Effect of chitooligosaccharide on the binding domain of the SARS-COV-2 receptor.

The receptor-binding domain (RBD) is crucial for understanding how severe acute respiratory syndrome coronavirus (SARS-CoV-2) recognizes and infects host cells. Chitooligosaccharide (CS) exhibits diverse antiviral activities, with its derivatives showing remarkable efficacy in blocking SARS-CoV-2 infection. Thus, this study employed spectroscopy, virus-infected cell experiments, and molecular simulation to investigate the molecular interactions between CS and SARS-CoV-2 RBD, as well as their mechanisms. In spectroscopic experiments, all four CS variants with different molecular weights formed interactions with the RBD. These variants increased the resistance of HEK293ACE2 cells to SARS-CoV-2 invasion. Molecular docking revealed that the four CS variants could bind to the RBD through hydrogen bonding or salt-bridge interactions, forming stable complexes. Chitotetraose provided stronger protection to HEK293ACE2 cells compared to other CS variants and displayed higher molecular docking scores. Further investigation into the optimal docking conformation of chitotetraose was conducted through molecular dynamics simulation methods. This study lays a solid theoretical foundation and provides a scientific basis for the development of targeted RBD inhibitors, as well as drug screening and application against novel coronaviruses.

Functional Thermoplastic Polyurethane Elastomers with α, ω-Hydroxyl End-Functionalized Polyacrylates.

Thermoplastic polyurethane (TPU) is an essential class of materials for demanding applications, from soft robotics and electronics to medical devices and batteries. However, traditional TPU development is primarily relied on specific soft segments, such as polyether, polyester, and polycarbonate polyols. Here, a novel method is introduced for developing TPU elastomers with enhanced performance and superior functionalities compared to conventional TPUs, achieved through the use of α,ω-hydroxyl end-functionalized polyacrylates. This approach involves a defect-free synthesis of α,ω-hydroxyl end-functionalized polyacrylates through visible-light-driven photoiniferter polymerization. By strategically blending these functionalized polyacrylates with conventional polyols, TPUs that exhibit exceptional toughness and notable self-healing capabilities, traits rarely found in existing TPUs are engineered. Furthermore, incorporating photo-crosslinkable acrylic monomers has enabled the creation of the first TPU with superior elastomeric properties and photopatterning capabilities. This approach paves the way for a new direction in polyurethane engineering, introducing a novel class of soft segments and unlocking the potential for a wide range of advanced applications.

Advancing Cardiovascular Drug Screening Using Human Pluripotent Stem Cell-Derived Cardiomyocytes.

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have emerged as a promising tool for studying cardiac physiology and drug responses. However, their use is largely limited by an immature phenotype and lack of high-throughput analytical methodology. In this study, we developed a high-throughput testing platform utilizing hPSC-CMs to assess the cardiotoxicity and effectiveness of drugs. Following an optimized differentiation and maturation protocol, hPSC-CMs exhibited mature CM morphology, phenotype, and functionality, making them suitable for drug testing applications. We monitored intracellular calcium dynamics using calcium imaging techniques to measure spontaneous calcium oscillations in hPSC-CMs in the presence or absence of test compounds. For the cardiotoxicity test, hPSC-CMs were treated with various compounds, and calcium flux was measured to evaluate their effects on calcium dynamics. We found that cardiotoxic drugs withdrawn due to adverse drug reactions, including encainide, mibefradil, and cetirizine, exhibited toxicity in hPSC-CMs but not in HEK293-hERG cells. Additionally, in the effectiveness test, hPSC-CMs were exposed to ATX-II, a sodium current inducer for mimicking long QT syndrome type 3, followed by exposure to test compounds. The observed changes in calcium dynamics following drug exposure demonstrated the utility of hPSC-CMs as a versatile model system for assessing both cardiotoxicity and drug efficacy. Overall, our findings highlight the potential of hPSC-CMs in advancing drug discovery and development, which offer a physiologically relevant platform for the preclinical screening of novel therapeutics.

Rational Design of Color-Pure Blue Organic Emitters by Poly-Heteroaromatic Omni-Delocalization.

