379 research outputs found

    Malignant Scalp Tumors: Retrospective Analysis of 1000 Patients.

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    Abstract Background: Limited data on large cohort of patients with malignant tumors of the scalp are available in the literature. e aim of this study was to review a large cohort of patients with malignant scalp tumors to determine epidemilogy, tumor characteristics of this region and treatment. Materials and Method: A retrospective review of patients with malignant scalp tumors diagnosed histopathologically between 2005 and 2021 was performed. Demographic features and tumor characteristics were analyzed. Results: A total of 1080 patients (M: F 3,5:1) were treated and followed up for a mean period of 42 months (12-120 months). Age at diagnosis ranged from 12 to 98 years. Most malignant scalp tumors (95,1%) occurred in those 50 years or older and in bald patients (87%). Basal cell carcinomas (59,2%), squamous cell carcinomas (32,2%) and melanomas were the most common histologic types. Incidence was highest on the frontal of temporal region (66,1%). Recurrence was frequently in squamous and basal cell carcinomas but uncommon in melanoma. Conclusions: Tumors of the scalp accounted about 8,01 % of all skin cancers. Tend to be basal and squamous cell carci- nomas, many of which occur in the temporal and frontal region of bald men. e outlook for patients with scalp tumor is positive, although we suggest excision margins of at least 3-4 mm and continued clinical vigilance is warranted given their higher recurrence rates. MLN: Melanom

    A difficult case of necrotizing fasciitis caused by Acinetobacter baumannii

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    This study reports the case of a 55-year-old woman with diabetes with a necrotizing fasciitis of the right lower limb and the perineum, first admitted at the emergency department for septic shock with cardiac arrest, and later transferred to the department of surgery. Microbiological and histopathological examination confirmed the diagnosis of necrotizing fasciitis caused by Acinetobacter baumannii. A broad-spectrum antibiotic therapy was administered and later readjusted according to the results of microbiological culture. Intensive hemodynamic support was required. Wounds were dressed daily with a 3 percent boric acid solution and a silver sulfadiazine-impregnated dressing. An extensive surgical debridement was promptly performed and repeated until complete control of the infection. Wounds were finally covered with split-thickness skin grafts. The infection was overcome 35 days after admission. The graft take was 100%. Postoperative rehabilitation was required because of the functional limitation of lower limb movements. Follow-up at 6 months showed no functional deficit and an acceptable aesthetic result. Necrotizing fasciitis is a life-threatening disorder, especially in patients with diabetes, whose clinical diagnosis may sometimes be challenging. Early recognition and treatment represent the most important factors influencing surviva

    The polyphasic Protocol for the Keloid

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    The occurrence of keloids is a common clinical problem that can cause functional impairment and cosmetic deformities. They are pathological cutaneous scars that occur due to surgery, burns or other traumatic wounds. Keloids are manifestations of a loss of the control mechanism that regulates wound repair (inflammation, neoangiogenesis and synthesis of extracellular matrix). The authors present their polyphasic protocol for the treatment of keloids: it consists of a combination of intralesional excision, steroid injections and dye-laser treatment over a period of four months. In our research, we have selected patients who have been clinically diagnosed to have keloid scars, which have been diagnosed for at least one year (50 patients, from January 2005 to December 2014). Our polyphasic protocol works on the different phases of the scarring process, altered in keloids; the uncontrolled process in keloid scars is kept in check by the combination of surgical and nonsurgical approaches, and is based on the knowledge on wound healing. In all cases the results obtained are satisfactory, with a keloid scar size decrease of at least 75% from the original dimensions and an improvement of the adaptation of the keloid to surrounding skin. The occurrence of keloids is a common clinical problem that can cause functional impairment and cosmetic deformities. They are pathological cutaneous scars that occur due to surgery, burns or other traumatic wounds. Keloids are manifestations of a loss of the control mechanism that regulates wound repair (inflammation, neoangiogenesis and synthesis of extracellular matrix). The authors present their polyphasic protocol for the treatment of keloids: it consists of a combination of intralesional excision, steroid injections and dye-laser treatment over a period of four months. In our research, we have selected patients who have been clinically diagnosed to have keloid scars, which have been diagnosed for at least one year (50 patients, from January 2005 to December 2014). Our polyphasic protocol works on the different phases of the scarring process, altered in keloids; the uncontrolled process in keloid scars is kept in check by the combination of surgical and nonsurgical approaches, and is based on the knowledge on wound healing. In all cases the results obtained are satisfactory, with a keloid scar size decrease of at least 75% from the original dimensions and an improvement of the adaptation of the keloid to surrounding skin

    Overview of the FTU results

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    Since the 2016 IAEA Fusion Energy Conference, FTU operations have been mainly devoted to experiments on runaway electrons and investigations into a tin liquid limiter; other experiments have involved studies of elongated plasmas and dust. The tearing mode onset in the high density regime has been studied by means of the linear resistive code MARS, and the highly collisional regimes have been investigated. New diagnostics, such as a runaway electron imaging spectroscopy system for in-flight runaway studies and a triple Cherenkov probe for the measurement of escaping electrons, have been successfully installed and tested, and new capabilities of the collective Thomson scattering and the laser induced breakdown spectroscopy diagnostics have been explored

    Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

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    Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate

    The role of ETG modes in JET-ILW pedestals with varying levels of power and fuelling

