14 research outputs found
Electrospun Biodegradable Nanofibers Coated Homogenously by Cu Magnetron Sputtering Exhibit Fast Ion Release. Computational and Experimental Study
Copper-coated nanofibrous materials are desirable for catalysis, electrochemistry, sensing, and biomedical use. The preparation of copper or copper-coated nanofibers can be pretty challenging, requiring many chemical steps that we eliminated in our robust approach, where for the first time, Cu was deposited by magnetron sputtering onto temperature-sensitive polymer nanofibers. For the first time, the large-scale modeling of PCL films irradiation by molecular dynamics simulation was performed and allowed to predict the ions penetration depth and tune the deposition conditions. The Cu-coated polycaprolactone (PCL) nanofibers were thoroughly characterized and tested as antibacterial agents for various Gram-positive and Gram-negative bacteria. Fast release of Cu2+ ions (concentration up to 3.4 mu g/mL) led to significant suppression of E. coli and S. aureus colonies but was insufficient against S. typhimurium and Ps. aeruginosa. The effect of Cu layer oxidation upon contact with liquid media was investigated by X-ray photoelectron spectroscopy revealing that, after two hours, 55% of Cu atoms are in form of CuO or Cu(OH)(2). The Cu-coated nanofibers will be great candidates for wound dressings thanks to an interesting synergistic effect: on the one hand, the rapid release of copper ions kills bacteria, while on the other hand, it stimulates the regeneration with the activation of immune cells. Indeed, copper ions are necessary for the bacteriostatic action of cells of the immune system. The reactive CO2/C2H4 plasma polymers deposited onto PCL-Cu nanofibers can be applied to grafting of viable proteins, peptides, or drugs, and it further explores the versatility of developed nanofibers for biomedical applications use
DsTau: Study of tau neutrino production with 400 GeV protons from the CERN-SPS
In the DsTau experiment at the CERN SPS, an independent and direct way to
measure tau neutrino production following high energy proton interactions was
proposed. As the main source of tau neutrinos is a decay of Ds mesons, produced
in proton-nucleus interactions, the project aims at measuring a differential
cross section of this reaction. The experimental method is based on a use of
high resolution emulsion detectors for effective registration of events with
short lived particle decays. Here we present the motivation of the study,
details of the experimental technique, and the first results of the analysis of
the data collected during test runs, which prove feasibility of the full scale
study of the process in future
The ATLAS ITk Strip Detector System for the Phase-II LHC Upgrade
ATLAS is currently preparing for the HL-LHC upgrade, with an all-silicon Inner Tracker (ITk) that will replace the current Inner Detector. The ITk will feature a pixel detector surrounded by a strip detector, with the strip system consisting of 4 barrel layers and 6 endcap disks. After completion of final design reviews in key areas, such as Sensors, Modules, Front-End electronics and ASICs, a large scale prototyping program has been completed in all areas successfully. We present an overview of the Strip System, and highlight the final design choices of sensors, module designs and ASICs. We will summarize results achieved during prototyping and the current status of production and pre-production on various detector components, with an emphasis on QA and QC procedures
Alpha2-Adrenergic Receptors as a Pharmacological Target for Spike-Wave Epilepsy
Spike-wave discharges are the hallmark of idiopathic generalized epilepsy. They are caused by a disorder in the thalamocortical network. Commercially available anti-epileptic drugs have pronounced side effects (i.e., sedation and gastroenterological concerns), which might result from a low selectivity to molecular targets. We suggest a specific subtype of adrenergic receptors (ARs) as a promising anti-epileptic molecular target. In rats with a predisposition to absence epilepsy, alpha2 ARs agonists provoke sedation and enhance spike-wave activity during transitions from awake/sedation. A number of studies together with our own observations bring evidence that the sedative and proepileptic effects require different alpha2 ARs subtypes activation. Here we introduce a new concept on target pharmacotherapy of absence epilepsy via alpha2B ARs which are presented almost exclusively in the thalamus. We discuss HCN and calcium channels as the most relevant cellular targets of alpha2 ARs involved in spike-wave activity generation
Intracortical synchronization pattern on the preclinical and clinical stages of absence epilepsy (analysis of wavelet bicoherence in WAG/Rij rats)
Here we examine the intracortical synchronization pattern in freely moving WAG/Rij rats (valid animal model of absence epilepsy). In all rats, electrocorticograms were recorded at the age 5 and 9 months (i.e., preclinical and clinical stages of absence epilepsy in epileptic subjects). To assess intracortical synchronization pattern, we measured wavelet bicoherence in unilateral (fronto-frontal) and bilateral (fronto-occipital) electrode pairs in five non-overlapping frequency bands (“1–4 Hz”; “5–9 Hz”; “9–12 Hz”; “12–14 Hz”; “14–20 Hz”) and two additional bands “0.5–1.5 Hz”; “10–14 Hz” bands. Bilateral fronto-frontal synchronization in epileptic subjects was lower than in non-epileptic ones only on the clinical stage of absence epilepsy. Unilateral fronto-occipital synchronization in epileptic rats was lower (“5–9 Hz” and “10–14 Hz”) than in non-epileptic ones only on preclinical stage. This finding may be interpreted as a marker of thalamo-cortical impairment associated with epileptogenic processes underlying long-term progression of absence epilepsy. We construct plots of synchronization patterns or diagnostic maps, which can be used for early diagnosis of absence epilepsy in predisposed subjects
