ABSTRACT
The phenomenon of hydrogen embrittlement (HE) in metals and alloys, which determines the performance of components in hydrogen environments, has recently been drawing considerable attention. This study explores the interplay between strain rates and solute hydrogen in inducing HE of Ti6Al4V alloy. For the hydrogen-charged sample, as the strain rate was decreased from 10-2/s to 10-5/s, the ductility decreased significantly, but the HE effect on mechanical strength was negligible. The low strain rate (LSR) conditions facilitated the development of high-angle grain boundaries, providing more pathways for hydrogen diffusion and accumulation. The presence of solute hydrogen intensified the formation of nano/micro-voids and intergranular cracking tendencies, with micro-crack occurrences observed exclusively in the LSR conditions. These factors expanded the brittle hydrogen-damaged region more deeply into the interior of the lattice. This, in turn, accelerated both crack initiation and intergranular crack propagation, finally resulting in a considerable HE effect and a reduction in ductility at the LSR. The current study underscores the influence of strain rate on HE, enhancing the predictability of longevity and improving the reliability of components operating in hydrogen-rich environments under various loading conditions.
ABSTRACT
In this study, the pristine MgO, MgO/CNT and Ni-MgO/CNT nanocomposites were processed using the impregnation and chemical vapor deposition methods and analyzed for hydrogen evolution reaction (HER) using the electrochemical water splitting process. Furthermore, the effect of nickel on the deposited carbon was systematically elaborated in this study. The highly conductive carbon nanotubes (CNTs) deposited on the metal surface of the Ni-MgO nanocomposite heterostructure provides a robust stability and superior electrocatalytic activity. The optimized Ni-MgO/CNT nanocomposite exhibited hierarchical, helical-shaped carbon nanotubes adorned on the surface of the Ni-MgO flakes, forming a hybrid metal-carbon network structure. The catalytic HER was carried out in a 1M alkaline KOH electrolyte, and the optimized Ni-MgO/CNT nanocomposite achieved a low (117 mV) overpotential value (ɳ) at 10 mA cm-2 and needed a low (116 mV/dec) Tafel value, denotes the Volmer-Heyrovsky pathway. Also, the high electrochemical active surface area (ECSA) value of the Ni-MgO/CNT nanocomposite attained 515 cm2, which is favorable for the generation of abundant electroactive species, and the prepared electrocatalyst durability was also performed using a chronoamperometry test for the prolonged duration of 20 h at 10 mA cm-2 and exhibited good stability, with a 72% retention. Hence, the obtained results demonstrate that the optimized Ni-MgO/CNT nanocomposite is a highly active and cost-effective electrocatalyst for hydrogen energy production.
ABSTRACT
The data presented here are related to the research article entitled "Strengthening and deformation behavior of as-cast CoCrCu1.5MnNi high-entropy alloy (HEA) with micro-/nanoscale precipitation [1]". Non-equimolar CoCrCu1.5MnNi was cast by the conventional induction melting under a high-purity Ar atmosphere. Scanning electron microscopy equipped with energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM) were used for micro- and nanostructure characterization. Subsize tensile specimens with two different gage length to width ratio were tested at room and cryogenic temperatures to assess the accuracy of strength and ductility data in the as-cast CoCrCu1.5MnNi HEAs. The mixing enthalpy (ΔHmix) versus lattice elastic energy (ΔHel) criterion was used to predict the stable phases. The data on the effects of microstructural and nanostructural distribution of various phases on mechani-cal properties in the as-cast HEA could be used in designing high entropy alloys with excellent as-cast mechanical performance.
