Extrinsic hydrophobicity-controlled silver nanoparticles as efficient and stable catalysts for CO2 electrolysis.

To realize economically feasible electrochemical CO2 conversion, achieving a high partial current density for value-added products is particularly vital. However, acceleration of the hydrogen evolution reaction due to cathode flooding in a high-current-density region makes this challenging. Herein, we find that partially ligand-derived Ag nanoparticles (Ag-NPs) could prevent electrolyte flooding while maintaining catalytic activity for CO2 electroreduction. This results in a high Faradaic efficiency for CO (>90%) and high partial current density (298.39 mA cm‒2), even under harsh stability test conditions (3.4 V). The suppressed splitting/detachment of Ag particles, due to the lipid ligand, enhance the uniform hydrophobicity retention of the Ag-NP electrode at high cathodic overpotentials and prevent flooding and current fluctuations. The mass transfer of gaseous CO2 is maintained in the catalytic region of several hundred nanometers, with the smooth formation of a triple phase boundary, which facilitate the occurrence of CO2RR instead of HER. We analyze catalyst degradation and cathode flooding during CO2 electrolysis through identical-location transmission electron microscopy and operando synchrotron-based X-ray computed tomography. This study develops an efficient strategy for designing active and durable electrocatalysts for CO2 electrolysis.

Development and Application of an Active Pharmacovigilance Framework Based on Electronic Healthcare Records from Multiple Centers in Korea.

INTRODUCTION: With the availability of retrospective pharmacovigilance data, the common data model (CDM) has been identified as an efficient approach towards anonymized multicenter analysis; however, the establishment of a suitable model for individual medical systems and applications supporting their analysis is a challenge. OBJECTIVE: The aim of this study was to construct a specialized Korean CDM (K-CDM) for pharmacovigilance systems based on a clinical scenario to detect adverse drug reactions (ADRs). METHODS: De-identified patient records (n = 5,402,129) from 13 institutions were converted to the K-CDM. From 2005 to 2017, 37,698,535 visits, 39,910,849 conditions, 259,594,727 drug exposures, and 30,176,929 procedures were recorded. The K-CDM, which comprises three layers, is compatible with existing models and is potentially adaptable to extended clinical research. Local codes for electronic medical records (EMRs), including diagnosis, drug prescriptions, and procedures, were mapped using standard vocabulary. Distributed queries based on clinical scenarios were developed and applied to K-CDM through decentralized or distributed networks. RESULTS: Meta-analysis of drug relative risk ratios from ten institutions revealed that non-steroidal anti-inflammatory drugs (NSAIDs) increased the risk of gastrointestinal hemorrhage by twofold compared with aspirin, and non-vitamin K anticoagulants decreased cerebrovascular bleeding risk by 0.18-fold compared with warfarin. CONCLUSION: These results are similar to those from previous studies and are conducive for new research, thereby demonstrating the feasibility of K-CDM for pharmacovigilance. However, the low quality of original EMR data, incomplete mapping, and heterogeneity between institutions reduced the validity of the analysis, thus necessitating continuous calibration among researchers, clinicians, and the government.

Understanding the Impact of the COVID-19 Pandemic on the Perception and Use of Urban Green Spaces in Korea.

Faced with the prospect that the impact of the COVID-19 pandemic and climate change will be far-reaching and long-term, the international community is showing interest in urban green space (UGS) and urban green infrastructure utilization as a solution. In this study, we investigated how citizens' perceptions and use of UGS have changed during COVID-19. We also collected their ideas on how UGS can raise its usability. As a result, more people became to realize the importance of UGS. In particular, the urban environmental purification function from UGS was recognized as giving great benefits to respondents. On the other hand, the patterns of UGS use were mixed with decreasing UGS use to maintain social distancing or increasing UGS use to maintain health or substitute other restricted facilities. More than half of respondents had their UGS visit patterns impacted by COVID-19. In particular, the increase rate of UGS use was rather high in the group that seldom used UGS before COVID-19. In addition, they increased the use of UGS to replace other limited facilities, and thus tended to demand an increase in rest facilities. Based on these results, this paper suggested securing social support and sustainability for the policy by reflecting users' demand in landscape planning related to the increase of UGS in the city. This study can contribute to improving the resilience of UGS and the sustainability of urban space planning.

Exploring dopant effects in stannic oxide nanoparticles for CO2 electro-reduction to formate.

