Development and Evaluation of Vibration Canceling System Utilizing Macro-Fiber Composites (MFCs) and Long Short-Term Memory (LSTM) Vibration Prediction AI Algorithms for Road Driving Vibrations.

This study developed an innovative active vibration canceling (AVC) system designed to mitigate non-periodic vibrations during road driving to enhance passenger comfort. The macro-fiber composite (MFC) used in the system is a smart material that is flexible, soft, lightweight, and applicable in many fields as a dual-purpose sensor and actuator. The target vibrations are road vibration data that were collected while driving on standard urban (Seoul) and highway roads at 40 km/s. To predict and cancel the target vibration accurately before passing it, we modeled the vibration prediction algorithm using a long short-term memory recurrent neural network (LSTM RNN). We regenerated vibrations on Seoul and highway roads at 40 km/s using MFCs and measured the displacements of the measured, predicted, and AVC vibrations of each road condition. To evaluate the vibration, we computed the root mean squared error (RMSE) and compared standard deviation (SD) values. The accuracies of LSTM RNN vibration prediction algorithms are 97.27% and 96.36% on Seoul roads and highway roads, respectively, at 40 km/s. Although the vibration ratio compared with the AVC results are different, there was no difference between the values of the AVC vibrations. According to a previous study and the principle of the AVC system, the target vibrations decrease by canceling the inverse vibration of the MFC actuator.

Transjugular intrahepatic portosystemic shunt for esophagojejunal variceal bleeding after total gastrectomy: A case report.

Esophagojejunal varices occurring after total gastrectomy are rare but potentially fatal in cases of variceal bleeding. Owing to their rarity, treatment strategies for this condition are not well established. Here, we describe the case of a 48-year-old woman who presented with hematemesis and melena. Four years prior, she underwent a total gastrectomy for gastric cancer. Esophagojejunal variceal bleeding supplied by a dilated jejunal vein, along with liver cirrhosis, was diagnosed as per endoscopy and computed tomography findings. Initial attempts at endoscopic therapy were unsuccessful. Subsequently, transjugular intrahepatic portosystemic shunt placement was performed to reduce the portal pressure gradient, resulting in the cessation of bleeding. At the 1-month follow-up endoscopy, the varices had resolved, and no rebleeding occurred during 6 months of follow-up. Transjugular intrahepatic portosystemic shunt placement may be considered as an effective treatment option for esophagojejunal variceal bleeding.

Measurement of 3D Wrist Angles by Combining Textile Stretch Sensors and AI Algorithm.

The wrist is one of the most complex joints in our body, composed of eight bones. Therefore, measuring the angles of this intricate wrist movement can prove valuable in various fields such as sports analysis and rehabilitation. Textile stretch sensors can be easily produced by immersing an E-band in a SWCNT solution. The lightweight, cost-effective, and reproducible nature of textile stretch sensors makes them well suited for practical applications in clothing. In this paper, wrist angles were measured by attaching textile stretch sensors to an arm sleeve. Three sensors were utilized to measure all three axes of the wrist. Additionally, sensor precision was heightened through the utilization of the Multi-Layer Perceptron (MLP) technique, a subtype of deep learning. Rather than fixing the measurement values of each sensor to specific axes, we created an algorithm utilizing the coupling between sensors, allowing the measurement of wrist angles in three dimensions. Using this algorithm, the error angle of wrist angles measured with textile stretch sensors could be measured at less than 4.5°. This demonstrated higher accuracy compared to other soft sensors available for measuring wrist angles.

Comparative Performance Analysis of Inverse Phase Active Vibration Cancellation Using Macro Fiber Composite (MFC) and Vibration Absorption of Silicone Gel for Vibration Reduction.

This study focuses on addressing the issue of unwanted vibrations commonly encountered in various fields by designing an Active Vibration Cancellation (AVC) structure using a flexible piezoelectric composite material macro fiber composite (MFC). A comparative performance analysis was conducted between the AVC and a traditional passive gel that continuously absorbs vibrations. The results showed that AVC was more effective in mitigating vibrations, making it a promising solution for vibration control. The results of this study from extensive vibration-sensing experiments and comparisons revealed that AVC effectively cancels the vibrations and vibration absorption performance of the passive gel. These findings underline the potential of AVC as an efficient method for eliminating and managing undesired vibrations in practical applications. Specifically, AVC demonstrated a high vibration cancellation ratio of approximately 0.96 at frequencies above 10 Hz. In contrast, passive gel exhibited a relatively consistent vibration absorption ratio, approximately 0.70 to 0.75 at all tested frequencies. These quantitative findings emphasize the superior performance of AVC in reducing vibrations to levels below a certain threshold, demonstrating its efficacy for vibration control in real-world scenarios.

