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BACKGROUND: This observational study evaluates retrospectively the long-term outcomes after pleurectomy/decortication for pleural mesothelioma, with and without the resection/reconstruction of diaphragm and pericardium. METHODS: Data from 155 consecutive patients undergoing lung-sparing surgery for epithelial pleural mesothelioma were reviewed. Selection criteria for surgery were cT1-3, cN0-1, good performance status, age 12 months was strongly related to the overall survival (P12 months is predictive of an increased survival when the macroscopic complete resection is achieved.

Stencil-based algorithms are a relevant class of computational kernels in high-performance systems, as they appear in a plethora of fields, from image processing to seismic simulations, from numerical methods to physical modeling. Among the various incarnations of stencil-based computations, Iterative Stencil Loops (ISLs) and Convolutional Neural Networks (CNNs) represent two well-known examples of kernels belonging to the stencil class. Indeed, ISLs apply the same stencil several times until convergence, while CNN layers leverage stencils to extract features from an image. The computationally intensive essence of ISLs, CNNs, and in general stencil-based workloads, requires solutions able to produce efficient implementations in terms of throughput and power efficiency. In this context, FPGAs are ideal candidates for such workloads, as they allow design architectures tailored to the stencil regular computational pattern. Moreover, the ever-growing need for performance enhancement leads FPGA-based architectures to scale to multiple devices to benefit from a distributed acceleration. For this reason, we propose a library of HDL components to effectively compute ISLs and CNNs inference on FPGA, along with a scalable multi-FPGA architecture, based on custom PCB interconnects. Our solution eases the design flow and guarantees both scalability and performance competitive with state-of-the-art works.

Adult, benign, non-iatrogenic bronchoesophageal fistula (BEF) is a rare condition, which is occasionally described in single case reports. Therefore, little is known about its possible causes, presentation and management. A systematic search of the literature in MEDLINE, PubMed Central and EMBASE databases between 1990 and 2020 was carried out to identify all cases of BEF. The initial database search identified 19,452 articles, of which 183 (251 individual patient cases) were included in the final analysis. Main causes of BEF were congenital malformations (97/251, 38.7%) and infections (82/251, 32.7%), while 33/251 (13.1%) fistulae were regarded as idiopathic and 39/251 (15.5%) attributed to other causes. Esophagograpy was the most sensitive method of diagnosis (97.4%) compared with esophagoscopy (78.9%), computed tomography (49.6%) and bronchoscopy (46.0%). Definitive treatment was surgical for 176 patients (70%), endoscopic for 25 (10%) and medical for 37 (14.7%). Compared with congenital BEFs, infective BEFs had shorter median symptom duration and were distributed more proximally over the bronchial tree. Definitive treatment was almost only surgical for congenital BEFs, while infective BEFs were treated also endoscopically (12%) and by medical therapy (38%). Morbidity, treatment failure and recurrence rates were higher for infective BEFs. BEFs are rare. Symptoms are non-specific and a high index of suspicion is necessary for diagnosis. Patients with infective BEF tend to have a more severe clinical picture than those with congenital BEF. Surgery is the main treatment for patients affected by congenital BEF, while infective BEFs may heal conservatively.

In a quest for making FPGA technology more accessible to the software community, Xilinx recently released PYNQ, a framework for Zynq that relies on Python and overlays to ease the integration of functionalities of the programmable logic into applications. In this work we build upon this framework to enable transparent hardware acceleration for scientific computations for Zynq. We do so by providing a custom NumPy library designed for PYNQ, as it is the de-facto scientific library for Python. We then demonstrate the effectiveness of the proposed approach on a biomedical use case involving the extraction of features from the Electroencephalography (EEG).

A greenhouse pot experiment was conducted to evaluate the effect of biochar on the growth and uptake of Pb and Zn by tomato plants (Solanum lycopersicum, L.) cultivated in two highly contaminated Kosovo soils, A and B. Plants were cultivated in the biochar amended and unamended soils. As expected, the biochar addition to the two polluted soils has contributed to significantly improve the crop yields, in terms of both fresh and dry weight. Further, results indicated that the effect of biochar on metal mobility is closely related, besides its properties, to soil's native characteristics. In fact, the addition of biochar to soil B had also beneficial effects on the uptake of both metals, halving in some cases the values of the biological accumulation and transfer coefficients, while it did not show the same efficacy on soil A.

