Identification, Characterization, and Electronic Structures of Interconvertible Cobalt-Oxygen TAML Intermediates.

The reaction of Li[(TAML)CoIII]·3H2O (TAML = tetraamido macrocyclic tetraanionic ligand) with iodosylbenzene at 253 K in acetone in the presence of redox-innocent metal ions (Sc(OTf)3 and Y(OTf)3) or triflic acid affords a blue species 1, which is converted reversibly to a green species 2 upon cooling to 193 K. The electronic structures of 1 and 2 have been determined by combining advanced spectroscopic techniques (X-band electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR), X-ray absorption spectroscopy/extended X-ray absorption fine structure (XAS/EXAFS), and magnetic circular dichroism (MCD)) with ab initio theoretical studies. Complex 1 is best represented as an S = 1/2 [(Sol)(TAML•+)CoIII---OH(LA)]- species (LA = Lewis/Brønsted acid and Sol = solvent), where an S = 1 Co(III) center is antiferromagnetically coupled to S = 1/2 TAML•+, which represents a one-electron oxidized TAML ligand. In contrast, complex 2, also with an S = 1/2 ground state, is found to be multiconfigurational with contributions of both the resonance forms [(H-TAML)CoIV═O(LA)]- and [(H-TAML•+)CoIII═O(LA)]-; H-TAML and H-TAML•+ represent the protonated forms of TAML and TAML•+ ligands, respectively. Thus, the interconversion of 1 and 2 is associated with a LA-associated tautomerization event, whereby H+ shifts from the terminal -OH group to TAML•+ with the concomitant formation of a terminal cobalt-oxo species possessing both singlet (SCo = 0) Co(III) and doublet (SCo = 1/2) Co(IV) characters. The reactivities of 1 and 2 at different temperatures have been investigated in oxygen atom transfer (OAT) and hydrogen atom transfer (HAT) reactions to compare the activation enthalpies and entropies of 1 and 2.

Integration of National Health Insurance claims data and animal models reveals fexofenadine as a promising repurposed drug for Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is a common and costly progressive neurodegenerative disease of unclear etiology. A disease-modifying approach that can directly stop or slow its progression remains a major unmet need in the treatment of PD. A clinical pharmacology-based drug repositioning strategy is a useful approach for identifying new drugs for PD. METHODS: We analyzed claims data obtained from the National Health Insurance Service (NHIS), which covers a significant portion of the South Korean population, to investigate the association between antihistamines, a class of drugs commonly used to treat allergic symptoms by blocking H1 receptor, and PD in a real-world setting. Additionally, we validated this model using various animal models of PD such as the 6-hydroxydopmaine (6-OHDA), α-synuclein preformed fibrils (PFF) injection, and Caenorhabditis elegans (C. elegans) models. Finally, whole transcriptome data and Ingenuity Pathway Analysis (IPA) were used to elucidate drug mechanism pathways. RESULTS: We identified fexofenadine as the most promising candidate using National Health Insurance claims data in the real world. In several animal models, including the 6-OHDA, PFF injection, and C. elegans models, fexofenadine ameliorated PD-related pathologies. RNA-seq analysis and the subsequent experiments suggested that fexofenadine is effective in PD via inhibition of peripheral immune cell infiltration into the brain. CONCLUSION: Fexofenadine shows promise for the treatment of PD, identified through clinical data and validated in diverse animal models. This combined clinical and preclinical approach offers valuable insights for developing novel PD therapeutics.

Factors affecting nurses' attitude toward withdrawal of life-sustaining treatment for children.