Patterns in renal diseases diagnosed by kidney biopsy: A single-center experience.

BACKGROUND: The worldwide incidence of renal disease diagnosed by a kidney biopsy varies with age, race, sex, and region. Owing to a lack of studies and limited research resources for this disease in Korea, we investigated renal disease patterns by analyzing data from kidney biopsies performed over 13 years in a university-based teaching hospital in Korea. METHODS: Among 2,053 kidney biopsies performed from 2001 to 2013 at Kyungpook National University Hospital, 1,924 were retrospectively analyzed for histopathologic, demographic, and clinical data as well as laboratory results. RESULTS: Among the 1,924 studied kidney biopsies, 1,078 were males (56.0%) and the mean age was 37.7 ± 16.5 years. Asymptomatic urinary abnormalities were the most common clinical manifestation (62.5%). Immunoglobulin A nephropathy (IgAN) was the most common primary glomerular disease (37.4%), followed by minimal change disease (MCD), membranous nephropathy (MN), focal segmental glomerulonephritis and crescentic glomerulonephritis. Secondary glomerular diseases accounted for 10.3% of the total biopsies, with lupus nephritis being the most common (4.6%) followed by Henoch-Schönlein purpura nephritis and diabetic nephropathy. The most common cause of nephrotic syndrome was MCD (42.1%) followed by MN. Among patients seropositive for hepatitis B or C, IgAN (28.3% and 21.4%, respectively) was the most common cause. CONCLUSION: IgAN and lupus nephritis were the most common primary and secondary glomerular diseases, respectively. Race, region, and practice patterns may affect renal disease patterns in different cohorts.

Vitamin D deficiency is associated with increased risk of bacterial infections after kidney transplantation.

BACKGROUND/AIMS: There may be an association between vitamin D levels and allograft outcomes in kidney transplant recipients (KTRs). However, few studies have been conducted to determine the association between vitamin D levels and post-transplant infections. This study investigated the impact of vitamin D deficiency on the risk of infection after kidney transplantation. METHODS: We measured 25-hydroxyvitamin D (25(OH)D) levels prior to kidney transplantation. Vitamin D deficiency was defined as a serum 25(OH)D level < 20 ng/mL. We examined the incidence of various post-transplant infections during follow-up period. We used Cox proportional hazards regression analysis to determine factors associated with increased risk of post-transplant infections during the follow-up period. RESULTS: A total of 164 KTRs were followed up for a mean of 24.8 ± 10.7 months. Among them, 135 patients (82.3%) had vitamin D deficiency. Patients with vitamin D deficiency had a significantly higher incidence of urinary tract infection (p = 0.027) and any bacterial infection (p = 0.010) compared to those without vitamin D deficiency. Vitamin D deficiency was not significantly associated with incidence of viral or fungal infections. Cox proportional hazards regression analysis revealed that vitamin D deficiency (hazard ratio, 11.07; 95% confidence interval, 1.46 to 84.03; p = 0.020) was independent risk factor for post-transplant bacterial infections. CONCLUSIONS: Pre-transplant vitamin D deficiency was a significant risk factor for bacterial infections after kidney transplantation. Further studies are needed on possible benefits of vitamin D supplementation for preventing post-transplant bacterial infection.

Low prealbumin levels are independently associated with higher mortality in patients on peritoneal dialysis.

BACKGROUND: Prealbumin, a sensitive marker for protein-energy status, is also known as an independent risk factor for mortality in hemodialysis patients. We investigated the impact of prealbumin on survival in incident peritoneal dialysis (PD) patients. METHODS: In total, 136 incident PD patients (mean age, 53.0 ± 15.8 years) between 2002 and 2007 were enrolled in the study. Laboratory data, dialysis adequacy, and nutritional parameters were assessed 3 months after PD initiation. Patients were classified into 2 groups according to prealbumin level: high prealbumin (≥ 40 mg/dL) and low prealbumin (< 40 mg/dL). RESULTS: The patients in the low-prealbumin group were older and had more comorbidities such as diabetes and cardiovascular diseases compared with the patients in the high-prealbumin group. Mean subjective global assessment scores were lower, and the high-sensitivity C-reactive protein levels were higher in the low-prealbumin group. Serum creatinine, albumin, and transferrin levels; percent lean body mass; and normalized protein catabolic rate were positively associated, whereas subjective global assessment scores and high-sensitivity C-reactive protein levels were negatively associated with prealbumin concentration. During the median follow-up of 49 months, patients in the lower prealbumin group had a higher mortality rate. Multivariate analysis revealed that prealbumin < 40 mg/dL (hazard ratio, 2.30; 95% confidence interval, 1.14-4.64) was an independent risk factor for mortality. In receiver operating characteristic curves, the area under the curve of prealbumin for mortality was the largest among the parameters. CONCLUSION: Prealbumin levels were an independent and sensitive predictor for mortality in incident PD patients, showing a good correlation with nutritional and inflammatory markers.