Background This group previously reported on the repair of a wide tracheoesophageal fistula with a bioabsorbable patch. The current study describes a consecutive series of patients operated on using the same technique. Methods Data of patients undergoing surgical closure of tracheoesophageal fistula at a single center from 2011 to 2018 were extracted and analyzed. Results An absorbable patch was used in 8 of 23 patients (34.8%) operated on for tracheoesophageal fistula during the study period. Causes of the fistulae included postintubation injury (n = 6), mediastinal radiotherapy (n = 1), and a complication of lung resection (n = 1). The median fistula size was 27.5 mm (range, 15 to 45 mm). In 3 patients, the surgical approach was through cervicotomy and in 5 it was through right thoracotomy. Prosthetic materials consisted of Gore Bio-A (W.L. Gore & Associates, Inc, Newark, DE) tissue reinforcement in 6 patients and polyglactin 910 knitted mesh in 2 patients. In every case, the prosthesis was covered with a pedicled muscle flap. The esophageal defect was treated by primary closure in 7 patients and by esophageal exclusion in 1. Fistula recurrence and postoperative death occurred in 1 patient (12.5%), whereas 7 patients experienced postoperative complications (87.5%). Five patients resumed oral intake, and 3 breathed without a tracheal appliance. Compared with the other patients, in those who underwent repair of their fistula using a prosthesis, the median size of the airway defect was larger, morbidity was greater, and the rate of resumption of oral intake was lower. Conclusions Repair of tracheoesophageal fistulae with synthetic prostheses is feasible and may be effective in complex cases. Further research is needed to identify the ideal prosthetic material.

About 15% of patients with myasthenia gravis are affected by thymoma. Precise tumor staging is necessary to plan the appropriate operation. In early stages, complete surgical resection is the mainstay of treatment. Minimally invasive approaches can be safely performed by highly trained surgeons, and may be preferred in myasthenic patients because they can ensure optimal results from the oncological, neurologic, and surgical point of views, avoiding the complications of open approach. For advanced stage thymoma in myasthenic patients, a careful, multidisciplinary planning of the therapeutic approach must be undertaken, particularly for extended resections involving the lung and great vessels.

A greenhouse pot experiment was conducted to evaluate the effect of biochar on the growth and uptake of Pb and Zn by tomato plants (

Background Chest drainage systems are affected by intra and inter-observer variability and poor sensibility in detecting minimal or apparent air leaks. Objectives Overcome intra and inter-observer variability in detecting air leaks. Methods After surgery, a single apical chest tube was connected to the Drentech™ PalmEVO device and air leaks were checked twice a day by observation of both bubbles-in-the-chamber and digital data. Results On a total of 624 observations, disagreement between digital and traditional systems was recorded in 60(9.6%) cases. In 25(21.4%) patients, a disagreement was recorded. Overall, the digital evaluation influenced clinical management in 13(52%). In 10(40%) patients with temporary discordant features, the presence of high pleural fluid output led to a progressive final concordance. Conclusions Disagreement between traditional and digital systems in checking air leaks is not negligible. Digital systems could give advantages in making an objective assessment of air leaks, standardizing the timing of chest tube removal.

