180 research outputs found
Asteroid Redirect Crewed Mission Space Suit and EVA System Architecture Trade Study
The Asteroid Redirect Crewed Mission (ARCM) requires a Launch/Entry/Abort (LEA) suit capability and short duration Extra Vehicular Activity (EVA) capability for Orion. The EVAs will involve a two-person crew for approximately four hours. Currently, two EVAs are planned with one contingency EVA in reserve. Providing this EVA capability is very challenging due to system level constraints and a new and unknown environment. The goal of the EVA architecture for ARCM is one that builds upon previously developed technologies and lessons learned, and that accomplishes the ARCM mission while providing a stepping stone to future missions and destinations. The primary system level constraints are to 1) minimize system mass and volume and 2) minimize the interfacing impacts to the baseline Orion design. In order to minimize the interfacing impacts and to not perturb the baseline Orion schedule, the concept of adding "kits" to the baseline system is proposed. These kits consist of: an EVA kit (converts LEA suit to EVA suit), EVA Servicing and Recharge Kit (provides suit consumables), the EVA Tools, Translation Aids & Sample Container Kit (the tools and mobility aids to complete the tasks), the EVA Communications Kit (interface between the EVA radio and the MPCV), and the Cabin Repress Kit (represses the MPCV between EVAs). This paper will focus on the trade space, analysis, and testing regarding the space suit (pressure garment and life support system). Historical approaches and lessons learned from all past EVA operations were researched. Previous and current, successfully operated EVA hardware and high technology readiness level (TRL) hardware were evaluated, and a trade study was conducted for all possible pressure garment and life support options. Testing and analysis was conducted and a recommended EVA system architecture was proposed. Pressure garment options that were considered for this mission include the currently in-use ISS EVA Mobility Unit (EMU), all variations of the Advanced Crew Escape Suit (ACES), and the Exploration Z-suit. For this mission, the pressure garment that was selected is the Modified ACES (MACES) with EVA enhancements. Life support options that were considered included short closed-loop umbilicals, long open-loop umbilicals, the currently in-use ISS EMU Portable Life Support System (PLSS), and the currently in development Exploration PLSS. For this mission, the life support option that was selected is the Exploration PLSS. The greatest risk in the proposed architecture is viewed to be the comfort and mobility of the baseline MACES and the delicate balance between adding more mobility features while not compromising landing safety. Feasibility testing was accomplished in low fidelity analogs and in the JSC Neutral Buoyancy Laboratory (NBL) to validate the concept before a final recommendation on the architecture was made. The proposed architecture was found to meet the mission constraints, but much more work is required to determine the details of the required suit upgrades, the integration with the PLSS, and the rest of the tools and equipment required to accomplish the mission. This work and further definition of the remaining kits will be conducted in government fiscal year 14
Un Modelo No Lineal de la Dinámica del Flujo Sanguíneo y la Pared Arterial
Con tendencia creciente, el modelado computacional se está empleando para evaluar causas, predecir el desarrollo y optimizar tratamientos de varias patologías del sistema arterial. Esto debido principalmente a la potencialidad de estas técnicas para producir información cada vez más realista, con un mejor nivel de detalle y mejor precisión. Más aún, los modelos computacionales personalizados -específicos para cada paciente- se han vuelto atractivos para médicos e investigadores debido a que aportan información de relevancia para las evaluaciones clínicas a bajo costo. Sin embargo, los resultados del modelado computacional son altamente dependientes de la complejidad y realismo de las hipótesis simplificativas y también de la precisión de las representaciones geométricas. En el caso particular de la hemodinámica de distritos