Ten-year outcomes for pathologic node-positive patients treated in RTOG 75-06

PURPOSE: This study was conducted to see what fraction of prostate cancer patients with biopsy-proven nodes are free of cancer 10 years after radiation treatment. METHODS AND MATERIALS: RTOG protocol #75-06 included 90 patients with biopsy-proven pelvic nodal involvement treated with radiation. They have been continuously follow-up since treatment. When feasible, current prostate-specific antigen (PSA) levels have been solicited from patients clinically cancer-free (no evidence of disease, NED) at 10 years, to confirm cure. RESULTS: The 10-year survival was 29%, the 10-year clinical NED survival 7%. PSA levels were obtained in 2 of 5 10-year clinical NED patients, they were both less than 0.8 ng/ml. The 2 proven cures were both clinical stage T-3, Gleason Score 6 and 8, and had 2 and 1 positive nodes, respectively. Multivariate analysis showed Gleason sum was significantly associated with clinical survival without disease. CONCLUSION: A small fraction of node-positive patients are cured at 10-year follow-up by radiation therapy (2 of 90 with PSA +3 of 90 by clinical endpoints). Innovative treatment programs should be directed at node-positive patients in an effort to improve the fraction cured.     

Analysis of entropy generation in a hydrogen-enriched turbulent non-premixed flame

The analysis of local entropy generation and exergy loss was performed in a turbulent non-premixed H₂-enriched CH₄–air bluff-body flame. Detailed chemical kinetic, transport properties, and turbulence-chemistry interaction were taken into account in using laminar flamelet model for the simulation of combustion process via an in-house, finite volume code. The analysis was based on local entropy generation calculation. Results showed that thermal conduction made the most contribution to entropy generation followed by chemical reaction and mass diffusion, while the contribution of viscous dissipation was negligible. Entropy generation resulting from thermal conduction occurs in a large volume of the domain, while entropy generation resulting from chemical reaction and mass diffusion occurs only near the bluff surface. The effect of H₂ addition to fuel and air preheating on the entropy generation rate was investigated. It was observed that entropy generation and exergy loss were decreased by H₂ addition, mainly due to a decrease in the chemical reaction component of entropy generation, while entropy generation resulting from thermal conduction slightly increased and entropy generation resulting from mass diffusion remained almost constant. Entropy generation resulting from heat conduction by preheating combustion air decreased, while entropy generation resulting from chemical reaction and mass diffusion remained almost constant. The decrease of thermal conduction contribution in entropy generation is so significant that, by preheating air up to 750 K in the case of pure CH₄, chemical reaction becomes the main source of irreversibility. These investigations show that H₂ addition and preheating the combustion air both lead to the improvement of the second law efficiency, although the second law efficiency is more sensitive to flame structure and air temperature.     

Investigation of Geyser Boiling Phenomenon in a Two-Phase Closed Thermosyphon

In this paper, geyser boiling phenomenon (GBP) in a two-phase closed thermosyphon has been investigated experimentally. Here, the effects of the inclination angle, filling ratio, input heat rate, mass flowrate of coolant, and inside diameter of the tube on the GBP have been discussed. Three copper thermosyphons with inside diameters of 14 mm, 20 mm, and 24 mm and a length of 1000 mm were employed. Distilled water was used as the working fluid. A series of experiments was carried out to investigate the effect of the inclination angle range of 5° to 90°, the input heat rate range of 50 to 312.4 W, the coolant mass flow rate range of 0.00389 to 0.0164 kg/s, and the filling ratio range of 15 to 45%. The GBP has been investigated by analyzing the time variations of the evaporator and adiabatic wall temperature and outlet water temperature from condenser jacket. The results show that the period of GBP was longer for higher inclination angles and filling ratios. Furthermore, it was discovered that the GBP did not take place for inclination angles of less than 15°.     

Periodic graphene nanobuds: A novel Li-storage material

The characteristics of lithium adsorption on graphene and periodic graphene nanobuds (PGNBs) have been studied by means of density functional theory calculations. All calculations have been performed within the Perdew–Burke–Erzenhof functional as implemented in the SIESTA package, with a double-ζ plus polarization basis set. Several starting configurations were considered for interacting systems. The results show that the Li atom is strongly adsorbed on a pure graphene with a binding energy of about −0.85 eV. However, the binding energy enhances to −2.58 eV when Li binds to a PGNB at the hollow site above the center of the nonagon ring. It was found that the increase in binding is due to significant charge transfer from the Li to the PGNB. The stability of the Li/PGNB system was evaluated within ab initio molecular dynamics simulation which has been carried out at room temperature. The very favorable binding energy obtained as well as high specific surface of PGNB (due to attached fullerenes) suggest a considerable possibility to experimentally apprehend these novel systems as a superior media for Li ions storage.     