ABSTRACT
PURPOSE: This study aimed to predict the composition of urolithiasis using deep learning from urinary stone images. MATERIALS AND METHODS: We classified 1,332 stones into 31 classes according to the stone composition. The top 4 classes with a frequency of 110 or more (class 1: calcium oxalate monohydrate [COM] 100%, class 2: COM 80%+struvite 20%, class 3: COM 60%+calcium oxalate dihydrate [COD] 40%, class 4: uric acid 100%) were selected. With the 965 stone images of the top 4 classes, we used the seven convolutional neural networks (CNN) to classify urinary stones and compared their classification performances. RESULTS: Among the seven models, Xception_Ir0.001 showed the highest accuracy, precision, and recall and was selected as the CNN model to predict the stone composition. The sensitivity and specificity for the 4 classes by Xception_Ir0.001 were as follows: class 1 (94.24%, 91.73%), class 2 (85.42%, 96.14%), class 3 (86.86%, 99.59%), and class 4 (94.96%, 98.82%). The sensitivity and specificity of the individual components of the stones were as follows. COM (98.82%, 94.96%), COD (86.86%, 99.64%), struvite (85.42%, 95.59%), and uric acid (94.96%, 98.82%). The area under the curves for class 1, 2, 3, and 4 were 0.98, 0.97, 1.00, and 1.00, respectively. CONCLUSIONS: This study showed the feasibility of deep learning for the diagnostic ability to assess urinary stone composition from images. It can be an alternative tool for conventional stone analysis and provide decision support to urologists, improving the effectiveness of diagnosis and treatment.
Subject(s)
Deep Learning , Urinary Calculi , Urolithiasis , Calcium Oxalate , Humans , Struvite , Uric Acid , Urinary Calculi/diagnostic imagingABSTRACT
PURPOSE: To investigate the risk of symptomatic urolithiasis requiring surgical treatment according to obesity and metabolic health status using a nationwide dataset of the Korean population. MATERIALS AND METHODS: Of the 5,300,646 persons who underwent health examinations between the year 2009 and 2016, within one year after the health examination, 35,137 patients who underwent surgical treatment for urolithiasis were enrolled. Participants were classified as "obese" or "non-obese" using a body mass index (BMI) cutoff of 25 kg/m². People who developed ≥1 metabolic disease component in the index year were considered "metabolically unhealthy", while those with none were considered "metabolically healthy". RESULTS: Out of 34,330 participants excluding 843 missing, 16,509 (48.1%), 4,320 (12.6%), 6,456 (18.8%), and 7,045 (20.5%) subjects were classified into the metabolically healthy non-obese (MHNO), metabolically unhealthy non-obese (MUNO), metabolically healthy obese (MHO), and metabolically unhealthy obese (MUO) group, respectively. Mean BMI was 22.1±1.9 kg/m², 22.9±1.6 kg/m², 26.9±1.8 kg/m², and 27.9±2.4 kg/m² respectively. After adjusting the age and sex, the subjects in the MUNO group had an HR (95% CI) of 1.192 (1.120-1.268), those in the MHO group, 1.242 (1.183-1.305), and those in the MUO group, 1.341 (1.278-1.407) for either extracorporeal shockwave lithotripsy or surgery, compared to those in the MHNO group. CONCLUSIONS: Metabolically healthy, obese individuals have a higher risk of developing symptomatic urolithiasis than non-obese, unhealthy, but have a lower risk than obese, unhealthy. It suggests that metabolic health and obesity have collaborative effects, independently affecting the development of symptomatic urinary stone diseases.
