Purpose: Apixaban is recommended for patients with atrial fibrillation. Although routine monitoring of plasma concentrations is not typically advised, factors such as ethnicity, sex, and comorbidities can influence these levels. Our study analyzed the plasma apixaban concentrations (PAC) in patients to explore whether these levels, along with underlying conditions, offer enhanced insights for risk stratification. Methods: This study analyzed 49 patients with atrial fibrillation who had been taking apixaban for over a month, examined factor Xa levels within 6 h post-administration, and correlated PAC with clinical characteristics such as age, body weight, estimated glomerular filtration rate (eGFR), presence of heart failure, and bleeding events. Results: The mean plasma concentration of apixaban in all patients was 160.3 ± 77.5 ng/mL. Those taking apixaban 5 mg twice daily had higher plasma concentrations than those taking 2.5 mg twice daily (191.2 ± 75.3 ng/mL vs.137.2 ± 72.0 ng/mL, p = 0.014). Among the patients receiving a reduced dose, renal function and heart failure were significantly associated with plasma concentrations. No factors were associated with the plasma concentrations in patients receiving the standard dose. Notably, reduced-dose patients with heart failure had plasma concentrations comparable to those of individuals receiving the standard dose and exhibited a higher incidence of bleeding than the other groups. Conclusions PAC measurement revealed that apixaban dosages, classified based on age, body weight, and eGFR, were generally effective. Nonetheless, heart failure may increase plasma levels and correlate with an increased bleeding risk in Korean patients on reduced doses. Therefore, tailoring apixaban prescriptions to account for heart failure and other comorbidities may enhance treatment efficacy.

Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Background: The optimal duration and net clinical benefit of dual antiplatelet therapy (DAPT) after transcatheter aortic valve replacement (TAVR) have not been elucidated in realworld situations. Methods: Using nationwide claims data from 2013 to 2021, we selected patients who underwent TAVR and categorized them into two groups: short- and long-term (≤ 3 and > 3 months, respectively) DAPT group. Propensity score matching was used to balance baseline characteristics. The primary endpoint was the occurrence of net adverse clinical events (NACEs), including all-cause death, myocardial infarction, stroke, any coronary and peripheral revascularization, systemic thromboembolism, and bleeding events, at 1 year. Survival analyses were conducted using Kaplan-Meier estimation and Cox proportional hazards regression. Results: Patients who met the inclusion criteria (1,695) were selected. Propensity score matching yielded 1,215 pairs of patients: 416 and 799 in the short- and long-term DAPT groups, respectively. In the unmatched cohort, the mean ages were 79.8 ± 6.1 and 79.7 ± 5.8 years for the short- and long-term DAPT groups, respectively. In the matched cohort, the mean ages were 80.6 ± 5.9 and 79.9 ± 5.9 years for the short- and long-term DAPT groups, respectively. Over one year in the unmatched cohort, the NACE incidence was 11.9% and 11.5% in the short- and long-term DAPT groups, respectively (P = 0.893). The all-cause mortality rates were 7.4% and 4.7% (P = 0.042), composite ischemic event rates were 2.5% and 4.7% (P = 0.056), and bleeding event rates were 2.7% and 4.7% (P = 0.056) in the shortand long-term groups, respectively. In the matched cohort, the incidence of NACE was 9.6% in the short-term DAPT group and 11.6% in the long-term DAPT group, respectively (P = 0.329).The all-cause mortality rates were 6.5% and 4.9% (P = 0.298), composite ischemic event rates were 1.4% and 4.5% (P = 0.009), and bleeding event rates were 2.2% and 4.4% (P = 0.072) in the short- and long-term groups, respectively. Conclusion In patients who successfully underwent transfemoral TAVR, the short- and longterm DAPT groups exhibited similar one-year NACE rates. However, patients in the long-term DAPT group experienced more bleeding and ischemic events.

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been acknowledged as an effective mean of preventing infection and hospitalization.However, the emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) has led to substantial increase in infections among children and adolescents. Vaccineinduced immunity and longevity have not been well defined in this population. Therefore, we aimed to analyze humoral and cellular immune responses against ancestral and SARSCoV-2 variants after two shots of the BNT162b2 vaccine in healthy adolescents. Although vaccination induced a robust increase of spike-specific binding Abs and neutralizing Abs against the ancestral and SARS-CoV-2 variants, the neutralizing activity against the Omicron variant was significantly low. On the contrary, vaccine-induced memory CD4+ T cells exhibited substantial responses against both ancestral and Omicron spike proteins.Notably, CD4+ T cell responses against both ancestral and Omicron strains were preserved at 3 months after two shots of the BNT162b2 vaccine without waning. Polyfunctionality of vaccine-induced memory T cells was also preserved in response to Omicron spike protein.The present findings characterize the protective immunity of vaccination for adolescents in the era of continuous emergence of variants/subvariants.

