Adapting of Non-Metallic Cookware for Induction Heating Technology via Thin-Layer Non-Magnetic Conductive Coatings

We analyze the feasibility of heating non-metallic cookware, unappropriate for heating by means of induced currents, with the purpose of extending the applicability range of the current induction heating cooktops. In order to turn materials as glass, ceramic, wood or plastic into suitable for the induction heating technology, we propose the use of thin layers of a metal (not necessarily a ferromagnetic material) which can be deposited on a surface by means of a thin or thick layer technology. For this purpose, the inductive performance of these layers is investigated by means of an analytical electromagnetic model, finite element simulations and experimental measurements. Calculations point out that for a specific induction arrangement working at a fixed frequency, it exists a thickness which maximizes the induction efficiency for each layer material. The suitability of this result is tested by means of a set of samples with copper thin layers whose thicknesses range from one hundred of nanometers to tens of micrometers, which are implemented using a phase vapor deposition (PVD) technology. The obtained induction efficiency and equivalent resistance are compared with those obtained with conventional ferromagnetic materials. As a proof of concept, the inner and outer bottoms of two glass pots are covered with a copper layer of 2µm, and 1.5µm , respectively, and 1 kW is inductively supplied by means of a series resonant inverter, reaching the boiling water conditions

Power factor correction stage and matrix zero voltage switching resonant inverter for domestic induction heating appliances

The technology of flexible cooking surfaces applied to domestic induction heating (IH) appliances offers several advantages that improve the experience of the users, not only because the safety or cleanness, but also due to the fast heating and flexibility. These cooktops have more challenging design requirements because of different mains connections, efficiency requirements, electromagnetic compatibility (EMC) standards, control complexity, and cost. In previous works, the use of a front-end power factor corrector (PFC) rectifier has been proposed to overcome these restrictions. In order to get a cost-effective implementation, this paper proposes the use of a front-end PFC stage and a matrix resonant inverter, which features zero voltage switching (ZVS), to achieve a reduced number of power devices, and get a high performance and reduced power losses in the converter. Finally, an experimental prototype with four outputs of 3.6 kW has been implemented to prove the feasibility of this proposal

Special section on induction heating systems

This special section aims at bringing some of the most recent and interesting ideas in this area by the worldwide research community and at presenting some of the latest advancements and developments in the field of induction heating technology

RF tumor ablation with internally cooled electrodes and saline infusion: what is the optimal location of the saline infusion?

<p>Abstract</p> <p>Background</p> <p>Radiofrequency ablation (RFA) of tumors by means of internally cooled electrodes (ICE) combined with interstitial infusion of saline may improve clinical results. To date, infusion has been conducted through outlets placed on the surface of the cooled electrode. However, the effect of infusion at a distance from the electrode surface is unknown. Our aim was to assess the effect of perfusion distance (PD) on the coagulation geometry and deposited power during RFA using ICE.</p> <p>Methods</p> <p>Experiments were performed on excised bovine livers. Perfusion distance (PD) was defined as the shortest distance between the infusion outlet and the surface of the ICE. We considered three values of PD: 0, 2 and 4 mm. Two sets of experiments were considered: 1) 15 ablations of 10 minutes (n ≥ 4 for each PD), in order to evaluate the effect of PD on volume and diameters of coagulation; and 2) 20 additional ablations of 20 minutes. The effect of PD on deposited power and relative frequency of uncontrolled impedance rises (roll-off) was evaluated using the results from the two sets of experiments (n ≥ 7 for each PD). Comparisons between PD were performed by analysis of variance or Kruskal-Wallis test. Additionally, non-linear regression models were performed to elucidate the best PD in terms of coagulation volume and diameter, and the occurrence of uncontrolled impedance rises.</p> <p>Results</p> <p>The best-fit least square functions were always obtained with quadratic curves where volume and diameters of coagulation were maximum for a PD of 2 mm. A thirty per cent increase in volume coagulation was observed for this PD value compared to other values (<it>P </it>< 0.05). Likewise, the short coagulation diameter was nearly twenty five per cent larger for a 2 mm PD than for 0 mm. Regarding deposited power, the best-fit least square function was obtained by a quadratic curve with a 2 mm PD peak. This matched well with the higher relative frequency of uncontrolled impedance rises for PD of 0 and 4 mm.</p> <p>Conclusion</p> <p>Saline perfusion at around 2 mm from the electrode surface while using an ICE in RFA improves deposition of energy and enlarges coagulation volume.</p