Biological evaluation of polyvinyl alcohol hydrogel crosslinked by polyurethane chain for cartilage tissue engineering in rabbit model

Polyvinyl alcohol (PVA) hydrogel chains were crosslinked by urethane pre-polymer (PPU) in order to fabricate a new substitute for cartilage lesions. The microscopy images showed that the cultured chondrocytes had spherical morphology on PVA–PPU sample after 4 weeks of isolation in vitro. The alcian blue and safranin O staining proved the presence of proteoglycan on the surface of PVA–PPU sample secreted by cultured chondrocytes. This was confirmed by the detection of sulfate ions in the wavelength dispersive X-ray (WDX) analysis. In addition, the expression of collagen type II and aggrecan were observed in chondrocytes cultured on PVA–PPU by RT-PCR. Moreover, the implantation of the PVA–PPU sample with autologous cultured chondrocytes revealed the formation of neocartilage tissue in a rabbit model during 12 weeks follow up. In conclusion, the results verified that isolated chondrocytes cultured on PVA–PPU retain their original phenotype and this composition can be considered as promising substrate for cartilage tissue engineering.     

Effect of Microwave Treatment on Starch Digestibility and Physico-chemical Properties of Three Barley Types

Samples of normal, high-amylose, and waxy barleys (NB, HAB, and WB, respectively) were tempered and then microwaved using three treatment protocols at each of three power levels. Microwave treatment increased starch digestibility, as rapidly digestible starch (RDS) concentrations were markedly higher and resistant starch (RS) and slowly digestible starch (SDS) concentrations were significantly lower, in all microwaved samples compared to corresponding unprocessed samples. Levels of RDS, on a dry sample basis, were similar in corresponding microwaved samples of the three barley types but were higher in WB when expressed on a starch basis. Levels of RS were lowest in microwaved WB samples. Microwave treatment was most effective in increasing starch digestibility at higher microwave power levels and when samples were tempered and then stored for 14 days at 4°C prior to microwaving, although the magnitude of the increase may not justify the cost of the storage step and might be achieved more economically through the use of an even higher power level. Increases in starch digestibility were attributed to gelatinization of starch. This conclusion was supported by degree of starch gelatinization, thermal analysis, and pasting data.     

Effects of Welding and rotational speeds on the Microstructure and Hardness of Friction Stir Welded Single-Phase Brass

This study focuses on the effects of rotational and welding speeds on the microstructure and hardness of joints in friction stir welded single-phase brass. Welds were achieved under low heat input conditions at rotational and welding speeds of 400-800 r/min and 100-300 mm/min, respectively. In order to characterize the obtained welds, optical microscopy and Vickers hardness measurements were taken on the weld cross sections. According to the obtained results, increasing the welding speed and/or decreasing the rotational speed caused the grain size of the stir zone to decrease and, hence, improved the average hardness of this region. These results are discussed with respect to the interplay between the welding parameters and the peak temperature in the weld thermal cycle.     

Kinetics of dehydrogenation of the Mg-Ti-H hydrogen storage system

Among the proposed hydrogen storage systems, magnesium alloys have proved to be promising since they are rechargeable with high hydrogen capacities (theoretically up to 7.6 wt.%), reversibility and low costs. Small particle size, which can be achieved by milling, and small amounts of transition-metal compounds as catalysts result in increased hydrogen release/uptake kinetics. In this work, we developed the rate expression for the dehydrogenation of milled 7MgH₂/TiH₂, 10MgH₂/TiH₂, and MgH₂ samples. The complete rate expressions, together with the values of activation energy and other rate parameters, were determined for the three milled samples by analyzing data obtained from non-isothermal thermogravimetric analysis (TGA). The MgH₂ doped with TiH₂ by high-energy milling displayed substantially reduced apparent activation energy of 107-118 kJ/mol and significantly faster kinetics, compared with 226 kJ/mol for similarly milled MgH₂ without TiH₂ doping.