9 research outputs found
Is the meiofauna a good indicator for climate change and anthropogenic impacts?
Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research
The Viability of Rehydrated Blood in Zero Gravity
Space, the final frontier has been fascinating us for hundreds of years and space travel has only just recently become possible in our species history. The farthest we have traveled in space is the closest object to our home planet, the moon. There are many challenges that come with interplanetary travel that will directly impact the success for the mission to Mars planned to occur around the year 2033. A major problem planning long-duration space flight will be the question on how to deal with emergency situations. What happens if someone gets hurt or needs a blood transfusion? Blood can currently only be stored refrigerated for 42 days at 4 °C (39 °F). This is a serious problem for astronauts because they would only have access to transfusable blood units for the first 42 days of the voyage and would have to spend very valuable energy and space to maintain the blood at 4° C. Our lab has determined a solution to this problem by developing a technique to maintain blood viability despite being in in a dried state at room temperature. However, it is unknown how dried blood powdered will mix with liquids during rehydration in space without gravity to aid in the mixing process. NASA has provided us with funds to test how rehydration of blood will be affected by simulated zero gravity. Rehydration is a gravity mediated process and our laboratory has developed techniques where gravity may not be needed during the rehydration process. We will be testing these rehydration techniques during conditions of microgravity on board of a reduced-gravity aircraft during parabolic flight maneuvers and the results will be discussed. (Supported by NASA-80NSSC18K1664)
Declining maerl vitality and habitat complexity across a dredging gradient: Insights from in situ sediment profile imagery (SPI)
Maerl beds form complex biogenic benthic habitats, characterized by high productivity as well as diverse biological communities. Disturbances associated with extraction and/or fishing activities using mobile bottom-contacting gears such as clam-dredges induce the most severe and long-term effects on these fragile habitats. We here investigated the effects of dredge-fishing on maerl in the bay of Brest (France). We quantified maerl beds structure and vitality across a fine scale quantified dredging intensity gradient through the acquisition of in-situ images of beds cross-section using Sediment Profile Imaging system (SPI). Declines in the proxies of maerl vitality and habitat complexity were measured across the gradient, and were associated with significant changes in the vertical distribution of live and dead maerl as well as of interstitial space. Fishing with dredges caused maerl mortality, substratum compaction, and decreasing habitat complexity. SPI imaging techniques also allowed for an assessment of changes in spatial heterogeneity that dredging created on several aspects of the structure and vitality of maerl beds. It suggests that direct and indirect disturbances induced by dredging are not acting at the same spatial scale, and can thereby differentially affect the ecosystem functions linked to vitality and habitat complexity
Glovebox for Experimentation in Reduced Gravity and Other Extreme Environments
Through parabolic and suborbital research flights, fluid mechanics, biological systems and other experimental topics can be investigated in reduced gravity. When testing under such extreme conditions, a secondary containment is needed in order to keep experimental and potentially hazardous material from floating freely through the aircraft; this stimulated the need for a flight research glovebox. The initial version of the research glovebox was adapted from a neonatal intensive-care incubator which was used on 18 parabolic flights. With the advent of research during suborbital flight opportunities, the glovebox needed to be redesigned to become a more compact and capable containment chamber. To meet this objective, a smaller, lighter glovebox was designed and constructed. By using aluminum and transparent polycarbonate, the weight of the glovebox was reduced to only 35 lbs. Based on current guidelines for experimental suborbital flights, this allows for 65 lbs. of experimental equipment. Mimicking the original glovebox, two side doors that fold down were implemented. These would allow for placing the experiment in the glovebox, proper fastening and easy removal of the experiment. During experimentation, arm access through ports with surgical gown sleeves allow for sample manipulation without the risk of experimental particulates leaving the glovebox, while allowing for up to three investigators to work inside the glovebox at once. Using a stand and mounting board, the experiment can be held at a comfortable height, provides feet restraints for investigators, and allows for attachment to the aircraft for parabolic and suborbital flights. This set-up has been implemented when testing a new surgical fluid-management system, leak-free surgical trocars, and rehydration of red blood cells for transfusion therapy during spaceflight. This glovebox will be able to provide an effective secondary containment for reduced gravity test conditions, as well as other extreme environment test conditions. (Supported by NASA-80NSSC18K1664 and NASA-NNX16AC59G)
Performance evaluation of a pediatric viscous impeller pump for Fontan cavopulmonary assist
Acute Hemodynamic Efficacy of a 32-ml Subcutaneous Counterpulsation Device in a Calf Model of Diminished Cardiac Function
Developments in control systems for rotary left ventricular assist devices for heart failure patients: a review
From the moment of creation to the moment of death, the heart works tirelessly to circulate blood, being a critical organ to sustain life. As a non-stopping pumping machine, it operates continuously to pump blood through our bodies to supply all cells with oxygen and necessary nutrients. When the heart fails, the supplement of blood to the body's organs to meet metabolic demands will deteriorate. The treatment of the participating causes is the ideal approach to treat heart failure (HF). As this often cannot be done effectively, the medical management of HF is a difficult challenge. Implantable rotary blood pumps (IRBPs) have the potential to become a viable long-term treatment option for bridging to heart transplantation or destination therapy. This increases the potential for the patients to leave the hospital and resume normal lives. Control of IRBPs is one of the most important design goals in providing long-term alternative treatment for HF patients. Over the years, many control algorithms including invasive and non-invasive techniques have been developed in the hope of physiologically and adaptively controlling left ventricular assist devices and thus avoiding such undesired pumping states as left ventricular collapse caused by suction. In this paper, we aim to provide a comprehensive review of the developments of control systems and techniques that have been applied to control IRBPs