The solid surface combustion space shuttle experiment hardware description and ground-based test results

The Lewis Research Center is developing a series of microgravity combustion experiments for the Space Shuttle. The Solid Surface Combustion Experiment (SSCE) is the first to be completed. SSCE will study flame spreading over thermally thin fuels (ashless filter paper) under microgravity conditions. The flight hardware consists of a combustion chamber containing the sample and a computer which takes the data and controls the experiment. Experimental data will include gas-phase and solid-phase temperature measurements and motion pictures of the combustion process. Flame spread rates will be determined from the motion pictures

The COLD-SAT Experiment for Cryogenic Fluid Management Technology

Future national space transportation missions will depend on the use of cryogenic fluid management technology development needs for these missions. In-space testing will be conducted in order to show low gravity cryogenic fluid management concepts and to acquire a technical data base. Liquid H2 is the preferred test fluid due to its propellant use. The design of COLD-SAT (Cryogenic On-orbit Liquid Depot Storage, Acquisition, and Transfer Satellite), an Expendable Launch Vehicle (ELV) launched orbital spacecraft that will perform subcritical liquid H2 storage and transfer experiments under low gravity conditions is studied. An Atlas launch vehicle will place COLD-SAT into a circular orbit, and the 3-axis controlled spacecraft bus will provide electric power, experiment control, and data management, attitude control, and propulsive accelerations for the experiments. Low levels of acceleration will provide data on the effects that low gravity might have on the heat and mass transfer processes used. The experiment module will contain 3 liquid H2 tanks; fluid transfer, pressurization and venting equipment; and instrumentation

EXPROPRIATIONS. Literary Confidences between Life and Death

This paper proposes the delimitation of a literary territory, or of certain speech acts as a form of expression specifically dissociated from religious and philosophical discourses, and the corresponding adaptation of such acts to the small and big screens. Expropriations, or confidences by characters on the verge of death, are used as a trope to convey this specific idea. They refer to a kind of speech that no longer bears the weight of worldly events, but that does not attempt to ignore the consequences of having been in the world. With this reconceptualization of the term, this article seeks to identify an ethics of the human intensity in three specific sequences: two stories for cinema and television –Visconti’s The Leopard, and the final episode of Brideshead Revisited– and André Gide’s “literary testament,” Et nunc manet in te.Este ensayo propone acotar un terreno literario, o ciertos actos de habla como forma de expresión específicamente deslindada de lo religioso y lo filosófico, y su correspondiente adaptación en términos visuales a la pequeña y gran pantalla. La expropiación, o confidencia de personajes a las puertas de la muerte, sería el tropo que puede transmitir esa especificidad. Se trata de un tipo de discurso que ya no soporta el peso de los hechos, pero que no trata de eludir las consecuencias de haber estado en el mundo. Con esta reconceptualización del término, el texto busca identificar una ética de la intensidad humana en tres secuencias específicas: dos relatos para el cine y la televisión –El Gatopardo, de Visconti, y el capítulo final de Retorno a Brideshead–, y el “testamento literario” de André Gide, Et nunc manet in te

Parthenolide induces caspase-independent cell death in osteosarcoma, melanoma and breast cancer cells through the induction of oxidative stress.

Parthenolide, a sesquiterpene lactone found in European feverfew, is used in traditional medicine for its anti-inflammatory activity. In addition, parthenolide has been considered as a novel and effective anti-tumor agent because it induces cytotoxic effects in several tumor cell lines. Our studies demonstrated that parthenolide exerted strong cytotoxic effects in osteosarcoma MG63 and melanoma SK-Mel28 cells in culture. Staining with Hoechst 33342 revealed in most cells after brief periods of treatments (3-5h) chromatin condensation and fragmentation, while only few cells were PI-positive. Prolonging the treatment (5-14h) PI-positive cells strongly augmented, denouncing the increase of necrotic effects. All these effects were prevented by NAC, while caspase inhibitors were ineffective, thus suggesting a caspase-independent cell death. The study of the mechanism of action provided evidence that treatment with parthenolide rapidly stimulated (1-2 h) ROS generation, in particular by inducing activation of extracellular signal-regulated kinase1/2 and NADPH oxidase. This event caused depletion of thiol groups and glutathione, NF-\u3baB inhibition, JNK activation and cell detachment from the matrix. ROS generation together with mitochondrial accumulation of Ca2+ favoured dissipation of \u394\u3c8m, which appeared primarily determined by the opening of the permeability transition pore (PTP), since \u394\u3c8m loss was partially prevented by cyclosporin A, an inhibitor of PTP opening. Recently, we focused our attention on MDA-MB231 cells, a very aggressive and poorly differentiated breast cancer cell line, which is negative for estrogen receptor alpha. Preliminary results suggested that parthenolide induced cell death in these cells with a mechanism similar to that demonstrated in osteosarcoma and melanoma cells. Interestingly, we demonstrated that in MDA-MB231 cells the effect of parthenolide was potentiated by the addition of z-VAD-fmk, a general inhibitor of caspases. Studies are in progress to elucidate the mechanism of this interaction which could suggest new strategies for the treatment of ER-\u3b1 negative breast cancer

VUV and X-ray coherent light with tunable polarization from single-pass free-electron lasers

Tunable polarization over a wide spectral range is a required feature of light sources employed to investigate the properties of local symmetry in both condensed and low-density matter. Among new-generation sources, free-electron lasers possess a unique combination of very attractive features, as they allow to generate powerful and coherent ultra-short optical pulses in the VUV and X-ray spectral range. However, the question remains open about the possibility to freely vary the light polarization of a free-electron laser, when the latter is operated in the so-called nonlinear harmonic-generation regime. In such configuration, one collects the harmonics of the free-electron laser fundamental emission, gaining access to the shortest possible wavelengths the device can generate. In this letter we provide the first experimental characterization of the polarization of the harmonic light produced by a free-electron laser and we demonstrate a method to obtain tunable polarization in the VUV and X-ray spectral range. Experimental results are successfully compared to those obtained using a theoretical model based on the paraxial solution of Maxwell's equations. Our findings can be expected to have a deep impact on the design and realization of experiments requiring full control of light polarization to explore the symmetry properties of matter samples

Okadaic acid-Parthenolide combination at subtoxic doses induces potent synergistic apoptotic effects in human retinoblastoma Y79 cells by upregulating PTEN.