arteriales paciente-específicos, el problema de interacción fluido estructura asociado presenta ciertos obstáculos relacionados con las características altamente nolineales de las ecuaciones gobernantes que deben ser abordados adecuadamente. Otro aspecto a ser considerado cuando se requiere evaluar las tensiones en la pared arterial, es que las geometrías obtenidas de imágenes médicas corresponden a configuraciones espaciales que no concuerdan con la configuración libre de cargas. Consecuentemente, esto puede llevar a evaluaciones incorrectas de los niveles de tensión parietal. Con estas cuestiones como guía, en este trabajo desarrollamos un modelo computacional de la pared arterial -considerada como un material hiperelástico- basado en una configuración deformada, por ejemplo la configuración diastólica. Esto se realiza para tener en cuenta las caracteristicas geométricas apropiadas de los distritos arteriales con el objetivo de mejorar la precisión de las deformaciones y las tensiones calculadas. De esta manera, el problema del equilibrio es planteado en una configuración predeformada y con precarga. La correspondiente formulación es linealizada asumiendo conocida dicha configuración espacial. Además, se plantea el problema de acoplamiento fluido estructura asumiendo como conocida la misma configuración diastólica. En este contexto, es provista una linealización completa tanto para la descripción ALE en la subregión de fluido como para el problema de equilibrio del sólido. Las ecuaciones resultantes son discretizadas mediante el método de Elementos Finitos. Finalmente, esta formulación es utilizada para evaluar la respuesta mecánica de un segmento arterial sujeto a cargas hemodinámicas realistas.Fil: Urquiza, Santiago Adrian. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Mecanica; Argentina. Instituto Nacional de Ciência e Tecnologia em Medicina Assistida por Computação Científica; BrasilFil: Aguero Parosi. Nicolas F.. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Mecanica; ArgentinaFil: Caballero, Daniel. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Mecanica; ArgentinaFil: Lombera, Guillermo Alfredo. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Mecanica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Blanco, Pablo Javier. Laboratório Nacional de Computação Científica. Petrópolis; Brasil. Instituto Nacional de Ciência e Tecnologia em Medicina Assistida por Computação Científica; BrasilFil: Ares, Gonzalo Damián. Laboratório Nacional de Computação Científica. Petrópolis; Brasil. Instituto Nacional de Ciência e Tecnologia em Medicina Assistida por Computação Científica; BrasilFil: Feijoo, Raul A.. Laboratório Nacional de Computação Científica. Petrópolis; Brasil. Instituto Nacional de Ciência e Tecnologia em Medicina Assistida por Computação Científica; Brasi
Short-term amiodarone therapy after reversion of persistent atrial fibrillation reduces recurrences at 18 months
Background: The aim of this study was to compare the outcome of 3 months vs. 18 months of amiodarone treatment after atrial fibrillation (AF) conversion in patients who experienced the first episode of persistent AF. Methods: We included 51 patients who experienced the first episode of persistent AF receiving amiodarone (600 mg) daily for 4–6 weeks. If AF persisted, electrical cardioversion (ECV) was performed. All patients received amiodarone (200 mg daily) for 3 months and then were randomized to amiodarone (Group I) or placebo (Group II) and followed for 15 months. The control group comprised 9 untreated patients undergoing ECV. Treatment effectiveness was evaluated using a Bayesian model. Results: Eighteen months after AF reversion, 22 (81.5%) patients in Group I, 13 (54.2%) patients in Group II, and 1 (11.1%) patient in the control group remained in sinus rhythm. No differences were found between Group I patients who required ECV and Group II patients. Sinus rhythm was preserved in all Group I patients when it was achieved during amiodarone administration. Limiting adverse effects occurred in 3 (11.1%) patients in Group I. Conclusions: In patients regaining sinus rhythm after the first episode of persistent AF, a 3-month amiodarone treatment after reversion is a reasonable option for rhythm control.