PURPOSE: The purpose of study was to investigate factors affecting nurses' attitudes toward withdrawal of life-sustaining treatment in children. DESIGN AND METHODS: This descriptive survey study included 167 nurses working at children's hospitals or children's wards. Data were collected through a structured self-administered survey in November 2022. Data were analyzed using descriptive analysis, t-test, ANOVA, the Dunnett's T3 test, Pearson's correlation coefficient, and multiple linear regression. RESULTS: Attitude toward withdrawal of life-sustaining treatment in children showed a significant positive correlation with knowledge of life-sustaining treatment decision-making (r = 0.38, p < .001) and meaning as a subcategory of moral sensitivity (r = 0.21, p 0.008). The factors affecting attitude toward withdrawal of life-sustaining treatment in children were knowledge of life-sustaining treatment decision-making (ß =0.31, p < .001) and meaning (ß = 0.18, p = .015). This model showed a 21.0% explanation of attitude toward withdrawal of life-sustaining treatment in children. CONCLUSIONS: Developing an effective educational program designed to improve nurses' knowledge and attitude toward life-sustaining treatment decision-making is necessary. PRACTICE IMPLICATIONS: It may have a positive influence on attitudes toward withdrawal of life-sustaining treatment in children by improving child nurses' knowledge about life-sustaining treatment decision-making and moral sensitivity.

Inhibition of Biofilm Formation in Cutibacterium acnes, Staphylococcus aureus, and Candida albicans by the Phytopigment Shikonin.

Skin microbiota, such as acne-related Cutibacterium acnes, Staphylococcus aureus, and fungal Candida albicans, can form polymicrobial biofilms with greater antimicrobial tolerance to traditional antimicrobial agents and host immune systems. In this study, the phytopigment shikonin was investigated against single-species and multispecies biofilms under aerobic and anaerobic conditions. Minimum inhibitory concentrations of shikonin were 10 µg/mL against C. acnes, S. aureus, and C. albicans, and at 1-5 µg/mL, shikonin efficiently inhibited single biofilm formation and multispecies biofilm development by these three microbes. Shikonin increased porphyrin production in C. acnes, inhibited cell aggregation and hyphal formation by C. albicans, decreased lipase production, and increased hydrophilicity in S. aureus. In addition, shikonin at 5 or 10 µg/mL repressed the transcription of various biofilm-related genes and virulence-related genes in C. acnes and downregulated the gene expression levels of the quorum-sensing agrA and RNAIII, α-hemolysin hla, and nuclease nuc1 in S. aureus, supporting biofilm inhibition. In addition, shikonin prevented multispecies biofilm development on porcine skin, and the antimicrobial efficacy of shikonin was recapitulated in a mouse infection model, in which it promoted skin regeneration. The study shows that shikonin inhibits multispecies biofilm development by acne-related skin microbes and might be useful for controlling bacterial infections.

Trajectories of quality of life among disaster victims: A national longitudinal study.

AIM: This study categorized quality-of-life trajectories among disaster victims in South Korea and identified the characteristics and predictors of each trajectory. BACKGROUND: Disaster victims experience tremendous physical and mental distress, which has a long-term impact on their quality of life. METHODS: We conducted a cross-sectional study using data obtained from the fourth Long-term Survey on the Change of Life of Disaster Victims conducted from 2017 to 2019. The study included 257 participants who experienced a typhoon, earthquake, or fire and completed the three-year follow-up. Latent transition analysis was used to identify the potential class of quality-of-life trajectories among disaster victims. Independent t tests, χ2 tests, and logistic regression were used to identify the predictors of quality-of-life trajectories. RESULTS: Two latent quality-of-life classes were identified: persistent low-level and persistent high-level. Factors associated with the persistent high-level trajectory included higher education level, no injury/disease from the disaster, better subjective health status, higher social support, and lower social maladjustment. DISCUSSION: Quality of life early after a disaster is maintained throughout subsequent years; early and active support following disasters is essential to promote its rapid improvement. CONCLUSION: Targeted educational programs in disaster-prone areas are recommended to bolster resilience among individuals with lower education. Moreover, governmental and institutional efforts are needed to support victims who lack resources for disaster recovery. IMPLICATIONS FOR NURSING AND HEALTH POLICY: There is a need to establish community-based social support systems and enhance nurses' disaster response capabilities to support vulnerable groups, with such interventions tailored to reflect disaster-affected victims' unique characteristics and needs, along with ongoing research and evaluation for continuous improvements to nursing practice and disaster response.

Iridium-Cooperated, Symmetry-Broken Manganese Oxide Nanocatalyst for Water Oxidation.

