Open-Closed-Loop Iterative Learning Control with the System Correction Term for the Human Soft Tissue Welding Robot in Medicine

By combining manual welders (with intelligence and versatility) and automatic welding systems (with accuracy and consistency), an intelligent welding system for human soft tissue welding can be developed in medicine. This paper presents a data-correction control approach to human welder intelligence, which can be used to control the automated human soft tissue welding process. Human soft tissue welding can preconnect the excised tissue, and the shape of the tissue at the junction ensures the recovery of the operative organ function. This welding technology has the advantages of rapid operation, minimal tissue damage, no need for suture materials, faster recovery of the mechanism and properties of the living tissue, and the maintenance of the function of the organs. Model of the welding system is identified from the data; an open-closed-loop iterative learning control algorithm is then proposed to improve the tracking accuracy of the system. The algorithm uses the tracking error of current and previous to update the control law. Meanwhile, to further improve the accuracy under the conditions of external interference, a system correction term is added to the proposed ILC algorithm, which can be adjusted according to the system’s errors and output and improve the capability of the target tracking greatly. A detailed convergence analysis for the ILC law has been given. Simulation results verify the feasibility and effectiveness of the proposed method for GTAW control tasks.

Expression of IL4Rα and IL13Rα1 Are Associated With Poor Prognosis of Soft-tissue Sarcoma of the Extremities, Superficial Trunk, and Retroperitoneum

BackgroundIL4Rα and IL13Rα1 are constituents of the type II IL4 receptor. Recently, IL4Rα and IL13Rα1 were reported to have roles in cancer progression and suggested as potential prognostic markers. However, studies on IL4Rα and IL13Rα1 in soft-tissue sarcomas have been limited. MethodsThis study investigated the expression of IL4Rα and IL13Rα1 in 89 soft-tissue sarcomas of the extremities, superficial trunk, and retroperitoneum. ResultsIn human soft-tissue sarcomas, immunohistochemical expression of IL4Rα was significantly associated with IL13Rα1 expression. Nuclear and cytoplasmic expression of IL4Rα and IL13Rα1 were significantly associated with shorter survival of soft-tissue sarcoma patients in univariate analysis. Multivariate analysis indicated that nuclear expression of IL4Rα and IL13Rα1 were independent indicators of shorter overall survival (IL4Rα; p = 0.002, IL13Rα1; p = 0.016) and relapse-free survival (IL4Rα; p = 0.022, IL13Rα1; p < 0.001) of soft-tissue sarcoma patients. Moreover, the co-expression pattern of nuclear IL4Rα and IL13Rα1 was an independent indicator of shorter survival of soft-tissue sarcoma patients (overall survival; overall p < 0.001, relapse-free survival; overall p < 0.001). ConclusionsThis study suggests IL4Rα and IL13Rα1 are associated with the progression of soft-tissue sarcoma, and the expression of IL4Rα and IL13Rα1 might be novel prognostic indicators of soft-tissue sarcoma patients.

Investigation of Assembly Forces During Creation of Head-Neck Taper Junction Following Total Hip Arthroplasty: A Biomechanical Study

