34 research outputs found

    A Flexible Magnetic Soft Continuum Robot for Manipulation and Measurement at Microscale

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    Magnetic soft continuum robots have received interest in diverse fields, because of their active steering and remote control capabilities. However, a more challenging task is the development of magnetic soft continuum robots for analyzing the mechanical properties of biological tissue during intravascular treatments. Here, we present a force-controlled soft continuum robot with a magnetic end-effector for measurement of biological mechanical properties. The magnetically driven system contains a set of Helmholtz coils and a permanent magnet. The Helmholtz coils produce an oscillating magnetic field for overcoming friction. The permanent magnet is responsible for steering and providing traction for forward motion. The force on the magnetic tip was calibrated with a soft rod with a known elasticity coefficient. Experimental results indicated that the magnetic soft continuum robot successfully achieved manipulation and stiffness measurement of biological embryos. This strategy for mechanical property analysis of biological tissue expands the opportunities for use of soft continuum robots and broadens the field of functionalization for continuum microrobots

    Dynamic Active Constraints for Surgical Robots using Vector Field Inequalities

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    Robotic assistance allows surgeons to perform dexterous and tremor-free procedures, but robotic aid is still underrepresented in procedures with constrained workspaces, such as deep brain neurosurgery and endonasal surgery. In these procedures, surgeons have restricted vision to areas near the surgical tooltips, which increases the risk of unexpected collisions between the shafts of the instruments and their surroundings. In this work, our vector-field-inequalities method is extended to provide dynamic active-constraints to any number of robots and moving objects sharing the same workspace. The method is evaluated with experiments and simulations in which robot tools have to avoid collisions autonomously and in real-time, in a constrained endonasal surgical environment. Simulations show that with our method the combined trajectory error of two robotic systems is optimal. Experiments using a real robotic system show that the method can autonomously prevent collisions between the moving robots themselves and between the robots and the environment. Moreover, the framework is also successfully verified under teleoperation with tool-tissue interactions.Comment: Accepted on T-RO 2019, 19 Page

    Characterisation and State Estimation of Magnetic Soft Continuum Robots

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    Minimally invasive surgery has become more popular as it leads to less bleeding, scarring, pain, and shorter recovery time. However, this has come with counter-intuitive devices and steep surgeon learning curves. Magnetically actuated Soft Continuum Robots (SCR) have the potential to replace these devices, providing high dexterity together with the ability to conform to complex environments and safe human interactions without the cognitive burden for the clinician. Despite considerable progress in the past decade in their development, several challenges still plague SCR hindering their full realisation. This thesis aims at improving magnetically actuated SCR by addressing some of these challenges, such as material characterisation and modelling, and sensing feedback and localisation. Material characterisation for SCR is essential for understanding their behaviour and designing effective modelling and simulation strategies. In this work, the material properties of commonly employed materials in magnetically actuated SCR, such as elastic modulus, hyper-elastic model parameters, and magnetic moment were determined. Additionally, the effect these parameters have on modelling and simulating these devices was investigated. Due to the nature of magnetic actuation, localisation is of utmost importance to ensure accurate control and delivery of functionality. As such, two localisation strategies for magnetically actuated SCR were developed, one capable of estimating the full 6 degrees of freedom (DOFs) pose without any prior pose information, and another capable of accurately tracking the full 6-DOFs in real-time with positional errors lower than 4~mm. These will contribute to the development of autonomous navigation and closed-loop control of magnetically actuated SCR

    Smoking and Second Hand Smoking in Adolescents with Chronic Kidney Disease: A Report from the Chronic Kidney Disease in Children (CKiD) Cohort Study

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    The goal of this study was to determine the prevalence of smoking and second hand smoking [SHS] in adolescents with CKD and their relationship to baseline parameters at enrollment in the CKiD, observational cohort study of 600 children (aged 1-16 yrs) with Schwartz estimated GFR of 30-90 ml/min/1.73m2. 239 adolescents had self-report survey data on smoking and SHS exposure: 21 [9%] subjects had “ever” smoked a cigarette. Among them, 4 were current and 17 were former smokers. Hypertension was more prevalent in those that had “ever” smoked a cigarette (42%) compared to non-smokers (9%), p\u3c0.01. Among 218 non-smokers, 130 (59%) were male, 142 (65%) were Caucasian; 60 (28%) reported SHS exposure compared to 158 (72%) with no exposure. Non-smoker adolescents with SHS exposure were compared to those without SHS exposure. There was no racial, age, or gender differences between both groups. Baseline creatinine, diastolic hypertension, C reactive protein, lipid profile, GFR and hemoglobin were not statistically different. Significantly higher protein to creatinine ratio (0.90 vs. 0.53, p\u3c0.01) was observed in those exposed to SHS compared to those not exposed. Exposed adolescents were heavier than non-exposed adolescents (85th percentile vs. 55th percentile for BMI, p\u3c 0.01). Uncontrolled casual systolic hypertension was twice as prevalent among those exposed to SHS (16%) compared to those not exposed to SHS (7%), though the difference was not statistically significant (p= 0.07). Adjusted multivariate regression analysis [OR (95% CI)] showed that increased protein to creatinine ratio [1.34 (1.03, 1.75)] and higher BMI [1.14 (1.02, 1.29)] were independently associated with exposure to SHS among non-smoker adolescents. These results reveal that among adolescents with CKD, cigarette use is low and SHS is highly prevalent. The association of smoking with hypertension and SHS with increased proteinuria suggests a possible role of these factors in CKD progression and cardiovascular outcomes

