Search Results (8)

In 2023, the Chinese company PIESAT launched the multi-static X-band SAR constellation Hongtu-1 (HT1). HT1 consists of the active monostatic SAR sensor HT1-A and the three additional passive SAR receivers HT1-B, HT1-C and HT1-D. The passive sensors are arranged as a cartwheel in a circle around the active sensor. For our SAR interferometric investigation, we were able to use a multi-static HT1 recording. After a brief introduction of HT1, we describe the processing performed. Based on the phases of the six single-pass interferometric pairs, we calculated height differences relative to the Copernicus DEM. Larger deviations were observed mainly for mining areas and for forest areas. Thanks to the simultaneous acquisition of the interferometric pairs, the high spatial resolution and the good signal quality, the necessary processing was relatively easy to perform. Besides the interferometric phase, we also investigated possible applications of multi-static coherence. Forest can be recognized by its reduced single-pass coherence values. Based on our results, we expect that the multi-static HT1 coherence and its dependence on the interferometric baseline can be used to estimate parameters such as forest biomass. Full article

The PIESAT-01 constellation is the world’s first multi-baseline distributed synthetic aperture radar (SAR) constellation with a “Cartwheel” formation. The “Cartwheel” formation is a unique formation in which four satellites fly in companion orbits, ensuring that at any given moment, the main satellite remains at the center, with three auxiliary satellites orbiting around it. Due to this unique configuration of the PIESAT-01 constellation, four images of the same region and six pairs of baselines can be obtained with each shot. So far, there has been no imaging and interference research based on four-satellite constellation measured data, and there is an urgent need to explore algorithms for the “Cartwheel” configuration imaging and digital surface model (DSM) production. This paper introduces an improved bistatic SAR imaging algorithm under the four-satellites interferometric mode, which solves the problem of multi-orbit nonparallelism in imaging while ensuring imaging coherence and focusing ability. Subsequently, it presents an interferometric processing method for the six pairs of baselines, weighted fusion based on elevation ambiguity from different baselines, to obtain a high-precision DSM. Finally, this paper selects the Dingxi region of China and other regions with diverse terrains for imaging and DSM production and compares the DSM results with ICESat-2 global geolocated photon data and TanDEM DSM data. The results indicate that the accuracy of PIESAT-01 DSM meets the standards of China’s 1:50,000 scale and HRTI-3, demonstrating a high level of precision. Moreover, PIESAT-01 data alleviate the reliance on simulated data for research on multi-baseline imaging and multi-baseline phase unwrapping algorithms and can provide more effective and realistic measured data. Full article

Pseudomonas aeruginosa is notorious for its ability to develop a high level of resistance to antimicrobial agents. Resistance-nodulation-division (RND) efflux pumps could mediate drug resistance in P. aeruginosa. The present study aimed to evaluate the antibacterial and anti-efflux activities of cinnamon essential oil either alone or combined with ciprofloxacin against drug resistant P. aeruginosa originated from human and animal sources. The results revealed that 73.91% of the examined samples were positive for P. aeruginosa; among them, 77.78% were of human source and 72.73% were recovered from animal samples. According to the antimicrobial resistance profile, 48.73% of the isolates were multidrug-resistant (MDR), 9.2% were extensive drug-resistant (XDR), and 0.84% were pan drug-resistant (PDR). The antimicrobial potential of cinnamon oil against eleven XDR and one PDR P. aeruginosa isolates was assessed by the agar well diffusion assay and broth microdilution technique. The results showed strong antibacterial activity of cinnamon oil against all tested P. aeruginosa isolates with inhibition zones’ diameters ranging from 34 to 50 mm. Moreover, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of cinnamon oil against P. aeruginosa isolates ranged from 0.0562–0.225 µg/mL and 0.1125–0.225 µg/mL, respectively. The cinnamon oil was further used to evaluate its anti-efflux activity against drug-resistant P. aeruginosa by phenotypic and genotypic assays. The cartwheel test revealed diminished efflux pump activity post cinnamon oil exposure by two-fold indicating its reasonable impact. Moreover, the real-time quantitative polymerase chain reaction (RT-qPCR) results demonstrated a significant (p < 0.05) decrease in the expression levels of MexA and MexB genes of P. aeruginosa isolates treated with cinnamon oil when compared to the non-treated ones (fold changes values ranged from 0.4204–0.7474 for MexA and 0.2793–0.4118 for MexB). In conclusion, we suggested the therapeutic use of cinnamon oil as a promising antibacterial and anti-efflux agent against drug-resistant P. aeruginosa. Full article

Mammals have a dorsal cochlear nucleus (DCN), which is thought to be a cerebellum-like structure with similar features in terms of structure and microcircuitry to the cerebellum. Both the DCN and cerebellum perform their functions depending on synaptic and neuronal networks mediated by various glutamate receptors. Kainate receptors (KARs) are one class of the glutamate receptor family and are strongly expressed in the hippocampus, the cerebellum, and cerebellum-like structures. The cellular distribution and the potential role of KARs in the hippocampus have been extensively investigated. However, the cellular distribution and the potential role of KARs in cerebellum-like structures, including the DCN and cerebellum, are poorly understood. In this review, we summarize the similarity between the DCN and cerebellum at the levels of structure, circuitry, and cell type as well as the investigations referring to the expression patterns of KARs in the DCN and cerebellum according to previous studies. Recent studies on the role of KARs have shown that KARs mediate a bidirectional modulatory effect at parallel fiber (PF)–Purkinje cell (PC) synapses in the cerebellum, implying insights into their roles in cerebellum-like structures, including the DCN, that remain to be explored in the coming years. Full article

