Kidney autotransplantation after nephrectomy and work bench surgery as an ultimate approach to nephron-sparing surgery

Kidney autotransplantation (KAT) is the ultimate approach for nephron-sparing surgery. It is a rarely used method in renal tumor surgery today as minimal invasive and open techniques for nephron-sparing surgery improve constantly. In this publication, the complication rate and the long-term functional and oncological outcome at a single center are analyzed.Methods A prospectively constructed database of patients with renal tumors who underwent renal surgery was retrospectively analyzed to identify patients with KAT and describe surgical and oncological outcomes and to obtain long-term follow-up. Data collection included detailed surgical technique, complications (Clavian-Dindo), and hospital stay, as well as functional and oncological outcome and long-term follow-up.Results Between 1976 and 2013, 12 patients (median age 50.5 years) underwent KAT for highly complex renal masses: in five cases for complex renal cell carcinoma (RCC), five cases for complex upper urinary tract carcinoma (UTUC), one case for a renal metastasis, and one case for nephroblastoma. The nephrectomy or nephron-ureterectomy was performed open via a flank or transabdominal. The median surgical time was 360 min (range 270–490 min). Intraoperatively, six cases required blood transfusions (50%). Six patients (50%) developed significant postoperative complications (Clavian-Dindo > 2). In two patients, intermittent hemodialysis for delayed graft function (16.6%) was needed, and in six cases (50%), additional blood transfusions postoperatively were necessary. At discharge from hospital, all patients had functioning grafts. The median hospital stay was 29.5 days (range 18–35). At follow-up (median follow-up of 83.5 ± 40.7 months), six patients had died (50%)—all with functioning grafts (free from hemodialysis). In five cases, recurrence of primary tumor or metastatic disease was recorded. In four cases, the recurrent carcinoma could be resected; in detail, UTUC in three cases and one partial nephrectomy of the autotransplanted kidney was performed. One patient suffered from bone and lung metastasis. Two patients died finally tumor-related. Five patients (41.6%) are presently alive, without evidence of tumor relapse. One patient developed terminal renal failure requiring hemodialysis 105 months after autotransplantation. One additional patient was lost to follow-up; after 69 months, this patient had a functioning kidney and no evidence of disease-recurrence at the last follow-up. A cumulative number of 1424 months without hemodialysis was gained for these 12 patients. In the literature to date, most KAT are performed in benign disease, with minor but frequent complication. Here, we report the largest series of KAT for malignant kidney tumors. The complication rates are similar, compared to the recently reported series for benign indications with an improved graft survival rate. Since KAT requires a complex and challenging surgical approach, it should be performed by experienced kidney transplant surgeons.Conclusion In very complex cases involving renal tumors and multi-morbidity, patients should be counseled well before KAT is considered. At the same time, KAT should not be abandoned in these very rare cases, especially when a nephron-sparing approach is otherwise not feasible. KAT can maintain renal function and quality of life and extend expectancy of life

Beryllium migration in JET ITER-like wall plasmas

JET is used as a test bed for ITER, to investigate beryllium migration which connects the lifetime of first-wall components under erosion with tokamak safety, in relation to long-term fuel retention. The (i) limiter and the (ii) divertor configurations have been studied in JET-ILW (JET with a Be first wall and W divertor), and compared with those for the former JET-C (JET with carbon-based plasma-facing components (PFCs)). (i) For the limiter configuration, the Be gross erosion at the contact point was determined in situ by spectroscopy as between 4% (E-in = 35 eV) and more than 100%, caused by Be self-sputtering (E-in = 200 eV). Chemically assisted physical sputtering via BeD release has been identified to contribute to the effective Be sputtering yield, i.e. at E-in = 75 eV, erosion was enhanced by about 1/3 with respect to the bare physical sputtering case. An effective gross yield of 10% is on average representative for limiter plasma conditions, whereas a factor of 2 difference between the gross erosion and net erosion, determined by post-mortem analysis, was found. The primary impurity source in the limiter configuration in JET-ILW is only 25% higher (in weight) than that for the JET-C case. The main fraction of eroded Be stays within the main chamber. (ii) For the divertor configuration, neutral Be and BeD from physically and chemically assisted physical sputtering by charge exchange neutrals and residual ion flux at the recessed wall enter the plasma, ionize and are transported by scrape-off layer flows towards the inner divertor where significant net deposition takes place. The amount of Be eroded at the first wall (21 g) and the Be amount deposited in the inner divertor (28 g) are in fair agreement, though the balancing is as yet incomplete due to the limited analysis of PFCs. The primary impurity source in the JET-ILW is a factor of 5.3 less in comparison with that for JET-C, resulting in lower divertor material deposition, by more than one order of magnitude. Within the divertor, Be performs far fewer re-erosion and transport steps than C due to an energetic threshold for Be sputtering, and inhibits as a result of this the transport to the divertor floor and the pump duct entrance. The target plates in the JET-ILW inner divertor represent at the strike line a permanent net erosion zone, in contrast to the net deposition zone in JET-C with thick carbon deposits on the CFC (carbon-fibre composite) plates. The Be migration identified is consistent with the observed low long-term fuel retention and dust production with the JET-ILW.EURATOM 63305