Subject(s)
Metabolic Diseases/complications , Obesity/complications , Urolithiasis/etiology , Adult , Aged , Body Mass Index , Female , Humans , Male , Middle Aged , Republic of Korea/epidemiology , Risk Assessment , Urolithiasis/epidemiology , Urolithiasis/surgery , Young AdultABSTRACT
BACKGROUND: The ureteral access sheath (UAS) is an ancillary device widely used by urologists, but acute ureter injury may occur following its insertion. Preoperative selective oral α1-blockers can reduce intraureteral pressure, and prevent ureteral wall injury during UAS insertion. OBJECTIVE: To compare perioperative data of patients who underwent flexible ureterorenoscopy (fURS) with UAS with and without premedication with silodosin. DESIGN, SETTING, AND PARTICIPANTS: Single-blind, 100 patients from a single institution who underwent retrograde intrarenal surgery for kidney and upper ureter stone removal were prospectively allocated from May 2018 to March 2019. INTERVENTION: The experimental groups received silodosin for 3 d preoperatively. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint included ureteral injuries after UAS insertion that were assessed according to endoscopic classification. The secondary endpoint was an evaluation of whether premedication with silodosin had any effect on postoperative outcomes. RESULTS AND LIMITATIONS: A total of 44 and 43 patients were randomly assigned to the control and experimental groups, respectively. Silodosin prevented significant postoperative ureteral injury involving the smooth muscle layer more successfully than in the control group (9.3% vs 27.3%; p = 0.031). There was no significant difference in the overall complication rate as determined by the modified Clavien-Dindo classification system and the computed tomography scan stone-free rate postoperatively. Patients who received silodosin before fURS reported lower pain scores than those in the control group using a visual analog scale (p = 0.009). Limitation included a lack of placebo comparison. CONCLUSIONS: Our data suggest that preoperative silodosin protects against significant ureteral injury related to UAS insertion during fURS and decreases postoperative pain level. Silodosin premedication might be an effective and safe technique to replace prestenting. PATIENT SUMMARY: We investigated the preventive effect of an α-blocker against perioperative complication caused by ureteral access sheath inserted during flexible ureterorenoscopy. Taking silodosin before surgery prevented ureter wall injury during surgery and immediately improved postoperative pain.
Subject(s)
Ureter , Humans , Indoles , Male , Pain, Postoperative , Single-Blind Method , Ureter/surgery , Ureteroscopy/adverse effects , Ureteroscopy/methodsABSTRACT
PURPOSE: This prospective, randomized, controlled study investigated the use of tamsulosin, a selective alpha-blocker, as a prophylactic medication to prevent postoperative urinary retention (POUR) following lower limb arthroplasty. MATERIALS AND METHODS: The criterion for diagnosing POUR was used a postoperative bladder volume over 400 mL with incomplete emptying. Patients who underwent primary total hip or knee arthroplasty were randomly assigned at a 1:1 ratio to tamsulosin treatment and non-treatment groups at a single center from September 2018 to November 2018. The treatment group received 0.2 mg of tamsulosin orally once at night for 3 days starting on postoperative day 1. During this 3-day period, an indwelling Foley catheter was maintained. The incidence of POUR according to tamsulosin treatment following lower limb arthroplasty was the primary outcome. RESULTS: In total, 100 patients were enrolled, of whom 5 discontinued participation. POUR was diagnosed in 20 of the remaining 95 patients (21.1%). The treatment group contained 48 patients, of whom 6 (12.5%) developed POUR, whereas POUR occurred in the 14 of the 47 patients (29.8%) in the non-treatment group. Tamsulosin treatment reduced the risk of POUR by two-thirds (odds ratio [OR], 0.337; 95% confidence interval [CI], 0.117-0.971; p=0.044). The risk reduction associated with tamsulosin treatment remained robust post-adjustment for potential covariates (OR, 0.250; 95% CI, 0.069-0.905; p=0.038). CONCLUSIONS: Tamsulosin administration immediately after lower limb arthroplasty reduced the incidence of urinary retention and diminished the need for long-term catheterization.
Subject(s)
Adrenergic alpha-1 Receptor Antagonists/therapeutic use , Arthroplasty, Replacement, Hip , Arthroplasty, Replacement, Knee , Postoperative Complications/prevention & control , Tamsulosin/therapeutic use , Urinary Retention/prevention & control , Aged , Aged, 80 and over , Female , Humans , Incidence , Male , Middle Aged , Postoperative Complications/epidemiology , Prospective Studies , Single-Blind Method , Urinary Retention/epidemiologyABSTRACT
We evaluate the risks of various urological disorders that require treatments according to obesity and metabolic health status using a nationwide dataset of the Korean population. 3,969,788 patients who had undergone health examinations were enrolled. Participants were classified as "obese" (O) or "non-obese" (NO) using a BMI cut-off of 25 kg/m2. People who developed ≥ 1 metabolic disease component in the index year were considered "metabolically unhealthy" (MU), while those with none were considered "metabolically healthy" (MH). There were classified into the MHNO, MUNO, MHO, and MUO group. In BPH, chronic renal disease, neurogenic bladder, any medication related to voiding dysfunction, alpha-blocker, and antidiuretics, age and gender-adjusted hazard ratio (HR) was highest in MUO, but higher in MUNO than in MHO. In stress incontinence, prostate surgery, and 5alpha-reductase, HR increased in the order of MUNO, MHO, and MUO. In prostatitis, anti-incontinence surgery, and cystocele repair, HR was higher in MHO than MUNO and MUO. In cystitis, cystostomy, and anticholinergics, HR was higher in MUNO and MUO than MHO. In conclusion, obesity and metabolic health were individually or collaboratively involved in urological disorders related to voiding dysfunction. Metabolic healthy obesity needs to be distinguished in the diagnosis and treatment of urological disorders.
