연료전지 및 바나듐 흐름전지 용 폴리설폰 소재 기반 음이온 교환막

정민석,Christopher Arges,Javier Parrondo,Vijay Ramani 한국막학회 2016 한국막학회 총회 및 학술발표회 Vol.2016 No.11

The water uptake, ionic conductivity, vanadium (VO2+) permeability and stability of polysulfone (PSF) based AEMs in alkaline media and in strongly oxidizing solutions were assessed. The highest ion conductivity was obtained with PSF-trimethylammonium (TMA)+. PSF-TMA+ also had better alkaline stability in comparison to PSF-AEM with different bases. PSF-TMA+ was demonstrated to show fuel cell performance. PSF-TMA+ demonstrated a 40-fold reduction in vanadium (VO2+) permeability when compared to Nafion® membrane. Comprehensive 2D NMR studies verified that PSF-TMA+ remained chemically stable even after exposure to a 1.5 M vanadium(V) solution for 90 days. Excellent energy efficiencies (85%) were attained and sustained over several charge–discharge cycles for a vanadium redox flow battery prepared using the PSF-TMA+ separator.

The Solvent Distribution Effect on the Self-Assembly of Symmetric Triblock Copolymers during Solvent Vapor Annealing

Xiong, Shisheng,Li, Dongxue,Hur, Su-Mi,Craig, Gordon S. W.,Arges, Christopher G.,Qu, Xin-Ping,Nealey, Paul F. American Chemical Society 2018 Macromolecules Vol.51 No.18

<P>Using a combination of systematic experiments and Monte Carlo simulations, this report demonstrates that the distribution of neutral solvent has a strong impact on the quality and kinetics of the self-assembly of block copolymers in thin films. Both methyl ethyl ketone (MEK, a good solvent) and acetone (a relatively poor solvent) were used for the solvent vapor annealing (SVA) of thin films of poly(2-vinylpyridine)-<I>block</I>-polystyrene-<I>block</I>-poly(2-vinylpyridine) (VSV) triblock copolymer. Acetone, the poorer solvent, accumulated at the interface of the VSV domains, while MEK was distributed more uniformly throughout the VSV. As a result, acetone screened the interactions between the blocks of the copolymer more than MEK. Because MEK afforded less screening of the different blocks, solvent annealing with MEK led to self-assembly of lower molecular weight VSV triblock copolymers than was possible with acetone. Solvent annealing with MEK also led to slower self-assembly kinetics and smaller correlation lengths in the assembled pattern compared to solvent annealing with acetone. Finally, long-range ordered structures of low molecular weight VSV triblock copolymer on a chemical pattern via directed self-assembly was demonstrated with 6× density multiplication by annealing in MEK.</P> [FIG OMISSION]</BR>

Participation of Potential Transient Receptors in the Antinociceptive Effect of Pharmacopuncture

Argôlo Isabella de Paula Ribeiro,Parisi Julia Risso,Silva Josie Resende Torres da,Silva Marcelo Lourenço da 사단법인약침학회 2022 Journal of Acupuncture & Meridian Studies Vol.15 No.2

Background: Despite the widespread clinical use of acupuncture in painful situations, the use of this treatment should be further clarified. Nociception is mediated by the activation of nociceptors, such as transient receptor potentials (TRPs). The family of TRPs includes TRPV1, TRPM8, and TRPA1, which can be stimulated by substances such as capsaicin, menthol, and methyl salicylate, respectively. Objectives: This study aimed to investigate the role of TRPs in antinociception via the administration of agonists of these receptors in the Zusanli acupoint (ST36) in models of inflammatory, acute, and neuropathic pain. Methods: Male Wistar rats were used for this experiment. All rats received a subcutaneous injection of TRP agonists (capsaicin, menthol, or methyl salicylate) in ST36; saline was injected as control. Nociception was evaluated using the electronic mechanical threshold test and tail-flick test before the administration of complete Freund’s adjunct or chronic constriction injury of the sciatic nerve and after the administration of TRP agonists. Results: Nociception was found to be attenuated after treatment with TRP agonists. The administration of different doses (0.03, 0.3, and 3.0 µg/20 µL) of capsaicin, menthol, and methyl salicylate in the different pain models (neuropathic, inflammatory, and nociceptive) induced antinociception in most of the evaluated time points. Conclusion: Based on the findings, we suggest that the activation of TRPV1, TRPM8, and TRPA1 receptors results in the antinociceptive effect of the stimulation of the ST36 acupoint. Thus, TRP receptors may present a new therapeutic opportunity for the control of inflammatory and neuropathic pain.