Human activities are negatively affecting ecosystems through the erosion and impoverishment of natural resources. Considering soil, global warming and unsustainable agricultural practices are reducing soil organic matter with consequent loss of fertility. An issue of major concern is also the soil pollution by organic and inorganic compounds affecting soil ability to generate ecosystem services. Polycyclic aromatic hydrocarbons are a large group of pollutants, made of two or more aromatic rings, widespread in the environment, soil included, and extremely toxicity for human and environmental health. Polycyclic aromatic hydrocarbons persistence in soil is an issue great concern that could be effectively faced by microbial remediation techniques.In this work we studied the remediation of pyrene polluted soil through two parallel tests: bioremediation and biostimulatin techniques. The first involves inoculation into soil of exogenous microorganisms, in our case Trichoderma harzianum, whereas the latter was aimed at promoting the degrading ability of endogenous microorganisms. Moreover, in order to sustain microorganisms growth, we incorporated olive husk biochar in the two tested bioremediation systems.Biochar is currently considered an excellent soil conditioner and its incorporation into soil seems to promote PAHs adsorption and to interact positively with soil microorganisms. Biochar is a carbonaceous matrix produced through thermal processing of organic biomasses at high temperature and at very low oxygen partial pressure. Here we converted olive husks, that is a potentially toxic by-product of olive oil extraction, by slow pyrolysis process with the aim of deprived this waste biomass of its noxious characteristics.Soil samples were spiked with 50 ppm of pyrene, biochar was incorporated at a concentration of 13 g·kg–1 d.w. of soil and endogenous microbial growth, T. harzianum growth and microbial pyrene-degradation activity were measured weekly up to 28 days.Pyrene concentration was reduced of approximately 70% in 28 days in both bioaugmentation and biostimulation remediation systems. T. harzianum did not display a distinctive ability in degrading pyrene and partially inhibited the endogenous soil microflora from degrading pyrene. Olive husks biochar application did not limited pyrene bioavailability or neither affected microbial pyrene degrading activity. However, our results underline that olive husks biochar increases T. harzianum growth and stimulates soil endogenous microorganisms.

The effective incidence of cutaneous squamous cell carcinoma of the skin (cSCC) is unknown, in general cSCC is the second most common skin cancer, accounting for 20% of all cutaneous malignancies, with a continuous increase in its frequency (1). The skin of the thorax is a very rare localization for this kind of tumor (1-4). Despite cSCC is a malignant proliferation of keratinizing cells of the epidermis, generally, when the diagnosis is made, early surgical resection with adequate surgical margins is curative in more than 95% of the cases (5). Here we present a very rare case of local recurrence of a huge cSCC involving the anterior chest wall that underwent extensive chest wall resection associated to complex reconstruction by using a combination of synthetic materials and autologous flaps.

Introduction The soluble receptor of urokinase plasminogen activator (suPAR) is an innate immunity/inflammation biomarker predicting cardiovascular (CV) and non-CV events in various conditions, including type 2 diabetic patients on dialysis. However, the relationship between suPAR and clinical outcomes in the hemodialysis population at large has not been tested. Methods We measured plasma suPAR levels (R&D enzyme-linked immunosorbent assay [ELISA]) in 1038 hemodialysis patients with a follow-up of 2.9 years (interquartile range = 1.7−4.2) who were enrolled in the PROGREDIRE study, a cohort study involving 35 dialysis units in 2 regions in Southern Italy. Results suPAR was strongly (P < 0.001) and independently related to female gender (β = −0.160), age (β = 0.216), dialysis vintage (β = 0.264), CV comorbidities (β = 0.105), alkaline phosphatase (β = 0.136), albumin (β = −0.147), and body mass index (BMI; β = 0.174) (all P < 0.006). In fully adjusted analyses, suPAR tertiles predicted the risk of all-cause mortality (third tertile vs. first tertile hazard ratio (HR) = 1.91, 95% confidence interval (CI) = 1.47 – 2.48, P < 0.001), CV mortality (HR = 1.47, 95% CI = 1.03–2.09, P = 0.03), and non-CV mortality (HR = 1.94, 95% CI = 1.28–2.93, P = 0.002); these relationships were not modified by diabetes or other risk factors. suPAR added only modest prognostic risk discrimination and reclassification power for these outcomes to parsimonious models based on simple clinical variables. Conclusion In conclusion, suPAR robustly predicted all-cause and both CV and non-CV mortality in a large unselected hemodialysis population. Intervention studies are needed to definitively test the hypothesis that suPAR is causally implicated in clinical outcomes in this population.