Subject(s)
Metabolic Diseases/complications , Obesity/complications , Population Surveillance , Urologic Diseases/complications , Adult , Body Mass Index , Humans , Republic of KoreaABSTRACT
BACKGROUND: Demographic change and advances in technology affect transurethral surgery and outpatient procedures in the urologic field. There are few population-based studies that accurately assess the trend of transurethral surgery and outpatient procedures including diagnostic tests. We investigated the recent epidemiologic trends in transurethral surgeries and urological outpatient procedures from 2009 to 2016 in Korea using the entire population-based cohort. METHODS: We analyzed medical service claim data of transurethral surgery, urological outpatient procedures submitted by medical service providers from the Health Insurance Review and Assessment Service from 2009 to 2016. RESULTS: Transurethral ureter surgery increased by 134.9% from 14,635 in 2009 to 34,382 in 2016 (B = 2,698; R² = 0.98; P < 0.001). The transurethral bladder surgery increased by 65.5% from 12,482 in 2009 to 20,658 in 2016 (B = 1,149; R² = 0.97; P < 0.001). Over the 8-years period, there were not significant changes in transurethral prostate (B = 43; R² = 0.04; P = 0.617) and urethral surgery (B =-12; R² = 0.18; P = 0.289). The significantly increasing trends in cystoscopy (B = 5,260; R² = 0.95; P < 0.001) and uroflowmetry (B = 53,942; R² = 0.99; P < 0.001) were observed during the 8-year period. There was no difference in bladder catheterization during the 8-year period. Urodynamic study (UDS: B =-2,156; R² = 0.77; P = 0.003) and electrical stimulation treatment (EST: B =-1,034; R² = 0.87; P < 0.001) significantly decreased. CONCLUSION: In Korea, transurethral ureter surgery and transurethral bladder surgery have been continuously increasing. Transurethral prostate surgery and transurethral urethral surgery remained constant with no increase or decrease. Cystoscopy and uroflowmetry continue to increase, while UDS and EST continue to decrease.
Subject(s)
Lower Urinary Tract Symptoms/surgery , Urologic Surgical Procedures/trends , Aged , Cohort Studies , Cross-Sectional Studies , Cystoscopy/trends , Databases, Factual , Electric Stimulation , Humans , Lower Urinary Tract Symptoms/pathology , Male , Middle Aged , Outpatients , Republic of Korea , UrodynamicsABSTRACT
PURPOSE: Postmicturition dribbling (PMD) is a stressful symptom in middle-aged men characterized by urinary leakage after the completion of normal voiding. Appropriate treatments have not yet been introduced. This study assessed the efficacy of treatment of PMD with 75 mg udenafil daily. MATERIALS AND METHODS: The study included 138 men with regular sexual lifestyles. The Hallym PMD questionnaire (HPMDQ) was used to assess PMD symptoms. After all basic examinations, patients were randomly assigned to either udenafil or placebo. Patients completed the surveys, uroflowmetry (UFM), a bladder scan, and the paper test during the follow-up visit. RESULTS: The mean age of the patients was 57.6 years. PMD with one of every three urinations was experienced by 59 patients (42.8%), whereas 45 patients (32.6%) experienced PMD with two of every three urinations. PMD with every urination was experienced by 34 patients (24.6%). More than half of the patients (89 patients, 65.4%) indicated that persistent PMD symptoms would likely result in moderate to severe discomfort in their daily activities. As time passed, the udenafil group showed significant improvement in PMD symptoms (p = 0.001). CONCLUSION: Udenafil 75 mg once daily can be an effective treatment for patients with PMD symptoms.