The water oxidation reaction, the most important reaction for hydrogen production and other sustainable chemistry, is efficiently catalyzed by the Mn4CaO5 cluster in biological photosystem II. However, synthetic Mn-based heterogeneous electrocatalysts exhibit inferior catalytic activity at neutral pH under mild conditions. Symmetry-broken Mn atoms and their cooperative mechanism through efficient oxidative charge accumulation in biological clusters are important lessons but synthesis strategies for heterogeneous electrocatalysts have not been successfully developed. Here, we report a crystallographically distorted Mn-oxide nanocatalyst, in which Ir atoms break the space group symmetry from I41/amd to P1. Tetrahedral Mn(II) in spinel is partially replaced by Ir, surprisingly resulting in an unprecedented crystal structure. We analyzed the distorted crystal structure of manganese oxide using TEM and investigated how the charge accumulation of Mn atoms is facilitated by the presence of a small amount of Ir.

Correlation between immune-related genes and depression-like features in an animal model and in humans.

A growing body of evidence suggests that immune-related genes play pivotal roles in the pathophysiology of depression. In the present study, we investigated a plausible connection between gene expression, DNA methylation, and brain structural changes in the pathophysiology of depression using a combined approach of murine and human studies. We ranked the immobility behaviors of 30 outbred Crl:CD1 (ICR) mice in the forced swim test (FST) and harvested their prefrontal cortices for RNA sequencing. Of the 24,532 analyzed genes, 141 showed significant correlations with FST immobility time, as determined through linear regression analysis with p ≤ 0.01. The identified genes were mostly involved in immune responses, especially interferon signaling pathways. Moreover, induction of virus-like neuroinflammation in the brains of two separate mouse cohorts (n = 30 each) using intracerebroventricular polyinosinic:polycytidylic acid injection resulted in increased immobility during FST and similar expression of top immobility-correlated genes. In human blood samples, candidate gene (top 5%) expression profiling using DNA methylation analysis found the interferon-related USP18 (cg25484698, p = 7.04 × 10-11, Δß = 1.57 × 10-2; cg02518889, p = 2.92 × 10-3, Δß =  - 8.20 × 10-3) and IFI44 (cg07107453, p = 3.76 × 10-3, Δß =  - 4.94 × 10-3) genes to be differentially methylated between patients with major depressive disorder (n = 350) and healthy controls (n = 161). Furthermore, cortical thickness analyses using T1-weighted images revealed that the DNA methylation scores for USP18 were negatively correlated with the thicknesses of several cortical regions, including the prefrontal cortex. Our results reveal the important role of the interferon pathway in depression and suggest USP18 as a potential candidate target. The results of the correlation analysis between transcriptomic data and animal behavior carried out in this study provide insights that could enhance our understanding of depression in humans.

Unlocking Cu(I)-Mediated Catalytic Pathways for Efficient ROS Generation by Incorporating an Oxazole-Based Histidine Surrogate into Cu(II)-ATCUN Complexes.

The catalytic redox activity of Cu(II) bound to the amino-terminal copper and nickel (ATCUN) binding motif (Xxx-Zzz-His, XZH) is stimulating the development of catalytic metallodrugs based on reactive oxygen species (ROS)-mediated biomolecule oxidation. However, low Cu(I) availability resulting from the strong Cu(II) binding affinity of the ATCUN motif is regarded as a limitation to efficient ROS generation. To address this, we replaced the imidazole moiety (pKa 7.0) of Gly-Gly-His-NH2 (GGHa, a canonical ATCUN peptide) with thiazole (pKa 2.7) and oxazole (pKa 0.8), yielding GGThia and GGOxa, respectively. A newly synthesized amino acid, Fmoc-3-(4-oxazolyl)-l-alanine, served as a histidine surrogate featuring an azole ring with the lowest pKa among known analogues. Despite similar square-planar Cu(II)-N4 geometries being observed for the three Cu(II)-ATCUN complexes by electron paramagnetic resonance spectroscopy and X-ray crystallography, the azole modification enabled the Cu(II)-ATCUN complexes to exhibit significant rate enhancement for ROS-mediated DNA cleavage. Further analyses based on Cu(I)/Cu(II) binding affinities, electrochemical measurements, density functional theory calculations, and X-ray absorption spectroscopy indicated that the azole modification enhanced the accessibility of the Cu(I) oxidation state during ROS generation. Our oxazole/thiazole-containing ATCUN motifs provide a new design strategy for peptide ligands with modulated N donor ability, with potential applications in the development of ROS-mediated metallodrugs.