Reduction of Hippocampal High-Frequency Activity in Wag/Rij Rats with a Genetic Predisposition to Absence Epilepsy
In temporal lobe epilepsy, high frequency oscillations serve as electroencephalographic (EEG) markers of epileptic hippocampal tissue. In contrast, absence epilepsy and other idiopathic epilepsies are known to result from thalamo-cortical abnormalities, with the hippocampus involvement considered to be only indirect. We aimed to uncover the role of the hippocampus in absence epilepsy using a genetic rat model of absence epilepsy (WAG/Rij rats), in which spike-wave discharges (SWDs) appear spontaneously in cortical EEG. We performed simultaneous recordings of local field potential from the hippocampal dentate gyrus using pairs of depth electrodes and epidural cortical EEG in freely moving rats. Hippocampal ripples (100–200 Hz) and high frequency oscillations (HFO, 50–70 Hz) were detected using GUI RIPPLELAB in MatLab (Navarrete et al., 2016). Based on the dynamics of hippocampal ripples, SWDs were divided into three clusters, which might represent different seizure types in reference to the involvement of hippocampal processes. This might underlie impairment of hippocampus-related cognitive processes in some patients with absence epilepsy. A significant reduction to nearly zero-ripple-density was found 4–8 s prior to SWD onset and during 4 s immediately after SWD onset. It follows that hippocampal ripples were not just passively blocked by the onset of SWDs, but they were affected by spike-wave seizure initiation mechanisms. Hippocampal HFO were reduced during the preictal, ictal and postictal periods in comparison to the baseline. Therefore, hippocampal HFO seemed to be blocked with spike-wave seizures. All together, this might underlie impairment of hippocampus-related cognitive processes in some patients with absence epilepsy. Further investigation of processes underlying SWD-related reduction of hippocampal ripples and HFO oscillations may help to predict epileptic attacks and explain cognitive comorbidities in patients with absence epilepsy
Measuring spatial ability for talent identification, educational assessment, and support: evidence from adolescents with high achievement in science, arts, and sport
Background. Spatial ability (SA) is a robust predictor of academic and occupational achievement. The present study investigated the psychometric properties of 10 tests for measuring of SA in a sample of talented schoolchildren. Objective. Our purpose was to identify the most suitable measurements for SA for the purpose of talent identification, educational assessment, and support. Design. Our sample consisted of 1479 schoolchildren who had demonstrated high achievement in Science, Arts, or Sports. Several criteria were applied to evaluate the measurements, including an absence of floor and ceiling effects, low redundancy, high reliability, and external validity. Results. Based on these criteria, we included the following four tests in an Online Short Spatial Ability Battery “OSSAB”: Pattern Assembly; Mechanical Reasoning; Paper Folding; and Shape Rotation. Further analysis found differences in spatial ability across the three groups of gifted adolescents. The Science track showed the highest results in all four tests. Conclusion. Overall, the study suggested that the Online Short Spatial Ability Battery (OSSAB) can be used for talent identification, educational assessment, and support. The analysis showed a unifactorial structure of spatial abilities. Future research is needed to evaluate the use of this battery with other specific samples and unselected populations
Keyhole into a Lost World: The First Purely Freshwater Species of the Ponto-Caspian Genus Clathrocaspia (Caenogastropoda: Hydrobiidae)
The species of the Ponto-Caspian gastropod genus Clathrocaspia Lindholm, 1930 have been recorded so far from the Caspian Sea Basin only from marine waters, whereas they inhabit the estuarine areas as well as the purely freshwater environments in the Azov–Black Sea Basin. This genus has recently been assessed as putatively extinct in the Caspian Sea. A new purely freshwater species Clathrocaspia laevigata sp. n. from the water-flows of the Samur River delta in Dagestan, Russia, is described. A morphological comparison of the new species with C. brotzkajae (Starobogatov in Anistratenko & Prisjazhnjuk, 1992) from the Caspian Sea and C. knipowitschii (Makarov, 1938) inhabiting the Azov–Black Sea Basin shows their overall similarity. The major difference is that C. laevigata sp. n. almost completely lacks the reticulate teleoconch sculpture, whereas it is well-developed in all known Clathrocaspia species. The molecular data revealed probable sister relationships between the new species and C. knipowitschii. All Dagestan populations are ecologically and spatially isolated from the open sea and and are very locally restricted. We suggest to consider newly described snail species as retained in a pure freshwater refuge located in the coastal area of the Caspian Sea. The discovery of such a refuge sheds more light on the origin, current state and the future of the unique Ponto-Caspian aquatic biota under global change and increasing anthropogenic impact