Spatial genetic structure (SGS) of plants results from the nonrandom distribution of related individuals. SGS provides information on gene flow and spatial patterns of genetic diversity within ...populations. Seed dispersal creates the spatial template for plant distribution. Thus, in zoochorous plants, dispersal mode and disperser behaviour might have a strong impact on SGS. However, many studies only report the taxonomic group of seed dispersers, without further details. The recent increase in studies on SGS provides the opportunity to review findings and test for the influence of dispersal mode, taxonomic affiliation of dispersers and their behaviour. We compared the proportions of studies with SGS among groups and tested for differences in strength of SGS using Sp statistics. The presence of SGS differed among taxonomic groups, with reduced presence in plants dispersed by birds. Strength of SGS was instead significantly influenced by the behaviour of seed dispersal vectors, with higher SGS in plant species dispersed by animals with behavioural traits that result in short seed dispersal distances. We observed high variance in the strength of SGS in plants dispersed by animals that actively or passively accumulate seeds. Additionally, we found SGS was also affected by pollination and marker type used. Our study highlights the importance of vector behaviour on SGS even in the presence of variance created by other factors. Thus, more detailed information on the behaviour of seed dispersers would contribute to better understand which factors shape the spatial scale of gene flow in animal‐dispersed plant species.
Abstract
Resistive Plate Chamber (RPC) detectors are widely employed in the muon trigger systems of three experiments at the CERN Large Hadron Collider (LHC). They are operated with gas mixture ...recirculation systems to reduce operational costs and greenhouse gas emissions since their gas mixture is based on C
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H
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F
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, which has a high global warning potential. It is well known that the C
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H
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F
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molecule can break down under the effect of radiation and electric field. This leads to the creation of several impurities and free fluoride ions (F
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), which could accumulate under gas recirculation and potentially attach to the RPC bakelite electrode inner surface. For these reasons, an extensive gas analysis campaign has been performed during LHC Run 2 for the CMS RPC system to verify gas mixture quality and possible accumulation of impurities.
During the entire LHC Run 2 period, a gas chromatograph has been used to analyze the RPC gas mixture at different points of the gas system: quality of pure C
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H
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F
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, fresh gas from the mixer, gas at the output of the detectors, and after the purifier module. Several impurities have been found and identified. Few impurities are already present in the C
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H
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F
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supply, as residuals of the industrial production. Nevertheless, it was found that some of these impurities, as well as others, are created inside the detector gas gap due to the fragmentation of the C
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H
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F
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molecule under the effects of electric field and radiation.
During the 2018 LHC Run several gas analysis points were added to measure the fluoride ions production in different sectors of the RPC detector system. Indeed the products of the C
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H
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F
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fragmentation do not always recombine and F
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species can stay free in the gas mixture. F
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analyses were performed on the gas at the output of the detectors both for barrel and endcap regions, where radiation levels and operational conditions were different. In this way, it was possible to correlate the F
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production with integrated charge, and gas mixture flow rate. In parallel, the RPC currents have been constantly monitored to look for possible correlations.
Fluoride measurements have also been performed at GIF++ to better understand the correlation between F
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production, radiation levels and gas volume exchanges.
A comprehensive overview of the results obtained from the different types of gas analyses and possible correlation with RPC currents and LHC luminosity will be presented.
Cardiac tissue engineering via the use of stem cells is the future for repairing impaired heart function that results from a myocardial infarction. Developing an optimised platform to support the ...stem cells is vital to realising this, and through utilising new 'smart' materials such as conductive polymers we can provide a multi-pronged approach to supporting and stimulating the stem cells via engineered surface properties, electrical, and electromechanical stimulation. Here we present a fundamental study on the viability of cardiac progenitor cells on conductive polymer surfaces, focusing on the impact of surface properties such as roughness, surface energy, and surface chemistry with variation of the polymer dopant molecules. The conductive polymer materials were shown to provide a viable support for both endothelial and cardiac progenitor cells, while the surface energy and roughness were observed to influence viability for both progenitor cell types. Characterising the interaction between the cardiac progenitor cells and the conductive polymer surface is a critical step towards optimising these materials for cardiac tissue regeneration, and this study will advance the limited knowledge on biomaterial surface interactions with cardiac cells.
Seed dispersal distance (SDD) critically influences the survival of seedlings, spatial patterns of genetic diversity within plant populations, and gene flow among plant populations. In ...animal‐dispersed species, foraging behavior and movement patterns determine SDD. Direct observations of seed dispersal events by animals in natural plant populations are mostly constrained by the high mobility and low visibility of seed dispersers. Therefore, diverse alternative methods are used to estimate seed dispersal distance, but direct comparisons of these approaches within the same seed dispersal system are mostly missing.