Background: In patients submitted to major pulmonary resection, post-operative length of stay is mainly influenced by duration of air leaks and chest tube removal. The measurement of air leaks largely relies on traditional chest drainage systems which are prone to subjective interpretation. Difficulty in differentiating between active air leaks and bubbles due to a pleural space effect may also lead to tentative drain clamping and prolonged time for chest drain removal. New digital systems allow continuous monitoring of air leaks, identifying subtle leakage that may be not visible during daily patient evaluation. Moreover, an objective assessment of air leaks may lead to a reduced interobserver variability and to an optimized timing of chest tube removal. Methods: This study is a prospective randomized, interventional, multicenter trial designed to compare the electronic chest drainage system (Drentech™ Palm Evo) with the traditional one (Drentech™ Compact) in a cohort of patients undergoing pulmonary lobectomy through a standard 3-ports VATS approach both for benign or malignant disease. It will enroll 382 patients in 3 Italian centers. Duration of chest drainage and length of hospital stay will be evaluated in the two groups. Moreover, it will be evaluated if the use of a digital chest system compared with a traditional system reduces theinterobserver variability. Finally, it will be evaluated if the digital drain system may help in distinguishing an active air leak from a pleural space effect, by the digital assessment of intrapleural differential pressure, and in identifying potential predictors of prolonged air leaks. Discussion : To date, few studies have been performed to evaluate clinical impact of digital drainage systems. The proposed prospective randomized trial will provide new knowledge to this research area by investigating and comparing the difference between digital and traditional chest drain systems. In particular, the objectives of this project are to evaluate the feasibility and usefulness of digital chest drainages and to provide new tools to identify patients at higher risk of developing prolonged air leaks.

Background/Aims: Fabry disease (FD) is a lysosomal storage disorder characterized by pervasive renal involvement. However, this disease is underdiagnosed in patient with chronic kidney disease (CKD), including those with end stage renal disease (ESRD), so their investigation represents an unexploited opportunity for early diagnosis of the disease and for its identification in relatives of affected patients. Methods: We investigated Fabry disease in a clinical and biological database including ESRD patients of unknown cause in a geographical area with 2 million residents. The study was based on state of art GLA gene sequencing and was extended to relatives of affected ESRD patients. Results: Among ESRD patients qualified for enrollment into this study, a previously undiagnosed young man harboring the mutation p.I91T was identified. The study of the proband's family led to the identification of 8 additional cases. In another ESRD male patient, we identified the functional polymorphism p.D313Y. Furthermore, in 55 ESRD patients (24.2%) we found intronic polymorphisms of uncertain functional relevance in the non-coding regions of the GLA gene. Conclusion: A comprehensive survey of ESRD patients in a geographical area of 2 million residents identified one undiagnosed case of Fabry disease and led to the identification of 8 additional cases among his relatives. Screening protocols starting from the dialysis population and upstream extended to families of affected individuals may be an effective strategy to maximize the early identification of subjects with Fabry disease.

Background In patients submitted to major pulmonary resection, post-operative length of stay is mainly influenced by duration of air leaks and chest tube removal. The measurement of air leaks largely relies on traditional chest drainage systems which are prone to subjective interpretation. Difficulty to differentiate between active air leaks and bubbles due to a pleural space effect may also lead to tentative drain clamping and prolonged time for chest drain removal. New digital systems allow continuous monitoring of air leaks, identifying subtle leakage that may be not visible during daily patient evaluation. Moreover, an objective assessment of air leaks may lead to a reduced interobserver variability and to an optimized timing of chest tube removal. Methods This study is a prospective randomized, interventional, multicenter trial designed to compare the electronic chest drainage system (Drentech™ Palm Evo) with the traditional system (Drentech™ Compact) in a cohort of patients undergoing pulmonary lobectomy through a standard 3-ports VATS approach for benign or malignant disease. It will enroll 382 patients in 3 Italian centers. Duration of chest drainage and length of hospital stay will be evaluated in the two groups. Moreover, it will be evaluated if the use of a digital chest system compared with a traditional system reduces the interobserver variability. Finally, it will be evaluated the possible advantages of the digital drain system to distinguish an active air leak from a pleural space effect, by the evaluation of intrapleural differential pressure, and to identify potential predictors of prolonged air leaks. Discussion To date few studies have been performed to evaluate clinical impact of digital drainage systems. The proposed prospective randomized trial will provide new knowledge to this research area by investigating and comparing the difference between digital and traditional chest drain systems. In particular, the objectives of this project are to evaluate the feasibility and usefulness of utilizing the digital chest drain and to provide new tools to identify patients at higher risk of developing prolonged air leaks. Trial registration number NCT03536130, Registered 24 May 2018 - Retrospectively registered, https://clinicaltrials.gov/ct2/results?cond=&term=NCT03536130&cntry=&state=&city=&dist=