Retinoblastoma is the most common intraocular malignancy afflicting children. The incidence is higher in developing countries, where treatment is limited and long-term survival rates are low. Vincristine, etoposide, and carboplatin -the agents commonly used in the treatment of retinoblastoma- determine side effects causing significant morbidity to pediatric patients and significantly limiting dosing. Thus, identifying new drugs and molecular targets to facilitate the development of novel therapeutics, and finding natural drug combinations to kill cancer cells by synergistically acting at subtoxic doses, may be a good goal. Here, we investigated the effects of two natural compounds, okadaic acid (OKA) and parthenolide (PN), in human retinoblastoma Y79 cells. We showed that OKA/PN combination at subtoxic doses induces potent synergistic apoptotic effects accompanied by decrease in p-Akt, increase in the stabilized p53 forms and potent decrease in pS166\u2013Mdm2. We also showed the key involvement of PTEN which, after OKA/PN treatment, potently increased before p53, suggesting that p53 activation was under PTEN action. PTEN-knockdown increased p-Akt/ pS166Mdm2 over basal levels and significantly lowered p53, while OKA/PN treatment failed both to lower p-Akt and pS166\u2013Mdm2 and to increase p53 below/over their basal levels respectively. OKA/PN treatment potently increased ROS levels while decreased those of GSH. Reducing cellular GSH by butathionine-sulfoximine treatment significantly anticipated the cytotoxic effect exerted by OKA/PN. The effects of OKA/PN treatment on both GSH content and cell viability were less pronounced in PTEN silenced cells than in control cells. Our study reports for the first time both a synergistic apoptotic action between OKA and PN and the involvement of PTEN as key player in the apoptotic mechanism in human retinoblastoma Y79 cells. The results provide strong suggestion for combined inhibition of the PTEN/Akt/Mdm2/p53 pathway

In human retinoblastoma Y79 cells okadaic acid\u2013parthenolide co-treatment induces synergistic apoptotic effects, with PTEN as a key player.

Retinoblastoma is the most common intraocular malignancy of childhood. In developing countries, treatment is limited, long-term survival rates are low and current chemotherapy causes significant morbidity to pediatric patients and significantly limits dosing. Therefore there is an urgent need to identify new therapeutic strategies to improve the clinical outcome of patients with retinoblastoma. here, we investigated the effects of two natural compounds okadaic acid (OKa) and parthenolide (PN) on human retinoblastoma Y79 cells. For the first time we showed that OKa/PN combination at subtoxic doses induces potent synergistic apoptotic effects accompanied by lowering in p-akt levels, increasing in the stabilized forms of p53 and potent decrease in ps166-Mdm2. We also showed the key involvement of PTeN which, after OKa/PN treatment, potently increased before p53, thus suggesting that p53 activation was under PTeN action. Moreover, after PTEN-knockdown p-akt/ ps166Mdm2 increased over basal levels and p53 significantly lowered, while OKa/PN treatment failed both to lower p-akt and ps166-Mdm2 and to increase p53 below/over their basal levels respectively. OKa/PN treatment potently increased ROs levels whereas decreased those of Gsh. Reducing cellular Gsh by l-butathionine-[s,R]-sulfoximine treatment significantly anticipated the cytotoxic effect exerted by OKa/ PN. Furthermore, the effects of OKa/PN treatment on both Gsh content and cell viability were less pronounced in PTeN silenced cells than in control cells. The results provide strong suggestion for combining a treatment approach that targets the PTeN/akt/Mdm2/p53 pathway

Electrostatic design and beam transport for a folded tandem electrostatic quadrupole accelerator facility for accelerator-based boron neutron capture therapy

Within the frame of an ongoing project to develop a folded Tandem-Electrostatic-Quadrupole (TESQ) accelerator facility for Accelerator-Based Boron Neutron Capture Therapy (AB-BNCT), we discuss here the electrostatic design of the machine, including the accelerator tubes with electrostatic quadrupoles and the simulations for the transport and acceleration of a high intensity beam.Fil: Thatar Vento, Vladimir. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Bergueiro, Javier R.. Comisión Nacional de Energía Atómica; ArgentinaFil: Cartelli, Daniel Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Valda Ochoa, Alejandro Aníbal. Universidad Nacional de San Martín; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Kreiner, Andres Juan. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Confinement, the gluon propagator and the interquark potential for heavy mesons

The interquark static potential for heavy mesons described by a massive One Gluon Exchange interaction obtained from the propagator of the truncated Dyson-Schwinger equations does not reproduced the expected Cornell potential. I show that no formulation based on a finite propagator will lead to confinement of quenched QCD. I propose a mechanism based on a singular nonperturbative coupling constant which has the virtue of giving rise to a finite gluon propagator and (almost) linear confinement. The mechanism can be slightly modified to produce the screened potentials of unquenched QCD.Comment: 12 pages and 7 figure