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    We present the results of GENE gyrokinetic calculations based on a series of JET-ITER-like-wall (ILW) type I ELMy H-mode discharges operating with similar experimental inputs but at different levels of power and gas fuelling. We show that turbulence due to electron-temperature-gradient (ETGs) modes produces a significant amount of heat flux in four JET-ILW discharges, and, when combined with neoclassical simulations, is able to reproduce the experimental heat flux for the two low gas pulses. The simulations plausibly reproduce the high-gas heat fluxes as well, although power balance analysis is complicated by short ELM cycles. By independently varying the normalised temperature gradients (omega(T)(e)) and normalised density gradients (omega(ne )) around their experimental values, we demonstrate that it is the ratio of these two quantities eta(e) = omega(Te)/omega(ne) that determines the location of the peak in the ETG growth rate and heat flux spectra. The heat flux increases rapidly as eta(e) increases above the experimental point, suggesting that ETGs limit the temperature gradient in these pulses. When quantities are normalised using the minor radius, only increases in omega(Te) produce appreciable increases in the ETG growth rates, as well as the largest increases in turbulent heat flux which follow scalings similar to that of critical balance theory. However, when the heat flux is normalised to the electron gyro-Bohm heat flux using the temperature gradient scale length L-Te, it follows a linear trend in correspondence with previous work by different authors

    Spectroscopic camera analysis of the roles of molecularly assisted reaction chains during detachment in JET L-mode plasmas

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    The roles of the molecularly assisted ionization (MAI), recombination (MAR) and dissociation (MAD) reaction chains with respect to the purely atomic ionization and recombination processes were studied experimentally during detachment in low-confinement mode (L-mode) plasmas in JET with the help of experimentally inferred divertor plasma and neutral conditions, extracted previously from filtered camera observations of deuterium Balmer emission, and the reaction coefficients provided by the ADAS, AMJUEL and H2VIBR atomic and molecular databases. The direct contribution of MAI and MAR in the outer divertor particle balance was found to be inferior to the electron-atom ionization (EAI) and electron-ion recombination (EIR). Near the outer strike point, a strong atom source due to the D+2-driven MAD was, however, observed to correlate with the onset of detachment at outer strike point temperatures of Te,osp = 0.9-2.0 eV via increased plasma-neutral interactions before the increasing dominance of EIR at Te,osp < 0.9 eV, followed by increasing degree of detachment. The analysis was supported by predictions from EDGE2D-EIRENE simulations which were in qualitative agreement with the experimental observations

    Disruption prediction at JET through deep convolutional neural networks using spatiotemporal information from plasma profiles

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    In view of the future high power nuclear fusion experiments, the early identification of disruptions is a mandatory requirement, and presently the main goal is moving from the disruption mitigation to disruption avoidance and control. In this work, a deep-convolutional neural network (CNN) is proposed to provide early detection of disruptive events at JET. The CNN ability to learn relevant features, avoiding hand-engineered feature extraction, has been exploited to extract the spatiotemporal information from 1D plasma profiles. The model is trained with regularly terminated discharges and automatically selected disruptive phase of disruptions, coming from the recent ITER-like-wall experiments. The prediction performance is evaluated using a set of discharges representative of different operating scenarios, and an in-depth analysis is made to evaluate the performance evolution with respect to the considered experimental conditions. Finally, as real-time triggers and termination schemes are being developed at JET, the proposed model has been tested on a set of recent experiments dedicated to plasma termination for disruption avoidance and mitigation. The CNN model demonstrates very high performance, and the exploitation of 1D plasma profiles as model input allows us to understand the underlying physical phenomena behind the predictor decision

    Comparing pedestal structure in JET-ILW H-mode plasmas with a model for stiff ETG turbulent heat transport

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    A predictive model for the electron temperature profile of the H-mode pedestal is described, and its results are compared with the pedestal structure of JET-ILW plasmas. The model is based on a scaling for the gyro-Bohm normalized, turbulent electron heat flux qe/qe,gB resulting from electron temperature gradient (ETG) turbulence, derived from results of nonlinear gyrokinetic (GK) calculations for the steep gradient region. By using the local temperature gradient scale length L-Te in the normalization, the dependence of q(e)/q(e,g)B on the normalized gradients R/L-Te and R/(Lne) can be represented by a unified scaling with the parameter eta(e) = L-ne/L-Te, to which the linear stability of ETG turbulence is sensitive when the density gradient is sufficiently steep. For a prescribed density profile, the value of R/L-Te determined from this scaling, required to maintain a constant electron heat flux qe across the pedestal, is used to calculate the temperature profile. Reasonable agreement with measurements is found for different cases, the model providing an explanation of the relative widths and shifts of the T-e and n(e) profiles, as well as highlighting the importance of the separatrix boundary conditions. Other cases showing disagreement indicate conditions where other branches of turbulence might dominate.This article is part of a discussion meeting issue "H-mode transition and pedestal studies in fusion plasmas'

    Overview of JET results for optimising ITER operation

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    The JET 2019–2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power in 2019–2020, and tested the technical and procedural preparation for safe operation with tritium. Research along three complementary axes yielded a wealth of new results. Firstly, the JET plasma programme delivered scenarios suitable for high fusion power and alpha particle (α) physics in the coming D–T campaign (DTE2), with record sustained neutron rates, as well as plasmas for clarifying the impact of isotope mass on plasma core, edge and plasma-wall interactions, and for ITER pre-fusion power operation. The efficacy of the newly installed shattered pellet injector for mitigating disruption forces and runaway electrons was demonstrated. Secondly, research on the consequences of long-term exposure to JET-ILW plasma was completed, with emphasis on wall damage and fuel retention, and with analyses of wall materials and dust particles that will help validate assumptions and codes for design and operation of ITER and DEMO. Thirdly, the nuclear technology programme aiming to deliver maximum technological return from operations in D, T and D–T benefited from the highest D–D neutron yield in years, securing results for validating radiation transport and activation codes, and nuclear data for ITER
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