Virus detection of measles-negative cases in Gyeonggi Province, South Korea, from 2017 to 2019.

To investigate viruses in measles-negative cases, 221 measles-suspected samples collected in Gyeonggi Province, South Korea were tested using a real-time PCR assay. Rubella virus was not detected. However, 11 cases of parvovirus B19 (5.0%), 47 cases of human herpesvirus 6 (21.3%), 25 cases of human herpesvirus 7 (11.3%), and one case of co-infection with parvovirus B19 and human herpesvirus 7 were confirmed, as were eight cases of co-infection with human herpesvirus 6 and human herpesvirus 7. This study showed that parvovirus B19, human herpesvirus 6, and human herpesvirus 7 should be considered by physicians for the diagnosis of measles-suspected patients.

Atomic-scale evidence for highly selective electrocatalytic N-N coupling on metallic MoS2.

Molybdenum sulfide (MoS2) is the most widely studied transition-metal dichalcogenide (TMDs) and phase engineering can markedly improve its electrocatalytic activity. However, the selectivity toward desired products remains poorly explored, limiting its application in complex chemical reactions. Here we report how phase engineering of MoS2 significantly improves the selectivity for nitrite reduction to nitrous oxide, a critical process in biological denitrification, using continuous-wave and pulsed electron paramagnetic resonance spectroscopy. We reveal that metallic 1T-MoS2 has a protonation site with a pKa of ∼5.5, where the proton is located ∼3.26 Šfrom redox-active Mo site. This protonation site is unique to 1T-MoS2 and induces sequential proton-electron transfer which inhibits ammonium formation while promoting nitrous oxide production, as confirmed by the pH-dependent selectivity and deuterium kinetic isotope effect. This is atomic-scale evidence of phase-dependent selectivity on MoS2, expanding the application of TMDs to selective electrocatalysis.

Protective Effects of Hemp (Cannabis sativa) Root Extracts against Insulin-Deficient Diabetes Mellitus In Mice.

The pharmacological potential of industrial hemp (Cannabis sativa) has been widely studied. However, the majority of studies have focused on cannabidiol, isolated from the inflorescence and leaf of the plant. In the present study, we evaluated the anti-diabetic potential of hemp root water (HWE) and ethanol extracts (HEE) in streptozotocin (STZ)-induced insulin-deficient diabetic mice. The administration of HWE and HEE ameliorated hyperglycemia and improved glucose homeostasis and islet function in STZ-treated mice (p < 0.05). HWE and HEE suppressed ß-cell apoptosis and cytokine-induced inflammatory signaling in the pancreas (p < 0.05). Moreover, HWE and HEE normalized insulin-signaling defects in skeletal muscles and apoptotic response in the liver and kidney induced by STZ (p < 0.05). Gas chromatography-mass spectrometry analysis of HWE and HEE showed possible active compounds which might be responsible for the observed anti-diabetic potential. These findings indicate the possible mechanisms by which hemp root extracts protect mice against insulin-deficient diabetes, and support the need for further studies geared towards the application of hemp root as a novel bioactive material.

Effects of metaverse-based career mentoring for nursing students: a mixed methods study.

BACKGROUND: There is a lack of studies on metaverse-based career mentoring for college students in both quantitative and qualitative research. This study aimed to examine the effect of metaverse-based career mentoring among nursing students and explore the experiences of mentors and mentees. METHODS: This study used a mixed methods design using both a survey for collecting quantitative data and focus group interviews for a qualitative one. A total of 8 mentors and 43 mentees participated in the metaverse-based career mentoring program. The program covered eight career fields and was delivered across eight sessions of 60 min each, over six days. Career decision-making self-efficacy among mentees and platform and program satisfaction were measured before and after the program. Afterwards, 7 mentors and 12 mentees participated in the focus group interviews to investigate their experience of participating in the metaverse-based career mentoring program. Quantitative data were analyzed using descriptive statistics, paired t-test, Wilcoxon signed-rank test, and Mann-Whitney U test. The qualitative data underwent thematic analysis. RESULTS: After the metaverse-based career mentoring program, mentees' career decision-making self-efficacy increased significantly compared to the baseline level. From the mentor-mentee focus group interviews, three key themes were derived: (i) communicating frankly and openly, (ii) being satisfied with realistic communication and program functions, and (iii) expecting an even more optimized program. CONCLUSIONS: A metaverse-based career mentoring program for nursing students can have a positive effect on their career decision-making self-efficacy. In addition, in terms of education, it is helpful as a non-face-to-face medium and feeling a sense of reality, so it is expected that it will be beneficial in education by applying various contents in the future.