We investigated two plant species with different life history traits, Leonia cymosa and Parkia panurensis, exclusively dispersed by two tamarin species, Saguinus mystax and Leontocebus nigrifrons. We compared SDD estimates obtained from direct observations, genetic identification of mother plants from seed coats, parentage analysis of seedlings/saplings, and phenomenological and mechanistic modeling approaches.
SDD derived from the different methods ranged between 158 and 201 m for P. panurensis and between 178 and 318 m for L. cymosa. In P. panurensis, the modeling approaches resulted in moderately higher estimates than observations and genotyping of seed coats. In L. cymosa, parentage analysis resulted in a lower estimate than all other methods. Overall, SDD estimates for P. panurensis (179 ± 16 m; mean ± SD) were significantly lower than for L. cymosa (266 ± 59 m; mean ± SD).
Differences among methods were related to processes of the seed dispersal loop integrated by the respective methods (e.g., seed deposition or seedling distribution). We discuss the merits and limitations of each method and highlight the aspects to be considered when comparing SDD derived from different methodologies. Differences among plant species were related to differences in reproductive traits influencing gut passage time and feeding behavior, highlighting the importance of plant traits on animal‐mediated seed dispersal distance.
The authors compare five methodologies for estimating seed dispersal distance (SDD) in two plant species dispersed by the same tamarin group but with different life history traits. They detect differences between the estimates from different methods that can be linked to the processes and patterns of the seed dispersal loop integrated by each method. Despite these differences, SDD estimates for Parkia panurensis are consistently lower than for Leonia cymosa, possibly related to differences in fruit characteristics and fruit abundance, factors that influence gut passage time, foraging behavior, and movement patterns of the tamarins.
Polymer‐based electrodes for interfacing biological tissues are becoming increasingly sophisticated. Their many functions place them at the cross‐roads of electromaterials, biomaterials, and ...drug‐delivery systems. For conducting polymers, the mechanism of conductivity requires doping with anionic molecules such as extracellular matrix molecules, a process that distinguishes them as biomaterials and provides a means to control interactions at the cellular–electrode interface. However, due to their complex structure, directly observing the selective binding of target molecules or proteins has so far eluded researchers. This situation is compounded by the polymer's ability to adopt different electronic states that alter the polymer–dopant interactions. Here, the ability to resolve sub‐molecular binding specificity between sulfate and carboxyl groups of dopants and heparin binding domains of human plasma fibronectin is demonstrated. The interaction exploits a form of biological ‘charge complementarity’ to enable specificity. When an electrical signal is applied to the polymer, the specific interaction is switched to a non‐specific, high‐affinity binding state that can be reversibly controlled using electrochemical processes. Both the specific and non‐specific interactions are integral for controlling protein conformation and dynamics. These details, which represent the first direct measurement of biomolecular recognition between a single protein and any type of organic conductor, give new molecular insight into controlling cellular interactions on these polymer surfaces.
An atomic force microscope (AFM) tip is functionalized with fibronectin protein and interacts with a conducting polymer electrode comprising a conjugated backbone with entrapped dopants such as chondroitin sulphate, hyaluronic acid, or dextran sulfate. The conducting polymer operates as the working electrode in a 3‐electrode electrochemical cell, including auxiliary and reference electrodes, positioned under the AFM. Force spectroscopy measurements are performed as a function of an applied voltage to study biomolecular interactions under electrical control.
Protecting wildlife movement corridors is critical for species conservation. Urban planning often aims to create corridors for animal movement through conservation initiatives. However, research on ...connectivity for urban wildlife is limited. Here, we assessed connectivity for coyotes (Canis latrans) dynamically across temporal scales and demographic traits, parametrized using the habitat selection of 27 global positioning system (GPS)‐collared coyotes in the city of Toronto, Canada. The habitat selection models accounted for human population density, impervious area, vegetation density, and distance to different linear features. Results indicated that (1) vegetation‐dense areas were key for connectivity in urban areas; (2) riverbanks, railways, and areas below power lines were predicted as movement corridors; and (3) commercial and industrial clusters strongly disrupted connectivity. Spatiotemporal differences in connectivity were associated with time of day and coyote social status but not with climate and biological seasonality or coyote age and sex. Residential roads were pivotal in the temporal dynamism of connectivity. The maintenance and enhancement of plant structural complexity along key infrastructure (for example, highways, waterways, and parking lots) should be considered when managing connectivity corridors in cities.