We describe the macular morpho-functional assessment of a 65-year-old man affected by stellate nonhereditary idiopathic foveomacular retinoschisis (SNIFR), studied by visual field, SD-OCT, autofluorescence, full-field electroretinogram (ffERG), multifocal electroretinogram (mfERG) and multifocal Photopic Negative Response (mfPhNR) recordings. The typical presentation consists of the foveal appearance of radial cartwheel pattern for the splitting of the retinal layers at the level of the Henle fiber layer (HFL) and the outer plexiform layer (OPL), perfectly seen by Spectral Domain-Optical Coherence Tomography (SD-OCT). Despite a normal function of the outer retina of the peripheral and central retina evaluated by ffERG and mfERG respectively, we observed a reduced function of the retinal elements involved in the retinoschisis by recording mfPhNR that assesses mainly inner retina function (retinal ganglion cells and their axons). Therefore, it is likely that the observed impaired mfPhNR responses reflect the signaling defects derived from the delaminated middle retina and transmitted to the innermost retinal layers. Full article

Background: During the first Austrian MotoGP Grand Prix of 2020, following a serious accident involving the riders J. Zarco and F. Morbidelli, Morbidelli’s riderless bike cartwheeled across turn 3, narrowly missing V. Rossi and M. Viñales by just a few centimeters. As is the case with ordinary traffic accidents, analyzing the dynamics of motorcycle racing accidents can help improve safety; however, to date, the literature lacks studies that analyze the causes and severity of such accidents. Hence, the purpose of this study was to analyze the main causes that led to the accident at the 2020 Austrian MotoGp Grand Prix, to quantify the speeds and distances of the bikes and riders involved, and to hypothesize several alternative scenarios using a low-cost method. Method: Kinovea and Google Earth Pro software were used to identify markers along the racetrack and to measure the distances and calculate the time it took the motorcycles to cover those distances. The analyses were carried out on three 30-fps (frames per second) videos. Results: Zarco’s average speed as he was overtaking Morbidelli on the straightaway before turn 2 was 302 ± 1.8 km/h, higher than that of Rins and Rossi (299.7 ± 1.7 and 296 ± 1.7 km/h, respectively). The speed of Zarco and Rossi’s bikes 44.5 m before the crash was the same (267 ± 7.9 km/h). Immediately after overtaking Morbidelli, Zarco moved 2.92 m towards the center of the racetrack from point A to B, crossing Morbidelli’s trajectory and triggering the accident. Morbidelli’s riderless bike flew across turn 3 at a speed of about 76 km/h, missing V. Rossi by just 20 cm. The consequences could have been catastrophic if Rossi had not braked just 0.42 s before encountering Morbidelli’s bike in turn 3. Conclusion: Through a low-cost quali-quantitative analysis, the present study helps us to gain a deeper understanding of the dynamics of the accident and its main causes. Furthermore, in light of our findings regarding the dynamics and severity of the accident and the particular layout of the Red Bull Ring circuit, racers should be aware that overtaking at the end of turn 2, following the same trajectory as the riders involved in the crash, could be very risky. Full article

Drosophila spermatocytes have giant centrioles that display unique properties. Both the parent centrioles maintain a distinct cartwheel and nucleate a cilium-like region that persists during the meiotic divisions and organizes a structured sperm axoneme. Moreover, the parent centrioles are morphologically undistinguishable, unlike vertebrate cells in which mother and daughter centrioles have distinct structural features. However, our immunofluorescence analysis of the parent centrioles in mature primary spermatocytes revealed an asymmetric accumulation of the typical Sas4 and Sas6 proteins. Notably, the fluorescence intensity of Sas4 and Sas6 at the daughter centrioles is greater than the intensity found at the mother ones. In contrast, the centrioles of wing imaginal disc cells display an opposite condition in which the loading of Sas4 and Sas6 at the mother centrioles is greater. These data underlie a subtle asymmetry among the parent centrioles and point to a cell type diversity of the localization of the Sas4 and Sas6 proteins. Full article

Centrioles make up the centrosome and basal bodies in animals and as such play important roles in cell division, signalling and motility. They possess characteristic 9-fold radial symmetry strongly influenced by the protein SAS-6. SAS-6 is essential for canonical centriole assembly as it forms the central core of the organelle, which is then surrounded by microtubules. SAS-6 self-assembles into an oligomer with elongated spokes that emanate towards the outer microtubule wall; in this manner, the symmetry of the SAS-6 oligomer influences centriole architecture and symmetry. Here, we summarise the form and symmetry of SAS-6 oligomers inferred from crystal structures and directly observed in vitro. We discuss how the strict 9-fold symmetry of centrioles may emerge, and how different forms of SAS-6 oligomers may be accommodated in the organelle architecture. Full article