Current research on organic light emitters which utilize multiple resonance-induced thermally activated delayed fluorescence (MR-TADF) materials is gaining significant interest because of the materials' ability to efficiently generate color-pure blue emission. However, the underlying reasons for high color purity remain unclear. It is shown here that these emitters share a common electronic basis, which is deduced from resonance structure considerations following Clar's rule, and which is termed as "poly-heteroaromatic omni-delocalization" (PHOD). The simple and clear design rules derived from the PHOD concept allow extending the known chemical space by new structural motifs. Based on PHOD, a set of novel high-efficiency color-pure emitters with brilliant deep-blue hue is specifically designed.

3D printable and biocompatible PEDOT:PSS-ionic liquid colloids with high conductivity for rapid on-demand fabrication of 3D bioelectronics.

3D printing has been widely used for on-demand prototyping of complex three-dimensional structures. In biomedical applications, PEDOT:PSS has emerged as a promising material in versatile bioelectronics due to its tissue-like mechanical properties and suitable electrical properties. However, previously developed PEDOT:PSS inks have not been able to fully utilize the advantages of commercial 3D printing due to its long post treatment times, difficulty in high aspect ratio printing, and low conductivity. We propose a one-shot strategy for the fabrication of PEDOT:PSS ink that is able to simultaneously achieve on-demand biocompatibility (no post treatment), structural integrity during 3D printing for tall three-dimensional structures, and high conductivity for rapid-prototyping. By using ionic liquid-facilitated PEDOT:PSS colloidal stacking induced by a centrifugal protocol, a viscoplastic PEDOT:PSS-ionic liquid colloidal (PILC) ink was developed. PILC inks exhibit high-aspect ratio vertical stacking, omnidirectional printability for generating suspended architectures, high conductivity (~286 S/cm), and high-resolution printing (~50 µm). We demonstrate the on-demand and versatile applicability of PILC inks through the fabrication of 3D circuit boards, on-skin physiological signal monitoring e-tattoos, and implantable bioelectronics (opto-electrocorticography recording, low voltage sciatic nerve stimulation and recording from deeper brain layers via 3D vertical spike arrays).

The degree of respiratory depression according to the effect-site concentration in remimazolam target-controlled infusion: A randomised controlled trial.

BACKGROUND: Remimazolam is not only associated with a lower incidence of respiratory depression than propofol but also in itself has the risk of respiratory depression. OBJECTIVE: We investigated respiratory depression following remimazolam infusion, targeting different effect-site concentrations using target-controlled infusion. DESIGN: A prospective, double-blind, randomised controlled study. SETTING: Tertiary hospital, Suwon, South Korea, from April 2022 to November 2022. PARTICIPANTS: One hundred and seven patients scheduled for general anaesthesia were randomised into three groups targeting remimazolam effect-site concentrations of 500 (RMZ-500) (n = 36), 1000 (RMZ-1000) (n = 35) and 1500 ng ml-1 (RMZ-1500) (n = 36). INTERVENTIONS: Remimazolam was solely infused for 10 min according to target effect-site concentrations. According to the degree of SpO2 decrease, oxygen desaturations were managed with the following respiratory supports: jaw-thrust for SpO2 less than 97%, 100% oxygen delivery for SpO2 less than 93% and assisted ventilation for SpO2 less than 90%. MAIN OUTCOME MEASURES: The incidence of each respiratory support, along with respiratory variables (at baseline, 5 min and 10 min after remimazolam infusion) and loss of consciousness were observed for 10 min after remimazolam target-controlled infusion. RESULTS: Both RMZ-1000 and RMZ-1500 required more frequent respiratory support than RMZ-500 (both P < 0.001), with nearly identical frequencies between RMZ-1000 and RMZ-1500. In terms of respiratory support, the incidence of assisted ventilation was significantly lower in RMZ-500 (2.8%) than RMZ-1000 (48.6%) and RMZ-1500 (50%) (P < 0.001). RMZ-1000 and RMZ-1500 achieved loss of consciousness in all patients; RMZ-500 only achieved loss of consciousness in 86.1% of patients (P = 0.010). In patients who maintained spontaneous respiration, tidal volume decreased by 41 to 48% and respiratory rate increased by 118 to 158% at 5 and 10 min, significantly compared to baseline in all groups (P < 0.001). CONCLUSIONS: Remimazolam infusion, like that of other benzodiazepines, led to respiratory depression, which was more prominent at higher target effect-site concentrations. Therefore, appropriate countermeasures should be developed to prevent oxygen desaturation. TRIAL REGISTRATION: CRIS (https://cris.nih.go.kr), identifier: KCT0006952.

