31 research outputs found
sj-pdf-1-ijq-10.1177_16094069211046429 – Supplemental Material for Lived Experience of Participants of a Korean Medicine-Based Postpartum Program: A Protocol for a Qualitative Research Study
No full textSupplemental Material, sj-pdf-1-ijq-10.1177_16094069211046429 for Lived Experience of Participants of a Korean Medicine-Based Postpartum Program: A Protocol for a Qualitative Research Study by Inae Youn, Han-Song Park, Do-Eun Lee, Hyo-Weon Suh and Joohee Seo in International Journal of Qualitative Methods</p
Electroreduction
No full textTuning the coordination environment and geometric structures of single atom catalysts is an effective approach for regulating the reaction mechanism and maximize the catalytic efficiency of single-atom centers. Here, a template-based synthesis strategy is proposed for the synthesis of high-density NiNx sites anchored on the surface of hierarchically porous nitrogen-doped carbon nanofibers (Ni-HPNCFs) with different coordination environments. First-principles calculations and advanced characterization techniques demonstrate that the single Ni atom is strongly coordinated with both pyrrolic and pyridinic N dopants, and that the predominant sites are stabilized by NiN3 sites. This dual engineering strategy increases the number of active sites and utilization efficiency of each single atom as well as boosts the intrinsic activity of each active site on a single-atom scale. Notably, the Ni-HPNCF catalyst achieves a high CO Faradaic efficiency (FECO) of 97% at a potential of -0.7 V, a high CO partial current density (j(CO)) of 49.6 mA cm(-2) (-1.0 V), and a remarkable turnover frequency of 24 900 h(-1) (-1.0 V) for CO2 reduction reactions (CO2RR). Density functional theory calculations show that compared to pyridinic-type NiNx, the pyrrolic-type NiN3 moieties display a superior CO2RR activity over hydrogen evolution reactions, resulting in their superior catalytic activity and selectivity.
Reduction: Identifying the Role of Pyrrolic–N and Synergistic Electrocatalysis
No full textEngineering the electronic structure of metal, N-doped carbon catalysts is a potential strategy for increasing the activity and selectivity of CO2 electroreduction reaction (CO2RR). However, establishing a definitive link between structure and performance is extremely difficult due to constrained synthesis approaches that lack the ability to precisely control the specific local environment of M-N-C catalysts. Herein, a soft-template aided technique is developed for the first time to synthesize pyrrolic N-4-Ni sites coupled with varying N-type defects to synergistically enhance the CO2RR performance. The optimal catalyst helps attain a CO Faradaic efficiency of 94% at a low potential of -0.6 V and CO partial current density of 59.6 mA cm(-2) at -1 V. Results of controlled experimental investigations indicate that the synergy between Ni-N-4 and metal free defect sites can effectively promote the CO2RR activity. Theoretical calculations revealed that the pyrrolic N coordinated Ni-N-4 sites and C atoms next to pyrrolic N (pyrrolic N-C) have a lower energy barrier for the formation of COOH* intermediate and optimum CO* binding energy. The pyrrolic N regulate the electronic structure of the catalyst, resulting in lower CO2 adsorption energy and higher intrinsic catalytic activity.
Photocathode Integrated with NiO Hole‐Selective Layer for Improved Photoelectrochemical Water Splitting
No full textCuBi2O4(CBO) has received considerable attention owing to its ideal optical bandgap and positive photocurrent onset potential. However, CBO photocathodes exhibit poor charge carrier separation and transfer across the conducting substrate interface. Herein, a systematic incorporation of Ag+-cations into nanosized porous CBO network (ACBO) using a simple pulsed-electrodeposition method. In ACBO photocathode, the Ag+-ions replace the Bi3+-ions, thereby building an increased hole concentration, which further signifies the photogenerated electron-hole separation. Additionally, introducing a low-cost NiO hole-selective layer between ACBO and the conducting substrate enables a back-interface-aided hole-extraction and electron blocking, resulting in an improved charge transfer across the back interface. Compared with an unmodified CBO, the NiO/ACBO photocathode exhibits a three-fold enhanced photocurrent performance. This enhances the photocurrent originating from the incorporation of a substantial amount of Ag+-ions into the CBO structure, leading to an increased acceptor density as well as the formation of an appropriate hole-selective layer across the back-contact. The absorption percentage, time-resolved photoluminescence, and photoelectrochemical impedance spectroscopy measurements unveil the potential light harvesting, charge separation, and transfer characteristics of the NACBO photoelectrode, respectively. Through this systematic study, an efficient and simple strategy is determined for developing ternary metal oxide-based photocathode/photoanode systems for sustainable energy applications.
Inverse Opal CuBi2O4 Photocathodes for Robust Photoelectrochemical Water Splitting
No full textIn general, p-type CuBi2O4 (CBO) photocathodes demonstrate excellent solar-to-hydrogen conversion efficiencies but have low quantum yields near the band-edge region (i.e., above 600 nm), which substantially impedes achieving photocurrent densities that match the theoretical values. This is the main obstacle in the construction of photoelectrochemical (PEC) water-splitting cells. To overcome this difficulty, we fabricated inverse opal-like structured CBO (IO-CBO) photocathodes using a layered self-assembly approach. The fabricated photocathodes have an interconnected macroporous structure that supports enhanced visible-light-harvesting capabilities and improves intrinsic charge-carrier transport properties. Optimized IO-CBO cathodes exhibit a high photocurrent density of 2.95 mA cm(-2) at 0.6 V versus a reversible hydrogen electrode with stability over 2 h of operation. Furthermore, IO-CBO cathodes have exceptional near-band-edge photon harvesting and quantum yields of 15% at 600 nm, which is unprecedented for CuBi2O4 -type photocathodes. We believe that the present work promotes the application of ternary-based nanostructures in solar-driven hydrogen production.
434: ASSOCIATION OF AGGRESSIVE NUTRITIONAL SUPPORT AND MORTALITY DURING THERAPEUTIC HYPOTHERMIA
No full text
Wnt-Signaling Inhibitor Wnt-C59 Suppresses the Cytokine Upregulation in Multiple Organs of Lipopolysaccharide-Induced Endotoxemic Mice via Reducing the Interaction between β-Catenin and NF-κB
No full textSepsis is characterized by multiple-organ dysfunction caused by the dysregulated host response to infection. Until now, however, the role of the Wnt signaling has not been fully characterized in multiple organs during sepsis. This study assessed the suppressive effect of a Wnt signaling inhibitor, Wnt-C59, in the kidney, lung, and liver of lipopolysaccharide-induced endotoxemic mice, serving as an animal model of sepsis. We found that Wnt-C59 elevated the survival rate of these mice and decreased their plasma levels of proinflammatory cytokines and organ-damage biomarkers, such as BUN, ALT, and AST. The Wnt/β-catenin and NF-κB pathways were stimulated and proinflammatory cytokines were upregulated in the kidney, lung, and liver of endotoxemic mice. Wnt-C59, as a Wnt signaling inhibitor, inhibited the Wnt/β-catenin pathway, and its interaction with the NF-κB pathway, which resulted in the inhibition of NF-κB activity and proinflammatory cytokine expression. In multiple organs of endotoxemic mice, Wnt-C59 significantly reduced the β-catenin level and interaction with NF-κB. Our findings suggest that the anti-endotoxemic effect of Wnt-C59 is mediated via reducing the interaction between β-catenin and NF-κB, consequently suppressing the associated cytokine upregulation in multiple organs. Thus, Wnt-C59 may be useful for the suppression of the multiple-organ dysfunction during sepsis