Subject(s)
Phosphodiesterase 5 Inhibitors , Prostatic Hyperplasia , Double-Blind Method , Humans , Male , Middle Aged , Prospective Studies , Pyrimidines , Sulfonamides , Treatment OutcomeABSTRACT
OBJECTIVES: Postmicturition dribble (PMD) is a very common symptom in males with lower urinary tract symptoms (LUTS) worldwide, but there is no adequate questionnaire to assess it. Therefore, we developed a questionnaire named the Hallym Post Micturition Dribble Questionnaire (HPMDQ) to assess PMD, and the aim of this study is to validate it. METHODS: A series of consecutive male patients newly diagnosed with LUTS and over 40 years of age who visited any of 5 medical institutions were included. LUTS were assessed in all patients using the International Prostate Symptom Score (IPSS), and PMD was assessed using the HPMDQ. RESULTS: In total, 2134 male patients aged 40 to 91 years were included in this study. Of these patients, 1088 (51.0%) reported PMD. In the PMD group, the mean values for HPMDQ-Q1, HPMDQ-Q2, HPMDQ-Q3 and HPMDQ total score were 1.39, 1.10, 1.76 and 4.25, respectively. In the non-PMD group, the mean values of these scores were 0, 0.18, 1.52 and 1.58, respectively. The difference in HPMDQ scores between the 2 groups was statistically significant. PMD was significantly associated with the voiding symptoms of LUTS, prostate size and postvoid residual but not with storage symptoms. CONCLUSIONS: The HPMDQ, which consists of 5 questions (frequency, severity, bother, quality of life and response to treatment for PMD), was developed, and its use for assessing PMD is validated in this study. It may be a useful tool for further research and in clinical practice for PMD.
Subject(s)
Lower Urinary Tract Symptoms/physiopathology , Symptom Assessment/methods , Adult , Age Distribution , Aged , Aged, 80 and over , Humans , Lower Urinary Tract Symptoms/epidemiology , Male , Middle Aged , Prevalence , Prospective Studies , Republic of Korea/epidemiology , Surveys and Questionnaires , UrinationABSTRACT
OBJECTIVE: To investigate the effects of reversing the coiling direction of nickeltitanium closed-coil springs (NiTi-CCSs) on the force-deflection characteristics. METHODS: The samples consisted of two commercially available conventional NiTi-CCS groups and two reverse-wound NiTi-CCS groups (Ormco-Conventional vs. Ormco-Reverse; GAC-Conventional vs. GAC-Reverse; n = 20 per group). The reverse-wound NiTi-CCSs were directly made from the corresponding conventional NiTi-CCSs by reversing the coiling direction. Tensile tests were performed for each group in a temperature-controlled acrylic chamber (37 ± 1â). After measuring the force level, the range of the deactivation force plateau (DFP) and the amount of mechanical hysteresis (MH), statistical analyses were performed. RESULTS: The Ormco-Reverse group exhibited a significant shift of the DFP end point toward the origin point (2.3 to 0.6 mm), an increase in the force level (1.2 to 1.3 N) and amount of MH (1.0 to 1.5 N) compared to the Ormco-Conventional group (all p < 0.001), which indicated that force could be constantly maintained until the end of the deactivation curve. In contrast, the GAC-Reverse group exhibited a significant shift of the DFP-end point away from the origin point (0.2 to 3.3 mm), a decrease in the force level (1.1 to 0.9 N) and amount of MH (0.6 to 0.4 N) compared to the GAC-Conventional group (all p < 0.001), which may hinder the maintenance of force until the end of the deactivation curve. CONCLUSIONS: The two commercially available NiTi-CCS groups exhibited different patterns of change in the force-deflection characteristics when the coiling direction was reversed.
