing causative factors, a few studies have investigated the predisposing factors in IC. This study aimed to identify the characteristics of patients with IC, particularly focusing on the predisposing factors. Methods. We conducted a single-center, retrospective analysis of 159 patients with IC. Clinical characteristics, laboratory data, endoscopic findings, and medical records were reviewed. Data were compared between groups of patients defined according to the predisposing factors. The predisposing factors are defined as temporary states or episodic events occurring within a week before the development of IC such as colonoscopy, enema, use of laxatives, heavy drinking, pancreatitis, shock, and burn. Results. Compared to the group of patients without predisposing factors of IC, the group of patients with predisposing factors was characterized by a relatively higher prevalence of male sex (56.9% versus 33.3%, p=0.005), younger age (60.9 ± 15.4 versus 67.2 ± 13.4 years, p=0.010), lower incidence of hypertension (43.1% versus 60.2%, p=0.044), and fewer risk factors (1.24 ± 1.18 versus 1.82 ± 1.22, p=0.005). Conclusions. Among men with predisposing factors, IC may develop even at a relatively younger age and in the absence of multiple risk factors, suggesting that predisposing factors may be involved in the pathogenesis of IC
Comparison of Clinical Efficacy between a Single Administration of Long-Acting Gonadotrophin-Releasing Hormone Agonist (GnRHa) and Daily Administrations of Short-Acting GnRHa in In Vitro Fertilization-Embryo Transfer Cycles
This study was aimed to evaluate the efficacy of a single administration of long-acting gonadotrophin-releasing hormone agonist (GnRHa) as compared with daily administrations of short-acting GnRHa in controlled ovarian hyperstimulation (COH) for in vitro fertilization and embryo transfer (IVF-ET) cycles. The mean dosage of recombinant follicle-stimulating hormone (rFSH) required for COH (2,354.5±244.2 vs. 2,012.5±626.1 IU) and the rFSH dosage per retrieved oocyte (336.7±230.4 vs. 292.1±540.4 IU) were significantly higher in the long-acting GnRHa group (N=22) than those in the short-acting GnRHa group (N=28) (p<0.05). However, the mean number of visit to the hospital that was required before ovum pick-up (3.3±0.5 vs. 22.2±2.0) and the frequency of injecting GnRHa and rFSH (12.8±1.2 vs. 33.5±3.5) were significantly decreased in the long-acting GnRHa group (p<0.0001). The clinical pregnancy rate, implantation rate, and early pregnancy loss rate were not significantly different between the 2 groups. So, we suggest that a single administration of long-acting GnRHa is a useful alternative for improving patient's convenience with clinical outcomes comparable to daily administrations of short-acting GnRHa in COH for IVF-ET cycles
Ordered mesoporous porphyrinic carbons with very high electrocatalytic activity for the oxygen reduction reaction
The high cost of the platinum-based cathode catalysts for the oxygen reduction reaction (ORR) has impeded the widespread application of polymer electrolyte fuel cells. We report on a new family of non-precious metal catalysts based on ordered mesoporous porphyrinic carbons (M-OMPC; M = Fe, Co, or FeCo) with high surface areas and tunable pore structures, which were prepared by nanocasting mesoporous silica templates with metalloporphyrin precursors. The FeCo-OMPC catalyst exhibited an excellent ORR activity in an acidic medium, higher than other non-precious metal catalysts. It showed higher kinetic current at 0.9a&#65533;...V than Pt/C catalysts, as well as superior long-term durability and MeOH-tolerance. Density functional theory calculations in combination with extended X-ray absorption fine structure analysis revealed a weakening of the interaction between oxygen atom and FeCo-OMPC compared to Pt/C. This effect and high surface area of FeCo-OMPC appear responsible for its significantly high ORR activity.open251
Acute Oral Poisoning Due to Chloracetanilide Herbicides
Chloracetanilide herbicides (alachlor, butachlor, metachlor) are used widely. Although there are much data about chronic low dose exposure to chloracetanilide in humans and animals, there are few data about acute chloracetanilide poisoning in humans. This study investigated the clinical feature of patients following acute oral exposure to chloracetanilide. We retrospectively reviewed the data on the patients who were admitted to two university hospitals from January 2006 to December 2010. Thirty-five patients were enrolled. Among them, 28, 5, and 2 cases of acute alachlor, metachlor, butachlor poisoning were included. The mean age was 49.8 ± 15.4 yr. The poison severity score (PSS) was 17 (48.6%), 10 (28.6%), 5 (14.3%), 2 (5.7%), and 1 (2.9%) patients with a PSS of 0, 1, 2, 3, and 4, respectively. The age was higher for the symptomatic patients (1-4 PSS) than that for the asymptomatic patients (0 PSS) (43.6 ± 15.2 vs 55.7 ± 13.5). The arterial blood HCO3 ¯ was lower in the symptomatic patients (1-4 PSS) than that in the asymptomatic patients (0 PSS). Three patients were a comatous. One patient died 24 hr after the exposure. In conclusion, although chloracetanilide poisoning is usually of low toxicity, elder patients with central nervous system symptoms should be closely monitored and cared after oral exposure
Nanoporous Silicified Phospholipids and Application to Controlled Glycolic Acid Release
This work demonstrates the synthesis and characterization of novel nanoporous silicified phospholipid bilayers assembled inorganic powders. The materials are obtained by silicification process with silica precursor at the hydrophilic region of phospholipid bilayers. This process involves the co-assembly of a chemically active phospholipids bilayer within the ordered porosity of a silica matrix and holds promise as a novel application for controlled drug release or drug containers with a high level of specificity and throughput. The controlled release application of the synthesized materials was achieved to glycolic acid, and obtained a zero-order release pattern due to the nanoporosity
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