Phase imaging in atomic force microscopy (AFM) is a useful technique for determining dissipative tip–sample interactions related to changes in the material surface properties such as local stiffness ...or adhesion. In this work, we applied both phase imaging and phase spectroscopy measurements to conducting polymer (polypyrrole) doped with either hyaluronic acid or chondroitin sulfate. As observed in previous studies, phase-separated regions correlating with the characteristic nodular topography of polypyrrole and attributed to crystalline (doped) and amorphous (undoped) regions were observed. However, through additional phase spectroscopy measurements, we show that the phase-separated regions can arise due to variation in attractive and repulsive tip–sample interactions across the polymer surface. We show that these attractive and repulsive interactions are dependent on the redox state and degree of doping and suggest that they are related to phase separation of the polymer surface charge and/or energy. The latter may have implications for these materials when under investigation in a fluid, or biological, environment. For example, such surface variations will play a role in electrostatic forces, which in turn can influence protein and cellular interactions.
Background. Nowadays, there is a lack of studies reporting techniques for the selective monitoring of the primary somatosensory cortex and the adjacent areas of the superior and inferior parietal ...lobules. We hypothesized a more specific and targeted test for awake surgery for monitoring the sensory area during resection of tumors involving it. Materials and Methods. We collected patients suffering from tumors involving the parietal areas and undergoing awake surgery for the resection. Intraoperative standard neurophysiological monitoring was performed, and we added a new intraoperative test. It consisted of a series of different objects with standard 3D conformations. The patient was asked to recognize the object shape using only the tactile sensibility, without seeing the object itself; in some cases, he was also asked to put the object in the corresponding hole, according to the shape. Results. We collected 6 patients. One patient with a right parieto-occipital lesion, at the stimulation of the anterior cortical margin of the surgical field, showed problems in naming the objects and collocating them in the corresponding spaces, while he was touching them with the left hand. Therefore, the areas of proprioception and perception of the objects were mapped and numbered. This deficit got better in the postoperative days with a total remission of the ideomotor apraxia and the psychomotor slowdown. The other 5 patients did not show an impairment with the new test. Conclusions. This is a preliminary study with the aim of enhancing the specificity of the neuropsychological test performed during awake surgery to allow the surgeon to monitor the neurological functions of the parietal cortex. More cases are needed to validate it.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, FZAB, GIS, IJS, KILJ, NUK, OILJ, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Due to their simplicity and comparatively low cost, Resistive Plate Chambers are gaseous detectors widely used in high-energy and cosmic rays physics when large detection areas are needed. However, ...the best gaseous mixtures are currently based on tetrafluoroethane, which has the undesirable characteristic of a large Global Warming Potential (GWP) of about 1400 and because of this, it is currently being phased out from industrial use. As a possible replacement, tetrafluoropropene (which has a GWP close to 1) has been taken into account. Since tetrafluoropropene is more electronegative than tetrafluoroethane, it has to be diluted with gases with a lower attachment coefficient in order to maintain the operating voltage close to 10 kV. One of the main candidates for this role is carbon dioxide. In order to ascertain the feasibility and the performance of tetrafluoropropene-CO2 based mixtures, an R&D program is being carried out in the ALICE collaboration, which employs an array of 72 Bakelite RPCs (Muon Identifier, MID) to identify muons. Different proportions of tetrafluoropropene and CO2, with the addition of small quantities of isobutane and sulphur hexafluoride, have been tested with 50 × 50 cm2 RPC prototypes with 2 mm wide gas gap and 2 mm thick Bakelite electrodes. In the presentation, results from tests with cosmic rays will be presented, together with data concerning the current drawn by a RPC exposed to the gamma-ray flux of the Gamma Irradiation Facility (GIF) at CERN.
Conjugated polymers have been proposed as promising materials for scaffolds in tissue engineering applications. However, the restricted processability and biodegradability of conjugated polymers ...limit their use for biomedical applications. Here we synthesized a block-co-polymer of aniline tetramer and PCL (AT–PCL), and processed it into fibrous non-woven scaffolds by electrospinning. We showed that fibronectin (Fn) adhesion was dependent on the AT–PCL oxidative state, with a reduced Fn unfolding length on doped membranes. Furthermore, we demonstrated the cytocompatibility and potential of these membranes to support the growth and osteogenic differentiation of MC3T3-E1 cells over 21 days.
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