Proof of concept planetary lander test article

The goal of this proof of concept planetary lander is to safely deliver an exploration rover to a planet surface. This lander was designed to be used as the last stage of landing in the existing entry, descent, and landing procedures used in previous Mars missions. The design improved upon past missions to Mars by reducing risk of failure during landing by utilizing a passive system with no electronics or control systems while also increasing landing site accuracy. These goals were accomplished by incorporating external crushable materials and internal damping systems. Five drop tests of our final design were completed. The test results can be used for scaling the components of the modular design to suit different planet conditions. Our scaled down test article design absorbed 7.40% of the energy absorbed by the previous Mars landing systems. The remote-controlled vehicle payload we used survived all of our tests. To scale up our design for a Spirit sized mission, we recommend using a crushable material design with 350 cylinders with the dimensions of 0.06 m radius, 0.00196 m thickness, and 0.1377 m height. Our design can be used for multiple payload landing applications, including care packages and supply deliveries

Qualitative Inquiry into Church-Based Assets for HIV/AIDS Prevention and Control: A Forum Focus Group Discussion Approach

Assets church members believed they needed to engage in effective HIV/AIDS prevention and control activities. We used the three-step forum focus group discussion (FFGD) methodology to elicit responses from 32 church leaders and lay members, representing five denominations in Aba, Nigeria. Concrete resources, health expertise, finances, institutional support, capacity building, and spiritual support connected to the collective interest of members were indicated as useful for church members to engage in HIV/AIDS prevention and control activities. Adequate planning and delivery of cost-effective, appropriate and sustainable health promotion programs require an understanding of perceived church-based assets

Serotonin controlling feeding and satiety

Serotonin has been implicated in the control of satiety for almost four decades. Historically, the insight that the appetite suppressant effect of fenfluramine is linked to serotonin has stimulated interest in and research into the role of this neurotransmitter in satiety. Various rodent models, including transgenic models, have been developed to identify the involved 5-HT receptor subtypes. This approach also required the availability of receptor ligands of different selectivity, and behavioural techniques had to be developed simultaneously which allow differentiating between unspecific pharmacological effects of these ligands and ‘true’ satiation and satiety. Currently, 5-HT1B, 5-HT2C and 5-HT6 receptors have been identified to mediate serotonergic satiety in different ways. The recently approved anti-obesity drug lorcaserin is a 5-HT2C receptor agonist. In brain, both hypothalamic (arcuate nucleus, paraventricular nucleus) and extrahypothalamic sites (parabrachial nucleus, nucleus of the solitary tract) have been identified to mediate the serotonergic control of satiety. Serotonin interacts within the hypothalamus with endogenous orexigenic (Neuropeptide Y/Agouti related protein) and anorectic (α-melanocyte stimulating hormone) peptides. In the nucleus of the solitary tract serotonin integrates peripheral satiety signals. Here, the 5-HT3, but possibly also the 5-HT2C receptor play a role. It has been found that 5-HT acts in concert with such peripheral signals as cholecystokinin and leptin. Despite the recent advances of our knowledge, many of the complex interactions between 5-HT and other satiety factors are not fully understood yet. Further progress in research will also advance the development of new serotonergic anti-obesity drugs

Perinatal asphyxia: current status and approaches towards neuroprotective strategies, with focus on sentinel proteins