    Front Lines of Thoracic Surgery

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    Front Lines of Thoracic Surgery collects up-to-date contributions on some of the most debated topics in today's clinical practice of cardiac, aortic, and general thoracic surgery,and anesthesia as viewed by authors personally involved in their evolution. The strong and genuine enthusiasm of the authors was clearly perceptible in all their contributions and I'm sure that will further stimulate the reader to understand their messages. Moreover, the strict adhesion of the authors' original observations and findings to the evidence base proves that facts are the best guarantee of scientific value. This is not a standard textbook where the whole discipline is organically presented, but authors' contributions are simply listed in their pertaining subclasses of Thoracic Surgery. I'm sure that this original and very promising editorial format which has and free availability at its core further increases this book's value and it will be of interest to healthcare professionals and scientists dedicated to this field

    Bladder Cancer

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    This book is an invaluable source of knowledge on bladder cancer biology, epidemiology, biomarkers, prognostic factors, and clinical presentation and diagnosis. It is also rich with plenty of up-to-date information, in a well-organized and easy to use format, focusing on the treatment of bladder cancer including surgery, chemotherapy, radiation therapy, immunotherapy, and vaccine therapy. These chapters, written by the experts in their fields, include many interesting, demonstrative and colorful pictures, figures, illustrations and tables. Due to its practicality, this book is recommended reading to anyone interested in bladder cancer

    Alternative site for the placement of totally implantable vascular access device (TIVAD). A case report of two successful TIVAD implantations in the thigh after femoral vein catheterization

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    Background: Totally implantable venous access devices (TIVADs) have improved the quality of life for seriously ill and cancer patients. These devices represent a convenient option when long-term venous access is indicated. The Subclavian and Internal Jugular Veins are the vessels of choice for catheterization [1]. However, if it is not possible to catheterize them, an alternative vein should be sought for [2]. Femoral vein can be used in such cases [3].Clinical problem: In 2 cases, it was not possible to catheterise any vein ending in the Superior Vena Cava and implant a TIVAD in the chest wall, although this was very necessary for them. Femoral vein was chosen despite higher risk of complications.Case 1: A 47 years old female with a metastatic breast cancer and infected ulcerations of the anterior chest wall. Veins in both arms were occluded. Her implanted TIVAD could not be used. Case 2: A 44 years old female who had a newly diagnosed lung cancer and Superior Vena Cava Syndrome. She was treated by a high-dose anti-coagulants.Surgical intervention: The catheter was inserted in the left femoral vein using ultrasound-guided percutaneous technique. After making a small incision, PORT-A-CATH® II POWER P.A.C. single-lumen standard port was implanted subcutaneously in the anterior surface of the left thigh. Verification of the catheter’s tip intra-operatively was difficult in Case 1 due to fluoroscopy problems. Prior consideration of the required instruments prevented the occurrence of a similar problem in Case 2. We performed these operations in the University Hospital of Norrland in Sweden in 2013.Follow-up: Apart from later adjustment of the catheter positioning in Case 1, we did not get any complications or problems with the use of the TIVAD. Frequent flushing of the device was recommended. Patients’ and staff’s satisfaction were good. Conclusion: Placement of TIVAD in the thigh is to be considered when the veins of the neck and upper arm are not accessible or the area on the chest wall is not appropriate for implanting the device. Experience improves with more cases.References: 1- Di Carlo I, Toro A. Choice of venous sites. Surgical Implant/technique. Springer-Verlag, Italia, 2011;43-54. 2- Toro A, Mannino M, Cappello G et al. Totally implanted venous access devices implanted in saphenous vein. Relation between the reservoir site and comfort/discomfort of the patient. Ann Vasc Surg 2012;26(8):1127.e9-1127.e13. 3- Chen SY, Lin CH, Chang HM, Hsu HM, Yu JC. A safe and effective method to implant a totally implantable access port in patients with synchronous bilateral mastectomies: modified femoral vein approach. J Surg Oncol 2008;98(3):197-199
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