Ultrasound-Guided Ethanol Percutaneous Ablation Versus Rescue Surgery in Patients With Locoregional Recurrence of Papillary Thyroid Cancer

Santiago Tofé,Iñaki Argüelles,Cristina Álvarez,Álvaro Tofé,Alessandra Repetto,Antonia Barceló,Vicente Pereg 대한이비인후과학회 2023 Clinical and Experimental Otorhinolaryngology Vol.16 No.4

Objectives. Neck recurrence of papillary thyroid cancer (PTC) is frequently detected after initial surgery. The managementof these lesions may include rescue surgery (RS) or minimally invasive techniques in selected patients, but compara-tive studies evaluating the effectiveness and safety of these techniques are lacking. In this paper, we compared ultra-sound-guided ethanol ablation (EA) in selected patients to RS in a matched cohort. Methods. We retrospectively compared 41 patients and 41 matched PTC patients without known distant metastases, whounderwent ultrasound-guided EA or RS (matched reference group), who had 63 and 75 thyroid bed and/or lymphnode confirmed PTC recurrences during a median follow-up of 72.8 and 89.6 months, respectively. The primary out-come was time until structural recurrence, compared using Kaplan-Meier survival curves. The secondary outcomesincluded time until biochemical recurrence, plasma thyroglobulin (Tg) levels, American Thyroid Association (ATA) re-sponse-to-therapy categories by the last available observation, and treatment-derived complications in each group. Results. No significant differences were found between the EA and RS groups for time until structural recurrence (log-ranktest, P =0.94). The time until biochemical recurrence was also similar (P =0.51); and the plasma Tg concentration re-duction and proportions of patients in the ATA reclassification categories were also similar. A significantly higher pro-portion of patients in the RS group presented treatment-derived complications (29.27% vs. 9.75%, P <0.05). Conclusion. In this retrospective analysis, the treatment of PTC neck recurrence with EA in selected patients was compara-ble to RS in a matched reference group for the long-term risk of structural or biochemical relapse, but with a lowerrisk of treatment-derived complications. These results support the effectiveness and safety of this minimally invasivetechnique in the management of selected patients with recurrent PTC.

Ultrasound-Guided Percutaneous Ethanol Ablation for the Management of Recurrent Thyroid Cancer: Evaluation of Efficacy and Impact on Disease Course

Santiago Tofé,Iñaki Argüelles,Guillermo Serra,Honorato García,Antonia Barcelo,Vicente Pereg 대한갑상선학회 2020 International Journal of Thyroidology Vol.13 No.2

Background and Objectives: Neck recurrences of thyroid cancer are frequently detected in routine ultrasound (US)follow-up. Broad management of these lesions may include active surveillance, surgery or local percutaneoustechniques, but for the latter, little is known about impact on long-term follow-up and need of subsequentradioactive iodine (RAI) therapy. Materials and Methods: 42 patients underwent US-guided ethanol ablation (EA)over 71 thyroid bed or lymph node confirmed recurrences. All volume reduction >50%, absence of power Dopplersignal and fine needle aspiration (FNA) washout thyroglobulin (Tg) value <1 ng/mL should be present to considera complete ablation. Patients with TNM stage I-II, ≤2 lesions and/or baseline plasma TSH-suppressed Tg level <0.2ng/mL did not undergo post-EA RAI therapy. Post-EA plasma Tg values were compared to baseline in patientswith and without subsequent RAI therapy. Results: 62 lesions (87.32%) achieved a complete ablation after a meanfollow-up of 40.5 months (range, 12-73). Four treated lesions (5.63%) recurred (3/39 and 1/32 in patients withand without subsequent RAI therapy), and 7 patients (16.66%) developed new recurrences throughout follow-up(5/19 and 2/23 with and without RAI therapy). Both plasma TSH-suppressed and TSH-stimulated Tg levelsdescended after EA in both groups, and 17/38 (44.73%) patients achieved a TSH-suppressed Tg <0.2 ng/mL,with no differences between both groups of patients. All EA procedures were conducted safely without seriousor persistent side effects. Conclusion: Successful EA were achieved safely in 87.32% of patients with recurrentthyroid cancer, with a positive effect on systemic disease as reflected by plasma post-EA Tg levels. A subset ofpatients with TNM stage III, ≤2 lesions and/or low pre-EA plasma Tg levels may not need subsequent RAI therapyafter successful ablation. Overall, EA is an effective and balanced therapy for selected patients with neck recurrentthyroid cancer as an alternative to surgery.

Lumped Damage Model Applied to Local Buckling in Steel Rectangular Hollow Section Subjected to Compressive Axial Force with Bending Moment

Leonardo A. B. Silva,Higor S. D. Argôlo,David L. N. F. Amorim 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.1

The search to reduce engineering costs leads to the development of new materials and design concepts to obtain lighter and slender structures. Consequently, when using structural parts with cross-sections composed by slender plates, the phenomenon of local instability becomes more evident and is usually treated as a form of collapse. Generally, the behaviour of the structure in terms of local buckling requires refi ned solutions. Then, it is usual to employ fi nite element modelling using meshes with several shell or three-dimensional elements, leading to high computational costs. Therefore, this study proposes a numerical model based on Lumped Damage Mechanics (LDM) applied to local buckling in steel rectangular hollow sections subjected to compressive axial force with bending moment. In the LDM, it is assumed that all the nonlinear eff ects of a fi nite element are concentrated in plastic hinges, where it signifi cantly reduces the computational cost of the computational analysis. For the proposed formulation, equations based on experiments of other authors were introduced to analytically calculate the model parameters. To evaluate the accuracy of the proposed model, the numerical results were compared to other experiments. Thus, it was concluded that the numerical results were satisfactory, since the numerical curves showed similar behaviour when compared to the experimental ones.