ABSTRACT
OBJECTIVES: To investigate polypharmacy and potentially inappropriate medications (PIMs) in elderly patients visiting the urology department for lower urinary tract symptoms (LUTS). METHODS: We retrospectively analyzed digital medical records of individuals over the age of 65 who visited the urology department for LUTS. This cross-sectional study was conducted in 10 hospitals located in South Korea, between September 2017 and December 2017. All prescribed medications were analyzed using electronic medical records. The updated 2015 Beers criteria were used to identify and assess the appropriateness of the prescribed drugs in elderly patients. RESULTS: We analyzed a total of 2143 patients aged over 65 years from 10 institutions. The mean age was 74.2 ± 6.26 years (65-97), 1634 (76.2%) were men. Patients took a mean of 6.48 ± 2.46 medications (range 0-18), and polypharmacy was found in 1762 patients (82.2%). The number of patients who received PIMs at least once was 1579 (73.7%). The average number of PIMs used per patient was 1.31 ± 1.25 (0-7). PIM use ratio was 18.9 ± 0.15% (0-67%). The number of chronic diseases, and concurrent medication and polypharmacy were predictive factors associated with PIM use. CONCLUSION: Our multi-institutional results show that a substantial proportion of elderly patients took PIMs when visiting the urology department. Factors associated with PIMs were the number of chronic diseases and polypharmacy. Medication use in elderly patients, especially in urology, should be monitored carefully.
Subject(s)
Lower Urinary Tract Symptoms/drug therapy , Polypharmacy , Potentially Inappropriate Medication List , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Male , Outpatients , Retrospective StudiesABSTRACT
A paramagnetic NiTi substrate was coated with diamagnetic carbon materials, i.e., graphene, graphene oxide (GO), and carbon nanotubes (CNTs), in order to reduce magnetic resonance (MR) image artifacts of NiTi implants. The present study focused on the effect of magnetic susceptibility variations in NiTi caused by the carbon coating on MR image artifacts. In the case of the graphene and GO coatings, the reduction of the magnetic susceptibility was greater along the perpendicular direction than the parallel direction. In contrast, the CNT coating exhibited a larger reduction along the parallel direction. The reduction of magnetic susceptibility measured in CNT-coated NiTi (CNT/NiTi) was smaller than the theoretical prediction especially when measured along the parallel direction, because CNTs on the NiTi surface were randomly arranged, rather than in a single direction. MR image artifacts were substantially reduced in all carbon-coated NiTi specimens, which is due to the reduction of magnetic susceptibility in NiTi by the carbon coating. This method can also be applied to other paramagnetic bio-metallic materials such as Co-Cr.
Subject(s)
Coated Materials, Biocompatible/chemistry , Magnetic Resonance Imaging/methods , Nanotubes, Carbon/chemistry , Magnetics , Nickel/chemistry , Titanium/chemistryABSTRACT
OBJECTIVES: To provide surgical treatment trends for urinary stone disease in Korea. METHODS: We analyzed medical service claim data of surgical treatments to urinary stone disease submitted by medical service providers from the Health Insurance Review and Assessment Service from 2009 to 2016. RESULTS: There was a significantly increasing trend among outpatients and inpatients for urinary stone disease from 2009 to 2016 (R2 = 0.643, P = 0.017; R2 = 0.575, P = 0.029). The number of shock wave lithotripsy for treating urinary stone disease increased by 16% from 89 553 in 2009 to 104 013 in 2016 (R2 = 0.684). The number of ureteroscopic lithotripsy increased by 97% from 6106 in 2009 to 12 057 in 2016 (R2 = 0.99). The number of flexible ureteroscopic lithotripsy increased by 16-fold from 219 in 2009 to 3712 in 2016 (R2 = 0.756). The number of percutaneous nephrolithotomy increased by 99.7% from 919 in 2009 to 1835 in 2016 (R2 = 0.987). The use of non-contrast and contrast-enhanced computed tomography in the diagnostic codes for urinary stone disease increased by 394.8% and 263.3% from 2009 to 2016, respectively (R2 = 0.83; R2 = 0.967). Conversely, the use of intravenous pyelography decreased 26.2% over the same period (R2 = 0.945). CONCLUSIONS: Outpatient and inpatient procedures for urinary stone disease have increased over the past 8 years in Korea. Shock wave lithotripsy is the most widely used treatment modality for urinary stone disease, and endoscopic surgical procedures are rapidly being implemented. There has been a steep increase in the use of computed tomography, whereas conventional intravenous pyelography is declining.