Factors associated with depression and suicidal ideation among oldest-old adults aged 85 years or older based on gender, using the survey data of South Korea.

BACKGROUND: South Korea is predicted to become a superaged society around 2025. Depression in older adults is a major factor influencing suicide. South Korea exhibits the highest suicide rate among the Organization for Economic Co-operation and Development countries. METHODS: This study aimed to examine the factors associated with depression and suicidal ideation among individuals aged 85 years or older based on gender. Data were obtained from the Korea Institute for Health and Social Affairs, 2017. Overall, 768 individuals aged ≥85 years were included in the final analysis. The participants' general, health-related, and social characteristics were analyzed as factors influencing depression and suicidal ideation. RESULTS: Among male oldest-old adults, living arrangements and the number of chronic diseases were factors affecting depression, while activities of daily living restrictions and the number of chronic diseases were factors affecting suicidal ideation. Among female oldest-old adults, only the number of chronic diseases affected depression, while financial status and the number of chronic diseases were the factors affecting suicidal ideation. CONCLUSIONS: The healthcare and welfare services for older adults must be expanded to cater to oldest-old adults who live alone, have activities of daily living restrictions, and have lower financial status. Additionally, the oldest age group's psychological health must be monitored regularly for depression and suicidal ideation to implement active interventions for this high-risk group.

Comparison of factors influencing fall recurrence in the young-old and old-old: a cross-sectional nationwide study in South Korea.

BACKGROUND: Recurrent falls are a concerning problem in the elderly. Elderly people aged > 65 years who are prone to fall often require medical treatment for severe fall-related injuries, which is associated with a substantial financial burden. Therefore, this study aimed to identify factors related to recurrent falls in the community-dwelling young-old (65-74 years old) and old-old (≥ 75 years) in South Korea. METHODS: This study used a cross-sectional, correlation design. Data from the 2017 National Survey of Older Koreans were used, and 5,838 young-old and 4,205 old-old elderly people were included in the analysis. The questionnaire included general characteristics, fall experience, physical status, mental status, and presence of chronic diseases. The data were analyzed using the chi-square test, one-way analysis of variance, and logistic regression analysis. RESULTS: In the young-old elderly people, limitations in activities of daily living (p < .001), use of visual aids (p = .002), cognitive function (p < .001), presence of suicidal ideations (p = .005), number of chronic diseases (p < .001), and number of prescribed medications used (p = .006) associated with fall recurrence. In the old-old elderly people, having a spouse (p = .034), being a beneficiary of the National Basic Livelihood Security System (p = .025), less exercise (p = .003), limitations in activities of daily living (p < .001), visual aid use (p = .002), presence of suicidal ideations (p = .015), number of chronic diseases (p < .001), and presence of Parkinson's disease (p < .001) associated with fall recurrence. CONCLUSIONS: This study identified differences in factors related to fall recurrence between the young-old and old-old elderly. The results of this study indicate that it is necessary to implement an intervention program to prevent fall recurrence by age group in consideration of the risk factors for fall recurrence in each elderly people group.

An Isolable Mononuclear Palladium(I) Amido Complex.