Delivery is a stressful and risky event menacing the newborn. The mother-dependent respiration has to be replaced by autonomous pulmonary breathing immediately after delivery. If delayed, it may lead to deficient oxygen supply compromising survival and development of the central nervous system. Lack of oxygen availability gives rise to depletion of NAD+ tissue stores, decrease of ATP formation, weakening of the electron transport pump and anaerobic metabolism and acidosis, leading necessarily to death if oxygenation is not promptly re-established. Re-oxygenation triggers a cascade of compensatory biochemical events to restore function, which may be accompanied by improper homeostasis and oxidative stress. Consequences may be incomplete recovery, or excess reactions that worsen the biological outcome by disturbed metabolism and/or imbalance produced by over-expression of alternative metabolic pathways. Perinatal asphyxia has been associated with severe neurological and psychiatric sequelae with delayed clinical onset. No specific treatments have yet been established. In the clinical setting, after resuscitation of an infant with birth asphyxia, the emphasis is on supportive therapy. Several interventions have been proposed to attenuate secondary neuronal injuries elicited by asphyxia, including hypothermia. Although promising, the clinical efficacy of hypothermia has not been fully demonstrated. It is evident that new approaches are warranted. The purpose of this review is to discuss the concept of sentinel proteins as targets for neuroprotection. Several sentinel proteins have been described to protect the integrity of the genome (e.g. PARP-1; XRCC1; DNA ligase IIIα; DNA polymerase β, ERCC2, DNA-dependent protein kinases). They act by eliciting metabolic cascades leading to (i) activation of cell survival and neurotrophic pathways; (ii) early and delayed programmed cell death, and (iii) promotion of cell proliferation, differentiation, neuritogenesis and synaptogenesis. It is proposed that sentinel proteins can be used as markers for characterising long-term effects of perinatal asphyxia, and as targets for novel therapeutic development and innovative strategies for neonatal care

REKINDLE : Robust Extraction of Kurtosis INDices with Linear Estimation

Purpose: Recent literature shows that diffusion tensor properties can be estimated more accurately with diffusion kurtosis imaging (DKI) than with diffusion tensor imaging (DTI). Furthermore, the additional non-Gaussian diffusion features from DKI can be sensitive markers for tissue characterization. Despite these benefits, DKI is more susceptible to data artifacts than DTI due to its increased model complexity, higher acquisition demands, and longer scanning times. To increase the reliability of diffusion tensor and kurtosis estimates, we propose a robust estimation procedure for DKI. Methods: We have developed a robust and linear estimation framework, coined REKINDLE (Robust Extraction of Kurtosis INDices with Linear Estimation), consisting of an iteratively reweighted linear least squares approach. Simulations are performed, in which REKINDLE is evaluated and compared with the widely used RESTORE (Robust EStimation of Tensors by Outlier REjection) method. Results: Simulations demonstrate that in the presence of outliers, REKINDLE can estimate diffusion and kurtosis indices reliably and with a 10-fold reduction in computation time compared with RESTORE. Conclusion: We have presented and evaluated REKINDLE, a linear and robust estimation framework for DKI. While REKINDLE has been developed for DKI, it is by design also applicable to DTI and other diffusion models that can be linearized

Influence of track foundation on the performance of ballast and concrete slab tracks under cyclic loading: physical modelling and numerical model calibration

In this paper, the performance of different railway structures – ballasted and two types of slab tracks (Rheda system and a ballastless track only constituted by the concrete slab) – is evaluated in terms of stresses and permanent deformations through the selection of some important parameters: wavelength of the unevenness profile, train’s speed, subgrade’s characteristics and spatial variability of the track unevenness profile. The elastodynamic response of 60 case studies is computed through a 2.5D model FEM-PML and the long-term behaviour is assessed by the implementation of a permanent deformation model. The obtained results are analysed through innovative stress and permanent deformation amplification factors in the subgrade layer. This study concludes that the train’s speed and the mechanical properties of the subgrade are the factors that most affect the long-term performance of the subgrade of railway structures, which must be considered for further optimization of the rail track structures.This work was partially carried out under the framework of In2Track2 (Shift2Rail). This work was also supported by FCT - ‘‘Fundação para a Ciência e a Tecnologia”, within ISISE, project UID/ECI/04029/2019. Additionally, by FCT: PD/BD/127814/2016 and FCT/MCTES (PIDDAC): UIDB/04708/2020 of the CONSTRUCT – ‘‘Instituto de I&D em Estruturas e Construções”. The authors are also grateful to the UK Engineering and Physical Sciences Research Council (EPSRC) for funding the LOCORPS project under Grant Number EP/N009207/