Duration of anuria predicts recovery of renal function after acute kidney injury requiring continuous renal replacement therapy.

BACKGROUND/AIMS: Little is known regarding the incidence rate of and factors associated with developing chronic kidney disease after continuous renal replacement therapy (CRRT) in acute kidney injury (AKI) patients. We investigated renal outcomes and the factors associated with incomplete renal recovery in AKI patients who received CRRT. METHODS: Between January 2011 and November 2013, 408 patients received CRRT in our intensive care unit. Of them, patients who had normal renal function before AKI and were discharged without maintenance renal replacement therapy (RRT) were included in this study. We examined the incidence of incomplete renal recovery with an estimated glomerular filtration rate < 60 mL/min/1.73 m(2) and factors that increased the risk of incomplete renal recovery after AKI. RESULTS: In total, 56 AKI patients were discharged without further RRT and were followed for a mean of 8 months. Incomplete recovery of renal function was observed in 20 of the patients (35.7%). Multivariate analysis revealed old age and long duration of anuria as independent risk factors for incomplete renal recovery (odds ratio [OR], 1.231; 95% confidence interval [CI], 1.041 to 1.457; p = 0.015 and OR, 1.064; 95% CI, 1.001 to 1.131; p = 0.047, respectively). In a receiver operating characteristic curve analysis, a cut-off anuria duration of 24 hours could predict incomplete renal recovery after AKI with a sensitivity of 85.0% and a specificity of 66.7%. CONCLUSIONS: The renal outcome of severe AKI requiring CRRT was poor even in patients without further RRT. Long-term monitoring of renal function is needed, especially in severe AKI patients who are old and have a long duration of anuria.

Impact of dialysis modality on technique survival in end-stage renal disease patients.

BACKGROUND/AIMS: This study analyzed the risk factors for technique survival in dialysis patients and compared technique survival rates between hemodialysis (HD) and peritoneal dialysis (PD) in a prospective cohort of Korean patients. METHODS: A total of 1,042 patients undergoing dialysis from September 2008 to June 2011 were analyzed. The dialysis modality was defined as that used 90 days after commencing dialysis. Technique survival was compared between the two dialysis modalities, and the predictive risk factors were evaluated. RESULTS: The dialysis modality was an independent risk factor predictive of technique survival. PD had a higher risk for technique failure than HD (hazard ratio [HR], 10.8; 95% confidence interval [CI], 1.9 to 62.0; p = 0.008) during a median follow-up of 11.0 months. In the PD group, a high body mass index (BMI) was an independent risk factor for technique failure (HR, 1.3; 95% CI, 1.0 to 1.8; p = 0.036). Peritonitis was the most common cause of PD technique failure. The difference in technique survival between PD and HD was more prominent in diabetic patients with a good nutritional status and in non-diabetic patients with a poor nutritional status. CONCLUSIONS: In a prospective cohort of Korean patients with end-stage renal disease, PD was associated with a higher risk of technique failure than HD. Diabetic patients with a good nutritional status and non-diabetic patients with a poor nutritional status, as well as patients with a higher BMI, had an inferior technique survival rate with PD compared to HD.

An assessment of a new navigatable percutaneous disc decompression device (l'DISQ) through histologic evaluation and thermo-mapping in human cadaveric discs.