Clinical characteristics and outcome of drug-induced liver injury in the older patients: from the young-old to the oldest-old
Old patients with hepatotoxicity have been scarcely studied in idiosyncratic drug-induced liver injury (DILI) cohorts. We sought for the distinctive characteristics of DILI in older patients across age groups. A total of 882 DILI patients included in the Spanish DILI Registry (33% ≥65 years) were categorized according to age: “young” (<65y); “young-old” (65-74y); “middle-old” (75-84y); and “oldest-old” (≥85y). All elderly groups had increasingly higher comorbidity burden (p<0.001) and polypharmacy (p<0.001). There was a relationship between jaundice and hospitalization (p<0.001), and both were more prevalent in the elderly age groups, especially in the oldest-old (88% and 69%, respectively) and the DILI episode was more severe (p=0.029). The proportion of females decreased across age groups from the young to the middle-old, yet in the oldest-old there was a distinct female predominance. Pattern of liver injury shifted towards cholestatic with increasing age among top culprit drugs amoxicillin- clavulanate, atorvastatin, levofloxacin, ibuprofen, and ticlopidine. The best cut-off point for increased odds of cholestatic DILI was 65y. Older patients had increased non-liver related mortality (p=0.030) as shown by the predictive capacity of MELD (OR=1.116; p<0.001), and comorbidity burden (OR=4.188; p=0.001) in the 6-month mortality. Older patients with DILI exhibited an increasingly predominant cholestatic phenotype across a range of culprit drugs other that amoxicillin-clavulanate, with increased non-liver related mortality and require a different approach to predict outcome. The oldest DILI patients exhibited a particular phenotype with more severe DILI episodes and need to be considered when stratifying older DILI populations.The present study has been supported by grants of Instituto de Salud Carlos III cofounded by Fondo Europeo de Desarrollo Regional - FEDER (contract numbers: PI 18/01804; PT17/0017/0020) and Agencia Española del Medicamento. SCReN and CIBERehd are funded by ISCIII. JSC holds a Rio Hortega (CM17/00243) and MR a “Joan Rodes” (JR16/00015) research contract from the National Health System, ISCIII. RAW held a University of Málaga visiting scientist scholarship
Muon Array with RPCs for Tagging Air showers (MARTA)
We discuss the concept of an array with Resistive Plate Chambers (RPC) for muon detection in ultra-high energy cosmic ray (UHECR) experiments. RPC have been used in particle physics experiments due to their fast timing properties and spatial resolution. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme en- vironments, with limited power and minimal maintenance. In its baseline configuration, each MARTA unit includes one 1.5x1.2 m 2 RPC, with 64 pickup electrodes (pads). The DAQ sys- tem is based on an ASIC, allowing one to read out the high number of channels with low power consumption. Data are recorded using a dual technique: single particle counting with a simple threshold on the signal from each pad and charge integration for high occupancy. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminum-sealed case, providing a com- pact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using very low gas flux, which allows running them for few years with a small gas reservoir. Several full-scale units are already installed and taking data in several locations and with different configurations, proving the viability of the MARTA concept. By shielding the detector units with enough slant mass to absorb the electro- magnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The specificities of a MARTA unit are presented, which include particle counting with high efficiency, time resolu- tion and spatial segmentation. The potential of the MARTA concept for muon measurements in air showers is assessed, as well as tentative methods for calibration and cross-calibrations with existing detectors.Peer Reviewe
Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells
Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells.Instituto de Salud Carlos III PI13/00021Ministerio de Economía y Competitividad BFU2012-32056Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía BIO-0216Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía CTS-6264Consejería de Salud, Junta de Andalucía PI13/ 0002
Clinical and pathological characteristics of peripheral T‐cell lymphomas in a Spanish population: a retrospective study
We investigated the clinicopathological features and prognostic factors of patients with peripheral T-cell lymphoma (PTCL) in 13 sites across Spain. Relevant clinical antecedents, CD30 expression and staining pattern, prognostic indices using the International Prognostic Index and the Intergruppo Italiano Linfomi system, treatments, and clinical outcomes were examined. A sizeable proportion of 175 patients had a history of immune-related disorders (autoimmune 16%, viral infections 17%, chemo/radiotherapy-treated carcinomas 19%). The median progression-free survival (PFS) and overall survival (OS) were 7·9 and 15·8 months, respectively. Prognostic indices influenced PFS and OS, with a higher number of adverse factors resulting in shorter survival (P 15% of cells were positive in anaplastic lymphoma kinase-positive and -negative anaplastic large-cell lymphoma and extranodal natural killer PTCL groups. We observed PTCL distribution across subtypes based on haematopathological re-evaluation. Poor prognosis, effect of specific prognostic indices, relevance of histopathological sub-classification, and response level to first-line treatment on outcomes were confirmed. Immune disorders amongst patients require further examination involving genetic studies and identification of associated immunosuppressive factors
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
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