Mononuclear Pd(I) species are putative intermediates in Pd-catalyzed reactions, but our knowledge about them is limited due to difficulties in accessing them. Herein, we report the isolation of a Pd(I) amido complex, [(BINAP)Pd(NHArTrip)] (BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthalene, ArTrip = 2,6-bis(2',4',6'-triisopropylphenyl)phenyl), from the reaction of (BINAP)PdCl2 with LiNHArTrip. This Pd(I) amido species has been characterized by X-ray crystallography, electron paramagnetic resonance, and multiedge Pd X-ray absorption spectroscopy. Theoretical study revealed that, while the three-electron-two-center π-interaction between Pd and N in the Pd(I) complex imposes severe Pauli repulsion in its Pd-N bond, pronounced attractive interligand dispersion force aids its stabilization. In accord with its electronic features, reactions of homolytic Pd-N bond cleavage and deprotonation of primary amines are observed on the Pd(I) amido complex.

How do the influencing factors of health-related quality of life of the injured patient differ according to activity limitations?

PURPOSE: This study aimed to ascertain the general characteristics of injured patients and use the Andersen Model to identify factors affecting health-related quality of life (QOL) in injured patients with or without activity limitations. METHODS: We used data of 1602 injured patients from 2014 to 2017 from the population-based Korea National Health and Nutrition Examination Survey, South Korea. QOL was measured using the EQ-5D-3L, and activity limitations were analyzed alongside predisposing factors (gender, age, education level, and marital status), enabling factors (basic living security, health insurance type, private insurance status, household income, and living with family), need factors (number of chronic diseases, subjective health status, and unmet medical needs), and health behaviors (smoking status, alcohol consumption, physical activity, and health screening). Data were analyzed using homogeneity testing, t tests, and logistic and multiple regression. RESULTS: The mean EQ-5D index was 0.8 with activity limitations and 0.9 without activity limitations. In mobility domain, patients without activity limitations showed significant effects of age, education level, number of chronic diseases, subjective health status, and unmet medical needs on mobility, whereas patients with activity limitations only showed a significant effect of age. In self-care domain, age, household income, and number of chronic diseases showed significant factors on patients without activity limitations, but there was no significant factor associated with activity limitations. Among the factors affecting usual activities, gender was found to have a significant effect only on patients with activity limitations, and subjective health status was found to have a significant effect regardless of activity limitations. Among the factors affecting pain/discomfort, living with family only affected pain/discomfort in patients with activity limitations. Among the factors affecting anxiety/depression, gender and alcohol consumption had significant effects only on patients with activity limitations. CONCLUSION: Factors affecting the QOL of injured patients differed depending on whether patients had activity limitations. Therefore, when assessing injured patients, it may be necessary to ascertain the extent of activity limitations, and medical institutions and local communities need when implementing education and interventions to improve their QOL.

Machine Learning Approach for Active Vaccine Safety Monitoring.

BACKGROUND: Vaccine safety surveillance is important because it is related to vaccine hesitancy, which affects vaccination rate. To increase confidence in vaccination, the active monitoring of vaccine adverse events is important. For effective active surveillance, we developed and verified a machine learning-based active surveillance system using national claim data. METHODS: We used two databases, one from the Korea Disease Control and Prevention Agency, which contains flu vaccination records for the elderly, and another from the National Health Insurance Service, which contains the claim data of vaccinated people. We developed a case-crossover design based machine learning model to predict the health outcome of interest events (anaphylaxis and agranulocytosis) using a random forest. Feature importance values were evaluated to determine candidate associations with each outcome. We investigated the relationship of the features to each event via a literature review, comparison with the Side Effect Resource, and using the Local Interpretable Model-agnostic Explanation method. RESULTS: The trained model predicted each health outcome of interest with a high accuracy (approximately 70%). We found literature supporting our results, and most of the important drug-related features were listed in the Side Effect Resource database as inducing the health outcome of interest. For anaphylaxis, flu vaccination ranked high in our feature importance analysis and had a positive association in Local Interpretable Model-Agnostic Explanation analysis. Although the feature importance of vaccination was lower for agranulocytosis, it also had a positive relationship in the Local Interpretable Model-Agnostic Explanation analysis. CONCLUSION: We developed a machine learning-based active surveillance system for detecting possible factors that can induce adverse events using health claim and vaccination databases. The results of the study demonstrated a potentially useful application of two linked national health record databases. Our model can contribute to the establishment of a system for conducting active surveillance on vaccination.

Patients' and Families' Experiences Regarding Disclosure of Patient Safety Incidents.

