Optimized sliding mode controller for trajectory tracking of flexible joints three-link manipulator with noise in input and output.

The aim of this study is to enhance the performance of a nonlinear three-rigid-link maneuver (RLM) in terms of trajectory tracking, disturbance and noise cancellation, and adaptability to joint flexibility. To achieve this, an optimized sliding mode controller with a proportional integral derivative surface (SMC-PID) is employed for maneuver control. An improved artificial bee colony algorithm with multi-elite guidance (MGABC) is utilized to obtain optimal values for the sliding surface and switching mode gain and attain the best performance for the robot maneuver system. The selection of the MGABC algorithm is based on its efficient exploration and exploitation techniques. The performance of the optimized SMC-PID robotic system is compared against other optimization algorithms found in existing literature, including Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Artificial Bee Colony (ABC), Ant Lion Optimizer (ALO), and Grey Wolf Optimizer (GWO). The implemented controller effectively reduces the tracking error to 0.00691 radians, eliminates chattering phenomena in the control effort, and demonstrates robustness against disturbances and noise. The controller ensures that the objective function (OBJF) is minimized, with 0.954% increase in OBJF under low disturbance and noise conditions and 14.55% under severe disturbance and noise conditions. Moreover, the optimized controller exhibits resilience to variations in payload mass analysis, with the percentage increase in OBJF values ranging from 5.726% under low uncertainty conditions to 18.887% under severe uncertainty conditions. Flexible-link maneuvers (FLM) offer advantages such as improved safety and increased operating speeds in real-world applications. In this study, we investigated the impact of joint flexibility on the performance of the FLM system. Our proposed controller demonstrated superior tracking performance, characterized by minimal vibrations in the movement of the end effector.

Optimization of PID trajectory tracking controller for a 3-DOF robotic manipulator using enhanced Artificial Bee Colony algorithm.

This study introduces and compares two optimization techniques, the basic Artificial Bee Colony (ABC) and the enhanced Artificial Bee Colony with multi-elite guidance (MGABC), for determining optimal gains of a Proportional-Integral-Derivative (PID) controller in a 3 degrees of freedom (DOF) rigid link manipulator (RLM) system. The objective function used in the optimization process is a novel function that is based on the well-known Lyapunov stability functions. This function is evaluated against established error-based objective functions commonly used in control systems. The convergence curves of the optimization process demonstrate that the MGABC algorithm outperforms the basic ABC algorithm by effectively exploring the search space and avoiding local optima. The evaluation of the controller's performance in trajectory tracking reveals the superiority of the Lyapunov-based objective function (LBF), with significant improvements over other objective functions such as IAE, ISE, ITAE, MAE and MRSE. The optimized system demonstrates robustness to diverse disturbance conditions and uncertainty in the mass of the payload, while also exhibiting adaptability to joints flexibility without inducing any vibrations in the movement of the end-effector. The proposed techniques and objective function offer promising avenues for the optimization of PID controllers in various robotic applications.

Does elective orthopaedic surgery in pandemic era increase risk of developing COVID-19? A combined analysis of retrospective and prospective study at Cipto Mangunkusumo Hospital, Jakarta, Indonesia.

BACKGROUND: To date, no recommendations have been published on when and how to start again carrying out elective, non-urgent surgery on COVID-19-negative patients after the epidemic peak has been reached in a given country or region and the pressure on healthcare facilities, healthcare workers and resources has been released by so far that elective surgery procedures can be safely and ethically programmed again. This study aims to investigate whether elective orthopaedic surgery will increase the risk of developing COVID-19. MATERIALS AND METHODS: This was a combined retrospective and prospective studies performed at a national tertiary hospital in Jakarta, Indonesia. Subjects were patients who underwent elective orthopaedic surgeries at our institution from April to May 2020. Those who were previously infected with COVID-19 from polymerase chain reaction (PCR) reverse transcriptase (RT) examination obtained via nasopharynx and oropharynx swab, as well as those who were reluctant to participate were excluded from the study. RESULTS: A total of 35 subjects (mean age 32.89 ± 17.42) were recruited. Fifteen (42.9%) subjects were male, and 20 subjects (57.1%) were female. Mean duration of surgery was 240 min with the longest and shortest duration of 690 and 40 min, respectively. General anaesthesia was performed in the majority of cases in 18 surgeries (51.4%) with local anaesthesia as the least in 2 surgeries (5.7%). Length of stay of our study was 6 days of average. None of the patients developed symptoms suggestive of COVID-19 infection. CONCLUSION: We found that elective orthopaedic surgery may not be associated with increased cases of COVID-19 cases. However, our study was limited by short duration of follow-up. Further studies are required in order to investigate the affect of undergoing elective surgery and the number of COVID-19 cases.

