73 research outputs found

    Comparison of Dynamics Stability Testing Techniques with Magnetic Suspension Wind Tunnel Capabilities

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    Dynamic stability testing techniques currently utilized at NASA Langley Research Center (LaRC) are conducted in multiple facilities and consists of free flight, forced oscillation, and free-to-oscillate tests. The NASA/ODU Magnetic Suspension and Balance System (MSBS) has been recommissioned to explore its utility as an additional facility to expand the dynamic stability test capabilities currently available at NASA LaRC. Simulations were created to replicate each current test facility and method as closely as possible. Data collected from the simulated environments was corrupted with replicated noise sources of the different testing environments and then compared to real data collected during tests when such data was available. The corrupted data was then passed through data reduction and System Identification (SID) to estimate the accuracy of the results with the known aerodynamic model that was utilized within the simulation to generate the original data. Magnitudes of noise were varied utilizing Monte Carlo analysis to perform sensitivity analysis of each noise source on the extracted dynamic stability coefficients. Some preliminary results will be presented

    Stellar equilibrium configurations of white dwarfs in the f(R,T)f(R,T) gravity

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    In this work we investigate the equilibrium configurations of white dwarfs in a modified gravity theory, na\-mely, f(R,T)f(R,T) gravity, for which RR and TT stand for the Ricci scalar and trace of the energy-momentum tensor, respectively. Considering the functional form f(R,T)=R+2λTf(R,T)=R+2\lambda T, with λ\lambda being a constant, we obtain the hydrostatic equilibrium equation for the theory. Some physical properties of white dwarfs, such as: mass, radius, pressure and energy density, as well as their dependence on the parameter λ\lambda are derived. More massive and larger white dwarfs are found for negative values of λ\lambda when it decreases. The equilibrium configurations predict a maximum mass limit for white dwarfs slightly above the Chandrasekhar limit, with larger radii and lower central densities when compared to standard gravity outcomes. The most important effect of f(R,T)f(R,T) theory for massive white dwarfs is the increase of the radius in comparison with GR and also f(R)f(R) results. By comparing our results with some observational data of massive white dwarfs we also find a lower limit for λ\lambda, namely, λ>3×104\lambda >- 3\times 10^{-4}.Comment: To be published in EPJ

    Anaplasma Marginale: evaluación de dosis mínima infectiva

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    El aislamiento de una cepa de Anaplasma margina-le en el Centro Regional de Investigación "La Libertad" en Villavicencio, con características de atenuación natural, motivó una seríe de ensayos orientados a obtener información sobre su patogenicidad, la protección que confiere y el estudio de la dosis mínima infectiva que fue el objetivo de este trabajo. Utilizando dieciséis terneros holstein de ocho a trece meses de edad se conformaron cuatro grupos experimentales (I, II, III y IV) de cuatro animales cada uno, los cuales fueron inoculados por vía endovenosa respectivamente con 101, 103, 105 y 107 anaplasmas de la cepa aislada en Villavicencio en 1973. Con estos inóculos no hubo infección de ana-plasmas en el grupo I; en el grupo II se infectaron tres de cuatro animales inoculados y en los grupos III y IV, todos los animales se infectaron. La parasitemia se detectó a partir del día 16 postinoculación, un día después de haberse detectado incremento de la temperatura rectal en el 68,75% de los animales. El hematocrito y la hemoglobina tuvieron un moderado descenso desde el día 18 en los animales de los grupos III y IV sin llegar a valores subnormales aún en los días 22 a 25, período en el cual se observaron clínica-mente mas afectados. La infección de anaplasmas se observó durante cinco semanas; no fue necesario tratar ningún animal y los valores del hematocrito y de la hemoglobina volvieron a los valores normales iniciales, 24 días después de comenzar la infección. En este ensayo, la dosis mínima infectiva se consideró en 105 anaplasmas por cuanto a partir de esta dosis todos los animales inoculados se infectaronThe isolation made at "La Libertad" experiment Station in Vilavicencio of an Anaplasma tnarginale strain with some characteristics of natural attenuation, stimulated trials aimed to gather information on its pathogenicity, the protection confered and its minimum infective dose, the latter being the objective of this paper. A total of sixteen, eight to thirteen months old Holstein calves formed four experimental groups (1, II, III and IV) of four calves each, which were inoculated intravenously with 101, 10, and 107 Anaplasma organisms (Villavicencio isolate) respectively. Anaplasma organisms were observed after inoculation in none of the calves in group I; in three of the calves in group II and in all calves in groups III and IV. Parasitemia was first detected on day sixteen post-inoculation, one day following a rectal temperature raise in 68 .75% of the cattle. Packed Cell Volume (PCV) and Hemoglobine (HB) decreased lightly from day 18 onwards in groups III and IV. However, from days 22 to 25 when the calves in these groups seemed slightly more affected, neither the PCV nor the HB reached sub-normal values. Anaplasma infection was observed for five weeks; treatment was not required for any of the calves and the PCV and HB reached their initial values twenty four days after the onset of the infection. A number of 105organisms was therefore considered as minimum infective dose in this trial since that was the minimum dose apparently ensuring infection in all the calves.Ganado de doble propósito-Ganaderia doble proposit