Pancreatic metastases from renal cell carcinoma. Postoperative outcome after surgical treatment in a Spanish multicenter study (PANMEKID)

Background: Renal Cell Carcinoma (RCC) occasionally spreads to the pancreas. The purpose of our study is to evaluate the short and long-term results of a multicenter series in order to determine the effect of surgical treatment on the prognosis of these patients. Methods: Multicenter retrospective study of patients undergoing surgery for RCC pancreatic metastases, from January 2010 to May 2020. Variables related to the primary tumor, demographics, clinical characteristics of metastasis, location in the pancreas, type of pancreatic resection performed and data on short and long-term evolution after pancreatic resection were collected. Results: The study included 116 patients. The mean time between nephrectomy and pancreatic metastases' resection was 87.35 months (ICR: 1.51-332.55). Distal pancreatectomy was the most performed technique employed (50 %). Postoperative morbidity was observed in 60.9 % of cases (Clavien-Dindo greater than IIIa in 14 %). The median follow-up time was 43 months (13-78). Overall survival (OS) rates at 1, 3, and 5 years were 96 %, 88 %, and 83 %, respectively. The disease-free survival (DFS) rate at 1, 3, and 5 years was 73 %, 49 %, and 35 %, respectively. Significant prognostic factors of relapse were a disease free interval of less than 10 years (2.05 [1.13-3.72], p 0.02) and a history of previous extrapancreatic metastasis (2.44 [1.22-4.86], p 0.01). Conclusions: Pancreatic resection if metastatic RCC is found in the pancreas is warranted to achieve higher overall survival and disease-free survival, even if extrapancreatic metastases were previously removed. The existence of intrapancreatic multifocal compromise does not always warrant the performance of a total pancreatectomy in order to improve survival. (C) 2021 The Authors. Published by Elsevier Ltd

A new single-instrument technique for parenchyma division and hemostasis in liver resection: a clinical feasibility study

[EN] The objective of this study was to evaluate the clinical feasibility of a new technique for liver resection based on a radiofrequency-assisted (485 kHz) device that has shown high performance in the animal setting in both transection speed and blood loss per transection area. Eight patients with colorectal hepatic metastasis underwent 11 partial hepatectomies using the proposed technique for both parenchyma division and hemostasis. Main outcome measures were blood loss per transection area and transection speed. No other instruments (including sutures or clips) were used in any of the cases; temporary vascular occlusion performed was not performed. No blood transfusions were required and no mortality or morbidity linked to the hepatic procedure were observed. The median blood loss per transection area and the median transection speed were .79 mL/cm2 (range, .05–7.37 mL/cm2) and 1.28 cm2/min (range, .49–1.87 mL/cm2), respectively. During the follow-up period (range, 4–12 mo) no late complications were detected and postoperative patients were free from hepatic recurrence. The proposed radiofrequency-assisted device was shown to achieve parenchymal division and hemostasis simultaneously, resulting in extremely reduced blood loss.This work was supported completely by a grant for medical research from the Spanish Government (FIS PI080934).Burdío, F.; Grande, L.; Berjano, E.; Martinez-Serrano, M.; Poves, I.; Burdío, JM.; Navarro, A.... (2010). A new single-instrument technique for parenchyma division and hemostasis in liver resection: a clinical feasibility study. American Journal of Surgery. 200(6):75-80. doi:10.1016/j.amjsurg.2010.02.020S7580200

Small ablation zones created previous to saline infusion result in enlargement of the coagulated area during perfusion RF ablation: an ex vivo experimental study

