Perception Study of Traditional Korean Medical Students on the Medical Education Using the Dundee Ready Educational Environment Measure

Background. In Korea, a few studies regarding traditional Korean medicine (TKM) education have been conducted. The aim of this study is to evaluate students’ perceptions regarding TKM education in Korea and compare them with those of other countries using a quantitative scale, Dundee Ready Educational Environment Measure (DREEM). Materials and Methods. We conducted a survey using DREEM in a TKM college. Totally, 325 students responded to this survey and we performed the descriptive statistics of scores in all items, subscales, and total. Additionally, subgroup comparisons according to gender, school year, and academic achievement were analyzed. Results. Mean overall DREEM score was 94.65 out of 200, which is relatively low compared to previous studies. Particularly, perceptions regarding subscales of learning, atmosphere, and self-perceptions were interpreted as problematic. There was no statistically significant difference between genders in spite of some differences among groups based on school year or academic achievement. Conclusions. We could examine students’ perceptions regarding TKM education at a TKM college using DREEM for which validity and reliability were verified. TKM education was perceived relatively poor, but these quantitative indicators suggested which parts of education need improvement. We expect DREEM to be used widely in TKM or traditional medical education field

Sign-tunable anomalous Hall effect induced by two-dimensional symmetry-protected nodal structures in ferromagnetic perovskite oxide thin films

Magnetism and spin-orbit coupling (SOC) are two quintessential ingredients underlying novel topological transport phenomena in itinerant ferromagnets. When spin-polarized bands support nodal points/lines with band degeneracy that can be lifted by SOC, the nodal structures become a source of Berry curvature; this leads to a large anomalous Hall effect (AHE). Contrary to three-dimensional systems that naturally host nodal points/lines, two-dimensional (2D) systems can possess stable nodal structures only when proper crystalline symmetry exists. Here we show that 2D spin-polarized band structures of perovskite oxides generally support symmetry-protected nodal lines and points that govern both the sign and the magnitude of the AHE. To demonstrate this, we performed angle-resolved photoemission studies of ultrathin films of SrRuO$_3$, a representative metallic ferromagnet with SOC. We show that the sign-changing AHE upon variation in the film thickness, magnetization, and chemical potential can be well explained by theoretical models. Our study is the first to directly characterize the topological band structure of 2D spin-polarized bands and the corresponding AHE, which could facilitate new switchable devices based on ferromagnetic ultrathin films

The evaluation of energy saving performance for the modular design centrifugal chiller

The modular concept design and operation of a centrifugal chiller offers the potential of increased cycle efficiency both at full load and off load conditions compared to the single compressor chiller. Modular chiller design is that a smaller, individual chiller can be connected with another, to make a larger capacity system. In the case of a tandem chiller, there would be faced to the higher initial cost or bigger foot print than a single compressor chiller at the same capacity because manufacturing cost, weight and size will be decreased according to increase of the refrigeration capacity. Therefore, it is obvious that a modular chiller have to be improved its efficiency first by both the operation algorithm and major cycle components. Eventually, the efficiency of the modular chiller achieves up to 6% at the full load condition after added series counter flow effect as much as 3% and more 3% added by improved aerodynamic design for impeller. Moreover, maximize off design potential through the capacity combination algorithm as the way of uneven loading makes 24% improved based on AHRI 550/590

Sodium-free synthesis of mesoporous zeolite to support Pt-Y alloy nanoparticles exhibiting high catalytic performance in propane dehydrogenation

© 2021 Elsevier Inc.Mesoporous zeolite-supported Pt3Y catalyst deactivates slowly in propane dehydrogenation, maintaining high propane conversion and propylene selectivity, but the formation of the intermetallic compound requires atomistic migration of yttrium through silanol nests on the zeolite. Compared to the cumbersome generation of silanols via framework demetallation, we report a direct synthesis of mesoporous MFI zeolite possessing silanol nests. The synthesis procedure employed a diammonium-type bromide surfactant [C18H37–N(CH3)2–C6H12–N(CH3)2–C4H9Br2] and a sodium-free silica source. The basicity of the synthesis mixture was adjusted by the addition of readily available N(CH3)4OH, instead of converting the surfactant to hydroxyl form. The presence of silanol nests in the resultant zeolite was confirmed by IR and NMR spectroscopies. When the zeolite was supported with 0.50 wt% Pt and 0.50 wt% Y using nitrate precursors, a remarkably long catalytic lifetime of 20 days was obtained with high propane conversion and propylene selectivity under the reaction condition using neat propane gas at 853 K.11Nsciescopu

Surface silanol sites in mesoporous MFI zeolites for catalytic Beckmann rearrangement

Silanol groups were generated in siliceous MFI zeolite nanosheets, via alkali-free synthesis routes, for catalytic application for gas-phase Beckmann rearrangement. The catalytic conversion by the zeolite nanosheets was investigated at 310 or 350 degrees C with cyclohexanone oxime, 4-phenylcyclohexanone oxime and cyclododecanone oxime. Here, cyclohexanone oxime was chosen as a small reactant that should be able to diffuse into the zeolite micropores, while the others were too bulky to diffuse. The catalytic conversion was analyzed in reference to a previous method used to generate hydrogen-bonded silanol nests in bulk-crystalline MFI zeolites using NH3/NH4+. The result of the analysis indicated that the silanol nest was necessary for the catalytic conversion of cyclohexanone oxime and 4-phenylcyclohexanone oxime, but isolated silanols on the external surface were sufficient for the reaction of cyclododecanone oxime.11Nsciescopu

Influence of catalyst pelletization on propane dehydrogenation over hierarchical MFI zeolite supported with platinum-yttrium nanoparticles