The electrosynthesis of formate from CO2 can mitigate environmental issues while providing an economically valuable product. Although stannic oxide is a good catalytic material for formate production, a metallic phase is formed under high reduction overpotentials, reducing its activity. Here, using a fluorine-doped tin oxide catalyst, a high Faradaic efficiency for formate (95% at 100 mA cm-2) and a maximum partial current density of 330 mA cm-2 (at 400 mA cm-2) is achieved for the electroreduction of CO2. Furthermore, the formate selectivity (≈90%) is nearly constant over 7 days of operation at a current density of 100 mA cm-2. In-situ/operando spectroscopies reveal that the fluorine dopant plays a critical role in maintaining the high oxidation state of Sn, leading to enhanced durability at high current densities. First-principle calculation also suggests that the fluorine-doped tin oxide surface could provide a thermodynamically stable environment to form HCOO* intermediate than tin oxide surface. These findings suggest a simple and efficient approach for designing active and durable electrocatalysts for the electrosynthesis of formate from CO2.

Electrode reconstruction strategy for oxygen evolution reaction: maintaining Fe-CoOOH phase with intermediate-spin state during electrolysis.

Computational calculations and experimental studies reveal that the CoOOH phase and the intermediate-spin (IS) state are the key factors for realizing efficient Co-based electrocatalysts for the oxygen evolution reaction (OER). However, according to thermodynamics, general cobalt oxide converts to the CoO2 phase under OER condition, retarding the OER kinetics. Herein, we demonstrate a simple and scalable strategy to fabricate electrodes with maintaining Fe-CoOOH phase and an IS state under the OER. The changes of phase and spin states were uncovered by combining in-situ/operando X-ray based absorption spectroscopy and Raman spectroscopy. Electrochemical reconstruction of chalcogenide treated Co foam affords a highly enlarged active surface that conferred excellent catalytic activity and stability in a large-scale water electrolyzer. Our findings are meaningful in that the calculated results were experimentally verified through the operando analyses. It also proposes a new strategy for electrode fabrication and confirms the importance of real active phases and spin states under a particular reaction condition.

Bottom-Up Evolution of Diamond-Graphite Hybrid Two-Dimensional Nanostructure: Underlying Picture and Electrochemical Activity.

The diamond-graphite hybrid thin film with low-dimensional nanostructure (e.g., nitrogen-included ultrananocrystalline diamond (N-UNCD) or the alike), has been employed in many impactful breakthrough applications. However, the detailed picture behind the bottom-up evolution of such intriguing carbon nanostructure is far from clarified yet. Here, the authors clarify it, through the concerted efforts of microscopic, physical, and electrochemical analyses for a series of samples synthesized by hot-filament chemical vapor deposition using methane-hydrogen precursor gas, based on the hydrogen-dependent surface reconstruction of nanodiamond and on the substrate-temperature-dependent variation of the growth species (atomic hydrogen and methyl radical) concentration near substrate. The clarified picture provides insights for a drastic enhancement in the electrochemical activities of the hybrid thin film, concerning the detection of important biomolecule, that is, ascorbic acid, uric acid, and dopamine: their limits of detections are 490, 35, and 25 nm, respectively, which are among the best of the all-carbon thin film electrodes in the literature. This work also enables a simple and effective way of strongly enhancing AA detection.

High crystallinity design of Ir-based catalysts drives catalytic reversibility for water electrolysis and fuel cells.

The voltage reversal of water electrolyzers and fuel cells induces a large positive potential on the hydrogen electrodes, followed by severe system degradation. Applying a reversible multifunctional electrocatalyst to the hydrogen electrode is a practical solution. Ir exhibits excellent catalytic activity for hydrogen evolution reactions (HER), and hydrogen oxidation reactions (HOR), yet irreversibly converts to amorphous IrOx at potentials > 0.8 V/RHE, which is an excellent catalyst for oxygen evolution reactions (OER), yet a poor HER and HOR catalyst. Harnessing the multifunctional catalytic characteristics of Ir, here we design a unique Ir-based electrocatalyst with high crystallinity for OER, HER, and HOR. Under OER operation, the crystalline nanoparticle generates an atomically-thin IrOx layer, which reversibly transforms into a metallic Ir at more cathodic potentials, restoring high activity for HER and HOR. Our analysis reveals that a metallic Ir subsurface under thin IrOx layer can act as a catalytic substrate for the reduction of Ir ions, creating reversibility. Our work not only uncovers fundamental, uniquely reversible catalytic properties of nanoparticle catalysts, but also offers insights into nanocatalyst design.