In high-performance systems, stencil computations play a crucial role as they appear in a variety of different fields of application, ranging from partial differential equation solving, to computer simulation of particles’ interaction, to image processing and computer vision. The computationally intensive nature of those algorithms created the need for solutions to efficiently implement them in order to save both execution time and energy. This, in combination with their regular structure, has justified their widespread study and the proposal of largely different approaches to their optimization. However, most of these works are focused on aggressive compile time optimization, cache locality optimization, and parallelism extraction for the multicore/multiprocessor domain, while fewer works are focused on the exploitation of custom architectures to further exploit the regular structure of Iterative Stencil Loops (ISLs), specifically with the goal of improving power efficiency. This work introduces a methodology to systematically design power-efficient hardware accelerators for the optimal execution of ISL algorithms on Field-programmable Gate Arrays (FPGAs). As part of the methodology, we introduce the notion of Streaming Stencil Time-step (SST), a streaming-based architecture capable of achieving both low resource usage and efficient data reuse thanks to an optimal data buffering strategy, and we introduce a technique called SSTs queuing that is capable of delivering a pseudolinear execution time speedup with constant bandwidth. The methodology has been validated on significant benchmarks on a Virtex-7 FPGA using the Xilinx Vivado suite. Results demonstrate how the efficient usage of the on-chip memory resources realized by an SST allows one to treat problem sizes whose implementation would otherwise not be possible via direct synthesis of the original, unmanipulated code via High-Level Synthesis (HLS). We also show how the SSTs queuing effectively ensures a pseudolinear throughput speedup while consuming constant off-chip bandwidth.

Stencil computations represent a highly recurrent class of algorithms in various high performance computing scenarios. The Streaming Stencil Time-step (SST) architecture is a recent implementation of stencil computations on Field Programmable Gate Array (FPGA). In this paper, we propose an automated framework for SST-based architectures capable of achieving the maximum performance level for a given FPGA device through 1) the maximization of basic modules instantiated in the design and 2) optimization of the design floorplanning. Experimental results show that the proposed approach reduces the design time up to 15× w.r.t. naive design space exploration approaches, and improves the performance of the 13%.

Convolutional Neural Network (CNN) is a deep learning algorithm extended from Artificial Neural Network (ANN) and widely used for image classification and recognition, thanks to its invariance to distortions. The recent rapid growth of applications based on deep learning algorithms, especially in the context of Big Data analytics, has dramatically improved both industrial and academic research and exploration of optimized implementations of CNNs on accelerators such as GPUs, FPGAs and ASICs, as general purpose processors can hardly meet the ever increasing performance and energy-efficiency requirements. FPGAs in particular are one of the most attractive alternative, as they allow the exploitation of the implicit parallelism of the algorithm and the acceleration of the different layers of a CNN with custom optimizations, while retaining extreme flexibility thanks to their reconfigurability. In this work, we propose a methodology to implement CNNs on FPGAs in a modular, scalable way. This is done by exploiting the dataflow pattern of convolutions, using an approach derived from previous work on the acceleration of Iterative Stencil Loops (ISLs), a computational pattern that shares some characteristics with convolutions. Furthermore, this approach allows the imple- mentation of a high-level pipeline between the different network layers, resulting in an increase of the overall performance when the CNN is employed to process batches of multiple images, as it would happen in real-life scenarios.