Tailoring the Degradation of Cyanoarene-Based Photocatalysts for Enhanced Visible-Light-Driven Halogen Atom Transfer.

We present the strategic design of donor-acceptor cyanoarene-based photocatalysts (PCs) aiming to augment beneficial PC degradation for halogen atom transfer (XAT)-induced dehalogenation reactions. Our investigation reveals a competitive nature between the catalytic cycle and the degradation pathway, with the degradation becoming dominant, particularly for less activated alkyl halides. The degradation behavior of PCs significantly impacts the efficiency of the XAT process, leading to exploration into manipulating the degradation behavior in a desirable direction. Recognizing the variation in the nature and rate of PC degradation, as well as its influence on the reaction across the range of PC structures, we carefully engineered the PCs to develop a pre-catalyst, named 3DP-DCDP-IPN. This pre-catalyst undergoes rapid degradation into an active form, 3DP-DCDP-Me-BN, exhibited an enhanced reducing ability in its radical anion form to induce better PC regeneration and consequently effectively catalyzes the XAT reaction, even with a challenging substrate.

Highly efficient dual photoredox/copper catalyzed atom transfer radical polymerization achieved through mechanism-driven photocatalyst design.

Atom transfer radical polymerization (ATRP) with dual photoredox/copper catalysis combines the advantages of photo-ATRP and photoredox-mediated ATRP, utilizing visible light and ensuring broad monomer scope and solvent compatibility while minimizing side reactions. Despite its popularity, challenges include high photocatalyst (PC) loadings (10 to 1000 ppm), requiring additional purification and increasing costs. In this study, we discover a PC that functions at the sub-ppm level for ATRP through mechanism-driven PC design. Through studying polymerization mechanisms, we find that the efficient polymerizations are driven by PCs whose ground state oxidation potential-responsible for PC regeneration-play a more important role than their excited state reducing power, responsible for initiation. This is verified by screening PCs with varying redox potentials and triplet excited state generation capabilities. Based on these findings, we identify a highly efficient PC, 4DCDP-IPN, featuring moderate excited state reducing power and a maximized ground state oxidation potential. Employing this PC at 50 ppb, we synthesize poly(methyl methacrylate) with high conversion, narrow molecular weight distribution, and high chain-end fidelity. This system exhibits oxygen tolerance and supports large-scale reactions under ambient conditions. Our findings, driven by the systematic PC design, offer meaningful insights for controlled radical polymerizations and metallaphotoredox-mediated syntheses beyond ATRP.

Silent gallbladder stone in kidney transplantation recipients: should it be treated? A retrospective cohort study.

