Herewith, first-principles calculations based on density functional theory are used to describe the ideal magnetization reversal through polarization switching in BaCuF4 which, according to our ...results, could be accomplished close to room temperature. We also show that this ideal coupling is driven by a single soft mode that combines both polarization, and octahedral rotation. The later being directly coupled to the weak ferromagnetism of BaCuF4. This, added to its strong Jahn-Teller distortion and its orbital ordering, makes this material a very appealing prototype for crystals in the ABX4 family for multifunctional applications. The described mechanism behaves ideally as it couples the ferroelectric and the magnetic properties naturally and it has not been reported previously.1
► Expanded schist for H2S biofiltration was studied at EBRT=35, 24 and 16s. ► The ability of the expanded schist to treat high H2S loading rates was demonstrated. ► The good mechanical behavior of ...the schist was observed over one year. ► Shock loads confirmed the ability of the schist to withstand sudden high load changes. ► Experimental results were fitted with Michaelis–Menten and Haldane models.
The performances of three laboratory-scale biofilters (BF1, BF2, BF3) packed with expanded schist for H2S removal were studied at different empty bed residence times (EBRT=35, 24 and 16s) in terms of elimination capacity (EC) and removal efficiency (RE). BF1 and BF2 were filled with expanded schist while BF3 was filled with both expanded schist and a nutritional material (UP20; 12% vol). BF1 and BF3 were inoculated with activated sludge, whereas BF2 was not inoculated. A maximum EC of 42gm−3h−1 was recorded for BF3 at EBRT=35s demonstrating the ability of schist to treat high H2S loading rates, and the ability of UP20 to improve H2S removal. Michaelis–Menten and Haldane models were fitted to the experimental elimination capacities while biofilter responses to transient-state conditions in terms of removal efficiency during shock load events were also evaluated for BF1 and BF3.
The present investigation demonstrated that through microwave treatment of natural fiber wastes, cellulose microfibrils with a purity of 86.82% by weight, a crystallinity percentage of 92.5%, lengths ...from 1 to 15 mm, and diameters between 7 and 12 µm are obtained. These results were obtained with a one-step methodology, where Agave fibers were suspended in ethylene glycol and irradiated for 5 min with a constant power of 200 W and temperature of 250 °C. In-situ analyses (heating rate, pressure, and aspect ratio of the reaction vial) performed during microwave irradiation, as well as the characterization (thermal, chemical, and morphological) of the treated agave fibers, indicated that dielectric heating of the components of the agave fibers (waxes, pectin, hemicellulose, lignin) produces their depolymerization and leaching towards the reaction medium (ethylene glycol) until their defibration is achieved. The reaction kinetics at different temperatures and times showed that the purification of the fibers starts at 12,000 W. However, to finally obtain the microfibrils, it is necessary to apply 69,812 W. This process has the advantage that the fiber does not have to be treated with chemical substances or mechanical processes before the microwave treatment. Moreover, no additives, reducers, or catalysts are used during or after the treatment, which makes it a novel and optimal process to produce highly pure and crystalline cellulose microfibrils for high-value-added applications.
Graphical abstract
Autoimmune comorbidity in achalasia patients Romero-Hernández, Fernanda; Furuzawa-Carballeda, Janette; Hernández-Molina, Gabriela ...
Journal of gastroenterology and hepatology
33, Številka:
1
Journal Article
Recenzirano
Idiopathic achalasia is a rare esophageal motor disorder. The disease state manifests local and systemic inflammation, and it appears that an autoimmune component and specific autoantibodies ...participate in the pathogenesis. The study aims to determine the prevalence of autoimmune and chronic inflammatory diseases in patients with achalasia and compare the results with those from patients with gastroesophageal reflux disease (GERD).
It was a cross-sectional and included 114 patients with idiopathic achalasia and 114 age-matched and sex-matched control patients with GERD. Data on the presence of autoimmune and inflammatory diseases, the time of presentation, and any family history of autoimmune disease were obtained from the hospital's medical records.