BackgroundAll current total hip arthroplasty (THA) systems are modular in design. Only during the operation femoral head and stem get connected by a Morse taper junction. The junction is realized by hammer blows from the surgeon. Decisive for the junction strength is the maximum force acting once in direction of the neck axis, which depends both on the applied impulse and the damping of human soft tissues. This leads to large differences in assembly forces between the surgeons. The investigation of assembly forces of different surgeons under influence of soft tissue damping is subject of this study.MethodsFirst, a measuring system, consisting of a prosthesis and a hammer, was developed. Both components are equipped with a piezoelectric force sensor. Initially, in situ experiments on human cadavers were carried out using this system in order to determine the actual assembly forces and to characterize the damping properties of human soft tissue. In addition to these experiments, an in vitro model in form of an artificial femur (Sawbones Europe AB, Malmo, Sweden) with implanted measuring stem embedded in gelatine was developed. The gelatine mixture was chosen in such a way that damping properties of the model correspond to those in situ. A study with 31 surgeons was carried out on the in vitro model mentioned above, in which the assembly forces were determined.ResultsA model has been developed, that represents the physiological damping behaviour of human soft tissue. The assembly forces measured on in vitro model were on average 2037.2 N ± 724.9 N and ranged from 822.5 N to 3835.2 N. The comparison of the surgeons showed no significant differences regarding sex (p=0.09), work experience (p=0.71) and number of THAs per year (p=0.69).ConclusionsAll measured assembly forces were below 4 kN, which is recommended in the literature. This could lead to increased corrosion following fretting in the head-neck interface. In addition, there was a very wide range of assembly forces among the surgeons, although other influencing factors such as different implant sizes or materials were not taken into account. To ensure optimal assembly force, the impaction should be standardized, e.g. by an appropriate surgical instrument.

Development of Silicone Elastomer for Use in the Assessment of Padded Clothing in Rugby Union

Rugby Union is a collision sport, with both player to player and player to pitch impacts being frequent. Current test standards for padded clothing in rugby use impact surrogates, which may not accurately replicate the human response. Modern technologies use silicone elastomers to represent human soft tissue when testing padding, however many commercially available silicones do not match the load response seen by human tissue. This paper describes the fabrication and validation of a bespoke formulation of commercially available silicone elastomer and deadener concentrations that portray a similar load response to relaxed organic muscle tissue. The mechanical responses, both at quasi-static and dynamic strain rates, have been compared, with improved, more representative behaviour being presented. The validation of this silicone elastomer formulation is important in developing a more biofidelic impact surrogate for the assessment of padded clothing in rugby.

Hyperthermia combined with nanoparticles to enhance cytotoxic effects of fresh human soft tissue sarcoma.

e23570 Background: Sarcomas represent 1% of all adult cancers and 20% of all pediatric cancers worldwide.Sarcomas are heterogeneous with more than 50 histologic subtypes involving the mesenchyme including bones, muscle, fat, blood vessels, and nerves. Patients with high-risk localized or advanced disease are treated with the combination of neoadjuvant or adjuvant chemotherapy, radiation, and surgical resection have all failed to substantially improve overall survival (OS).4 Novel treatments are desperately needed in the management of soft tissue sarcoma. Thermal ablation of sarcoma may offer a novel method for eradicating the disease. Polymer based nanoparticles that can be stimulated with light to generate heat (photothermal nanoparticles) have been developed previously and used to induce. The goal of the current work is to utilize these nanoparticles for selected ablation of sarcoma. Methods: Polymer nanoparticles were first prepared in the in our lab through the synthesis of 2‐ethylhexyl cyclopentadithiophene 2,1,3‐benzoselenadiazole (PCPDTBSe). Nanoparticles of this polymer were prepared using an oil-water emulsion technique, with FITC labeled polyethylene glycol as the stabilizing agent, to create an aqueous suspension. The nanoparticles were characterized for their size and ability to generate heat when stimulated with 800 nm laser light (180J/cm2). Fresh Soft tissue sarcoma samples are obtained through informed consent and approval of the institutional IRB. Nanoparticles were injected into sarcoma in a volume of 100ul, at a concentration of 250ug/ml. The tissues were then exposed to the laser source to generate heat. Controls included the injection of the sarcoma with the nanoparticles and no laser exposure, as well as the injection of water, plus laser exposure. Results: Sarcomas vary in their ability to take up and response to nanoparticles. We have found that liposarcoma samples are extremely leaky and do not hold the injection of nanoparticles, which leach out of the tumor. Conclusions: Future directions include studies that would involve targeted, immunotherapy and chemotherapy given with nanoparticles that facilitate combinatory and unique individual cytotoxic effects of the soft tissue sarcoma subtypes.