Palliative Short-course Radiotherapy in Advanced Pelvic Cancer: A Phase II Study (SHARON Project).

AIM: To define safety and efficacy of a palliative, short-course accelerated radiation therapy for symptomatic locally advanced primary pelvic cancer. MATERIALS AND METHODS: A phase II trial was planned based on the minimax Simon's two-stage design. A total of 18 Gy in 4.5 Gy/fraction administered twice a day was delivered (SHARON). Pain and quality of life were recorded according to the Visual Analogue self-assessment and the cancer linear analog scales (CLAS), respectively. RESULTS: Twenty-five patients were enrolled in the study. The most frequent baseline symptoms were pain (48%), bleeding (40%), bleeding/pain (8%), and intestinal sub-occlusion (4%). The overall palliative response rate was 96.0%, with a median palliative duration of 6 months. An improvement of quality-of-life indices (well-being, fatigue, and ability to perform daily activities) was noted in 64.0%, 36.0%, and 48.0% of patients, respectively. CONCLUSION: The SHARON regimen was well tolerated and effective in the palliative treatment of patients with locally advanced pelvic cancer. Based on these results, a multicentric prospective phase III trial is ongoing to compare this regimen with traditional 2-week radiotherapy treatment.

Definition of fields margins for the optimized 2D radiotherapy of prostate carcinoma.

Prostate cancer (PCa) is one of the most common malignancies in men both in western and developing countries. Radiotherapy (RT) is an important therapeutic option. New technologies (including 3D, intensity modulated RT, image-guided RT and, volumetric modulated arc therapy) have been introduced in the last few decades with progressive improvement of clinical outcomes. However, in many developing countries, the only treatment option is the traditional two-dimensional (2D) technique based on standard simulation. The guidelines for 2D field definition are still based on expert's opinions. The aim of the present study was to propose new practical guidelines for 2D fields definition based on 3D simulation in PCa. A total of 20 patients were enrolled. Computed tomography-simulation and pelvic magnetic resonance images were merged to define the prostate volumes. Clinical Target Volume (CTV) was defined using the European Organisation for Research and Treatment of Cancer guidelines in consideration of the four risk categories: Low, intermediate, and high risk with or without seminal vesicles involvement, respectively. Planning Target Volume (PTV) was defined by adding 10 mm to the CTV. For each category, two treatment plans were calculated using a cobalt source or 10 MV photons. Progressive optimization was achieved by evaluating 3D dose distribution. Finally, the optimal distances between field margins and radiological landmarks (bones and rectum with contrast medium) were defined. The results were reported in tabular form. Both field margins (PTV D98% >95%) needed to adequately irradiate all patients and to achieve a similar result in 95% of the enrolled patients are reported. Using a group of patients with PCa and based on a 3D planning analysis, we propose new practical guidelines for PCa 2D-RT based on current criteria for risk category and CTV, and PTV definition.

Wide resection versus curettage with adjuvant therapy for giant cell tumour of bone.