Since the end of Moore's law is limiting the growth of general purpose processors, High Performance Processing (HPC) systems are considering FPGA-based accelerators as a promising solution for several application fields. However, their employment poses challenges the research is still tackling, and existing tools and workflows do not naturally adapt to the scale and complexity of HPC domains. To help researchers and practitioners, this paper proposes CAOS, a platform that implements an FPGA development workflow tailored to HPC systems while being open to external contributions. Indeed, researchers and developers can plug into CAOS to experiment and compare their solutions at each step of the design flow. This paper describes the CAOS workflow and validates it against several case studies to assess its generality and highlight possible research contributions.

Polycyclic aromatic hydrocarbons (PAHs) are a large group of compounds composed of two or more aromatic rings. They are extremely toxic pollutants largely produced by anthropogenic activities and characterised by high persistence in the environment. Soils contaminated by PAHs could be depolluted by bioremediation techniques, an effective in-situ procedure which provides the addition of exogenous substrates able to sustain and enhance the autochthonous soil microflora and the allochthon microbial inoculum. Our research aims to study the effects of biochar, produced by slow pyrolysis of olive pomace, as a bio-stimulant of soil microflora or support for the colonisation of the allochthon Trichoderma harzianum, on degradation of pyrene used here as model molecule for the PAH family. Biochar is considered an excellent soil conditioner because of its positive effect on soil physical and chemical properties and its positive interaction with soil microorganisms. Autochthonous microbial growth, T. harzianum growth and microbial pyrene-degradation activity were surveyed in soil samples spiked with 50 ppm of pyrene and incubated for up to 28 days. Pyrene concentration was reduced by ~70% in 28 days in both bioaugmentation and biostimulation tests. Olive mill pomace biochar did not interfere with pyrene bioavailability and did not affect microbial pyrene-degrading activity. The T. harzianum did not display a distinctive ability in degrading pyrene and partially inhibited the endogenous soil microflora.

Background— The role of inflammatory markers is not well defined for either diagnosis or treatment of pericarditis. The aim of this study is to prospectively evaluate the frequency of high-sensitivity C-reactive protein (hs-CRP) elevation in patients with acute pericarditis, its time course of normalization, and the possible importance for diagnosis, therapy, and prognosis. Methods and Results— Two hundred consecutive patients with viral or idiopathic acute pericarditis (mean age, 53±15.5 years; 103 men) were studied from August 2005 to August 2007 in 2 Italian referral centers. Hs-CRP was determined at presentation and then every week until normalization. Hs-CRP elevation was recorded in 156 of 200 cases (78%) at presentation. Recognized causes of a negative hs-CRP at presentation were early assessment in 15 of 44 cases (34%) and previous anti-inflammatory therapies in 22 of 44 cases (50%). Hs-CRP normalization was achieved with the following time course: 120 of 200 (60%) at week 1, 170 of 200 (85%) at week 2, 190 of 200 (95%) at week 3, and all cases (100%) at week 4. In multivariable analysis, incomplete response to empirical anti-inflammatory therapy at week 1 (hazard ratio, 2.98; 95% confidence interval, 1.80 to 4.94; P P P =0.004) were independent risk factors for recurrence. Conclusions— Hs-CRP is elevated at the initial presentation in ≈3 of 4 cases of acute pericarditis, identifies patients at higher risk of recurrence, and could be used to monitor disease activity and select appropriate therapy length.

Acquired benign tracheoesophageal fistulas (TEFs) are a challenging condition which most often arises as a result of iatrogenic injury. Most common causes are prolonged intubation and esophageal or laryngeal surgery. Endoscopic intervention with esophageal or tracheal stenting is of unproven benefit in the management of such lesions, whereas surgical repair is almost invariably required. In this paper, the principles of surgical management of TEFs are described, including preoperative preparation, operative techniques and postoperative care.

Thymectomy is the main therapeutic option in the treatment of thymoma. Different surgical techniques have been described, but transternal approach is still considered the gold standard. Anyway, in the last decades, robotic approach has gained attention and nowadays may be considered a standard operation for early stage disease. The improvement of the robotic surgical technique and the introduction of dedicated instruments have allowed challenging resections, thus rendering the robotic approach indicated also for advanced stage thymoma in highly experienced centers.