Comparison of risk of cardiovascular disease related adverse events between selective serotonin reuptake inhibitor users and serotonin norepinephrine reuptake inhibitor users in Korean adult patients with depression: retrospective cohort study.

Serotonin norepinephrine reuptake inhibitor (SNRI) has been increasingly administered, but the associated cardiovascular disease (CVD) related adverse events risk is not clearly understood. So, we conducted a cohort study to identified CVD-related adverse events risk of SNRI comparing to selective serotonin reuptake inhibitor (SSRI). We used Korea Health Insurance Review and Assessment data. During the period from April 2009 to March 2011, patients who were prescribed SSRI or SNRI for depression, who were followed up till March 2018, were the subjects. Hemorrhagic stroke, ischemic stroke, and myocardial infarction were selected as the outcomes. High-dimensional propensity scores were used to adjust the unmeasured confounders. the cox proportional hazard model was used for the statistical analysis. A total of 1,016,136 patients diagnosed with depression over the age of 20 were screened and there were 64,739 SSRI users and 3,711 SNRI users in the group of patients. The adjusted hazard ratio did not differ between the two groups, but the subgroup analysis according to comorbidities showed a high risk of hemorrhagic stroke in SNRI users with hypertension or diabetes mellitus.

Activation of Hydrogen Peroxide by a Titanium Oxide-Supported Iron Catalyst: Evidence for Surface Fe(IV) and Its Selectivity.

Iron immobilized on supports such as silica, alumina, titanium oxide, and zeolite can activate hydrogen peroxide (H2O2) into strong oxidants. However, the role of the support and the nature of the oxidants produced in this process remain elusive. This study investigated the activation of H2O2 by a TiO2-supported catalyst (FeTi-ox). Characterizing the catalyst surface in situ using X-ray absorption spectroscopy (XAS), together with X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR), revealed that the interaction between H2O2 and the TiO2 phase played a key role in the H2O2 activation. This interaction generated a stable peroxo-titania ≡Fe(III)-Ti-OOH complex, which reacted further with H2O to produce a surface oxidant, likely ≡Fe[IV] ═ O2+. The oxidant effectively degraded acetaminophen, even in the presence of chloride, bicarbonate, and organic matter. Unexpectedly, contaminant oxidation continued after the H2O2 in the solution was depleted, owing to the decomposition of ≡Fe(III)-Ti-OOH by water. In addition, the FeTi-ox catalyst effectively degraded acetaminophen over five testing cycles. Overall, new insights gained in this study may provide a basis for designing more effective catalysts for H2O2 activation.

Single-atom catalysts for the oxygen evolution reaction: recent developments and future perspectives.

Single-atom catalysts (SACs) possess the potential to achieve unique catalytic properties and remarkable catalytic mass activity by utilizing low-coordination and unsaturated active sites. However, smaller particles tend to aggregate into clusters or particles owing to their high surface energy. In addition, support materials that have strong interactions with isolated metal atoms, extremely large surface areas, and electrochemical stability are required. Therefore, sufficient information about these factors is needed to synthesize and utilize SACs. Herein, we review the recent investigations and advances in SACs for the oxygen evolution reaction (OER). We present not only the structural characterization of SACs, but also in situ/operando spectroscopic techniques and computational research for SACs to understand the mechanism and reveal the origin of their excellent OER activity. Furthermore, the OER catalytic activity and stability of SACs are summarized to evaluate the current level of SACs. Currently, research on single-atoms as OER catalysts is in the infant stage for synthesis, characterization and mechanism studies. We discuss some challenges for understanding the fundamentals of SACs and enhancing the catalytic performance of SACs for industrial applications.

Duloxetine and cardiovascular adverse events: A systematic review and meta-analysis.