PURPOSE: To determine the association between type of surgery (wide resection versus curettage with adjuvant therapy) and outcome in patients with giant cell tumour (GCT) of bone. METHODS: Records of 30 male and 52 female consecutive patients aged 10 to 62 years who underwent wide resection (n=57) or curettage with adjuvant therapy (n=25) for primary GCT of bone were reviewed. The surgical decision was based on patient age, tumour location, functional demand, and patient preference. The median tumour size was 8.5 cm. Tumours were classified as stage 1 (n=4), stage 2 (n=60), and stage 3 (n=18), and 25%, 68.3%, and 83.3% of them were treated with wide resection, respectively. Functional outcome was assessed using the Musculoskeletal Tumor Society (MSTS) score; the maximum score was 30. RESULTS: The wide resection and curettage with adjuvant therapy groups were comparable in terms of patient age, gender, tumour size, location, symptoms, tumour stage, type of biopsy, and MSTS score. The MSTS score was excellent in 50.2% of patients, good in 38.7% of patients, and fair and poor in the remaining patients. The MSTS score was not associated with tumour stage or type of surgery. Four patients in the wide resection group had metastasis to the lung. They also had lower haemoglobin level (10.6 vs. 12.7 g/dl, p=0.020) and higher percentage of stage-3 tumour (100% vs. 17.9%, p=0.001) but had no recurrence (0% vs. 6.4%, p=0.774), compared with those without metastatsis. All died from massive haemoptysis and respiratory failure. Eight patients died; their haemoglobin level was lower than that of patients who were still living (11.2 vs. 12.7 g/dl, p=0.032). Mortality was associated with metastasis (100% vs 5.2%, p<0.001) but not recurrence or complication. Two patients in each group had recurrence; recurrence was not associated with type of surgery. CONCLUSION: There was no association between type of surgery and tumour recurrence, metastasis, or outcome. Curettage with adjuvant therapy was more commonly performed for stage 1 and 2 tumours, whereas wide resection was more for stage 3 tumours. Metastasis was associated with stage 3 tumour and mortality but not recurrence.

Effect of povidone iodine and hydrogen peroxide on fracture healing: a histomorphometric study on rats.

PURPOSE: To evaluate the effect of povidone iodine and hydrogen peroxide on fracture healing in a rat model. METHODS: The middle section of the right femur of 36 male Sprague Dawley rats was osteotomised with a saw. In the control group (n=9), the wound was irrigated with 100 ml 0.9% saline. In the 10% povidone iodine (n=9), 1% povidone iodine (n=9), and 3% hydrogen peroxide (n=9) groups, the wound was completely soaked with the respective solution for 2 minutes, and then irrigated with 100 ml saline. The osteotomy was fixed with an intramedullary Kirschner wire. Rats were euthanised at week 1, 2, and 5. In each femur, the percentage area of osseous, cartilaginous, and fibrous tissue in the callus was evaluated in 3 slides (one median and 2 paramedian). RESULTS: The control group differed significantly to the other 3 groups (p=0.023 to p<0.001) in weeks 1, 2, and 5, except for the 1% povidone iodine group in terms of percentage of osseous (p=0.349) and fibrous (p=0.999) tissue. The healing process was similar in the 1% povidone iodine group and the control group, whereas healing was impaired in the 10% povidone iodine group and 3% hydrogen peroxide group, as indicated by the lower percentage of osseous tissue, higher percentage of fibrous tissue, and increased percentage of cartilaginous tissue between weeks 2 and 5 (delayed bone healing). CONCLUSION: The 1% povidone iodine solution is recommended as the irrigation adjuvant in fracture surgery.

Noncontingent positive and negative feedback during maximal exercise.

A closed skill, maximal effort on a bicycle ergometer was used to study the effects of noncontingent external feedback on performance, perceived effort, and the subject's assessment of the quality and accuracy of the feedback. The 47 subjects included elite athletes as well as physical education majors. They were asked to perform a series of 5 60-sec. trials of maximal effort, trials which included positive, negative, positive and negative, and no-feedback conditions. Although there were no significant effects on performance for the various feedback conditions, subjects judged the positive feedback favourably and as accurate, but negative feedback was judged unfavourably and considered to be inaccurate. This result is seen as supportive of the 1982 McCarrey, et al. supposition that successful athletes may have less need to internalize attributions of effect.

Informational feedback and self-esteem among male and female athletes.

The self-esteem of male and female competitive athletes was compared after each was provided either positive or negative (verbal) informational feedback on a nonathletic task, a series of single-solution anagrams. Subjects were 50 men and 50 women, aged 18 to 25 years, who were tested on the semantic differential to estimate athletes' self-esteem before and after receiving the informational feedback. Over-all, female athletes responded more strongly to both feedback conditions, with both groups being more influenced by negative rather than by positive feedback.