Model based visualization of vibrations in mechanical systems

To visualize vibrations in mechanical systems, e.g., machine tools, their movements are measured by means of suitable sensors. The signals from these sensors are processed and displayed as animated pictures on a computer screen. Accelerometers have been chosen as the most suitable sensors for this purpose. Their main advantages include small size, wide sensitivity range and frequency bandwidth. In addition, accelerometers measure signals with reference to the Earth, so they do not require stable fixtures such as used with cameras or lasers. The visualization methodology involves nine accelerometers attached to a mechanical component, e.g., a dynamometer's platform. Vibration signals were acquired using a data acquisition (DAQ) system which is controlled by a LabVIEW®-based program. These signals are processed to suppress errors and convert acceleration into generalized coordinate that describes motion of the visualized component as a rigid plate's movement in 3-D space. The animation is accomplished by displaying a time series of pictures representing instantaneous position of the plate. The animation program employs homogenous coordinate transformation to draw 3-D 'wireframe' pictures. Since various errors distort the measured signals, the animated movement may be inaccurate. The knowledge of a mathematical model of the system whose vibrations are animated allows detection and suppression of distortions. For this purpose, the signals measured from the actual dynamic system are compared with the signals simulated by the system's model subjected to the same excitation as the actual system. Discrepancies between the actual and simulated signals are detected. They are analyzed to identify possible sources and forms of distorting signals. As the next step, the measured (actual) signals are corrected by removing estimated distortions. A methodology and software package capable of performing all functions necessary to implement the visualization of vibration have been developed in this research using LabVIEW® programming environment. As compared with commercial software for experimental modal analysis, the most distinctive feature of the developed package is improved accuracy achieved by applying concepts utilized in control theory, such as modeling of multi-input-multi-output (MIMO) systems and on-line system identification for the model development and correction of signals

Structure and health status of the sand crab, Emerita taiwanesis Hsueh, 2015 from Sangchan Beach, Thailand: The histopathological approach

Although the impacts of environmental problems on aquatic organisms have been broadly reported in Thailand, the literature has not covered the sand crab, Emerita taiwanesis Hsueh, 2015. In this study, we focused on the structure and health status of E. taiwanesis, an economically important crab species, living close to human activity areas in Sangchan Beach, Rayong Province, Thailand. A total of 60 individuals were collected from the conservation and restoration of coastal resource project in Ban Rue Leg Kao Yod-based participatory during December 2016 – January 2017. We identified histopathological changes in the gill structure, but not in other vital organs, including ganglion, stomach, intestine, hepatopancreas and muscular bundles. The histological alterations in the gill include hematocyte infiltration, pyknotic nuclei and degeneration of pillar cells in the gill (50% prevalence), suggesting that the gill is a sensitive organ to environmental changes. Our observation provided a better understanding of E. taiwanesis morphology and its overall healthy state on Sangchan Beach. Additionally, we suggest that the sand crab would be a suitable sentinel species for monitoring the environment of coastal areas in Thailand.

Administration of Renin-Angiotensin System Inhibitor Affects Tumor Recurrence and Progression in Non-Muscle Invasive Bladder Cancer Patients

Objective: To evaluate the effects of renin-angiotensin system inhibitors (RASIs) on tumor-recurrence and diseaseprogression in non-muscle invasive bladder cancer (NMIBC) patients. Methods: From 2006-2015, 348 NMIBC patients at Siriraj Hospital were recruited for this study. Tumor-recurrence was identified after the transurethral resection of bladder cancer (TUR-BT) and pathological confirmation of NMIBC, while stage-progression was defined as muscularis-propria invasion after pathological review or metastases. Cox proportional hazards models were used to assess the recurrence-free survival (RFS) and progression-free survival (PFS) rates. Results: Of the 348 patients, 86 (24.7%) received RASIs at the first TUR-BT. The median age was 68 years, and it was significantly older for the RASI cohort. No differences in the tumor characteristics of the groups were found. The median follow-up periods for tumor-recurrence and stage-progression were 2.3 and 3.7 years, respectively. Forty percent of the patients experienced tumor-recurrence, with the no-RASI cohort experiencing a significantly higher tumor-recurrence rate (46% versus 22%, p<0.001). The 5-year RFS rates were 54% and 78% for the no-RASI and RASI cohorts, respectively (p=0.001). Stage-progression was observed in 6% of the patients. The 5-year PFS rates were 87% and 97% for the no-RASI and RASI cohorts, respectively. On univariate and multivariate analyses, a tumor size ≥3 cm and tumor multifocality were associated with recurrent bladder cancer (p<0.02). On the other hand, the administration of RASIs was associated with a reduced recurrence (p≤0.002). Conclusion: Our study suggests that RASI administration might be a potential factor to prevent bladder cancer recurrence. Further study is needed to evaluate the effects of RASIs

Administration of Renin-Angiotensin System Inhibitor Affects Tumor Recurrence and Progression in Non-Muscle Invasive Bladder Cancer Patients