Subject(s)
Lithotripsy/trends , Nephrolithotomy, Percutaneous/trends , Ureteroscopy/trends , Urolithiasis/epidemiology , Urolithiasis/therapy , Cross-Sectional Studies , Female , Humans , Linear Models , Male , Republic of Korea/epidemiology , Treatment OutcomeABSTRACT
PURPOSE: The aim of this study was to develop and validate a decision support model using a machine learning algorithm to predict treatment success after single session shock wave lithotripsy in ureteral stone cases. MATERIALS AND METHODS: Of the 1,803 patients treated with shock wave lithotripsy we selected those with ureteral stones who had preoperative computerized tomography available. Treatment success after single session shock wave lithotripsy was defined as freedom from stones or residual stone fragments less than 2 mm long on computerized tomography or plain x-ray of the kidneys, ureters and bladder 2 weeks later. Decision tree analysis was done using a machine learning algorithm to identify relevant parameters. A decision support model was developed to calculate the probability of treatment success. RESULTS: A total of 791 patients were enrolled in study. Mean ± SD stone length was 5.9 ± 2.3 mm and mean stone volume was 89.3 ± 140.0 mm3. The overall treatment success rate after SWL was 64.4% (509 cases). The rate for upper, middle and lower ureter stones was 59.8%, 65.5% and 69.6%, respectively. On decision tree analysis the top 3 performance criteria factors were volume, length and HU. Decision models were constructed with all possible combinations of factors. The model with 15 factors had greater than 92% accuracy and an average ROC AUC of 0.951. CONCLUSIONS: We applied a machine learning algorithm, a subfield of artificial intelligence, to predict the outcome after single session shock wave lithotripsy for ureteral stones. A 92.29% accurate decision model was developed with 15 factors and an average ROC AUC of 0.951.
Subject(s)
Lithotripsy , Machine Learning , Ureteral Calculi/surgery , Adult , Algorithms , Computer Simulation , Decision Support Techniques , Female , Humans , Male , Middle Aged , Prognosis , Retrospective Studies , Tomography, X-Ray Computed , Treatment Outcome , Ureteral Calculi/diagnostic imagingABSTRACT
The microstructure and corrosion properties of as-cast AZ61 (Mg-6%Al-1%Zn) and AZ61 alloys doped with titanium and calcium and subjected to high ratio differential speed rolling were investigated. Addition of the alloying elements to the AZ61 alloy resulted in remarkable modification of the morphology and the amount of continuous ß (Mg17Al12)-phase. Addition of Ti to the as-cast AZ61 alloy causes a decrease in the volume fraction (or discontinuity of the ß-phase), leading to strong anodic dissolution. In contrast, addition of Ca to the as-cast AZ61 alloy is rather effective for preventing pitting corrosion. This is attributed to the formation of a semi-continuous network ß-structure. The (Mg, Al)4Ca phases dispersed between the ß (Mg17Al12)-phases led to continuity in the AZ61 alloy with Ca. The AZ61 and AZ61-X(Ca, Ti) alloys subjected to severe plastic deformation via high-ratio differential speed rolling possessed a nano-composite-like microstructure in which the α-Mg matrix with an ultra-fine grain was surrounded by a large number of fine ß particles. These particles were either dynamically precipitated or broken at the grain boundaries, as well as in the grain interiors, by the high ratio differential speed rolling process. The corrosion resistance of the AZ61 and AZ61-X (X = Ca, Ti) alloys subjected to high ratio differential speed rolling was largely improved by the microstructural modification. The high ratio differential speed rolling process greatly influenced the texture of the Mg alloys, which significantly affected their corrosion behavior.
