This study evaluated the effects of various mechanical debridement methods on the surface roughness (Ra) of dental implants, comparing femtosecond laser-treated surfaces with conventionally machined and sandblasted with large-grit sand... more
This study evaluated the effects of various mechanical debridement methods on the surface roughness (Ra) of dental implants, comparing femtosecond laser-treated surfaces with conventionally machined and sandblasted with large-grit sand and acid-etched (SLA) implant surfaces. The fabrication of grade 4 titanium (Ti) disks (10 mm in diameter and 1 mm thick) and the SLA process were carried out by a dental implant manufacturer (DENTIS; Daegu, Republic of Korea). Subsequently, disk surfaces were treated with various methods: machined, SLA, and femtosecond laser. Disks of each surface-treated group were post-treated with mechanical debridement methods: Ti curettes, ultrasonic scaler, and Ti brushes. Scanning electron microscopy, Ra, and wettability were evaluated. Statistical analysis was performed using the Kruskal–Wallis H test, with post-hoc analyses conducted using the Bonferroni correction (α = 0.05). In the control group, no significant difference in Ra was observed between the mac...
In this study, the directed energy deposition (DED) process was applied to additively manufacture cobalt-chromium alloy materials, which are commonly used in molds, dental/orthopedic medical applications, vehicles, and aircraft. The... more
In this study, the directed energy deposition (DED) process was applied to additively manufacture cobalt-chromium alloy materials, which are commonly used in molds, dental/orthopedic medical applications, vehicles, and aircraft. The quality of the deposition obtained by using the DED technology is affected by process parameters. Therefore, the aim of this experiment, was to evaluate the microstructure changes caused by varying parameters such as the laser power, laser header moving speed, and powder feeding rate, with the goal of improving and optimizing the stacking quality. The shape, heat-affected zone, and dilution ratio of the microstructure were analyzed using an optical microscope. Furthermore, the global energy density(GED) was calculated because it affects the quality of the 3D-printed product. The optimal process conditions for the DED method determined by calculating the GED under various process conditions.
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The quality and properties of products manufactured using metal three dimensional (3D) printing technology differs based on the process parameters. In addition, the characteristics and uses vary depending on the material used. In this... more
The quality and properties of products manufactured using metal three dimensional (3D) printing technology differs based on the process parameters. In addition, the characteristics and uses vary depending on the material used. In this study, the Direct Energy Deposition(DED) technology using a precipitation hardening type STS630 was investigated. The experimental process parameters, namely, the beam size, powder feeding rate, laser header moving speed, laser output power were set, and the deposition height and dilution were analyzed through deposition cross-section analysis after experiments according to each Additive Manufacturing(AM) process variable. The results showed that the deposition height decreased as the laser header moved faster. It was further observed that the dilution ratio and the width of the heat affected zone depended on the laser power and powder feed rate. The optimal process parameters were identified as a beam size of 1 mm, powder feeding rate of 6 g/min, lase...
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There has been debate regarding the added benefit of high-intensity statins compared with low-moderate-intensity statins, especially in patients with acute myocardial infarction (AMI).Methods and Results:The Korea Acute Myocardial... more
There has been debate regarding the added benefit of high-intensity statins compared with low-moderate-intensity statins, especially in patients with acute myocardial infarction (AMI).Methods and Results:The Korea Acute Myocardial Infarction Registry-National Institutes of Health consecutively enrolled 13,104 AMI patients. Of these, a total of 12,182 patients, who completed 1-year follow-up, were included in this study, and all patients were classified into 3 groups (no statin; low-moderate-intensity statin; and high-intensity statin). The primary outcome was major adverse cardiac event (MACE) including cardiac death, non-fatal MI, and repeat revascularization at 1 year. Both low-moderate-intensity and high-intensity statin significantly reduced low-density lipoprotein cholesterol (LDL-C; all P<0.001). Compared with the no statin group, both statin groups had significantly lower risk of MACE (low-moderate intensity: HR, 0.506; 95% CI: 0.413-0.619, P<0.001; high intensity: HR, ...
