We present 5321 mas-resolution total intensity and linear polarization maps of 437 active galactic nuclei (AGNs) obtained with the VLBA at 15 GHz as part of the MOJAVE survey, and also from the NRAO ...data archive. The former is a long-term program to study the structure and evolution of powerful parsec-scale outflows associated with AGNs. The targeted AGNs are drawn from several flux-limited radio and γ-ray samples, and all have correlated VLBA flux densities greater than ∼50 mJy at 15 GHz. Approximately 80% of these AGNs are associated with γ-ray sources detected by the Fermi LAT instrument. The vast majority were observed with the VLBA on 5-15 occasions between 1996 January 19 and 2016 December 26, at intervals ranging from a month to several years, with the most typical sampling interval being six months. A detailed analysis of the linear and circular polarization evolutions of these AGN jets is presented in the other papers in this series.
We present an analysis of the core linear polarization properties of 387 parsec-scale active galactic nuclei (AGNs) jets. Using 15 GHz VLBA data, we revisit the conclusions of the first paper in this ...series with multiepoch measurements and more detailed analysis of a larger AGN sample that spans a broader range of synchrotron peak frequencies. Each AGN has been observed for at least five epochs between 1996 and 2017. We find that BL Lac objects have core electric vector position angles (EVPAs) that tend toward alignment with the local jet direction; compared to flat spectrum radio quasars, their EVPAs are also less variable over time. The AGN cores that are most fractionally polarized and least variable in polarization have EVPAs that are closely aligned with the local jet direction; they also have low variability in EVPA. These results support the popular model of a standing transverse shock at the base of the jet that collimates the jet magnetic field perpendicular to the jet direction, increasing the fractional polarization and leading to greater polarization stability over time. High-synchrotron-peaked BL Lac objects form a low luminosity, low fractional polarization population. The five narrow line Seyfert 1 galaxies in our sample have low fractional polarization and large EVPA-jet misalignments. Although AGNs detected at γ-rays are thought to be more Doppler boosted than nondetected AGNs, we find no significant differences in fractional polarization based on detection by Fermi-LAT; the γ-loud AGNs are, however, more variable in core EVPAs.
Polymer electrolyte membrane (PEM) water electrolysis represents, in combination with renewable energy, progressive technology of hydrogen production. However, material-related issues still represent ...an obstacle in improvement of energy efficiency of the process. Porous transport layer (PTL) made usually of Ti, acting as a current collector and distributor of the water-gas flow, is a crucial part of the PEM water electrolysers. In this work, we investigate the impact of sintered Ti PTL structures on both the cathode and anode on the internal resistance of a single cell by means of voltage loss analysis. Less conventional and rarely applied porous transport electrode design favourable for high current density operation is used for the study. While activation and Ohmic resistance-related voltage losses were comparable for PTLs with different bulk porosities and pore opening diameters, mass transfer losses significantly increased when a less porous PTL was used on the anode. While the majority of mass transfer-related losses comes from the anode, it was proven that use of less porous cathode PTL mitigates these losses, pointing out a suitable combination of PTLs for improved performance.
•Porous transport layer parameters have strong effect on the electrolyser performance.•Porous transport layer bulk structure highly impacts the mass transport efficiency.•The effect of porous transport layer surface structure onto performance is negligible.•Advanced porous transport electrode design facilitates high current density operation.
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We report on a multiwavelength campaign for the radio-loud narrow-line Seyfert 1 (NLS1) galaxy PMNJ0948+0022 (z= 0.5846) performed in 2010 July-September and triggered by a high-energy γ-ray outburst ...observed by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. The peak flux in the 0.1-100 GeV energy band exceeded, for the first time in this type of source, the value of 10-6 photon cm-2s-1, corresponding to an observed luminosity of 1048ergs-1. Although the source was too close to the Sun position to organize a densely sampled follow-up, it was possible to gather some multiwavelength data that confirmed the state of high activity across the sampled electromagnetic spectrum. The comparison of the spectral energy distribution of the NLS1 PMNJ0948+0022 with that of a typical blazar - such as 3C273 - shows that the power emitted at γ-rays is extreme. PUBLICATION ABSTRACT
Single crystal halide perovskites with microscale dimensions are an emerging class of objects for various advanced photonic and optoelectronic applications. Particularly, defect tolerance and ...broadband tunability of luminescence make them one of the most prospective candidates to develop microlasers for visible range. However, their post‐processing by standard nanolithography methods face a number of problems related to worsening of their properties, thus making gentle laser processing one of best solutions for perovskite patterning. Here, it is shown that femtosecond laser irradiation of single‐crystal halide perovskite CsPbBr3 allows for its precise and ultraclean ablation fully controlled at subwavelength scale by the intensity and polarization distribution of the complex laser field applied. Indeed, the extremely low thermal conductivity (over 300 times lower than that of silicon) and ultrafast thermalization rate makes it possible to reduce heat‐affected zone and avoid melting layer contribution, while the high refractive index (larger than 2) provides high spatial resolution in case of irradiation of pre‐patterned focusing perovskite nanostructures. These features allow for direct imprinting of the incident laser field at wavelength λ = 515 nm, creating micro‐lens and various light‐emitting metasurfaces with deeply subwavelength spatial resolution (down to λ/7).