BACKGROUND: Treatment and follow-up strategies for silent gallbladder stones in patients before kidney transplantation (KT) remain unknown. Therefore, the authors aimed to elucidate the role of pre-KT cholecystectomy in preventing biliary and surgical complications. MATERIALS AND METHODS: This study retrospectively analyzed 2295 KT recipients and 3443 patients waiting for KT at a single tertiary center from January 2005 to July 2022. The primary outcomes were the incidences of biliary and postcholecystectomy complications in KT recipients. Firth's logistic regression model was used to assess the risk factors for biliary complications. RESULTS: Overall, 543 patients awaiting KT and 230 KT recipients were found to have biliary stones. Among the KT recipients, 16 (7%) underwent cholecystectomy before KT, while others chose to observe their biliary stones. Pre-KT cholecystectomy patients did not experience any biliary complications, and 20 (9.3%) patients who chose to observe their stones experienced complications. Those who underwent cholecystectomy before KT developed fewer postcholecystectomy complications (6.3%) compared with those who underwent cholecystectomy after KT (38.8%, P =0.042), including reduced occurrences of fatal postoperative complications based on the Clavien-Dindo classification. Multiple stones [odds ratio (OR), 3.09; 95% CI: 1.07-8.90; P =0.036), thickening of the gallbladder wall (OR, 5.39; 95% CI: 1.65-17.63; P =0.005), and gallstones >1 cm in size (OR 5.12, 95% CI: 1.92-13.69, P =0.001) were independent risk factors for biliary complications. Among patients awaiting KT, 23 (4.2%) underwent cholecystectomy during the follow-up, resulting in one postcholecystectomy complication. CONCLUSION: Gallstone-related biliary complications following KT and subsequent cholecystectomy was associated with more serious complications and worse treatment outcomes. Therefore, when KT candidates had risk factor for biliary complications, pre-emptive cholecystectomy for asymptomatic cholecystolithiasis could be considered to reduce further surgical risk.

Overcoming low initial coulombic efficiencies of Si anodes through prelithiation in all-solid-state batteries.

All-solid-state batteries using Si as the anode have shown promising performance without continual solid-electrolyte interface (SEI) growth. However, the first cycle irreversible capacity loss yields low initial Coulombic efficiency (ICE) of Si, limiting the energy density. To address this, we adopt a prelithiation strategy to increase ICE and conductivity of all-solid-state Si cells. A significant increase in ICE is observed for Li1Si anode paired with a lithium cobalt oxide (LCO) cathode. Additionally, a comparison with lithium nickel manganese cobalt oxide (NCM) reveals that performance improvements with Si prelithiation is only applicable for full cells dominated by high anode irreversibility. With this prelithiation strategy, 15% improvement in capacity retention is achieved after 1000 cycles compared to a pure Si. With Li1Si, a high areal capacity of up to 10 mAh cm-2 is attained using a dry-processed LCO cathode film, suggesting that the prelithiation method may be suitable for high-loading next-generation all-solid-state batteries.

Ultraviolet light blocking optically clear adhesives for foldable displays via highly efficient visible-light curing.

In developing an organic light-emitting diode (OLED) panel for a foldable smartphone (specifically, a color filter on encapsulation) aimed at reducing power consumption, the use of a new optically clear adhesive (OCA) that blocks UV light was crucial. However, the incorporation of a UV-blocking agent within the OCA presented a challenge, as it restricted the traditional UV-curing methods commonly used in the manufacturing process. Although a visible-light curing technique for producing UV-blocking OCA was proposed, its slow curing speed posed a barrier to commercialization. Our study introduces a highly efficient photo-initiating system (PIS) for the rapid production of UV-blocking OCAs utilizing visible light. We have carefully selected the photocatalyst (PC) to minimize electron and energy transfer to UV-blocking agents and have chosen co-initiators that allow for faster electron transfer and more rapid PC regeneration compared to previously established amine-based co-initiators. This advancement enabled a tenfold increase in the production speed of UV-blocking OCAs, while maintaining their essential protective, transparent, and flexible properties. When applied to OLED devices, this OCA demonstrated UV protection, suggesting its potential for broader application in the safeguarding of various smart devices.

Biomass-Derived Optically Clear Adhesives for Foldable Displays.

Novel acrylate monomers, derived from terpenes are synthesized for use in optically clear adhesives (OCAs) suitable for foldable displays. These OCAs are prepared using visible-light-driven polymerization, an eco-friendly method. Through physical, rheological, and mechanical characterization, the prepared OCAs possess low modulus and exhibit outstanding creep and recovery properties, making them suitable for foldable devices.

Establishment of an inspection standard for decomposition and methane production rates of organic waste co-digestion facilities in Korea.