Duloxetine has been increasingly administered, but the associated cardiovascular adverse event risk is not clearly understood. Therefore, we identified the association between duloxetine and cardiovascular adverse events through an analysis of heart rate and blood pressure change. We searched PubMed, EMBASE, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and psycINFO in June 2019. The title, abstract, and full text were checked in order to obtain articles. A meta-analysis was conducted with random effect model and quality of articles was evaluated using Cochrane Risk of Bias 2.0. The manuscript has been written according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) harm checklist. A total of 4009 studies were screened by the title and abstract. After reviewing 186 full texts, 17 studies were finally selected for the meta-analysis. Nine of the 17 studied duloxetine given for mood disorders and 8 for pain control. The duration of 14 studies was under 13 weeks. Cardiovascular adverse events (hypertension, myocardial infarction, transient ischemic attack, tachycardia atrial fibrillation, and cerebrovascular accident) were reported. The meta-analysis demonstrated that duloxetine increased heart rate by 2.22 beats/min (95% confidence intervals [CIs]: 1.53, 2.91) and diastolic blood pressure by 0.82 mmHg (95% CI: 0.17, 1.47). Our findings may be the signal for the safety of cardiovascular disease for short-term use of duloxetine. Well-designed pharmaco-epidemiological studies evaluating the causal relationship between long-term use of duloxetine and cardiovascular disease is still necessary.

Comparison of bleeding risks among non-vitamin K antagonist oral anticoagulants using the Korea adverse event reporting system database.

BACKGROUND: In order to ensure safer use of non-vitamin K antagonist oral anticoagulants (NOACs), continuously detecting unexpected adverse drug reactions (ADRs) after market approval is necessary. METHODS: We performed disproportionality analysis to evaluate association between ADRs and NOACs including apixaban, dabigatran, and rivaroxaban using data from the Korea Institute of Drug Safety and Risk Management-Korea Adverse Event Reporting System database (KIDS-KD) between 2012 and 2016. There was no significant signal other than bleeding when considering quantity, signal strength, seriousness, and causality. In order to evaluate the NOAC reports about bleeding, we selected 62 WHO-ART diagnostic codes associated with bleeding. Among the 26 codes that referred to major bleeding, 18 codes referred to gastrointestinal bleeding and 8 were referred to intracranial bleeding. We evaluated the significance of the signals using reporting odds ratios (RORs) adjusted for age and sex. RESULTS: Treatments with apixaban, dabigatran, and rivaroxaban were associated with 1989, 1668, and 2960 adverse events, respectively. Any type of bleeding with apixaban, dabigatran, rivaroxaban, and warfarin was reported in 174 (8.8%), 209 (12.5%), 523 (17.8%), and 620 (9.5%) events, respectively. For any bleeding, adjusted RORs of apixaban, dabigatran, and rivaroxaban were 0.99 [95% confidence interval (CI): 0.83-1.17], 1.47 (95% CI: 1.25-1.75), and 2.48 (95% CI: 2.16-2.84), respectively. With respect to major bleeding, the adjusted RORs of apixaban, dabigatran, and rivaroxaban were 1.08 (95% CI: 0.82-1.41), 1.46 (95% CI: 1.10-1.90), and 1.82 (95% CI: 1.43-2.32), respectively. CONCLUSION: Rivaroxaban might have stronger association with bleeding than apixaban and dabigatran.

Medial Buttress Plating for Humerus Fractures With Unstable Medial Column.

The purpose of this study was to report surgical tips and techniques on the use of additional medial buttress plate fixation in proximal humeral fractures with unstable medial column restoration after lateral locking compression plate fixation. Between April 2011 and January 2017, 17 patients with medial cortical deficiency were treated using this technique. The average follow-up period was 30 (range, 12-81) months. Successful fracture healing was achieved in all 17 cases. The mean neck-shaft angle change was 1.33 degree (range, 0-7.4 degree). Anterior glenoid rim erosion occurred in 1 patient. No avascular necrosis of the humeral head or significant loss of reduction, and no implant failure or screw perforation occurred. In the first part of this study, we described in detail the indications and surgical technique applied to these fractures. In the second part, we reviewed the clinical and radiographic outcomes of these patients. Supplemental medial buttress plate fixation after lateral locking compression plate fixation was effective in preventing varus collapse and implant failure for proximal humeral fractures with an unstable medial column.

Complementing conventional infectious disease surveillance with national health insurance claims data in the Republic of Korea.