Properties of the energy landscape of network models for covalent glasses

We investigate the energy landscape of two dimensional network models for covalent glasses by means of the lid algorithm. For three different particle densities and for a range of network sizes, we exhaustively analyse many configuration space regions enclosing deep-lying energy minima. We extract the local densities of states and of minima, and the number of states and minima accessible below a certain energy barrier, the 'lid'. These quantities show on average a close to exponential growth as a function of their respective arguments. We calculate the configurational entropy for these pockets of states and find that the excess specific heat exhibits a peak at a critical temperature associated with the exponential growth in the local density of states, a feature of the specific heat also observed in real glasses at the glass transition.Comment: RevTeX, 19 pages, 7 figure

CPVMatch - Concentrating photovoltaic modules using advanced technologies and cells for highest efficiencies

This paper presents the project Concentrating Photovoltaic modules using advanced technologies and cells for highest efficiencies (CPVMatch), which is funded from the European Union’s Horizon 2020 research and innovation programme. V multi-junction solar cells and CPV modules. Concerning cells, novel wafer bonded four-junction solar cells made of GaInP/GaAs//GaInAs/Ge are optimized with the target of reaching 48% efficiency under concentration at the end of the project. Moreover, multi-junction solar cell technologies with advanced materials - like ternary IV element mixtures (i.e. SiGeSn) and nanostructured anti-reflective coatings - are investigated. Concerning CPV modules the project focuses on both Fresnel-based and mirror-based technologies with a target efficiency of 40% under high concentrations beyond 800x. Achromatic Fresnel lenses for improved light management without secondary optics are investigated. In addition, smart, mirror-based HCPV modules are developed, which include a new mirror-based design, the integration of high efficiency, low cost DC/DC converters and an intelligent tracking sensor (PSD sensor) at module level. A profound life-cycle and environmental assessment and the development of adapted characterization methods of new multi-junction cells and HCPV modules complete the work plan of CPVMatch

Photoreflectance analysis of a GaInP/GaInAs/Ge multijunction solar cell

We have analyzed the photoreflectance spectra of a GaInP/GaInAs/Ge triple junction solar cell. The spectra reveal signatures from the window layer and middle and top subcells included in the stack. Additional contributions from the multilayer buffer introduced between the mismatched bottom and middle cells have been detected. Franz–Keldysh oscillations (FKOs) dominate the spectra above the fundamental bandgaps of the GaInP and GaInAs absorbers. From the FKO analysis, we have estimated the dominant electric fields within each subcell. In light of these results, photoreflectance is proposed as a useful diagnostic tool for quality assessment of multijunction structures prior to completion of the device or at earlier stages during its processing

Dynamics of erosion and deposition in tokamaks

In recent years, a general qualitative understanding has been reached about the major pathways of material migration in divertor tokamaks. Main chamber wall components have been identified as the major source of material erosion. The eroded material is transported by scrape-off layer flows, in the case of the ion B x del B drift pointing towards the X-point, predominately towards the inner divertor leg, where it is deposited in the form of amorphous layers. On JET, where carbon is the main plasma-facing material, it has been found that the presence of deposited carbon rich layers determines the dynamic characteristics of further re-distribution of carbon, in particular towards remote areas. The transport from the strike point to the deposition location is mainly line-of-sight. The amount of eroded carbon depends on the surface type, with lower rates for the bare CFC and higher rates for deposited layers. The erosion rates in the inner divertor increase non-linearly with increasing ELM energies. (C) 2009 Elsevier B.V. All rights reserved