Domestic organic waste resources have increased over the past decade and treatment of this waste via co-digested biogasification facilities is increasing annually. However, inspection standards for such facilities are not well-established. Herein, we aimed to derive calculation formulas and factors related to organic matter decomposition efficiency and methane production rate in accordance with waste treatment facility inspection standards. We also aimed to determine the optimum waste mixing ratio. Sample (field) surveys of 18 treatment facilities and complete enumeration of 110 facilities were conducted. Calculation formulas and factors were derived using the survey data and biochemical methane potential (BMP) test. The calculated coefficients derived through the BMP test were 0.512 m3 CH4/kgVSin for food waste, 0.601 m3 CH4/kgVSin for livestock manure, and 0.382 m3 CH4/kgVSin for sewage sludge. The final derived calculation factors were 65.0% for food waste, 36.0% for livestock manure, and 20.0% for sewage sludge for organic matter decomposition efficiency, and 0.380 m3 CH4/kgVSin for food waste, 0.27 m3 CH4/kgVSin for livestock manure, and 0.140 m3 CH4/kgVSin for sewage sludge for methane production rates. The derived effective capacity calculation factors can be utilized in future waste treatment facility inspection methods by aiding in the establishment of appropriate inspection standards for co-digested biogasification facilities other than single food waste treatment facilities. In addition, the optimum mixing ratio can be used as design data for co-digested biogasification facilities.

The synergistic effect of herbal medicine and probiotics in pediatric functional constipation: A systematic review and meta-analysis.

BACKGROUND: Pediatric functional constipation (PFC) is a prevalent and persistent gastrointestinal disorder, that requires various treatments, including alternative approaches. This review assessed the synergistic efficacy of herbal medicine (HM) and probiotics for PFC. METHODS: We conducted a comprehensive search of 11 databases, including English, Chinese, and Korean databases, until June 29, 2023. The inclusion criteria were randomized clinical trials (RCTs) comparing the intervention of HM with probiotics to that of the same probiotics. Statistical analyses included calculation of the mean difference (MD), standardized MD, risk ratio (RR) with a 95% confidence interval (CI), and assessment of risk of bias using Review Manager Version 5.4 software. The Grading of Recommendations Assessment, Development, and Evaluation rating system was used to evaluate evidence quality. Potential publication bias was assessed using funnel plots, Egger test, the fail-safe N test, and Duval and Tweedie trim and fill method. RESULTS: A total of 22 RCTs involving 2228 patients were included in the meta-analysis. The HM and probiotics group exhibited superior outcomes compared to the probiotics alone group in various parameters: total effective rate (RR: 1.24, 95% CI: 1.19-1.29, P < .001), Bristol fecal Score (MD: 0.80, 95% CI: 0.71-0.89, P < .001), gastrointestinal peptide hormone (motilin) (MD: 35.37, 95% CI: 24.64-64.10, P < .001), inflammation indicator (nitrous oxide) (MD: -12.45, 95% CI: -15.12 to -9.77, P < .001), minimal sensitive volume of the rectum (MD: -8.7, 95% CI: -10.91 to -6.49, P < .001), and recurrence rate (RR: 0.30, 95% CI: 0.21-0.43, P < .001). CONCLUSION: The combination of HM and probiotics may exhibit a synergistic effect on PFC. Nevertheless, it is imperative to undertake rigorously planned RCTs to comprehensively evaluate the synergistic efficacy of HM and probiotics.

Magnetically Actuated Trigger Transient Soft Actuators Comprising On-Demand Photo-Initiated and Thermo-Degradable Polypropylene Carbonate-Photo-Acid Generator.

Lifetime-reconfigurable soft robots have emerged as a new class of robots, emphasizing the unmet needs of futuristic sustainability and security. Trigger-transient materials that can both actuate and degrade on-demand are crucial for achieving life-reconfigurable soft robots. Here, we propose the use of transient and magnetically actuating materials that can decompose under ultraviolet light and heat, achieved by adding photo-acid generator (PAG) and magnetic particles (Sr-ferrite) to poly(propylene carbonate) (PPC). Chemical and thermal analyses reveal that the mechanism of PPC-PAG decomposition occurs through PPC backbone cleavage by the photo-induced acid. The self-assembled monolayer (SAM) encapsulation of Sr-ferrite preventing the interaction with the PAG allowed the transience of magnetic soft actuators. We demonstrate remotely controllable and degradable magnetic soft kirigami actuators using blocks with various magnetized directions. This study proposes novel approaches for fabricating lifetime-configurable magnetic soft actuators applicable to diverse environments and applications, such as enclosed/sealed spaces and security/military devices.