Surveillance remains an important tool for timely outbreak detection and response. Many countries, including Korea, have established national infectious disease surveillance systems with clinical notification. We aimed to evaluate the National Health Insurance Claims-based Surveillance (NHICS) compared to conventional passive report-based National Infectious Diseases Surveillance (NIDS). Reported to claimed cases ratios (R/C ratio) were evaluated from monthly notifiable disease cases captured by NIDS and NHICS. The relationships between 26 infectious diseases and each surveillance system were analysed using Pearson's correlation analysis and linear regression. There was an overall increase in R/C ratio from 2010-2017 (0.37 to 0.78). In 22 infectious diseases, there was a correlation between NIDS and NHICS. Moreover, claim-based surveillance showed less fluctuating disease incidence rates than report-based surveillance for specific infectious diseases, such as varicella, mumps, and scarlet fever. However, for infectious diseases with episodic outbreaks or low incidence, it was difficult to assess NHICS usefulness. Claim-based surveillance is less affected by limitations of conventional report-based surveillance systems, such as reporting rate. Given delays in claim systems, a claim-based surveillance is expected to be complementary to conventional systems for the detection of various infectious diseases with the advancement of bio-information technology.

Fluoxetine and Risk of Bleeding in Patients Aged 60 Years and Older Using the Korea Adverse Event Reporting System Database: A Case/Noncase Study.

BACKGROUND: Depression, the leading cause of nonfatal disease burden, has a strong correlation with suicide and affects approximately 7% of the general elderly population. Adverse drug reactions in older patients are particularly important because of reduced drug metabolism, polypharmacy, drug-drug interactions, and drug-disease interactions. Fluoxetine is the first representative selective serotonin reuptake inhibitor but is associated with the possibility of hemorrhage based on its mechanism of action. Serious cases of gastrointestinal bleeding and cerebral hemorrhage have been reported, raising concerns about the safety of this drug. METHODS: We detected signals of bleeding risk associated with fluoxetine in an elderly population using the Korea Adverse Event Reporting System database. Reporting odds ratios and 95% confidence intervals (CIs) were calculated. RESULTS: A total of 16,517 adverse events related to antidepressants were reported. The reporting odds ratios for fluoxetine were 2.34 (95% CI, 1.03-5.34) for total bleeding, 4.41 (95% CI, 1.60-12.15) for major bleeding, 2.06 (95% CI, 0.28-15.03) for gastrointestinal bleeding, and 6.12 (95% CI, 2.14-22.60) for brain hemorrhage compared with those of all other antidepressants. CONCLUSIONS: We detected safety signals with total bleeding, major bleeding, and brain hemorrhage related to fluoxetine. For patients with a high risk of bleeding, such as the elderly population, prescribing antidepressants other than fluoxetine can be considered. The results of this study provide preliminary evidence of a relationship between fluoxetine and hemorrhage but have wide 95% CIs. Further pharmacoepidemiological studies will be needed to confirm the risk of bleeding associated with fluoxetine.

Epidemiological Impact of the Korean National Immunization Program on Varicella Incidence.

The number of reported varicella cases is continuously increasing in Korea; however, associated medical utilization is declining. The ratio between varicella insurance claims and reports of passive infectious disease surveillance has gradually increased to > 80% since the second half of 2017. The recent increase in reported varicella cases is influenced by improved reporting. We calculated the varicella incidence and cumulative incidence in each birth cohort according to age. The cumulative incidence rate among children aged < 6 years in the birth cohort born after the National Immunization Program introduced the varicella vaccine was about 60% lower than among children born before.

Strong chromate-adsorbent based on pyrrolic nitrogen structure: An experimental and theoretical study on the adsorption mechanism.

Chromate is considered a toxic contaminant in various water sources because it poses a risk to animal and human health. To meet the stringent limits for chromium in water and wastewater, pyrrolic nitrogen structure was investigated as a chromate adsorbent for aqueous solutions, employing a polypyrrole coating on carbon black. The characteristics of the adsorbent were analyzed by high-resolution transmission electron microscopy, energy-filtered transmission electron microscopy, and X-ray photoelectron spectroscopy. Chromate was adsorbed as both Cr(III) and Cr(VI). The chromate adsorption capacity increased (from 50.84 to 174.81 mg/g) with increasing amounts of pyrrole monomers (from 50 to 86%) in the adsorbent. The adsorption capacity was well-correlated with the pyrrolic nitrogen content (from 2.06 to 6.57 at%) in the adsorbent, rather than other types of nitrogen. The optimized adsorption capacity (174.81 mg/g in the equilibrium batch experiment and 211.10 mg/g at an initial pH of 3) was far superior to those of conventional adsorbents. We investigated the mechanism behind this powerful chromate adsorption on pyrrolic nitrogen via physical/chemical analyses of the pH-dependent adsorption behavior, supported by first-principles calculation based on density functional theory. We found that Cr(III) and Cr(VI) adsorption followed different reaction paths. Cr(III) adsorption occurred in two sequential steps: 1) A Jones oxidation reaction (JOR)-like reaction of Cr(VI) with pyrrolic N that generates Cr(III), and 2) Cr(III) adsorption on the deprotonated pyrrolic N through Cr(III)-N covalent bonding. Cr(VI) adsorption followed an alternative path: hydrogen-bonding to the deprotonation-free pyrrolic N sites. The pH-dependent fractional deprotonation of the pyrrolic N sites by the JOR-like reaction in the presence of chromate played an important role in the adsorption.

