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A Baseline-Tracking Single-Channel I/Q Impedance Plethysmogram IC for Neckband-Based Blood Pressure and Cardiovascular Monitoring
No full textAn impedance plethysmogram (IPG) IC with wide-range fine baseline tracking capability is proposed to provide continuous blood pressure (BP) and cardiovascular monitoring just by wearing a neckband wearable device. For the baseline tracking, a mixed-mode baseline cancellation (MM-BC) scheme is proposed to achieve wide dynamic range (DR) and high SNR performance, where an artifact-detecting continuous-time (CT)- ???? ADC is included together for high-resolution conversion. For cost-effective IPG design, a phase synchronizer concept is introduced to provide I/Q detection capability with single readout channel, supporting both configurations of two-electrode and four-electrode. A proposed readout integrated circuit (ROIC) prototype for the proposed IPG was fabricated, where an electrocardiogram (ECG) readout path is integrated together. The proposed IPG schemes were experimentally verified to achieve good performances of 145.2-dB DR and 103.5-dB SNR. For system-level feasibility, a neckband device prototype was also manufactured, and its cardiovascular monitoring functionality was functionally verified. Based on its IPG and ECG measurements, continuous BP measurement based on the pulse arrival time (PAT) was experimentally verified with a reference BP device
Comprehensive shape analysis of the cortex in Huntington's disease
No full textThe striatum has traditionally been the focus of Huntington's disease research due to the primary insult to this region and its central role in motor symptoms. Beyond the striatum, evidence of cortical alterations caused by Huntington's disease has surfaced. However, findings are not coherent between studies which have used cortical thickness for Huntington's disease since it is the well-established cortical metric of interest in other diseases. In this study, we propose a more comprehensive approach to cortical morphology in Huntington's disease using cortical thickness, sulcal depth, and local gyrification index. Our results show consistency with prior findings in cortical thickness, including its limitations. Our comparison between cortical thickness and local gyrification index underscores the complementary nature of these two measures???cortical thickness detects changes in the sensorimotor and posterior areas while local gyrification index identifies insular differences. Since local gyrification index and cortical thickness measures detect changes in different regions, the two used in tandem could provide a clinically relevant measure of disease progression. Our findings suggest that differences in insular regions may correspond to earlier neurodegeneration and may provide a complementary cortical measure for detection of subtle early cortical changes due to Huntington's disease
Recent Advancements in the Treatment of Emerging Contaminants Using Activated Persulfate Oxidation Process
No full textEmerging contaminants (ECs) usually refer to pesticides, polycyclic aromatic hydrocarbons (PAHs), dioxins, personal care products, cosmetics, and medications. Due to the strong demand and quick growth of these businesses, the ECs have continuously been found in alarming amounts in groundwater, surface water, and wastewater. These ECs provide a significant non-esthetic threat to the ecosystem as a whole and can cause significant non-esthetic contamination when released into the aquatic environment. The conventional wastewater treatment techniques such as activated sludge, membrane filtration, coagulation, adsorption, and ozonation showed ECs removal performance to a certain extent. In turn, numerous emerging advanced oxidation processes (AOPs), especially activated persulfate oxidation, have garnered a huge amount attention due to their outstanding performance in the remediation of ECs. This article presents a systematic and critical review of electro, sono and thermal activation of persulfate for the treatment of ECs. The effect of key parameters such as electrode materials, solution pH, persulfate concentration, current density, and temperature on electro, sono- and thermal-activated degradation of ECs was discussed. The possible reaction mechanism of ECs degradation was also elucidated in detail. It was closed with a note on the situation now and the future course of electro, sono and thermal activation in ECs degradation applications. Experiments performed in recent studies show that with the aid of persulfate in electro activation, the removal efficiency of chemical oxygen demand can be achieved up to 72.8%. Persulfate activated by sono shows 100% removal efficiency of 1,1,1-trichloroethane and sulfamethoxazole. While for thermal activation of persulfate, 100% removal efficiency of carbamazepine, atrazine and sulfamethazine was achieved. All these vital shreds of evidence are substantial enough to picture the negative impact of ECs on the environment
Low temperature selective catalytic reduction of NOx with NH3 with improved SO2 and water resistance by using N-doped graphene dots-CuO-CeO2 nano-heterostructures modified vanadate catalysts
No full textHerein, we report a facile strategy for efficient NH3-SCR catalytic performance of vanadate-based catalysts with superior sulfur and water resistance at low temperature (<200 degrees C). The catalyst design strategy is based on the selective adsorption of NO2 via the functionalization of N-doped graphene quantum dots (N-GQDs) and fast-SCR via the functionalization of CuO-CeO2 (CuCe) on 4V1W/Ti catalysts. The impregnation of 1 wt% N-GQDs and 2.8 wt% CuCe leads to more surface acid sites and facilitate the strong interaction between Cu-Ce-V oxides, thus improving NOx adsorption and improved redox process in low temperature ranges (180-220 degrees C). The synthe-sized CuCe-N-GQD-4V1W/Ti catalyst shows high DeNOx activity over 92 % with excellent N2 selectivity and SO2/H2O resistance at 200 degrees C. In situ diffuse reflectance Fourier transform analysis confirmed the Eley-Rideal SCR reaction pathway over the CuCe-N-GQDs-4V1W/Ti catalyst