In this study, surface characteristics of plasma electrolytic oxidized Ti-mesh for dental use were studied using various experimental instruments. The titanium mesh was used as a substrate for PEO. Using a pulsed DC power supply, PEO treatment was carried out at 280 V for 3 min in the electrolytic solution containing Ca, Mg, and P ions. And the electrolyte used for PEO was prepared by mixing with Ca(CH 3COO)2·H 2O, C 3H 7CaO 6P, and (CH 3COO) 2Mg·4H 2O. The PEO-treated surface was observed by using X-ray diffraction, field-emission scanning electron microscope, energy dispersive X-ray spectroscopy, atomic force microscopy (AFM), and nanoindentation tester.PEO-treated Ti-mesh in solution containing Ca, Mg, and P ions (CaMgP) sample showed the active spark discharge reaction compared to in solution containing Ca and P ions (CaP) sample. In CaP and CaMgP samples, the PEO surface of Ti-mesh showed mainly circular, irregular, and oval shapes of pores. In the case of CaMgP, the defects and precipitates such as MgO were formed on the surface. On the sample surface, the distribution of the desired element was detected homogeneously.The PEO-treated CaP and CaMgP specimens were mainly composed of anatase, Mg, and hydroxyapatite. From the AFM result, the average roughness was 0.247 µm for CaP and 0.226 µm for CaMgP, respectively. The hardness of CaMgP containing Mg ions was increased compared to CaP containing without Mg ions, also, the elastic modulus of CaMgP sample was higher than that of CaP sample.

In this study, the surface characteristics of nanotube-formed Ti-Ta-Ag-Pt alloys for dental implants were studied using various experimental instruments. The Ti-xTa-2Ag-2Pt quaternary alloys were manufactured using a vacuum arc-melting furnace with varying Ta contents (10, 30, and 50 wt%) and then homogenized by heat treatment at 1050 ℃ for 1 h. The nanotube formation of Ti-xTa-2Ag-2Pt (x = 10–50 wt%) alloy was performed using a DC power source of 30 V in 1.0 M H3PO4 + 0.8 wt% NaF electrolyte solution. The surface characterization was performed using optical microscopy (OM), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and wettability and nano-indentation tests. The microstructure of the Ti-xTa alloy was composed of an α''-phase (Widmanstätten structure) and a β-phase equiaxed structure. The XRD peak of the α phase became weaker and that of the β phase became stronger with increasing Ta content. The elastic modulus of Ti-30Ta-2Ag-2Pt alloy was lower than those of the other alloys. The highly ordered nanotubes were formed in the Ti-10Ta-2Ag-2Pt and Ti-30Ta-2Ag-2Pt alloys; nanoparticles were found in the Ti-50Ta-2Ag-2Pt alloy. The diameters of the large and small nanotubes increased and decreased, respectively, with increasing Ta content. Nanotubes did not grow in a needle-like structure (Widmanstätten), and nanotubes are not formed at the grain boundaries and edges. The anatase phase of TiO2 was detected in Ti-30Ta-2Ag-2Pt alloy and disappeared in Ti-50Ta-2Ag-2Pt alloy. The contact angle of the nanotube-formed Ti-30Ta-2Ag-2Pt alloy was lower than those of the other alloys.

In this study, the surface characteristics of nanotube-formed Ti-Ta-Ag-Pt alloys for dental implants were studied using various experimental instruments. The Ti-xTa-2Ag-2Pt quaternary alloys were manufactured using a vacuum arc-melting furnace with varying Ta contents (10, 30, and 50 wt%) and then homogenized by heat treatment at 1050 ℃ for 1 h. The nanotube formation of Ti-xTa-2Ag-2Pt (x = 10–50 wt%) alloy was performed using a DC power source of 30 V in 1.0 M H3PO4 + 0.8 wt% NaF electrolyte solution. The surface characterization was performed using optical microscopy (OM), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and wettability and nano-indentation tests. The microstructure of the Ti-xTa alloy was composed of an α''-phase (Widmanstätten structure) and a β-phase equiaxed structure. The XRD peak of the α phase became weaker and that of the β phase became stronger with increasing Ta content. The elastic modulus of Ti-30Ta-2Ag-2Pt alloy was lower than those of the other alloys. The highly ordered nanotubes were formed in the Ti-10Ta-2Ag-2Pt and Ti-30Ta-2Ag-2Pt alloys; nanoparticles were found in the Ti-50Ta-2Ag-2Pt alloy. The diameters of the large and small nanotubes increased and decreased, respectively, with increasing Ta content. Nanotubes did not grow in a needle-like structure (Widmanstätten), and nanotubes are not formed at the grain boundaries and edges. The anatase phase of TiO2 was detected in Ti-30Ta-2Ag-2Pt alloy and disappeared in Ti-50Ta-2Ag-2Pt alloy. The contact angle of the nanotube-formed Ti-30Ta-2Ag-2Pt alloy was lower than those of the other alloys.

In this study, in order to form a micropore oxide film containing (Mg/Si)-hydroxyapatite on the surface of a Ti-29Nb-xHf alloy, pores were formed on the surface of the alloy by plasma electrolytic oxidation (PEO) and the morphology of the surface was studied. For this, Ti-29Nb, Ti-29Nb-3Hf, Ti-29Nb-7Hf, and Ti-29Nb-15Hf alloys were prepared by arc melting. Micropores were formed on the surface in an electrolyte solution containing Mg and Si ions using PEO. Surface characteristics and mechanical properties of all specimens were investigated using OM, FE-SEM, XRD, EDS, Vickers hardness and nanoindenter. Bone formation was performed in SBF solution, and the following results were obtained. Ti-29Nb, Ti-29Nb-3Hf, and Ti-29Nb-7Hf showed mainly needle-like martensitic structures, and Ti-29Nb-15Hf alloys showed mainly equiaxed structures. From the result of the mechanical property analysis, the elastic modulus and hardness of the Ti-29Nb alloy decreased, as the Hf content increased.Under the condition of same applied voltage, as the content of Mg ions increased, the diameter of the micropores became smaller and uniform pores were formed. The Ca/P and (Ca+Mg)/(Si+P) ratios decreased, as the Mg content increased, and at 5% Mg, the ratio was similar to that of natural bone. Bone growth was nucleated around the pore.