Surgical versus nonsurgical management of lumbar degenerative spondylolisthesis based on spinal canal cross-sectional area.

Disability and pain associated with lumbar degenerative spondylolisthesis (LDS) result in a significant burden on both the healthcare costs and patients' quality of life. Currently, there exists controversy regarding employment of either nonsurgical management (NSM) or surgical management (SM) in a clinical setting. Spinal canal cross-sectional area (SCA) has been an important morphological parameter for the analysis of LDS. However, there is lack of research about the comparative value of NSM and SM according to SCA. Moreover, previous research have not yet evaluated the clinical most suitable cutoff values of SCA. The objective of this research was to evaluate the effective of NSM and SM for LDS using SCA as an objective morphological parameter. The axial T2 magnetic resonance imaging images were obtained from each patient. We collected SCA samples from 149 patients with LDS. 72 patients underwent SM and the rest did NSM. We measured SCA at the L4/5 LDS on magnetic resonance imaging using a picture archiving and communications system. We measured SCA at the intervertebral disk posterior border, turning down to reach the facet joint side on the opposite edge at the L4/5 level. The average SCA value was 114.34 ±â€…48.11 mm2 in the NSM group and 69.88 ±â€…27.87 mm2 in the SM group. Therefore, the SM group had considerably lower SCA (P < .001). In view of the effectiveness of SCA as a prediction factor of surgical option, Receiver Operating Characteristic curve analysis show the optimal cutoff value for SCA as 83.21 mm2, with 70.8% sensitivity, 71.4% specificity, and an area under the curve of 0.80 (95% CI, 0.73-0.87). The narrower the SCA, the higher the probability of SM. Thus, it is proposed that to evaluate surgical decision making, the pain physician should carefully inspect the SCA.

Visible-Light-Driven Rapid 3D Printing of Photoresponsive Resins for Optically Clear Multifunctional 3D Objects.

Light-driven 3D printing is gaining significant attention for its unparalleled build speed and high-resolution in additive manufacturing. However, extending vat photopolymerization to multifunctional, photoresponsive materials poses challenges, such as light attenuation and interference between the photocatalysts (PCs) and photoactive moieties. This study introduces novel visible-light-driven acrylic resins that enable rapid, high-resolution photoactive 3D printing. The synergistic combination of a cyanine-based PC, borate, and iodonium coinitiators (HNu 254) achieves an excellent printing rate and feature resolution under low-intensity, red light exposure. The incorporation of novel hexaarylbiimidazole (HABI) crosslinkers allows for spatially-resolved photoactivation upon exposure to violet/blue light. Furthermore, a photobleaching mechanism inhibited by HNu 254 during the photopolymerization process results in the production of optically-clear 3D printed objects. Real-time Fourier transform infrared spectroscopy validates the rapid photopolymerization of the HABI-containing acrylic resin, whereas mechanistic evaluations reveal the underlying dynamics that are responsible for the rapid photopolymerization rate, wavelength-orthogonal photoactivation, and observed photobleaching phenomenon. Ultimately, this visible-light-based printing method demonstrates: (i) rapid printing rate of 22.5 mm h-1, (ii) excellent feature resolution (≈20 µm), and (iii) production of optically clear object with self-healing capability and spatially controlled cleavage. This study serves as a roadmap for developing next-generation "smart" 3D printing technologies.

Ultraviolet Light Debondable Optically Clear Adhesives for Flexible Displays through Efficient Visible-Light Curing.