    Fermionic matter under the effects of high magnetic fields and its consequences in white dwarfs

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    We investigate a recently proposed effect of strong magnetic fields in Fermionicmatter that is important to the structure of magnetic white dwarfs. This work is highly relevant in view of the recent observations of magnetized white dwarfs (B ~ 108-9 G), and possible candidates for white dwarfs pulsars as an alternative descriptions for SGRs and AXPs. Here, we consider the matter inside white dwarfs composed by ions surrounded by an electron degenerate Fermi gas subject to a strong magnetic field. We investigate the effect of the Landau levels due to the huge magnetic field on the equation of state (EoS). We see that the behaviour of the equation of state as a function of the mass and energy density is much stiffer when only one Landau level is occupied. We also investigate the regime of lower magnetic fields where many Landau levels are occupied

    Limpieza del agua miel proveniente del beneficiado húmedo del café mediante polímeros naturales orgánicos

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    The wet processing of coffee generates a liquid residue called honey water, which has become a latent problem to be solved for coffee organizations in Peru with a view to sustainable coffee growing and for a production that targets special markets. The objective of this work was to develop a protocol for the treatment of honey water from the wet processing of coffee through the use of organic natural polymers, preparing polymer broths which were applied to the honey water. Two more effective polymers were selected in cleaning honey water, one with an anionic charge and the other with a cationic charge. We worked with three small wet-processing plants of coffee producers of the Valles del Café Agrarian Cooperative where important results were obtained in terms of the reduction of at least 8 to 10 indicators, of 15 physicochemical and microbiological indicators analyzed, thus exceeding the Limits Maximum Permissible of several indicators of the Peruvian norm in terms of water for irrigation level three.El procesamiento húmedo del café genera un residuo líquido llamado agua miel, el cual se ha convertido en un problema latente a ser resuelto para las organizaciones cafetaleras en el Perú con miras a una caficultura sostenible y para una producción que apunta a mercados especiales. El presente trabajo tuvo como objetivo desarrollar un protocolo para el tratamiento de aguas mieles del beneficio húmedo del café mediante el uso de polímeros naturales orgánicos, preparándose caldos de polímero los cuales fueron aplicados a las aguas mieles. Se seleccionó dos polímeros más efectivos en la limpieza del agua miel, uno de carga aniónica y otro de carga catiónica. Se trabajó con tres pequeñas plantas de beneficiado húmedo de productores cafetaleros de la Cooperativa Agraria Valles del Café donde se obtuvieron importantes resultados en cuanto a la reducción de al menos 8 a 10 indicadores, de 15 indicadores fisicoquímicos y microbiológicos analizados, lográndose así superar los Límites Máximos Permisibles de varios indicadores de la norma peruana en cuanto a agua para riego nivel tres

    Lethal iron deprivation induced by non-neutralizing antibodies targeting transferrin receptor 1 in malignant B cells

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    A number of antibodies have been developed that induce lethal iron deprivation (LID) by targeting the transferrin receptor 1 (TfR1/CD71) and either neutralizing transferrin (Tf) binding, blocking internalization of the receptor and/or inducing its degradation. We have developed recombinant antibodies targeting human TfR1 (ch128.1 and ch128.1Av), which induce receptor degradation and are cytotoxic to certain malignant B-cells. We now show that internalization of TfR1 bound to these antibodies can lead to its sequestration and degradation, as well as reduced Tf uptake, and the induction of a transcriptional response consistent with iron deprivation, which is mediated in part by downstream targets of p53. Cells resistant to these antibodies do not sequester and degrade TfR1 after internalization of the antibody/receptor complex, and accordingly maintain their ability to internalize Tf. These findings are expected to facilitate the rational design and clinical use of therapeutic agents targeting iron import via TfR1 in hematopoietic malignancies.Fil: Rodríguez, José A.. University of California at Los Angeles; Estados UnidosFil: Luria Pérez, Rosendo. University of California at Los Angeles; Estados Unidos. Hospital infantil de México “Federico Gómez”; MéxicoFil: López Valdés, Héctor E.. University of California at Los Angeles; Estados UnidosFil: Casero, David. University of California at Los Angeles; Estados UnidosFil: Daniels, Tracy R.. University of California at Los Angeles; Estados UnidosFil: Patel, Shabnum. University of California at Los Angeles; Estados UnidosFil: Avila, David. University of California at Los Angeles; Estados UnidosFil: Leuchter, Richard. University of California at Los Angeles; Estados UnidosFil: So, Sokuntheavy. University of California at Los Angeles; Estados UnidosFil: Ortiz Sánchez, Elizabeth. University of California at Los Angeles; Estados UnidosFil: Bonavida, Benjamin. University of California at Los Angeles; Estados UnidosFil: Martínez Maza, Otoniel. University of California at Los Angeles; Estados UnidosFil: Charles, Andrew C.. University of California at Los Angeles; Estados UnidosFil: Pellegrini, Matteo. University of California at Los Angeles; Estados UnidosFil: Helguera, Gustavo Fernando. University of California at Los Angeles; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Penichet, Manuel L.. University of California at Los Angeles; Estados Unido