In South Korea, disclosure of patients' safety incidents is not common in health care settings. Thus, this study identified patients' and families' experiences regarding disclosure of patient safety incidents. Data were collected through in-depth individual interviews from May 25, 2020, to June 23, 2020, and analyzed using Colaizzi's phenomenological method. The participants consisted of 15 patients and their families who had experienced patient safety incidents in hospitals. It is essential to form a base of mutual understanding to enable disclosure and promote follow-up management systems that can ethically and responsibly handle patient safety incidents. Concrete protocols and policies need to be developed to protect patients and their families from physical/psychological injury and the stress experienced due to patient safety incidents. The patients and their families desired changes to improve protocols for proper disclosure, help health care professionals adopt an ethical and mature attitude, and develop professional health care policies regarding patients' safety incidents.

Enhanced Redox Reactivity of a Nonheme Iron(V)-Oxo Complex Binding Proton.

Acid effects on the chemical properties of metal-oxygen intermediates have attracted much attention recently, such as the enhanced reactivity of high-valent metal(IV)-oxo species by binding proton(s) or Lewis acidic metal ion(s) in redox reactions. Herein, we report for the first time the proton effects of an iron(V)-oxo complex bearing a negatively charged tetraamido macrocyclic ligand (TAML) in oxygen atom transfer (OAT) and electron-transfer (ET) reactions. First, we synthesized and characterized a mononuclear nonheme Fe(V)-oxo TAML complex (1) and its protonated iron(V)-oxo complexes binding two and three protons, which are denoted as 2 and 3, respectively. The protons were found to bind to the TAML ligand of the Fe(V)-oxo species based on spectroscopic characterization, such as resonance Raman, extended X-ray absorption fine structure (EXAFS), and electron paramagnetic resonance (EPR) measurements, along with density functional theory (DFT) calculations. The two-protons binding constant of 1 to produce 2 and the third protonation constant of 2 to produce 3 were determined to be 8.0(7) × 108 M-2 and 10(1) M-1, respectively. The reactivities of the proton-bound iron(V)-oxo complexes were investigated in OAT and ET reactions, showing a dramatic increase in the rate of sulfoxidation of thioanisole derivatives, such as 107 times increase in reactivity when the oxidation of p-CN-thioanisole by 1 was performed in the presence of HOTf (i.e., 200 mM). The one-electron reduction potential of 2 (Ered vs SCE = 0.97 V) was significantly shifted to the positive direction, compared to that of 1 (Ered vs SCE = 0.33 V). Upon further addition of a proton to a solution of 2, a more positive shift of the Ered value was observed with a slope of 47 mV/log([HOTf]). The sulfoxidation of thioanisole derivatives by 2 was shown to proceed via ET from thioanisoles to 2 or direct OAT from 2 to thioanisoles, depending on the ET driving force.

Probing the Structure and Binding Mode of EDTA on the Surface of Mn3O4 Nanoparticles for Water Oxidation by Advanced Electron Paramagnetic Resonance Spectroscopy.

Identification of the surface structure of nanoparticles is important for understanding the catalytic mechanism and improving the properties of the particles. Here, we provide a detailed description of the coordination modes of ethylenediaminetetraacetate (EDTA) on Mn3O4 nanoparticles at the atomic level, as obtained by advanced electron paramagnetic resonance (EPR) spectroscopy. Binding of EDTA to Mn3O4 leads to dramatic changes in the EPR spectrum, with a 5-fold increase in the axial zero-field splitting parameter of Mn(II). This indicates significant changes in the coordination environment of the Mn(II) site; hence, the binding of EDTA causes a profound change in the electronic structure of the manganese site. Furthermore, the electron spin echo envelope modulation results reveal that two 14N atoms of EDTA are directly coordinated to the Mn site and a water molecule is coordinated to the surface of the nanoparticles. An Fourier transform infrared spectroscopy study shows that the Ca(II) ion is coordinated to the carboxylic ligands via the pseudobridging mode. The EPR spectroscopic results provide an atomic picture of surface-modified Mn3O4 nanoparticles for the first time. These results can enhance our understanding of the rational design of catalysts, for example, for the water oxidation reaction.