Reticulated Vitreous Carbon Foams from Sucrose: Promising Materials for Bone Tissue Engineering Applications

Natalia Terán Acuña,Viviana Güiza-Argüello,Elcy Córdoba-Tuta 한국고분자학회 2020 Macromolecular Research Vol.28 No.10

Reticulated vitreous carbon (RVC) foams have shown favorable biocompatibility and the potential to support osteoblastic adhesion. In this work, RVC foams were fabricated via template route, using a low-cost sucrose-based resin. The effect of several process parameters, such as template porosity (cell size between 500 and 1400 μm) and carbonization conditions, were studied. The resulting RVC foams displayed highly interconnected porosity (˃ 85%) with controllable cell size, bone-like morphology, and compressive strength of 0.06-0.26 MPa. The results suggested that the decrease in the cell size of the sacrificial sponge, the increase in the thickness of the sponge cell ligaments, and the carbonization temperature of 1500 °C, contributed to the enhancement of the mechanical response of the fabricated scaffolds. Finally, cytotoxicity and cell adhesion assays were carried out using normal human osteoblasts as a preliminary assessment of the cytocompatibility of the synthesized RVC foams. Although the mechanical strength of these foams could still be improved, these results contribute towards the development of low-cost bioactive scaffolds that resemble the morphological properties of the trabecular bone.

Alternative Woods for Aging Distillates -An Insight into Their Phenolic Profiles and Antioxidant Activities

Roberto Rodríguez Madrera,Belén Suárez Valles,Yolanda Diñeiro García,Paula del Valle Argüelles,Anna Picinelli Lobo 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.4

Work has commenced on the study and characterization of wood native species (oak, chestnut,cherry, alder, ash, and beech), employed to a minor extent in enology, for their application in the elaboration of distillates. To this end, furanic and low molecular weight phenol compounds, total phenolic content, and antioxidant activity in alcoholic extracts by maceration of wood chips at 2 toasting levels were studied. Significant differences between samples, technologically relevant, were due both to species and toasting time. Furthermore, extracts showed interesting antioxidant activities equivalent in some cases to than those reported for alcoholic beverages aged in wood.

On the Distribution of Dark Matter in Galaxies: Quantum Treatments

Carlos R. Arg¨uelles,Remo Ruffini,Ivan Siutsou,Bernardo Fraga 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.6

The problem of modeling the distribution of dark matter in galaxies in terms of equilibriumconfigurations of collisionless self-gravitating quantum particles is considered. We first summarizethe pioneering model of a Newtonian self-gravitating Fermi gas in thermodynamic equilibriumdeveloped by Ruffini and Stella (1983), which is shown to be a generalization of the King modelfor fermions. We further review the extension of the former model developed by Gao, Merafinaand Ruffini (1990), done for any degree of fermion degeneracy at the center (0), within generalrelativity. Finally, we present here for the first time the solutions of the density profiles and rotationcurves corresponding to the model of Gao et al. Those solutions have a definite mass Mh and acircular velocity vh at the halo radius rh of the configurations, which are typical of spiral galaxies. This treatment allows us to determine a novel core-halo morphology for the dark-matter profiles,as well as a novel bound on the particle mass associated with those profiles.

Critical Configurations for a System of Semidegenerate Fermions

Carlos R. Arg¨uelles,Remo Ruffini,Bernardo M. O. Fraga 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.6

We study an isothermal system of semidegenerate self-gravitating fermions in general relativity. Such systems present mass density solutions with a central degenerate core, a plateau and a tail, thislast following a power law behavior r−2. The different solutions are governed by the free parametersof the model: the degeneracy and the temperature parameters at the center and the particle mass m. We then analyze in detail the free parameter space for a fixed m in the keV region, by studying theone-parameter sequences of equilibrium configurations up to the critical point, which is representedby the maximum in a central density (0) vs. core mass (Mc) diagram. We show that for fullydegenerate cores, the known expression for the critical core mass Mcrc / m3pl/m2 is obtained, whilefor low degenerate cores, the critical core mass increases, showing temperature effects in a nonlinearway. The main result of this work is that when applying this theory to model the distribution ofdark matter in galaxies from the very center to the outer halos, we do not find any critical corehaloconfiguration of self-gravitating fermions that would be able to explain the super-massive darkobject in their centers and the outer halo simultaneously.