Radiotherapy in the multimodal treatment of esophageal carcinoma. A review

BACKGROUND: The curative potential of exclusively applied surgery or radiotherapy on esophageal carcinoma is exhausted. The 5-year survival rate of surgically treated esophageal carcinoma is stagnant at 20 to 30%, that for radiotherapeutically treated esophageal carcinoma at < or = 10%. The unchanged bad prognoses motivate the search for multimodal therapeutical concepts in order to improve the results of basic therapies. METHOD, RESULTS AND CONCLUSIONS: While neither perioperative radiotherapy nor perioperative chemotherapy were able to improve the treatment results significantly, a progress in the field of primary and preoperative radiochemotherapy emerges. On locally restricted tumors the latest findings show that a simultaneous radiochemotherapy with Cisplatin is more effective than radiotherapy alone. 20 to 30% histologically verified complete remissions can be reached through preoperative radiochemotherapy. These results will influence future treatment concepts. Brachytherapy can be taken into consideration in highly palliative situations as exclusive method of treatment or for support of laser treatment or bouginage for removal of stenosis. As the number of clinically controlled studies is not sufficient the importance of the brachytherapy boost for potentially curative intentions is not yet clear. Up to now the intraluminal hyperthermia is a underestimated method for improving the results of radiotherapy. Our overview summarizes all presently published randomized studies and relevant phase I/II-studies.     

Expression of nerve-regulated genes in muscles of mouse mutants affected by spinal muscular atrophies and muscular dystrophies

OBJECTIVE: Mature lobar transplantation will increase the pediatric donor organ pool, but it remains unknown whether such grafts will grow in a developing recipient and provide adequate long-term support. We hypothesized that a mature pulmonary lobar allograft implanted in an immature recipient would grow. METHODS: We investigated our hypothesis in a porcine orthotopic left lung transplant model using animals matched by the major histocompatibility complex to minimize the effects of chronic rejection. Twenty-three immature animals (< 12 weeks of age and < 10 kg total body weight) received either sham left thoracotomy (SH control, n = 4), left upper lobectomy to study compensatory growth (UL control, n = 4), age-matched immature whole left lung transplants (IWL TXP, n = 6), mature (donor > 1 yr in age and > 40 kg in total body weight) left lower lobe transplants (MLL TXP, n = 5), or mature left upper lobe transplants (MUL TXP, n = 4). Twelve weeks after implantation, functional residual capacity of the left lung was measured and arterial blood gas samples were obtained after the native right lung had been excluded. The graft was excised and weighed, and samples for microscopy and wet/dry ratios were collected. RESULTS: Initial and final graft weights were as follows: IWL TXP group (34.6 +/- 1.5 and 107.8 +/- 5.9 gm, p < 0.0001), MLL TXP group (72.4 +/- 6.8 and 111.4 +/- 8.7, p < 0.001), and MUL TXP group (32.8 +/- 1.3 and 92.8 +/- 7.1 gm, respectively, p < 0.004). No significant differences between groups were demonstrated when functional residual capacity, wet/dry ratios, or oxygenation were compared. Immunohistochemical staining for the nuclear antigen Ki-67 demonstrated dividing pneumocytes. CONCLUSIONS: We conclude that a mature lobar graft implanted into an immature recipient grows by pneumocyte division in this model. Mature lobar transplants can be expected to grow and provide adequate long-term function in developing recipients.     

Coalescence Behaviour of Two Metallic Particles as Base Mechanism of Selective Laser Sintering

In many R&D places, the process of Selective Laser Sintering (SLS) of high performance metals is subject of investigations. An observation often made in SLS of metals is, that certain materials show a proper bonding behaviour while others tend to form welding pearls («balling» effect). This paper aims to identify and explain process mechanisms related to this effect. The dominating physical mechanisms are investigated. In addition, it is described which material properties mainly affect the results. The attained insights are transferred to the conditions of SLS in a powder bed layer by process modelling and experimental testing.     

Thermally stable current-collecting silver grid coated with ceramic-capping layer for low-temperature solid oxide fuel cells

In an effort to decrease the operating temperature of solid oxide fuel cells (SOFCs), nano-porous thin Pt layers have been used as a cathode material with catalytic activity. Because of porous and thin characteristic of the Pt cathode, however, a large cathode area results in a significant performance deterioration because of the increased sheet resistance of the Pt cathode. In this study, we developed a Ag-patterned grid as a current-collecting layer and a samaria-doped ceria (SDC) oxide-capping layer on the porous Pt cathode to decrease sheet resistance and enhance electrochemical performance. Enhanced electron transportation and thermo-stable behavior of fabricated fuel cells indicated three-fold enhanced peak power density and more than two-fold thermomechanical stability, as per scanning electron microscopy (SEM) and electrochemical analysis results.     