[EN] One of the strategies for enlarging coagulation zone dimensions during RF ablation of liver tumours is to infuse saline solutions into the tissue during ablation. The aim of this study was to evaluate experimentally whether the creation of a small coagulation adjacent to a bipolar RF applicator and prior to perfused RF ablation would allow enlargement of the coagulation zone. Thirty bipolar RF ablations (group A, n = 15; group B, n = 15) were performed in excised bovine livers. Additionally, in group B a monopolar RF application (60 W, 20 s) was performed before bipolar ablation using three small additional electrodes. Electrical parameters and dimensions of the ablation zone were compared between groups. Despite the fact that all three ablation zone diameters were greater in group B, only one of the minor diameters was significantly longer (5.52 +/- 0.66 cm versus 4.87 +/- 0.47 cm). Likewise, volume was significantly bigger in group B(100.26 +/- 24.10 cm(3) versus 79.56 +/- 15.59 cm(3)). There were no differences in the impedance evolution, allowing a relatively high constant power in both groups (around 90 W). The efficacy of delivering energy (expressed as the delivered energy per coagulation volume) was significantly better in group B, showing a lower value (578 J cm(-3) versus 752 J cm(-3)). These results suggest that the creation of small ablation zones prior to saline infusion improves the performance of this perfusion system, and hence the total volume.The authors would like to thank the R+D+i Linguistic Assistance Office at the Universidad Politécnica of Valencia for their help in revising this paper. They also thank the reviewers for their constructive comments. This work was partially supported by the Programa de Promoción de la Investigación Biomédica y en Ciencias de la Salud del Ministerio de Sanidad y Consumo of Spain (PI052498) and by the Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica del Ministerio de Educación y Ciencia of Spain (TEC 2005-04199/TCM).Navarro, AC.; Burdío, F.; Berjano, E.; Güemes, A.; Burdío, JM.; Sousa, R.; Lozano, R.... (2007). Small ablation zones created previous to saline infusion result in enlargement of the coagulated area during perfusion RF ablation: an ex vivo experimental study. Physiological Measurement. 28(6):29-37. https://doi.org/10.1088/0967-3334/28/6/N02S2937286Aubé, C., Schmidt, D., Brieger, J., Schenk, M., Kroeber, S., Vielle, B., … Pereira, P. L. (2006). Influence of NaCl Concentrations on Coagulation, Temperature, and Electrical Conductivity Using a Perfusion Radiofrequency Ablation System: An Ex Vivo Experimental Study. CardioVascular and Interventional Radiology, 30(1), 92-97. doi:10.1007/s00270-006-0091-yBerjano, E. J., Burdío, F., Navarro, A. C., Burdío, J. M., Güemes, A., Aldana, O., … Gregorio, M. A. de. (2006). Improved perfusion system for bipolar radiofrequency ablation of liver: preliminary findings from a computer modeling study. Physiological Measurement, 27(10), N55-N66. doi:10.1088/0967-3334/27/10/n03Boehm, T., Malich, A., Goldberg, S. N., Reichenbach, J. R., Hilger, I., Hauff, P., … Kaiser, W. A. (2002). Radio-frequency Tumor Ablation: Internally Cooled Electrode versus Saline-enhanced Technique in an Aggressive Rabbit Tumor Model. Radiology, 222(3), 805-813. doi:10.1148/radiol.2223010573Bowles, B. J. (2001). Safety and Efficacy of Radiofrequency Thermal Ablation in Advanced Liver Tumors. Archives of Surgery, 136(8), 864. doi:10.1001/archsurg.136.8.864Burdı́o, F., Güemes, A., Burdı́o, J. M., Navarro, A., Sousa, R., Castiella, T., … Lozano, R. (2003). Large hepatic ablation with bipolar saline-enhanced radiofrequency: an experimental study in in vivo porcine liver with a novel approach. Journal of Surgical Research, 110(1), 193-201. doi:10.1016/s0022-4804(02)00091-4Burdío, F., Güemes, A., Burdío, J. M., Navarro, A., Sousa, R., Castiella, T., … Lozano, R. (2003). Bipolar Saline-enhanced Electrode for Radiofrequency Ablation: Results of Experimental Study of in Vivo Porcine Liver. Radiology, 229(2), 447-456. doi:10.1148/radiol.2292020978Burdío, F., Navarro, A., Sousa, R., Burdío, J. M., Güemes, A., Gonzalez, A., … de Gregorio, M. A. (2006). Evolving technology in bipolar perfused radiofrequency ablation: assessment of efficacy, predictability and safety in a pig liver model. European Radiology, 16(8), 1826-1834. doi:10.1007/s00330-005-0131-zCurley, S. A. (2003). Radiofrequency Ablation of Malignant Liver Tumors. Annals of Surgical Oncology, 10(4), 338-347. doi:10.1245/aso.2003.07.017Elias, D., Baton, O., Sideris, L., Matsuhisa, T., Pocard, M., & Lasser, P. (2004). Local Recurrences After Intraoperative Radiofrequency Ablation of Liver Metastases: A Comparative Study with Anatomic and Wedge Resections. Annals of Surgical Oncology, 11(5), 500-505. doi:10.1245/aso.2004.08.019Nahum Goldberg, S., Scott Gazelle, G., Solbiati, L., Rittman, W. J., & Mueller, P. R. (1996). Radiofrequency tissue ablation: Increased lesion diameter with a perfusion electrode. Academic Radiology, 3(8), 636-644. doi:10.1016/s1076-6332(96)80188-7Haemmerich, D., Lee, F. T., Schutt, D. J., Sampson, L. A., Webster, J. G., Fine, J. P., & Mahvi, D. M. (2005). Large-Volume Radiofrequency Ablation of ex Vivo Bovine Liver with Multiple Cooled Cluster Electrodes. Radiology, 234(2), 563-568. doi:10.1148/radiol.2342031122Haemmerich, D., Staelin, T., Tungjitkusolmun, S., Lee, F. T., Mahvi, D. M., & Webster, J. G. (2001). Hepatic bipolar radio-frequency ablation between separated multiprong electrodes. IEEE Transactions on Biomedical Engineering, 48(10), 1145-1152. doi:10.1109/10.951517Haemmerich, D., Wright, A. W., Mahvi, D. M., Lee, F. T., & Webster, J. G. (2003). Hepatic bipolar radiofrequency ablation creates coagulation zones close to blood vessels: A finite element study. Medical and Biological Engineering and Computing, 41(3), 317-323. doi:10.1007/bf02348437Hänsler, J., Neureiter, D., Wasserburger, M., Janka, R., Bernatik, T., Schneider, T., … Strobel, D. (2004). Percutaneous US-guided Radiofrequency Ablation with Perfused Needle Applicators: Improved Survival with the VX2 Tumor Model in Rabbits. Radiology, 230(1), 169-174. doi:10.1148/radiol.2301021136HOEY, M. F., DIXON, C. M., & PAUL, S. (1998). Transurethral Prostate Ablation Using Saline-Liquid Electrode Introduced via Flexible Cystoscope. Journal of Endourology, 12(5), 461-468. doi:10.1089/end.1998.12.461Kettenbach, J., Köstler, W., Rücklinger, E., Gustorff, B., Hüpfl, M., Wolf, F., … Goldberg, S. N. (2003). Percutaneous Saline-Enhanced Radiofrequency Ablation of Unresectable Hepatic Tumors: Initial Experience in 26 Patients. American Journal of Roentgenology, 180(6), 1537-1545. doi:10.2214/ajr.180.6.1801537Lee, J. M., Han, J. K., Kim, S. H., Lee, J. Y., Choi, S. H., & Choi, B. I. (2004). Hepatic bipolar radiofrequency ablation using perfused-cooled electrodes: a comparative study in theex vivobovine liver. The British Journal of Radiology, 77(923), 944-949. doi:10.1259/bjr/67069976Lee, J. M., Han, J. K., Kim, S. H., Sohn, K. L., Choi, S. H., & Choi, B. I. (2004). Bipolar radiofrequency ablation in ex vivo bovine liver with the open-perfused system versus the cooled-wet system. European Radiology, 15(4), 759-764. doi:10.1007/s00330-004-2375-4Livraghi, T., Goldberg, S. 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Industrial electronics for biomedicine: a new cancer treatment using electroporation