A positive result for antinuclear antibodies (ANA), often as a fortuitous observation, may be cause for concern in idiopathic recurrent pericarditis (IRP), nevertheless data are lacking on their prevalence and clinical significance. This study is sought to investigate the prevalence and clinical significance of ANA in IRP.ANA titres were assessed in consecutive patients with recurrent pericarditis, and matched healthy controls. Baseline and follow-up data were recorded and compared according to ANA results.A total of 145 consecutive patients with recurrent pericarditis were studied: 122 patients with IRP, 23 patients with pericarditis due to known etiologies (rheumatologic diagnoses and postpericardiotomy syndrome), and 122 healthy controls. ANA were detected in 53 of 122 (43.4%) patients with IRP, and in only 12 of 122 (9.8%) controls (p0.001). Low titres (1/40-1/80) were found in the majority of cases, while moderate positivity (1/160-1/320) was more common in patients with a known rheumatic disease (26.7% vs. 5.7%; p=0.020). High concentrations of ANA (or =1/640) were not recorded. Women were at increased risk for ANA (OR 2.22 95%CI 1.07-4.60; p=0.033). During a mean follow-up of 32 months, complications and new diagnoses were similar in patients with or without ANA positivity.Low-positive titres are more common in patients with IRP than in controls, suggesting a possible autoimmune pathogenesis. Nevertheless, they are often a clinically non-specific finding. Routine serologic testing for ANA suggests a source for recurrent pericarditis in less than 10% of cases, and in these cases other evidence typically suggests the underlying disease.

The present paper introduces a theoretical model in order to describe ground surface anomalies of radon emissions as a volcano is perturbed from its quiescent (steady) state. Based upon modern thermo-poro-elasticity theory which has been found to successfully explain rock deformation-fracturing, these anomalies are considered as being due to the build up of a buried thermo-mechanical source which in turn gives rise to the upsurge of a thermo-mechanical (or T-P) soliton. This sort of fluid solitary wave, travelling upwards through induced deformed–fractured horizons, locally perturbes a pre-existing stationary radon concentration profile as the wave approaches the ground surface. In order to model radon anomalies, a diffusive–convective transport equation of radon is adopted with Darcy's velocity change controlled by the upsurge of the T-P soliton. As a result, a new flow mechanism of radon emission is found, which we call shock wave radon propagation. Some cases of volcanic eruptions which have been preceded and accompanied by anomalies in radon emissions are examined in the light of the model. A reasonably good agreement in the pattern between the observed radon concentration changes and the theoretical curves is found. A theoretical tool for volcanic surveillance is thus proposed, corresponding to both an effort to shed more light on the correlations that may exist between geophysics and geochemistry of fluid emissions and the recognition, through ground surface radon anomalies, of subsurface thermo-mechanical instabilities possibly preceding volcanic eruptions.

SUMMARY In this paper, hot-fluid migration dynamics for a fluid-saturated porous rock is analysed theoretically. We first recall a Bonafede model implemented with a classical scale analysis; this allows us to discuss a fully non-linear formulation related to transient phenomena, which is solved analytically as a solitary shock wave. The resulting time-scales are particularly small, corresponding to intense short-time geothermal phenomena. A novel non-linear migration mechanism, related to Darcy convection, is also discussed.

A nonlinear model of temperature and pressure waves in one-dimensional fluid-saturated porous-permeable rocks is discussed in order to investigate hydrogeological problems affecting hyperthermal areas. Nonlinear solutions, consisting in waves moving with constant velocity V, are analyzed. They behave as perturbations that increase with time till a critical value for vertical pressure gradient is reached, a gradient that is related to the time-asymptotic Darcy velocity. From the geological point of view, the effect of rock fracturing phenomena can be schematized by using some of the solutions of our model, if one postulates that our coefficients depend on the waves vertical pressure gradients. This allows to interpret measurement of the time-evolution of the Darcy velocity, as measured in a superficial position, as a way to reconstruct the porous rock reaction to the temperature-pressure jump carried by these nonlinear waves.