ablation

摘要： The ablation of ultra-high-temperature ceramics(UTHCs)is a complex physicochemical process including mechanical behavior,temperature effect,and chemical reactions.In order to realize the structural optimization and functional design of ultra-high temperature ceramics,a coupled thermo-chemo-mechanical bond-based peridynamics(PD)model is proposed based on the ZrB2 ceramics oxidation kinetics model and coupled thermomechanical bond-based peridynamics.Compared with the traditional coupled thermo-mechanical model,the proposedmodel considers the influenceof chemical reactionprocessonthe ablation resistanceof ceramicmaterials.In order to verify the reliability of the proposed model,the thermo-mechanical coupling model,damage model and oxidation kinetic model are established respectively to investigate the applicability of the proposedmodel proposed in dealing with thermo-mechanical coupling,crack propagation,and chemical reaction,and the results show that the model is reliable.Finally,the coupled thermo-mechanical model and coupled thermo-chemo-mechanical model are used to simulate the crack propagation process of the plate under the thermal shock load,and the results show that the oxide layer plays a good role in preventing heat transfer and protecting the internal materials.Based on the PD fully coupled thermo-mechanical model,this paper innovatively introduces the oxidation kinetic model to analyze the influence of parameter changes caused by oxide layer growth and chemical growth strain on the thermal protection ability of ceramics.The proposed model provides an effective simulation technology for the structural design of UTHCs.

摘要： There has been a growing interest in developing endoscopic ultrasound(EUS)-guided interventions for pancreatic cancer,some of which have become standard of care.There are two main factors that drive these advancements to facilitate treatment of patients with pancreatic cancer,ranging from direct locoregional therapy to palliation of symptoms related to inoperable pancreatic cancer.Firstly,an upper EUS has the capability to access the entire pancreas–lesions in the pancreatic head and uncinate process can be accessed from the duodenum,and lesions in the pancreatic body and tail can be accessed from the stomach.Secondly,there has been a robust development of devices that allow through-theneedle interventions,such as placement of fiducial markers,brachytherapy,intratumoral injection,gastroenterostomy creation,and ablation.While these techniques are rapidly emerging,data from a multicenter randomized controlled trial for some procedures are awaited prior to their adoption in clinical settings.

摘要： Hepatocellular carcinoma(HCC)is the most common cause of liver malignancy and the fourth leading cause of cancer deaths universally.Cure can be achieved for early stage HCC,which is defined as 3 or fewer lesions less than or equal to 3 cm in the setting of Child-Pugh A or B and an ECOG of 0.Patients outside of these criteria who can be down-staged with loco-regional therapies to resection or liver transplantation(LT)also achieve curative outcomes.Traditionally,surgical resection,LT,and ablation are considered curative therapies for early HCC.However,results from recently conducted LEGACY study and DOSISPHERE trial demonstrate that transarterial radio-embolization has curative outcomes for early HCC,leading to its recent incorporation into the Barcelona clinic liver criteria guidelines for early HCC.This review is based on current evidence for curativeintent loco-regional therapies including radioembolization for early-stage HCC.

摘要： The management of hepatocellular carcinoma(HCC)is challenging because most patients have underlying cirrhosis,and the treatment provides,historically,a limited impact on the natural history of patients with advanced-stage disease.Additionally,recurrence rates are high for those patients who receive local and locoregional modalities,such as surgical(resection and transplantation)or imageguided(ablation and intra-arterial)therapies.Translational research has led to new concepts that are reshaping the current clinical practice.Substantial advancements were achieved in the understanding of the hallmarks that drive hepatocarcinogenesis.This has primed a successful incorporation of novel agents with different targets,such as anti-angiogenic drugs,targeted-therapies,and immune-checkpoint inhibitors.Although clinical trials have proven efficacy of systemic agents in advanced stage disease,there is no conclusive evidence to support their use in combination with loco-regional therapy.While novel local modalities are being incorporated(e.g.,radioembolization,microwave ablation,and irreversible electroporation),emerging data indicate that locoregional treatments may induce tumor microenvironment changes,such as hyperexpression of growth factors,release of tumor antigens,infiltration of cytotoxic lymphocytes,and modulation of adaptative and innate immune response.Past trials that evaluated the use of antiangiogenic drugs in the adjuvant setting after ablation or chemoembolization fail to demonstrate a substantial improvement.Current efforts are directed to investigate the role of immunotherapy-based regimens in this context.The present review aims to describe the current landscape of systemic and locoregional treatments for HCC,present evidence to support combination approaches,and address future perspectives.

摘要： This study numerically simulated and investigated the flow field characteristics of a typical dual-pulse solid rocket motor with a soft pulse separation device through thermal insulation ablation under high-temperature dual-pulse erosion.The ablation rate of ethylene-propylene-diene monomer(EPDM)insulator was measured after the experiment.Experimental results were analyzed through scanning electron microscopy and microcomputed tomography.The ablation mechanism of the EPDM insulator under the operation conditions of a dual-pulse solid rocket motor was evaluated by analyzing the results.The results reveal that the internal flow field of the motor with a soft pulse separation device is uniform.The original charred layer existing on the EPDM insulator surface in the first pulse combustor is the decisive factor affecting the final ablation rate of the dual-pulse motor during the second pulse operation,and the ablation characteristic region is easily formed with the exfoliation of the charred layer.The ablation rate difference of the insulator increases with gas velocity.