Platinum-yttrium (PtY) nanoparticles supported on a siliceous form of mesoporous MFI zeolite (MZ) were recently found to exhibit excellent catalytic performance in propane dehydrogenation (PDH). Herein, potential shaping of the PtY/MZ catalyst is investigated from the laboratory-synthesized powder form into industrially preferable pellets. The MZ zeolite powder was synthesized using multi-ammonium surfactants as a structure-directing agent and then pelletized in a hydraulic press by itself or with inorganic binders (i.e., pseudoboehmite, fumed silica, or hydrotalcite). As a part of the sequential pelletization process, pressing was followed by a high-temperature treatment (923 K). Addition of 20 wt% pseudoboehmite resulted in the highest mechanical strength without a significant loss of the initial zeolite mesoporosity. The pseudoboehmite-bound pellet also showed high catalytic activity and longevity in PDH application when simultaneously impregnated with 1 wt% Pt [Pt(NH3)4(NO3)2] and 1 wt% Y [Y(NO3)2·6H2O]. Notwithstanding the observed high propane conversion, the pseudoboehmite-bound catalyst produced an unsatisfactory result of low propylene selectivity (∼60%). Image analyses of HAADF-STEM EDS and solid-state 31P NMR spectroscopic data suggest that such findings could be attributed to Al migration from pseudoboehmite onto zeolite regime during the phase transformation of pseudoboehmite in the shaping process. Alternatively, the uses of non-acidic binders, such as fumed silica and hydrotalcite binders were also demonstrated. The silica-bound catalyst yielded high propane conversion with high propylene selectivity although mechanical strengths of the pellet were compromised to a moderate level. © 2023 Elsevier Inc.11Nsciescopu

A photoacoustic finder fully integrated with a solid-state dye laser and transparent ultrasound transducer

The standard-of-care for evaluating lymph node status in breast cancers and melanoma metastasis is sentinel lymph node (SLN) assessment performed with a handheld gamma probe and radioisotopes. However, this method inevitably exposes patients and physicians to radiation, and the special facilities required limit its accessibility. Here, we demonstrate a non-ionizing, cost-effective, handheld photoacoustic finder (PAF) fully integrated with a solid-state dye laser and transparent ultrasound transducer (TUT). The solid-state dye laser handpiece is coaxially aligned with the spherically focused TUT. The integrated finder readily detected photo acoustic signals from a tube filled with methylene blue (MB) beneath a 22 mm thick layer of chicken tissue. In live animals, we also photoacoustically detected both SLNs injected with MB and subcutaneously injected melanomas. We believe that our radiation-free and inexpensive PAF can play a vital role in SLN assessment.11Nsciescopu

Base-type nitrogen doping in zeolite-templated carbon for enhancement of carbon dioxide sorption

© 2022 The Authors.Nitrogen-doped microporous carbons were synthesized via pyrolytic carbonization of pyrrole in a FAU zeolite template, using a carbonization temperature of either 600 or 700 °C. The carbon products, which were freed by dissolution of the template, all possessed a zeolite-like ordered pore arrangement with a high specific surface area of 2300-2500 m2 g-1 and a sharp distribution of pore diameters centered at 0.9 nm. The N content was similarly 5 wt%, but X-ray photoelectron spectroscopy analysis indicated that the 600 °C-pyrolized carbon had a relatively higher content of base-type N atoms (i.e., pyridinic and pyrrolic) than non-basic N (graphenic and oxidic), compared to the case at 700 °C. The 600 °C-pyrolized carbon exhibited an outstandingly high CO2 uptake. A breakthrough test with a CO2-H2O-N2 mixture at 1 bar indicated that the 600 °C-pyrolized carbon could capture CO2 effectively under humid conditions. This result suggests that it is important for CO2 capture, to achieve a high N content when doping with pyridinic or pyrrolic N as the major species. The high adsorption performance of zeolite-template carbon was attributable to the higher content of pyridinic N and pyrrolic N over graphitic N in the carbon, which provided basicity resulting in a strong chemisorption interaction with CO2.11Nsciescopu

Improved Lung Cancer Detection in Ultra Low dose CT with Combined AI-based Nodule Detection and Denoising Techniques

In this study, we evaluated the synergy between the two artificial intelligence solutions by applying the deep learning based denoising technique to determine if the performance of the AI-based lung nodule detection solution is enhanced.N

CO2 capture performance of fluorinated porous carbon composite derived from a zinc-perfluoro metal-organic framework

© 2022 The AuthorsNanoporous carbon composite was derived via carbonization of a zinc-perfluoro metal organic framework {MOF: Zn-hfipbb (H2hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid))}. The MOF-derivative exhibits extra 0.5 nm and 5.5 nm pores in addition to 0.45 nm pores from bare Zn-hfipbb. Accordingly, BET surface areas (560–1000 m2 g−1) of Zn-hfipbb derived material greater than for Zn-hfipbb (360 m2 g−1) were obtained by varying carbonization temperatures in the range 500–900 °C, which trend is opposite those of other MOF derivative. The C-F bond of di-trifluoro on the aromatic ligand in an MOF structure is strong; therefore, some fluorine remains as C-F within the carbon structure after carbonization. The obtained MOF derived composite (carbonized at 700 °C) exhibits 5-times higher CO2 uptake than the pristine MOF does at 1000 kPa and 20 °C, and exhibits higher heat of adsorption for CO2 at zero-coverage. A breakthrough experiment using a CO2/N2 gas mixture (1:99 M ratio) demonstrated that Zn-hfippb derivative (carbonized at 700 °C) exhibits a longer breakthrough time and is repeatedly used as CO2 adsorbents under high humid condition.11Nsciescopu