Femtosecond laser irradiation of single‐crystal halide perovskite CsPbBr3 allows for its precise and ultraclean ablation fully controlled at subwavelength scale by the intensity and polarization distribution of the complex laser field applied. The direct imprinting of the incident laser field results in the creation of micro‐lens and various light‐emitting metasurfaces with deeply subwavelength spatial resolution (down to lambda/7).
The efficient production of gaseous oxygen used in many branches of industry to provide human life in anaerobic environments and in medicine (e.g., in the case of acute respiratory failure as one of ...COVID-19 complications) is challenging nowadays. The electrochemical oxygen pump (concentrator) with a solid polymer electrolyte representing an electrolyzer with air cathode depolarization is a very promising device, which provides the portable, safe, and efficient in situ production of highly pure oxygen at a twice lower energy consumption as compared to the water electrolyzer with a solid polymer electrolyte. The effect produced by the hydrophobization of a nanostructured oxygen reduction catalyst on the oxygen pump characteristics and the endurance of a cathode catalytic layer to flooding has been considered. The modification of a carbon support with polytetrafluoroethylene particles improves the removal of excessive water from the catalytic layer and increases the limiting current characterizing the appearance of transport limitations. The operational parameters (air temperature, flow rate, and pressure) also have an essential effect on the oxygen pump performance and must be optimized to improve water transport in catalytic layers, increase the operating current densities, and reduce the energy consumption in oxygen production.
Thin films and nanowires based on lead halide perovskites are promising objects for the design of various optoelectronic devices as well as nano- and microlasers. One of the main advantages of such ...materials is their absorption and photoluminescence spectra tuning across the visible range via the change in their chemical composition, for instance, by substitution of one halide atom (Br) for another one (I) in the crystal lattice of CsPb(Br1-xIx)3. However, this approach gives materials showing unstable photoluminescence behavior caused by light-induced perovskite phase separation under high-intensity excitation at room temperature. In this work, CsPb(Br1-xIx)3 thin films and nanowires are obtained by chemical vapor anion exchange method from their CsPbBr3 counterparts fabricated by improved wet chemical methods. Spontaneous and stimulated emission from the mixed-halide and pristine bromide samples are studied. Tribromide nanowires exhibit lasing with relatively low thresholds (10–100 μJ/cm2) and high Q-factor of the laser mode up to 3500. The temperature dependence of the photoinitiated phase separation in CsPbBr1.5I1.5 samples is investigated, showing that light-induced phase instability of the mixed-halide nanowires can be suppressed at the somewhat higher temperature (250 K) than the value observed for the thin films having a similar chemical composition. The results obtained are important for the optimization of the functioning of optoelectronic devices based on considered perovskite materials.
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•No phase separation occurs at 200 K for CsPbBr1.5I1.5 films and 250 K for nanowires.•СsPbBr3 nanowires show high Q-factor lasing (~3500) at low thresholds (10–100 μJ/cm2).•Nature of the phase instability is a migration of photoactivated ions in perovskite.
We report on a multiwavelength campaign for the radio-loud narrow-line Seyfert 1 (NLS1) galaxy PMN J0948+0022 (z= 0.5846) performed in 2010 July-September and triggered by a high-energy γ-ray ...outburst observed by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. The peak flux in the 0.1-100 GeV energy band exceeded, for the first time in this type of source, the value of ∼10−6 photon cm−2 s−1, corresponding to an observed luminosity of ∼1048 erg s−1. Although the source was too close to the Sun position to organize a densely sampled follow-up, it was possible to gather some multiwavelength data that confirmed the state of high activity across the sampled electromagnetic spectrum. The comparison of the spectral energy distribution of the NLS1 PMN J0948+0022 with that of a typical blazar - such as 3C 273 - shows that the power emitted at γ-rays is extreme.
Background.
Modern minimally invasive surgical techniques reduce traumatism of operative interventions and aggressive anaesthesia, which accordingly shortens the patient’s hospital stay and ...rehabilitation period.
Aim.
An improvement of surgical outcomes in patients with purulent pyelonephritis via introduction of laparoscopic techniques.
Materials and methods
. Th e study included 80 purulent pyelonephritis patients operated at the Territorial Clinical Hospital during 2006—2018. Th e patients were divided between two cohorts. Cohort 1 included 40 (50 %) patients operated with standard techniques (ST), cohort 2 — 40 (50 %) patients having surgery by an original minimally invasive technique (OT). Kidney decapsulation was found to outcome in parenchymal decompression and blood circulation restore in cortical layer. Intraarterial infusion of alprostadil prevents further spread of purulent-destructive processes in kidney.
Results and discussion
. In patients with the minimally invasive technique, postoperative period proceeded at no complications. On day 1, the patients reported reduced pain syndrome in the surgical area. Contrasted renal MSCT before and aft er surgery showed the recovery of renal blood flow and significant diminishing of destruction foci in short term. Nephrectomy was not performed as no-indication.
Conclusion.
The treatment outcomes in 40 patients having the new surgical technique demonstrate its efficacy and applicability in clinical practice.
Primary hyperoxaluria is a group of rare inherited diseases characterized by impaired oxalate metabolism with the early manifestation of urolithiasis and the development of the chronic kidney ...disease. The mutations in the AGXT, GRHPR, HOGA1 genes are attributable for different types of primary hyperoxaluria leading to the dysfunction of specific enzymes involved in the oxalate metabolism. The article summary the current data on the epidemiology, genetic and biochemical aspects of pathogenesis of the primary hyperoxaluria types 1-3. The variety of clinical signs and disease severity depend on the type of hyperoxaluria.
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