摘要： To the Editor:In recent decades,local ablative therapies have evolved considerably and played an increasingly important role in the treatment of inoperable tumors.Conventional modalities are mainly based on thermal ablation to destroy targeted lesions,such as radiofrequency ablation[1].The clinical application of pulsed electric fields[2]is emerging as an innovative and promising technique for tumor ablation,which does not depend on heat energy and preserves surrounding tissues adjacent to tumors[3].Highvoltage ultrashort electric pulses compromise the integrity of the plasma membrane and destroy intracellular homeostasis.Nanosecond pulsed electric fields(nsPEFs),with a strength of several tens of kV/cm and a nanosecond duration,have attracted much attention and been extensively studied in cancer ablation[4,5].

摘要： The new coronavirus disease 2019 (COVID-19) pandemic has resulted in a globalhealth emergency that has also caused profound changes in the treatment ofcancer. The management of hepatocellular carcinoma (HCC) across the world hasbeen modified according to the scarcity of care resources that have been divertedmostly to face the surge of hospitalized COVID-19 patients. Oncological andhepatobiliary societies have drafted recommendations regarding the adaptation ofguidelines for the management of HCC to the current healthcare situation. Thisreview focuses on specific recommendations for the surgical treatment of HCC (i.e., hepatic resection and liver transplantation), which still represents the bestchance of cure for patients with very early and early HCC. While surgery shouldbe pursued for very selected patients in institutions where standards of care aremaintained, alternative or bridging methods, mostly thermoablation and transarterialtherapies, can be used until surgery can be performed. The prognosis ofpatients with HCC largely depends on both the characteristics of the tumour andthe stage of underlying liver disease. Risk stratification plays a pivotal role indetermining the most appropriate treatment for each case and needs to balancethe chance of cure and the risk of COVID-19 infection during hospitalization.Current recommendations have been critically reviewed to provide a reference forbest practices in the clinical setting, with adaptation based on pandemic trendsand categorization according to COVID-19 prevalence.

摘要： Cholangiocarcinoma and pancreatic cancer are the most common causes of malignant biliary obstruction.The majority of patients are diagnosed at a late stage when surgical resection is rarely possible.In these cases,palliative chemotherapy and radiotherapy provide only limited benefit and are associated with poor survival.Radiofrequency ablation(RFA)is a procedure for locoregional control of tumours,whereby a high-frequency alternating current turned into thermal energy causes coagulative necrosis of the tissue surrounding the catheter.The subsequent release of debris and tumour antigens by necrotic cells can stimulate local and systemic immunity.The development of endoluminal RFA catheters has led to the emergence of endoscopically delivered RFA,a treatment mainly used for malignant biliary strictures to prolong survival and/or stent patency.Other indications include recanalisation of occluded biliary stents and treatment of intraductal ampullary adenoma or benign biliary strictures.This article presents a comprehensive review of endobiliary RFA,mainly focusing on its use in patients with malignant biliary obstruction.The available data suggest that biliary RFA may be a promising modality,having positive impacts on survival and stent patency and boasting a reasonable safety profile.However,further studies with better characterised and stratified patient populations are needed before the method becomes accepted within routine clinical practice.

摘要： Secondary cancers of the liver are more than twenty times more common than primary tumors and are incurable in most cases.While surgical resection and systemic chemotherapy are often the first-line therapy for metastatic liver disease,a majority of patients present with bilobar disease not amenable to curative local resection.Furthermore,by the time metastasis to the liver has developed,many tumors demonstrate a degree of resistance to systemic chemotherapy.Fortunately,catheter-directed and percutaneous locoregional approaches have evolved as major treatment modalities for unresectable metastatic disease.These novel techniques can be used for diverse applications ranging from curative intent for small localized tumors,downstaging of large tumors for resection,or locoregional control and palliation of advanced disease.Their use has been associated with increased tumor response,increased disease-free and overall survival,and decreased morbidity and mortality in a broad range of metastatic disease.This review explores recent advances in liver-directed therapies for metastatic liver disease from primary colorectal,neuroendocrine,breast,and lung cancer,as well as uveal melanoma,cholangiocarcinoma,and sarcoma.Therapies discussed include bland transarterial embolization,chemoembolization,radioembolization,and ablative therapies,with a focus on current treatment approaches,outcomes of locoregional therapy,and future directions in each type of metastatic disease.

摘要： Pancreatic cancer is the 7th leading cause of death due to cancer in industrializedcountries and the 11th most common cancer globally, with 458918 new cases (2.5%of all cancers) and 432242 deaths (4.5% of all cancer deaths) in 2018. Unfortunately,80% to 90% of the patients present with unresectable disease, and thereported 5-year survival rate range between 10% and 25%, even after successfulresection with tumor-free margins. Systemic chemotherapy, radiotherapy, andminimally invasive image-guided procedures that have emerged over the pastyears, are used for the management of non-operable PC. This review focuses oncurrently available non-surgical options of locally advanced pancreatic cancer.