Dual Fistulas of Ascending Aorta and Coronary Artery to Pulmonary Artery

Coronary artery fistula to pulmonary artery is common. However, to the best of our knowledge, a case of coronary artery fistula to pulmonary artery associated with aortopulmonary fistula remains unreported. We herein report a 64-year-old female with a left anterior descending coronary artery and ascending aorta to pulmonary artery fistulas, and conduct a brief review of the literature

Pharmacogenetics Meets Metabolomics: Discovery of Tryptophan as a New Endogenous OCT2 Substrate Related to Metformin Disposition

Genetic polymorphisms of the organic cation transporter 2 (OCT2), encoded by SLC22A2, have been investigated in association with metformin disposition. A functional decrease in transport function has been shown to be associated with the OCT2 variants. Using metabolomics, our study aims at a comprehensive monitoring of primary metabolite changes in order to understand biochemical alteration associated with OCT2 polymorphisms and discovery of potential endogenous metabolites related to the genetic variation of OCT2. Using GC-TOF MS based metabolite profiling, clear clustering of samples was observed in Partial Least Square Discriminant Analysis, showing that metabolic profiles were linked to the genetic variants of OCT2. Tryptophan and uridine presented the most significant alteration in SLC22A2-808TT homozygous and the SLC22A2-808G>T heterozygous variants relative to the reference. Particularly tryptophan showed gene-dose effects of transporter activity according to OCT2 genotypes and the greatest linear association with the pharmacokinetic parameters (Clrenal, Clsec, Cl/F/kg, and Vd/F/kg) of metformin. An inhibition assay demonstrated the inhibitory effect of tryptophan on the uptake of 1-methyl-4-phenyl pyrinidium in a concentration dependent manner and subsequent uptake experiment revealed differential tryptophan-uptake rate in the oocytes expressing OCT2 reference and variant (808G>T). Our results collectively indicate tryptophan can serve as one of the endogenous substrate for the OCT2 as well as a biomarker candidate indicating the variability of the transport activity of OCT2

Synthesis and Characterization of a Polyurethane Phase Separated to Nano Size in an Epoxy Polymer

Epoxy resins are widely applicable in the aircraft, automobile, coating, and adhesive industries because of their good chemical resistance and excellent mechanical and thermal properties. However, upon external impact, the crack propagation of epoxy polymers weakens the overall impact resistance of these materials. Therefore, many impact modifiers have been developed to reduce the brittleness of epoxy polymers. Polyurethanes, as impact modifiers, can improve the toughness of polymers. Although it is well known that polyurethanes (PUs) are phase-separated in the polymer matrix after curing, connecting PUs to the polymer matrix for enhancing the mechanical properties of polymers has proven to be challenging. In this study, we introduced epoxy functional groups into polyol backbones, which is different from other studies that focused on modifying capping agents to achieve a network structure between the polymer matrix and PU. We confirmed the molecular weight of the prepared PU via gel permeation chromatography. Moreover, the prepared material was added to the epoxies and the resulting mechanical and thermal properties of the materials were evaluated. Furthermore, we conducted tensile, flexural strength, and impact resistance measurements. The addition of PU to the epoxy compositions enhanced their impact strength and maintained their mechanical strength up to 10 phr of PU. Furthermore, the morphologies observed with field emission scanning electron microscopy and transmission electron microscopy proved that the PU was phase separated in the epoxy matrix

Self-Compliant Bipolar Resistive Switching in SiN-Based Resistive Switching Memory

Here, we present evidence of self-compliant and self-rectifying bipolar resistive switching behavior in Ni/SiNx/n+ Si and Ni/SiNx/n++ Si resistive-switching random access memory devices. The Ni/SiNx/n++ Si device’s Si bottom electrode had a higher dopant concentration (As ion > 1019 cm−3) than the Ni/SiNx/n+ Si device; both unipolar and bipolar resistive switching behaviors were observed for the higher dopant concentration device owing to a large current overshoot. Conversely, for the device with the lower dopant concentration (As ion < 1018 cm−3), self-rectification and self-compliance were achieved owing to the series resistance of the Si bottom electrode

Catalytic formation of acetic anhydride over tungstophosphoric acid modified SBA-15 mesoporous materials

Tungstophosphoric acid H3PW12O40 (TPA) was impregnated on mesoporous materials SBA-15 with pore sizes 91.9 and 63.9 A ° at different loadings. TPA-containing SBA-15 samples were synthesized with various TPA contents. The samples were characterized by means of XRD, FTIR, TEM, ICP, and N2 adsorption. For the impregnated samples, TPA species was finely dispersed. TPA IR spectrum was not detected for loading up to 1:5 (TPA:SBA-15, w:w) and became obvious with the increase in loading. The XRD diffraction peaks of HPAwere not found for samples with loading up to 1:4 and were very weak for the samples with loading 2:3, while the TPA XRD diffraction peaks of physical mixtures of TPA and mesoporous (1:10, w:w) were very strong. The chemically high-dispersed TPA species thus favored the selectivity of acetic anhydride catalytically condensed from acetic acid at 823 K. The bigger the pore size, the better the selectivity. For the directly synthesized TPA-containing samples, the chemically bound TPA species remained after hot water extraction at 373 K for 3 h. The selectivity of acetic anhydride was further increased to 96% over the TPA-containing sample with 6.37 wt.% of chemically bound TPA species, regardless of the smaller pore size (30.4 A ° ) compared to those of the TPA-impregnated samples, but the activity was decreased at low TPA content ( 3.37 wt.%). Generally, results revealed that the finely dispersed and chemically bound TPA species and pore size were responsible for the enhanced selectivity in our systems, bigger pore size favored both the activity and selectivity over samples with TPA loading 5 wt.%, while the pure bulk TPA showed no selectivity for acetic anhydride under investigation.the BK 21 Program of South Kore

4-bit Multilevel Operation in Overshoot Suppressed Al2O3/TiOx Resistive Random-Access Memory Crossbar Array

To apply resistive random-access memory (RRAM) to the neuromorphic system and improve performance, each cell in the array should be able to operate independently by reducing device variation. In addition, it is necessary to lower the operating current of the RRAM cell and enable gradual switching characteristics to mimic the low-energy operations of biological. In most filamentary RRAMs, however, overshoot current occurs in the forming stage, and the RRAM shows large device variation, high operating current, and abrupt set and reset switching characteristics. Herein, the shortcomings occurring in the forming stage are overcome by introducing and optimizing an overshoot suppression layer. Consequently, the RRAM exhibits gradual switching characteristics both in the set and reset regions, thereby enabling implementation of 4-bit multilevel operation. In addition, the forming step can be easily performed in a 16 x 16 crossbar array owing to its self-compliance characteristics without disturbing neighboring cells in the array. The tuning and vector-matrix multiplication (VMM) operations are also experimentally verified in the array. Finally, classification performance with off-chip training is compared in terms of accuracy and robustness to tuning tolerance depending on the number of bits of the implemented multiconductance levels.N