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There have been conflicting reports regarding the association of perioperative blood transfusion (PBT) with oncologic outcomes including recurrence rates and survival outcomes in prostate cancer. We aimed to evaluate whether perioperative... more
There have been conflicting reports regarding the association of perioperative blood transfusion (PBT) with oncologic outcomes including recurrence rates and survival outcomes in prostate cancer. We aimed to evaluate whether perioperative blood transfusion (PBT) affects biochemical recurrence-free survival (BRFS), cancer-specific survival (CSS), and overall survival (OS) following radical prostatectomy (RP) for patients with prostate cancer. A total of 2,713 patients who underwent RP for clinically localized prostate cancer between 1993 and 2014 were retrospectively analyzed. We performed a comparative analysis based on receipt of transfusion (PBT group vs. no-PBT group) and transfusion type (autologous PBT vs. allogeneic PBT). Univariate and multivariate Cox-proportional hazard regression analysis were performed to evaluate variables associated with BRFS, CSS, and OS. The Kaplan-Meier method was used to calculate survival estimates for BRFS, CSS, and OS, and log-rank test was used ...
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Successful percutaneous coronary intervention (PCI) of the occluded infarct-related artery (IRA) in latecomers may improve long-term survival mainly by reducing left ventricular remodeling. It is not clear whether inhibition of... more
Successful percutaneous coronary intervention (PCI) of the occluded infarct-related artery (IRA) in latecomers may improve long-term survival mainly by reducing left ventricular remodeling. It is not clear whether inhibition of renin-angiotensin system (RAS) brings additional better clinical outcomes in this specific population subset. Between January 2008 and June 2013, 669 latecomer patients with acute ST-segment elevation myocardial infarction (STEMI) (66.2±12.1 years, 71.0% males) in Korea Acute Myocardial Infarction Registry (KAMIR) who underwent a successful PCI were enrolled. The study population underwent a successful PCI for a totally occluded IRA. They were divided into two groups according to whether they were prescribed RAS inhibitors at the time of discharge: group I (RAS inhibition, n=556), and group II (no RAS inhibition, n=113). During the one-year follow-up, major adverse cardiac events (MACE), which consist of cardiac death and myocardial infarction, occurred in 71...
Research Interests: Cardiology, Medicine, Echocardiography, Humans, Internal Medicine, and 15 moreFemale, Male, Registries, Mace, Republic of Korea, Aged, Middle Aged, Percutaneous Coronary Intervention, Myocardial Infarction, Ejection Fraction, Angiotensin Converting Enzyme Inhibitors, Proportional Hazards Models, Combined Modality Therapy, Cardiovascular medicine and haematology, and hazard ratio
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This study inquired the relationship between serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and left ventricular (LV) dysfunction and extracellular water in continuous ambulatory peritoneal dialysis (CAPD) patients. We... more
This study inquired the relationship between serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels and left ventricular (LV) dysfunction and extracellular water in continuous ambulatory peritoneal dialysis (CAPD) patients. We conducted a cross-sectional study of 30 CAPD patients. Each patient was admitted to the department of internal medicine, Chosun University Hospital between February and October, 2006. Echocardiography was performed using HDI 5000, allowing M-mode, two-dimensional measurement. A multifrequency bioimpedance analyzer was used; extracellular water was calculated as a percentage of total body water and was understood as the index of volume load of CAPD patients. The mean age was 47±12 years. Underlying causes of renal failure were 14 with diabetes mellitus, 7 with hypertension, and 9 with chronic glomerulonephritis. The mean serum NT-proBNP level was 14236.56 (83-35,000) pg/mL. LV mass index and LV ejection fraction were 151.67±42.5 g/m(2) and 57.48±12.9...
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Extracorporeal Shock Wave Lithotripsy (ESWL) has shown successful outcomes for ureteral stones. We investigated predictive factors for failure of ESWL for treating ureteral stones. A total of 153 patients who underwent ESWL between July... more
Extracorporeal Shock Wave Lithotripsy (ESWL) has shown successful outcomes for ureteral stones. We investigated predictive factors for failure of ESWL for treating ureteral stones. A total of 153 patients who underwent ESWL between July 2006 and July 2009 for ureteral stones diagnosed by non-enhanced spiral computed tomography were divided into two groups: (group A, stone size ≤10 mm; and group B, stone size >10 mm). The failure was defined as remnant stones >4 mm. We assessed age, sex, body mass index, stone size, laterality, location, skin-to-stone distance (SSD), Hounsfield unit, and the presence of secondary signs (hydronephrosis, renal enlargement, perinephric fat stranding, and tissue rim sign). We analyzed predictive factors by using logistic regression in each group. The success rates were 90.2% and 68.6% in group A and B, respectively. In the univariate analysis of each group, stone size, SSD, and all secondary signs showed statistically significant differences in ter...