Impact of the Health Insurance Coverage Policy on Oral Anticoagulant Prescription among Patients with Atrial Fibrillation in Korea from 2014 to 2016.

BACKGROUND: To evaluate oral anticoagulant (OAC) utilization in patients with atrial fibrillation after the changes in the health insurance coverage policy in July 2015. METHODS: We used the Health Insurance Review and Assessment Service-National Patient Samples (HIRA-NPS) between 2014 and 2016. The HIRA-NPS, including approximately 1.4 million individuals, is a stratified random sample of 3% of the entire Korean population using 16 age groups and 2 sex groups. The HIRA-NPS comprises personal and medical information such as surgical or medical treatment provided, diagnoses, age, sex, region of medical institution, and clinician characteristics. The studied drugs included non-vitamin K antagonist OACs (NOACs) such as apixaban, dabigatran, edoxaban, and rivaroxaban, and were compared with warfarin. We analyzed drug utilization pattern under three aspects: person, time, and place. RESULTS: The number of patients with atrial fibrillation who were prescribed OACs was 3,114, 3,954, and 4,828; and the proportions of prescribed NOACs to total OACs were 5.1%, 36.2%, and 60.8% in 2014, 2015, and 2016, respectively. The growth rate of OACs prescription increased from 61.4 patients/quarter before June 2015 to 147.7 patients/quarter thereafter. These changes were predominantly in elderly individuals aged more than 70 years. The proportion of NOACs to OACs showed significant regional difference. CONCLUSION: The change of health insurance coverage policy substantially influenced OACs prescription pattern in whole Korean region. But the impact has been significantly different among regions and age groups, which provides the evidence for developing standard clinical practice guideline on OACs use.

Chromate adsorption mechanism on nanodiamond-derived onion-like carbon.

The onion-like carbon (OLC) was prepared as adsorbent and tested for the removal of chromate ions from aqueous solutions. The OLC was thermally derived from nanodiamond by vacuum annealing at 1000-2000°C. An investigation was conducted the chromate adsorption mechanism of OLC, by analysing the temperature-dependent evolution of the various oxygen-carbon bonds and the chemisorbed water by X-ray photo electron spectroscopy, as well as by the first principle calculation of the bond energies for relevant bond configurations. The present work demonstrated the importance of the carbon-oxygen bond type and carbon dangling bonds for chromate adsorption, as well as for other anionic heavy metals adsorbed from wastewater and sewage.

Inherently-Forced Tensile Strain in Nanodiamond-Derived Onion-like Carbon: Consequences in Defect-Induced Electrochemical Activation.

We analyzed the nanodiamond-derived onion-like carbon (OLC) as function of synthesis temperature (1000~1400 °C), by high-resolution electron microscopy, electron energy loss spectroscopy, visible-Raman spectroscopy, ultraviolet photoemission spectroscopy, impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The temperature dependences of the obtained properties (averaged particle size, tensile strain, defect density, density of states, electron transfer kinetics, and electrochemical oxidation current) unanimously coincided: they initially increased and saturated at 1200 °C. It was attributed to the inherent tensile strains arising from (1) the volume expansion associated with the layer-wise diamond-to-graphite transformation of the core, which caused forced dilation of the outer shells during their thermal synthesis; (2) the extreme curvature of the shells. The former origin was dominant over the latter at the outermost shell, of which the relevant evolution in defect density, DOS and electron transfer kinetics determined the electrochemical performances. In detection of dopamine (DA), uric acid (UA) and ascorbic acid (AA) using the OLC as electrode, their oxidation peak currents were enhanced by factors of 15~60 with annealing temperature. Their limit of detection and the linear range of detection, in the post-treatment-free condition, were as excellent as those of the nano-carbon electrodes post-treated by Pt-decoration, N-doping, plasma, or polymer.