This article reviewed the application of IEs to biomedicine, with an emphasis on the practice's potential benefits and necessary collaboration between specialist engineers and medical practitioners. The design of high-voltage generators for electroporation is a challenging task due to the stiff requirements for the voltage amplitude, controllability, isolation, and output impedance. electroporation has been acknowledged as a key tool for cancer treatment that has a growing importance despite the significant challenges that must still be faced, The future of this technology will require the development of versatile generators that overcome all of the current limitations and provide useful tools for research and clinical treatments. To achieve the goal, several IE technologies will play a fundamental role. Research on advanced topologies will be essential, as will be the use of faster and higher-voltage devices, such as those based on silicon carbide and gallium nitride. Advanced control architectures and will be required to accurately control the generator, monitor and optimize the treatment, and guarantee the safety of patients and medical teams. There is a brilliant future for the IEs that are applied to ER.This work was supported by Spain’s Ministry of Economy and Competitiveness and State Research Agency (grant TEC2016-78358-R), the European Regional Development Fund, the Diputación General de Aragón–Fondo Social Europeo (DGA-FSE), the DGA (grant LMP106-18), Centre national de la recherche scientifique, Université Paris-Sud, Gustave ROussy, and L’Agence nationale de la recherche Accompagnement Spécifique des Travaux de Recherches et d’Innovation Défense