Synthesis of Si–C–O Bulk Ceramics with Various Chemical Compositions from Polycarbosilane

Si-C-O bulk ceramics with various atomic ratios were produced by pyrolysis and high-temperature treatment (HTT) of a polycarbosilane (PCS) precursor with a given amount of oxygen. The oxygen introduction within the PCS molecular structure makes the compact infusible during the pyrolysis step, and supports sintering. The derived chemical compositions are mapped on a Si-C-O constitution diagram, with their transition behaviors due to HTT described. Upon heating between 1500° and 1700°C, the chemical compositions of the as-pyrolyzed specimens were as follows: PCS-6 (SiC_1.36O_0.26), PCS-8 (SiC_1.25O_0.45), and PCS-10 (SiC_1.02O_0.68), moving toward C/Si = 1.2, 1.0, and 0.8 with a reduction of the oxygen content, respectively. It is also shown that there are influences of the initial oxygen content on the resulting microstructure of both as-pyrolyzed and heat-treated specimens.     

Innovative TPV two-phase polymers: Formulation,morphology formation,property profiles and processing characteristics

An innovative TPV two-phase polymeric system is described. The new TPV is composed of a polypropylene (PP) matrix in which a metallocene-type ethylene/octene copolymer (EO) is dispersed. The EO-copolymers are grafted with vinyl organosilanes, then blended with PP, hydrolyzed and water-crosslinked in a co-rotating, intermeshing twin-screw extruder. The resulting TPV-grades are easy to process into articles showing an attractive range of properties. The advantages are due to blend composition and crosslinking concept. The new TPV's can be-processed without pre-drying. Molding are characterized by excellent surface quality and absence of odor as a result of the innovative use of the EO elastomer and the modified crosslinking concept. They can easily be colored to any desirableshade. The reduced cost of ingredients is another advantage of the newly developed thermoplastic elastomers. High ultimate strength (σ_R) and elongation-at-break (ε_R) values as well as a broad spectrum of different Shore A grades open up many new fields of application. The main focus has been on the automotive applications not least because of very low fogging rates.     

Photocatalyzed oxidation in zeolite cages

A new concept of room temperature selective oxidation of olefins, alkyl substituted benzenes and alkanes by electron transfer from the hydrocarbon to the oxygen molecule induced by irradiation with visible light is shown. The hydrocarbon radical cation–O₂ charge-transfer pair is generated inside the cavities of alkali or alkaline-earth ion-exchanged zeolites, in which the large electrostatic field stabilizes the highly polar charge-transfer states of hydrocarbon–O₂ collisional pair and allows to control the pathways of further transformation. High selectivities to useful products are obtained using this approach.     

Correction to: Development and validation of a new friction model for cutting processes

The authors wish to thank the German Research Foundation (DFG) for funding the research within the project "Modelling of broaching processes by multi-     

Matrix spectral factorization for SA4 multiwavelet

Multidimensional Systems and Signal Processing - In this paper, we investigate Bauer’s method for the matrix spectral factorization of an r-channel matrix product filter which is a half-band...     

Modeling the coupling between free and forced convection in a vertical permeable slot: Implications for the heat production of an Enhanced Geothermal System

The aim of the hydraulic stimulations in the Soultz-sous-Forêts, France, Enhanced Geothermal System (EGS) project was to create, in crystalline rocks, a fractured reservoir 750 m high, 750 m long and 35 m thick interconnecting the injection and production wells. Increasing the permeability in a zone with a high geothermal gradient will trigger free convection, which will interact with the forced flow driven by pumping. A systematic numerical study of the coupling between forced and free convective flows has been performed by considering a large range of injection rates and Rayleigh numbers. The simulations showed that if there is weak or no free convection in an EGS reservoir, economic exploitation of the system will rapidly end because of a decrease in produced fluid temperature. The maximum injection rate preventing such a temperature drop increases with the Rayleigh number and the height of the stimulated domain. The model establishes constraints on the conditions for achieving optimal heat extraction at the Soultz-sous-Forêts EGS site. It was also shown that, although mineral precipitation may partially close or heal some open fissures, it does not lead to a major decrease of the hydraulic conductivity in the stimulated reservoir.