ABSTRACT
The funding number was incorrect in the original published article. The correct funding number should read as follows.
ABSTRACT
OBJECTIVE: To verify the efficacy and safety of tamsulosin 0.4 mg and tamsulosin 0.2 mg compared with those of placebo in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH). METHODS: A total of 494 patients from multiple centers participated in this double-blind, randomized, phase 3 trial. Eligible patients were randomly assigned to the tamsulosin 0.4 mg group, tamsulosin 0.2 mg group or placebo group. The International Prostate Symptom Score (IPSS), maximum flow rate (Qmax), post-void residual (PVR) urine volume, blood pressure, heart rate and adverse events were compared among the three groups at 4, 8 and 12 weeks. RESULTS: A total of 494 BPH patients were analyzed. There were no differences in the baseline characteristics among the three groups. After 12 weeks of treatment, total IPSS was improved in the 0.2 mg and 0.4 mg tamsulosin groups; however, the extent of improvement was greater in the 0.4 mg group than in the 0.2 mg group (0.4 mg: -9.59 vs. 0.2 mg: -5.61; least-squares mean difference [95% confidence interval]: -3.95 [-5.01, -2.89], p < .0001). In addition, in the patients with severe symptoms (IPSS ≥20), total IPSS was improved the most in the 0.4 mg group (-11.27 ± 5.00, p < .0001). Qmax and PVR were improved in the 0.4 mg and 0.2 mg groups; however, the differences were not statistically significant between treatment groups. No patients experienced any serious adverse effects in any of the three groups. CONCLUSIONS: Tamsulosin 0.4 mg and 0.2 mg appear to be superior to placebo treatment, and tamsulosin 0.4 mg is more effective than 0.2 mg in terms of total IPSS improvement. Tamsulosin 0.4 mg has favorable efficacy and tolerability in Asian men with symptomatic BPH. ClinicalTrials.gov Identifier: NCT02390882.
Subject(s)
Lower Urinary Tract Symptoms , Prostatic Hyperplasia , Tamsulosin , Aged , Asian People/statistics & numerical data , Dose-Response Relationship, Drug , Double-Blind Method , Drug Monitoring/methods , Humans , Lower Urinary Tract Symptoms/drug therapy , Lower Urinary Tract Symptoms/etiology , Male , Middle Aged , Prostatic Hyperplasia/drug therapy , Prostatic Hyperplasia/pathology , Prostatic Hyperplasia/physiopathology , Republic of Korea , Tamsulosin/administration & dosage , Tamsulosin/adverse effects , Treatment Outcome , Urological Agents/administration & dosage , Urological Agents/adverse effectsABSTRACT
PURPOSE: We compared the outcomes of SWL to treat distal ureter stones with regard to the conventional prone and supine positions using the transgluteal approach through the greater sciatic foramen. METHODS: A prospective, randomized, single-blind, and multicenter study was conducted between October 2014 and July 2015. The inclusion criteria were radio-opaque distal ureter stones with a maximum diameter of 0.5-2 cm as measured on a CT scan. The included 160 patients were randomly assigned to two groups: the prone group (n = 80; treated in the conventional prone position) and the transgluteal group (n = 80; treated in the supine position using a transgluteal approach). In the latter group, the focused shock wave was transmitted through the greater sciatic foramen with the head positioned at a 40° angle to the vertical. "Stone-free" was defined as the complete clearance of stone fragments, assessed using a CT scan at 2 weeks after treatment. Overall satisfaction was self-reported using a 0-5 Likert scale. RESULTS: The overall efficacy was 66.9%. The stone-free rate was significantly higher in the transgluteal group (72.6%) than in the prone group (54.7%; odds ratio 2.413, 95% CI 1.010-5.761, P = 0.023). No serious adverse events due to treatment were observed in either group. The satisfaction score of the transgluteal group was 4.21 ± 0.81, and 83.6% were willing to repeat the same procedure if necessary. CONCLUSIONS: SWL using the transgluteal approach via a supine position through the greater sciatic foramen was more effective than via the conventional prone position. Furthermore, this approach provided a comparably safe and satisfactory procedure.