With growing sustainability concerns, the need for products that facilitate easy disassembly and reuse has increased. Adhesives, initially designed for bonding, now face demands for selective removal, enabling rapid assembly-disassembly and efficient maintenance across industries. This need is particularly evident in the display industry, with the rise of foldable devices necessitating specialized adhesives. A novel optically clear adhesive (OCA) is presented for foldable display, featuring a unique UV-stimulated selective removal feature. This approach incorporates benzophenone derivatives into the polymer network, facilitating rapid debonding under UV irradiation. A key feature of this method is the adept use of visible-light-driven radical polymerization for OCA film fabrication. This method shows remarkable compatibility with various monomers and exhibits orthogonal reactivity to benzophenone, rendering it ideal for large-scale production. The resultant OCA not only has high transparency and balanced elasticity, along with excellent resistance to repeated folding, but it also exhibits significantly reduced adhesion when exposed to UV irradiation. By merging this customized formulation with strategically integrated UV-responsive elements, an effective solution is offered that enhances manufacturing efficiency and product reliability in the rapidly evolving field of sustainable electronics and displays. This research additionally contributes to eco-friendly device fabrication, aligning with emerging technology demands.

Waste-Wood-Isolated Cellulose-Based Activated Carbon Paper Electrodes with Graphene Nanoplatelets for Flexible Supercapacitors.

Waste wood, which has a large amount of cellulose fibers, should be transformed into useful materials for addressing environmental and resource problems. Thus, this study analyzed the application of waste wood as supercapacitor electrode material. First, cellulose fibers were extracted from waste wood and mixed with different contents of graphene nanoplatelets (GnPs) in water. Using a facile filtration method, cellulose papers with GnPs were prepared and converted into carbon papers through carbonization and then to porous activated carbon papers containing GnPs (ACP-GnP) through chemical activation processes. For the morphology of ACP-GnP, activated carbon fibers with abundant pores were formed. The increase in the amount of GnPs attached to the fiber surfaces decreased the number of pores. The Brunauer-Emmett-Teller surface areas and specific capacitance of the ACP-GnP electrodes decreased with an increase in the GnP content. However, the galvanostatic charge-discharge curves of ACPs with higher GnP contents gradually changed into triangular and linear shapes, which are associated with the capacitive performance. For example, ACP with 15 wt% GnP had a low mass transfer resistance and high charge delivery of ions, resulting in the specific capacitance value of 267 Fg-1 owing to micropore and mesopore formation during the activation of carbon paper.

Characterization of the Reversible Intersystem Crossing Dynamics of Organic Photocatalysts Using Transient Absorption Spectroscopy and Time-Resolved Fluorescence Spectroscopy.

Thermally activated delayed fluorescence (TADF) emitters are molecules of interest as homogeneous organic photocatalysts (OPCs) for photoredox chemistry. Here, three classes of OPC candidates are studied in dichloromethane (DCM) or N,N-dimethylformamide (DMF) solutions, using transient absorption spectroscopy and time-resolved fluorescence spectroscopy. These OPCs are benzophenones with either carbazole (2Cz-BP and 2tCz-BP) or phenoxazine/phenothiazine (2PXZ-BP and 2PTZ-BP) appended groups and the dicyanobenzene derivative 4DP-IPN. Dual lifetimes of the S1 state populations are observed, consistent with reverse intersystem crossing (RISC) and TADF emission. Example fluorescence lifetimes in DCM are (5.18 ± 0.01) ns and (6.22 ± 1.27) µs for 2Cz-BP, (1.38 ± 0.01) ns and (0.32 ± 0.01) µs for 2PXZ-BP, and (2.97 ± 0.01) ns and (62.0 ± 5.8) µs for 4DP-IPN. From ground state bleach recoveries and time-correlated single photon counting measurements, triplet quantum yields in DCM are estimated to be 0.62 ± 0.16, 0.04 ± 0.01, and 0.83 ± 0.02 for 2Cz-BP, 2PXZ-BP, and 4DP-IPN, respectively. 4DP-IPN displays similar photophysical behavior to the previously studied OPC 4Cz-IPN. Independent of the choice of solvent, 4DP-IPN, 2Cz-BP, and 2tCz-BP are shown to be TADF emitters, whereas emission by 2PXZ-BP and 2PTZ-BP depends on the molecular environment, with TADF emission enhanced in aggregates compared to monomers. Behavior of this type is representative of aggregation-induced emission luminogens (AIEgens).