213 research outputs found
Real-time optical manipulation of cardiac conduction in intact hearts
Optogenetics has provided new insights in cardiovascular research, leading to new methods for cardiac pacing, resynchronization therapy and cardioversion. Although these interventions have clearly demonstrated the feasibility of cardiac manipulation, current optical stimulation strategies do not take into account cardiac wave dynamics in real time. Here, we developed an allâoptical platform complemented by integrated, newly developed software to monitor and control electrical activity in intact mouse hearts. The system combined a wideâfield mesoscope with a digital projector for optogenetic activation. Cardiac functionality could be manipulated either in freeârun mode with submillisecond temporal resolution or in a closedâloop fashion: a tailored hardware and software platform allowed realâtime intervention capable of reacting within 2 ms. The methodology was applied to restore normal electrical activity after atrioventricular block, by triggering the ventricle in response to optically mapped atrial activity with appropriate timing. Realâtime intraventricular manipulation of the propagating electrical wavefront was also demonstrated, opening the prospect for realâtime resynchronization therapy and cardiac defibrillation. Furthermore, the closedâloop approach was applied to simulate a reâentrant circuit across the ventricle demonstrating the capability of our system to manipulate heart conduction with high versatility even in arrhythmogenic conditions. The development of this innovative optical methodology provides the first proofâofâconcept that a realâtime optically based stimulation can control cardiac rhythm in normal and abnormal conditions, promising a new approach for the investigation of the (patho)physiology of the heart
Drift simulation of MH370 debris using superensemble techniques
On 7 March 2014 (UTC), Malaysia Airlines flight 370 vanished without a trace.
The aircraft is believed to have crashed in the southern Indian Ocean, but
despite extensive search operations the location of the wreckage is still
unknown. The first tangible evidence of the accident was discovered almost
17 months after the disappearance. On 29 July 2015, a small piece of the right
wing of the aircraft was found washed up on the island of RĂ©union,
approximately 4000âŻkm from the assumed crash site. Since then a number of
other parts have been found in Mozambique, South Africa and on Rodrigues Island.
This paper presents a numerical simulation using high-resolution
oceanographic and meteorological data to predict the movement of floating
debris from the accident. Multiple model realisations are used with different
starting locations and wind drag parameters. The model realisations are
combined into a superensemble, adjusting the model weights to best represent
the discovered debris. The superensemble is then used to predict the
distribution of marine debris at various moments in time. This approach can
be easily generalised to other drift simulations where observations are
available to constrain unknown input parameters.
The distribution at the time of the accident shows that the discovered debris
most likely originated from the wide search area between 28Â and
35° S. This partially overlaps with the current underwater search
area, but extends further towards the north. Results at later times show that
the most probable locations to discover washed-up debris are along the
African east coast, especially in the area around Madagascar. The debris
remaining at sea in 2016 is spread out over a wide area and its distribution
changes only slowly
Temporal Evolution of Bacterial Endophytes Associated to the Roots of Phragmites australis Exploited in Phytodepuration of Wastewater
Improvement of industrial productions through more environment-friendly processes is a hot topic. In particular, land and marine environment pollution is a main concern, considering that recalcitrant compounds can be spread and persist for a long time. In this context, an efficient and cost-effective treatment of wastewater derived from industrial applications is crucial. Phytodepuration has been considered as a possible solution and it is based on the use of plants and their associated microorganisms to remove and/or transform pollutants. In this work we investigated the culturable microbiota of Phragmites australis roots, sampled from the constructed wetlands (CWs) pilot plant in the G.I.D.A. SpA wastewater treatment plant (WWTP) of Calice (Prato, Tuscany, Italy) before and after the CW activation in order to check how the influx of wastewater might affect the resident bacterial community. P. australis specimens were sampled and a panel of 294 culturable bacteria were isolated and characterized. This allowed to identify the dynamics of the microbiota composition triggered by the presence of wastewater. 27 out of 37 bacterial genera detected were exclusively associated to wastewater, and Pseudomonas was constantly the most represented genus. Moreover, isolates were assayed for their resistance against eight different antibiotics and synthetic wastewater (SWW). Data obtained revealed the presence of resistant phenotypes, including multi-drug resistant bacteria, and a general trend regarding the temporal evolution of resistance patterns: indeed, a direct correlation linking the appearance of antibiotic- and SWW-resistance with the time of exposure to wastewater was observed. In particular, nine isolates showed an interesting behavior since their growth was positively affected by the highest concentrations of SWW. Noteworthy, this study is among the few investigating the P. australis microbiota prior to the plant activation
Effect of Wastewater on the Composition of Bacterial Microbiota of Phragmites australis Used in Constructed Wetlands for Phytodepuration
Phytodepuration occurs in the plant-mediated remediation processes exploited to remove pollutants from wastewater, and Phragmites australis is one of the most used plants. This goal is achieved using constructed wetlands (CW), which are engineered systems designed to mimic the natural processes of pollutants removal. The aim of this work was to characterize the bacterial communities associated to P. australis, soils, and permeates of the CW of Calice (Prato, Italy), to evaluate the possible effect of wastewaters on the CW bacterial communities, through a next-generation sequencing-based approach. A total of 122 samples were collected from different tissues of P. australis (i.e., roots, aerial parts, and stem), soil (i.e., rhizospheric and bulk soil), and permeates, and analyzed. All samples were collected during five sampling campaigns, with the first one performed before the activation of the plant. Obtained results highlighted a specific microbiota of P. australis, conserved among the different plant tissues and during time, showing a lower alpha diversity than the other samples and not influenced by the more complex and variable environmental (soils and permeates) bacterial communities. These data suggest that P. australis is able to select and maintain a defined microbiota, a capacity that could allow the plant to survive in hostile environments, such as that of CW
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