STUDY DESIGN: This is an in vitro experimental study of the technical capability and safety study of a navigable percutaneous disc decompression device named L'DISQ. OBJECTIVES: The objectives of this study were to determine if L'DISQ could adequately reach certain target zones in the disc and to measure the distribution of rises in temperature in the surrounding tissue when the device was used to ablate the disc. METHODS: Placement of the wand of L'DISQ was attempted into the posterior annulus of the discs of four fresh human cadavers. During disc ablation, thermocouple probes were used to measure the temperature within the nucleus pulposus and annulus fibrosus, on the surface of the annulus, and on the posterior longitudinal ligament. Tissues harvested from around the disc were examined histologically. RESULTS: The tip of the wand could be successfully navigated to the posterolateral or posterocentral annulus at all levels above L5-S1 using a lateral approach. Rises in temperature did not exceed 13.25 ± 0.84°C within the disc, and did not exceed 1°C on the surface of the disc. Histology demonstrated no thermal damage to the surrounding neural tissues. CONCLUSION: L'DISQ can be successfully navigated to the target zones, and disc tissue ablated without thermal or structural damage to the adjacent neural tissues.

Correlation between urodynamic test results, perineal ultrasound and degree of stress urinary incontinence.

OBJECTIVE: To evaluate whether the results of urodynamic tests and the perineal ultrasound were different between grade 1 and 2 stress urinary incontinence. STUDY DESIGN: Forty premenopausal women with a diagnosis of stress urinary incontinence according to urodynamic tests were enrolled in this study. Stress urinary incontinence was defined as urine leakage during stress without detrusor contraction. Twenty patients had grade 1 and 20 had grade 2 stress urinary incontinence. We compared the parameters of uroflowmetry, filling cystometry, urethral pressure profile, dynamic urethral function test, perineal ultrasound and stress urethral axis between grade 1 and 2 levels of stress urinary incontinence. RESULTS: There were no significant differences in age, parity or body mass index between the grade 1 and 2 patients. Uroflowmetry results showed that there were no significant differences in maximal flow rate, average flow rate, voided volume or residual urine between grade 1 and 2. As to cystometry results, only the first desire to void was significantly increased in grade 2 over 1 (304 +/- 113.65 vs. 194 +/- 48.24 [mL], P = .04). There were no significant differences in any of the urethral pressure profile parameters. In the dynamic test, the Valsalva leak point pressure and cough leak point pressure were not significantly different between the 2 groups. There were no significant differences in perineal ultrasound parameters or the stress urethral axis. CONCLUSION: Most stress urinary incontinence-related parameters showed no difference between the grade 1 and 2, and no urodynamic or ultrasonographic evidence for a difference between the grade 1 and 2 was demonstrated.

Steroid hormone metabolism in women with pelvic organ prolapse.

OBJECTIVE: To identify whether endogenous steroid hormone metabolism in women with pelvic organ prolapse (POP) is different from that in normal women and the relationship between endogenous steroid hormone metabolites and POP stage. STUDY DESIGN: Twenty postmenopausal women who were clinically diagnosed as having POP and 20 volunteer postmenopausal women without prolapse were included in the study. We compared the urinary profiles of endogenous steroids between the two groups and investigated the relationship between urinary profiles of endogenous steroids and degree of prolapse. Urinary profiles of endogenous steroids were assayed by gas chromatography/mass spectrometry. RESULTS: The ages of the patients and control group were 64.6 +/- 6.5 and 63.5 +/- 3.9 years, and the body mass index was 23.96 +/- 3.14 and 24.11 +/- 2.73 kg/m2 in patients and normal subjects, respectively. The number of patients were 4 at stage I, 4 at stage II, 6 at stage III and 6 at stage IV. 5-Androstene-3 beta,16 beta,17 beta-triol (5-AT), 11 beta-hydroxy an and 17 beta-estradiol were significantly increased in the POP group as compared with the control group (0.76 +/- 0.67 vs. 0.06 +/- 0.03 mumol/g creatinine, P = .002, 1.16 +/- 0.83 vs. 0.65 +/- 0.23 mumol/g creatinine, P = .04; and 15.08 +/- 9.81 vs. 8.53 +/- 6.19 mumol/g creatinine, P = .04). However, tetrahydrocortisone (THE) was significantly increased in the control group as compared with the patient group (9.80 +/- 6.21 vs. 5.22 +/- 4.89 mumol/g creatinine, P = .04). Androgen metabolites 5-AT and THE significantly correlated with the pelvic organ prolapse quantitation (POP-Q) stage (R = .418; P = .027; R = .46, P = .016). Among the estrogen metabolites, 17 beta-estradiol correlated with POP-Q stage, but not significantly so (R = .38, P = .05), and the 17 beta-estradiol/estrone ratio weakly correlated with stage (R = .14, P = .49). CONCLUSION: The metabolites of endogenous steroid hormones could be contributing factors in the pathogenesis of POP.