Objective: To evaluate the effects of renin-angiotensin system inhibitors (RASIs) on tumor-recurrence and disease-progression in non-muscle invasive bladder cancer (NMIBC) patients. Methods: From 2006-2015, 348 NMIBC patients at Siriraj Hospital were recruited for this study. Tumor-recurrence was identified after the transurethral resection of bladder cancer (TUR-BT) and pathological confirmation of NMIBC, while stage-progression was defined as muscularis-propria invasion after pathological review or metastases. Cox proportional hazards models were used to assess the recurrence-free survival (RFS) and progression-free survival (PFS) rates. Results: Of the 348 patients, 86 (24.7%) received RASIs at the first TUR-BT. The median age was 68 years, and it was significantly older for the RASI cohort. No differences in the tumor characteristics of the groups were found. The median follow-up periods for tumor-recurrence and stage-progression were 2.3 and 3.7 years, respectively. Forty percent of the patients experienced tumor-recurrence, with the no-RASI cohort experiencing a significantly higher tumor-recurrence rate (46% versus 22%, p<0.001). The 5-year RFS rates were 54% and 78% for the no-RASI and RASI cohorts, respectively (p=0.001). Stage-progression was observed in 6% of the patients. The 5-year PFS rates were 87% and 97% for the no-RASI and RASI cohorts, respectively. On univariate and multivariate analyses, a tumor size ≥3 cm and tumor multifocality were associated with recurrent bladder cancer (p<0.02). On the other hand, the administration of RASIs was associated with a reduced recurrence (p≤0.002). Conclusion: Our study suggests that RASI administration might be a potential factor to prevent bladder cancer recurrence. Further study is needed to evaluate the effects of RASIs

Survival benefits after radical nephrectomy and IVC thrombectomy of renal cell carcinoma patients with inferior vena cava thrombus

Objective: The role of tumor thrombus as a predictor of survival in patients with renal cell carcinoma (RCC) is controversial. This study aims to evaluate surgical and oncological outcomes after surgery in RCC with inferior vena cava (IVC) tumor thrombus patients. Materials and methods: A total of 58 patients (2002–2019) underwent radical nephrectomy and IVC thrombectomy at our institute, were retrospectively reviewed. Kaplan-Meier analysis was utilized to compare survival benefits between cohorts and Cox-regression to evaluate potential predictors of patient survival. Results: There were 5(8.6%), 21(36.2%), 23(39.7%) and 9 (15.5%) patients with tumor thrombus level I, II, III and IV respectively. The major complications (Clavien 3–5) were observed in 15 patients (25.8%) and 12 patients (80%) were patients with high thrombus level (III-IV). There was 9%mortality (5patients): 2 intraoperatively and 3 postoperatively. Median follow-up was 15 months (IQR:5–41). Two-year overall survival (OS) was 80% and 75% in all patients and pN0M0 cohort, respectively. There was significant difference in OS among each IVC thrombus level cohort (p < 0.02). Two-year OS of metastatic RCC patients was 67% and not significantly different when compared to non-metastatic cohort (p = 0.12). On multivariate analysis, only sarcomatoid dedifferentiation was associated with OS(p = 0.04). Disease-free survival was not significantly different among thrombus-level cohorts (p = 0.65). Conclusions: Our study suggested that surgical treatment for RCC with IVC thrombus provided substantial OS outcomes. Although survival was significantly reduced with higher IVC thrombus level cohort, the level of thrombus itself was not an independent factor. Only sarcomatoid dedifferentiation was a predictor for reduced OS after radical nephrectomy and tumor thrombectomy. Meticulous patient selection and prompt counselling are substantial step for the operation

Role of preoperative magnetic resonance imaging on the surgical outcomes of radical prostatectomy: Does preoperative tumor recognition reduce the positive surgical margin in a specific location? Experience from a Thailand prostate cancer specialized center

Objective: Multiparametric magnetic resonance imaging (MRI) has become the standard of care for the diagnosis of prostate cancer patients. This study aimed to evaluate the influence of preoperative MRI on the positive surgical margin (PSM) rates. Methods: We retrospectively reviewed 1070 prostate cancer patients treated with radical prostatectomy (RP) at Siriraj Hospital between January 2013 and September 2019. PSM rates were compared between those with and without preoperative MRI. PSM locations were analyzed. Results: In total, 322 (30.1%) patients underwent MRI before RP. PSM most frequently occurred at the apex (33.2%), followed by posterior (13.5%), bladder neck (12.7%), anterior (10.7%), posterolateral (9.9%), and lateral (2.3%) positions. In preoperative MRI, PSM was significantly lowered at the posterior surface (9.0% vs. 15.4%, p=0.01) and in the subgroup of urologists with less than 100 RP experiences (32% vs. 51%, odds ratio=0.51, p<0.05). Blood loss was also significantly decreased when a preoperative image was obtained (200 mL vs. 250 mL, p=0.02). Multivariate analysis revealed that only preoperative MRI status was associated with overall PSM and PSM at the prostatic apex. Neither the surgical approach, the neurovascular bundle sparing technique, nor the perioperative blood loss was associated with PSM. Conclusion: MRI is associated with less overall PSM, PSM at apex, and blood loss during RP. Additionally, preoperative MRI has shown promise in lowering the PSM rate among urologists who are in the early stages of performing RP