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Partial nephrectomy (PN) for patients with T1a renal cell carcinoma (RCC) has increasingly become accepted, although its role for patients with T1b RCC remains controversial. We retrospectively evaluated and then compared the oncologic... more
Partial nephrectomy (PN) for patients with T1a renal cell carcinoma (RCC) has increasingly become accepted, although its role for patients with T1b RCC remains controversial. We retrospectively evaluated and then compared the oncologic and functional outcomes of patients with pT1b RCC who were treated with PN or radical nephrectomy (RN). A total of 70 patients who were diagnosed with pT1bN0M0 RCC between January 1995 and December 2004 were included. The 5-year overall survival (OS), the 5-year recurrence-free survival (RFS), and the 5-year cancer-specific survival (CSS) were compared between the groups. Preoperative and postoperative serum creatinine and estimated glomerular filtration rate (GFR) levels were analyzed to assess renal function. The 5-year OS (92.3% vs. 87.8%, p=0.501), RFS (92.3% vs. 77.8%, p=0.175), and CSS (92.3% vs. 94.5%, p=0.936) of the PN and RN groups were not statistically different. The proportion of patients with decreased renal function was lower in the PN ...
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Although numerous sources of evidence show that regular physical activity is beneficial to health, most individuals do not engage in a sufficient amount of physical activity to meet the guidelines set out by expert panels. In addition,... more
Although numerous sources of evidence show that regular physical activity is beneficial to health, most individuals do not engage in a sufficient amount of physical activity to meet the guidelines set out by expert panels. In addition, the minimum amount of physical activity associated with reduced cardiovascular disease risk markers is not clear in older adults. The purpose of this study was to determine the effects of a 12-week walking program involving an exercise volume below the current minimum physical activity recommendation on cardiovascular disease risk markers in older adults. The participants were recruited from the following two groups separately: a walking group (n = 14) and a control group (n = 14). In the walking group, participants walked 30 to 60 minutes per session on 2 days per week for 12 weeks (average walking time, 49.4 ± 8.8 min/session). Plasma oxidised low-density lipoprotein concentrations tended to be lower than baseline values in the walking group after 1...
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Serum procalcitonin (PCT) levels are low in healthy individuals but are elevated in patients with a serious bacterial infection or sepsis. In this study, we examined the ability of serum PCT concentration to diagnose infections in... more
Serum procalcitonin (PCT) levels are low in healthy individuals but are elevated in patients with a serious bacterial infection or sepsis. In this study, we examined the ability of serum PCT concentration to diagnose infections in end-stage renal disease (ESRD) patients, and sought to determine an appropriate threshold level. Serum PCT levels were measured in ESRD patients on antibiotic therapy for a suspected bacterial infection (ESRD infection [iESRD] group, n = 21), and compared with those of ESRD patients on hemodialysis with no sign of infection (ESRD control [cESRD] group, n = 20). The mean serum PCT concentration of the iESRD group was significantly higher than in the cESRD group (2.95 ± 3.67 ng/mL vs. 0.50 ± 0.49 ng/mL, p = 0.006), but serum PCT concentrations did not correlate with severity of infection. The optimized threshold level derived for serum PCT was 0.75 ng/mL, rather than the currently used 0.5 ng/mL; this threshold demonstrated a sensitivity and specificity of 7...
Research Interests: Gastroenterology, Biomarkers, Medicine, Humans, Internal Medicine, and 15 moreEnd Stage Renal Disease, Female, Hemodialysis, Male, Aged, Middle Aged, Biomarker, Adult, Peritoneal Dialysis, Bacterial infections, Calcitonin, Area Under Curve, Predictive value of tests, Case Control Studies, and Inflammation Mediators
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Background Both exercise and vitamin E supplementation have been shown to reduce oxidative stress and cardiovascular disease risk in older adults, and when combined there is evidence suggesting that they act synergistically. The currently... more
Background Both exercise and vitamin E supplementation have been shown to reduce oxidative stress and cardiovascular disease risk in older adults, and when combined there is evidence suggesting that they act synergistically. The currently recommended amount of exercise for older adults is 150 min/week of moderate-intensity exercise; however, the minimum amount of exercise necessary to achieve health benefits is not known. The purpose of this study was to investigate the effects of 12 weeks of participation in a low-volume walking exercise programme (i.e. 90 min/week) combined with daily vitamin E supplementation on thiobarbituric acid reactive substances (TBARS) and oxidised low-density lipoprotein (LDL) concentrations in older adults. Methods The participants were recruited from the following four groups separately: 1) control (CG, n = 14), 2) vitamin E supplementation (SG, n = 10), 3) walking (WG, n = 7), or 4) walking + supplementation (WSG, n = 7). In the CG, participants were a...