Dithieno[3,2-f:2 ',3 '-h]quinoxaline-Based Photovoltaic-Thermoelectric Dual-Functional Energy-Harvesting Wide-Bandgap Polymer and its Backbone Isomer
No full textBoth organic solar cells (OSCs) and organic thermoelectrics (OTEs) are promising energy-harvesting technologies for future renewable and sustainable energy sources. Among various material systems, organic conjugated polymers are an emerging material class for the active layers of both OSCs and OTEs. However, organic conjugated polymers showing both OSC and OTE properties are rarely reported because of the different requirements toward the OSCs and OTEs. In this study, the first simultaneous investigation of the OSC and OTE properties of a wide-bandgap polymer PBQx-TF and its backbone isomer iso-PBQx-TF are reported. All wide-bandgap polymers form face-on orientations in a thin-film state, but PBQx-TF has more of a crystalline character than iso-PBQx-TF, originating from the backbone isomeric structures of alpha,alpha '/beta,beta '-connection between two thiophene rings. Additionally, iso-PBQx-TF shows inactive OSC and poor OTE properties, probably because of the absorption mismatch and unfavorable molecular orientations. At the same time, PBQx-TF exhibits both decent OSC and OTE performances, indicating that it satisfies the requirements for both OSCs and OTEs. This study presents the OSC and OTE dual-functional energy-harvesting wide-bandgap polymer and the future research directions for hybrid energy-harvesting materials
Efficient and Stable Perovskite Nanocrystal Light-Emitting Diodes with Sulfobetaine-Based Ligand Treatment
No full textPerovskite nanocrystals (PNCs) possess outstanding optical properties such as narrow full-width at half-maximum (fwhm) emission and color tunability. However, the labile ionic nature and weakly bound surface ligands of PNCs result in colloidal instability and crystal structure deformation, thus degrading their optical properties. In this study, we treated CsPbBr3 PNCs with 3-(dodecyldimethylammonio)propane-1-sulfonate (12-SBE) ligands and successfully stabilized the PNCs under ambient air and heat. Under optimum ligand exchange conditions, 12-SBE PNCs showed near 100% photoluminescence quantum yield (PLQY) without an increase in the size of the PNCs. After 12-SBE treatment, the agglomeration of PNCs in solution due to ligand loss was suppressed, and PNC size growth induced by moisture and oxygen under heating was reduced. Finally, we fabricated 12-SBE PNC LEDs exhibiting 6.7% external quantum efficiency (EQE). Moreover, the PL lifetime of 12-SBE PNC LEDs was enhanced 2-fold compared to oleylamine (OAM) PNC LEDs
Single-molecule imaging reveals the molecular mechanisms underlying collision between a replicating DNA polymerase and a single R-loop
No full textTheoretical and mechanistic insights into control factor-assisted CO2 mineralization with olivine
No full textWe elucidate the CO2 mineralization mechanism with Mg-rich forsterite via theoretical approach including density functional theory (DFT) calculations and molecular dynamics (MD) simulations. Here, the CO2 mineralization follows two steps: the ion dissolution pathway for dissolving Mg ions from the forsterite surface, and the cluster growth pathway, where ion pairs agglomerate into molecular-sized MgCO3 clusters in aqueous solution. Step-by-step reaction mechanism for the dissolution of Mg ion was investigated via DFT calculations, and the formation procedure of solvated magnesite clusters and their structural changes over time were observed through MD simulations. Afterward, the effects of three control factors of pH, temperature, and hetero-metal ions were studied for both pathways. We found that the adjustment of pH contributed to the structural changes of the mineral surface and clustering ion pairs, which in turn affected the kinetics of reaction pathway. Also, high-temperature condition induced positive effects for accelerating both mineralization pathways. Lastly, calcium and ferrous ions showed opposite effects, promoting and hindering the overall processes, respectively. Importantly, our mechanistic study suggests that the pH of the solution changes alternatively between acid and base conditions during each mineralization pathway and pH condition induced by the preceding mineralization pathway facilitates the subsequent one. (c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved
Efficient and stable perovskite solar cells by build-in pi-columns and ionic interfaces in covalent organic frameworks
No full textPerovskite solar cells (PSCs) have attracted much attention due to their rapidly increased power conversion efficiencies, however, their inherent poor long-term stability hinders their commercialization. The degradation of PSCs first comes from the degradation of hole transport materials (HTMs). Here, we report the construction of periodic p-columnar arrays and ionic interfaces over the skeletons by introducing cationic covalent organic frameworks (C-COFs) to the HTM. Periodic p-columnar arrays can optimize the charge transport ability and energy levels of the hole transport layer and suppress the degradation of HTM, and ionic interfaces over the skeletons can produce stronger electric dipole and electrostatic interactions, as well as higher charge densities. The C-COFs were designed and synthesized via Schiff base reaction by using 1,3,5-triformylphloroglucinol as a neutral knot and dimidium bromide as cationic linker. The neutral COFs (N-COFs) were also synthesized as a reference by using 3,8-diamino-6-phenylphenanthridine as neutral linker. PSCs with cationic COF exhibit the highest efficiency of 23.4% with excellent humidity and thermal stability. To the best of our knowledge, this is the highest efficiency among the meso-structured PSCs fabricated by a sequential process