    Decreased but persistent epigenetic age acceleration is associated with changes in T-cell subsets after initiation of highly active antiretroviral therapy in persons living with HIV

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    IntroductionPersons living with HIV (PLWH) experience the early onset of age-related illnesses, even in the setting of successful human immunodeficiency virus (HIV) suppression with highly active antiretroviral therapy (HAART). HIV infection is associated with accelerated epigenetic aging as measured using DNA methylation (DNAm)-based estimates of biological age and of telomere length (TL).MethodsDNAm levels (Infinium MethylationEPIC BeadChip) from peripheral blood mononuclear cells from 200 PLWH and 199 HIV-seronegative (SN) participants matched on chronologic age, hepatitis C virus, and time intervals were used to calculate epigenetic age acceleration, expressed as age-adjusted acceleration residuals from 4 epigenetic clocks [Horvath’s pan-tissue age acceleration residual (AAR), extrinsic epigenetic age acceleration (EEAA), phenotypic epigenetic age acceleration (PEAA), and grim epigenetic age acceleration (GEAA)] plus age-adjusted DNAm-based TL (aaDNAmTL). Epigenetic age acceleration was compared for PLWH and SN participants at two visits: up to 1.5 years prior and 2–3 years after HAART (or equivalent visits). Flow cytometry was performed in PLWH and SN participants at both visits to evaluate T-cell subsets.ResultsEpigenetic age acceleration in PLWH decreased after the initiation of HAART but remained greater post-HAART than that in age-matched SN participants, with differences in medians of 6.6, 9.1, and 7.7 years for AAR, EEAA, and PEAA, respectively, and 0.39 units of aaDNAmTL shortening (all p < 0.001). Cumulative HIV viral load after HAART initiation was associated with some epigenetic acceleration (EEAA, PEAA, and aaDNAmTL), but even PLWH with undetectable HIV post-HAART showed persistent epigenetic age acceleration compared to SN participants (p < 0.001). AAR, EEAA, and aaDNAmTL showed significant associations with total, naïve, and senescent CD8 T-cell counts; the total CD4 T-cell counts were associated with AAR, EEAA, and PEAA (p = 0.04 to <0.001). In an epigenome-wide analysis using weighted gene co-methylation network analyses, 11 modules demonstrated significant DNAm differences pre- to post-HAART initiation. Of these, nine were previously identified as significantly different from pre- to post-HIV infection but in the opposite direction.DiscussionIn this large longitudinal study, we demonstrated that, although the magnitude of the difference decreases with HAART is associated with the cumulative viral load, PLWH are persistently epigenetically older than age-matched SN participants even after the successful initiation of HAART, and these changes are associated with changes in T-cell subsets

    Effects of highly active antiretroviral therapy initiation on epigenomic DNA methylation in persons living with HIV

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    Introduction: Highly active antiretroviral therapy (HAART) helps improve some measures of accelerated epigenetic aging in persons living with HIV (PLWH), but its overall impact on the epigenome is not fully understood.Methods: In this study, we analyzed the DNA methylation profiles of PLWH (n = 187) shortly before and approximately 2–3 years after they started HAART, as well as matched seronegative (SN) controls (n = 187), taken at two time intervals. Our aim was to identify specific CpGs and biologic pathways associated with HIV infection and initiation of HAART. Additionally, we attempted to identify epigenetic changes associated with HAART initiation that were independent of HIV-associated changes, using matched HIV seronegative (SN) controls (matched on age, hepatitis C status, and interval between visits) to identify CpGs that did not differ between PLWH and SN pre-HAART but were significantly associated with HAART initiation while being unrelated to HIV viral load. Epigenome-wide association studies (EWAS) on >850,000 CpG sites were performed using pre- and post-HAART samples from PLWH. The results were then annotated using the Genomic Regions Enrichment of Annotations Tool (GREAT).Results: When only pre- and post-HAART visits in PLWH were compared, gene ontologies related to immune function and diseases related to immune function were significant, though with less significance for PLWH with detectable HIV viral loads (>50 copies/mL) at the post-HAART visit. To specifically elucidate the effects of HAART separately from HIV-induced methylation changes, we performed EWAS of HAART while also controlling for HIV viral load, and found gene ontologies associated with transplant rejection, transplant-related diseases, and other immunologic signatures. Additionally, we performed a more focused analysis that examined CpGs reaching genome-wide significance (p < 1 × 10−7) from the viral load-controlled EWAS that did not differ between all PLWH and matched SN controls pre-HAART. These CpGs were found to be near genes that play a role in retroviral drug metabolism, diffuse large B cell lymphoma proliferation, and gastric cancer metastasis.Discussion: Overall, this study provides insight into potential biological functions associated with DNA methylation changes induced by HAART initiation in persons living with HIV
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