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Research Interests: Biology, Inflammation, Cell Biology, Medicine, Lipopolysaccharide, and 15 moreHumans, Mice, Animals, Mucin, Pseudomonas aeruginosa, Lipopolysaccharides, Epithelial cells, ATP, Pseudomonas Aeruginosa, Mucus, Overproduction, Nasal Mucosa, Adenosine Triphosphate, Cardiovascular medicine and haematology, and Metaplasia
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Research Interests: Endocrinology, Cardiology, Medicine, Lipids, Humans, and 15 moreInternal Medicine, Hyperlipidemia, Female, Male, Nitrates, Middle Aged, Matrix Metalloproteinases, Coronary Artery Disease, Fenofibrate, Matrix Metalloproteinase, Brachial artery, Hypertriglyceridemia, Low density lipoprotein cholesterol, Cardiovascular medicine and haematology, and Hyperlipidemias
Objective— The effects of hormone replacement therapy (HRT) can affect many aspects relevant to cardiovascular disease, including vasomotor function, inflammation, and hemostasis. Recent studies have demonstrated that current doses of HRT... more
Objective— The effects of hormone replacement therapy (HRT) can affect many aspects relevant to cardiovascular disease, including vasomotor function, inflammation, and hemostasis. Recent studies have demonstrated that current doses of HRT exert a mixture of both protective and adverse effects. In the current study, we compared the effects of lower doses of HRT (L-HRT) and conventional doses of HRT (C-HRT) on a variety of relevant cardiovascular parameters. Methods and Results— This randomized, double-blind, crossover study included 57 women who received micronized progesterone 100 mg with either conjugated equine estrogen 0.625 mg (C-HRT) or 0.3 mg (L-HRT) daily for 2 months. L-HRT showed comparable effects to C-HRT on high-density lipoprotein cholesterol and triglyceride levels, but not on low-density lipoprotein cholesterol levels. C-HRT and L-HRT significantly improved the percent flow-mediated dilator response to hyperemia from baseline values (both P <0.001) by a similar deg...
Research Interests: Endocrinology, Inflammation, Menopause, Cardiovascular disease, Medicine, and 15 moreHumans, Internal Medicine, Korea, Female, Clinical Sciences, C reactive protein, Endothelial Function, Hemostasis, Hormone Therapy, Hormone Replacement Therapy, Brachial artery, Low density lipoprotein cholesterol, Adverse effect, high sensitivity C reactive protein, and Cardiovascular medicine and haematology
Objective— The objective was to compare the effects of tibolone and hormone therapy (HT) on lipid profile, vasodilation, and factors associated with inflammation and hemostasis. Methods and Results— Fifty-three women received micronized... more
Objective— The objective was to compare the effects of tibolone and hormone therapy (HT) on lipid profile, vasodilation, and factors associated with inflammation and hemostasis. Methods and Results— Fifty-three women received micronized progesterone (MP, 100 mg) with conjugated equine estrogen (CEE, 0.625 mg) or tibolone (2.5 mg) daily for 2 months, with a 2-month washout period. Compared with HT, tibolone significantly reduced total cholesterol ( P <0.001), triglyceride ( P <0.001), and HDL cholesterol ( P <0.001) levels as well as triglyceride/HDL cholesterol ratios ( P <0.001) but not LDL cholesterol levels. Tibolone significantly improved flow-mediated brachial artery dilator response to hyperemia from baseline values ( P <0.001) by a magnitude similar to that found with HT ( P =0.628). Compared with tibolone, which showed no changes, HT significantly increased high-sensitivity C-reactive protein (hsCRP, P =0.030) and reduced antithrombin III ( P <0.001). HT an...