Seventy three (64%) were female patients (mean age: 42.3 ± 15.5; median disease duration: 12 months). We identified the presence of autoimmune disease in 19 patients with achalasia (16.7%), hypothyroidism was the main diagnosis, and it was present in 52.6% of patients compared with 4.2% in controls. Thirteen of the 19 achalasia patients (68.4%) with autoimmune disease had history of familial autoimmunity. We identified 11 achalasia (9.6%) and 5 GERD patients (4.16%) with an inflammatory condition. Compared with the GERD, the achalasia group was 3.8 times more likely to have an autoimmune disease (95% CI: 1.47-9.83), 3.0 times more likely to have thyroidopathies (95% CI: 1.00-9.03), and 3.02 times more likely to suffer from any chronic inflammatory disease (95% CI: 1.65-6.20).
The non-negligible number of patients with autoimmune diseases identified among the patients with idiopathic achalasia supports the hypothesis that achalasia has an autoimmune component.
•In the AlCoCrCuFeNi High-Entropy Alloy, copper was replaced by titanium for hardening effects.•Samples were synthesized following a solid-state route (mechanical alloying and vacuum ...sintering).•Hardness and elastic modulus were determined using nanoindentation testing.•Evidence shows a clear correlation between composition/crystalline structure and final mechanical properties.•Prepared samples were composed of three main phases and nanometric precipitates.
The concept of High-Entropy Alloy (HEA) expanded the research field of advanced metallic materials for various applications, like the development of ultra-hardness ballistic protection materials for national security. Although there can be hundreds of compositions, carefully selecting the constituent is mandatory to improve their mechanical behavior, keeping in mind their microstructural array based on chemical composition. In the present study, the AlCoCrCuFeNi HEA was modified, replacing copper with titanium, looking for the formation of a Ti-rich BCC phase for hardening effects. Samples were prepared following the powder metallurgy route, including mechanical alloying favoring the generation of a nanocrystalline microstructure. Studies based on structure, microstructure and nanoindentation testing on each phase of the alloy were performed to determine the correlation between their composition, crystalline structure and mechanical properties. Evidence showed the formation of three main micrometric phases (two BCC and one tetragonal) coexisting with a nanometric dispersion of rounded precipitates. Nanoindentation testing shows that the main hardening effect was related to the tetragonal phase formation by a solid-solution strengthening mechanism. This phase reached the highest hardness (14.9 GPa); meanwhile, the richest Ti phase showed the lowest elastic modulus, titanium favors the material ductility.
To investigate the impact of the adjustment of initial intracerebral hemorrhage (ICH) volume by onset-to-imaging time (ultraearly hematoma growth uHG) on further hematoma enlargement and outcome in ...patients with acute ICH.
We studied 133 patients with acute (<6 hours) supratentorial ICH. Patients underwent baseline and 24-hour CT scans for ICH volume measurement, and a CT angiography (CTA) for the detection of the spot sign. We defined uHG as the relation between baseline ICH volume/onset-to-imaging time, hematoma growth (HG) as hematoma enlargement >33% or >6 mL at 24 hours, early neurologic deterioration (END) as increase ≥4 points in the NIH Stroke Scale score or death at 24 hours, and poor long-term outcome as modified Rankin Scale score >2 at 3 months.
The uHG was significantly faster in spot sign patients (p < 0.001), as well as in patients who experienced HG (p = 0.021), END (p < 0.001), 3-month mortality (p < 0.001), and poor long-term outcome (p < 0.001). The uHG improved the accuracy of baseline ICH volume in the prediction of END (sensitivity 93.1% vs 82.8%, specificity 85.3% vs 82.4%) and 3-month mortality (sensitivity 77.5% vs 70%, specificity 87.9% vs 84.6%). A uHG >10.2 mL/hour emerged as the most powerful predictor of HG (odds ratio OR 3.55, 95% confidence interval CI 1.39-9.07, p = 0.008), END (OR 70.22, 95% CI 14.63-337.03, p < 0.001), 3-month mortality (OR 16.96, 95% CI 5.32-54.03, p < 0.001), and poor long-term outcome (OR 6.19, 95% CI 1.32-28.98, p = 0.021).
The uHG represents a powerful and easy-to-use tool for improving the prediction of HG and outcome in patients with acute ICH.
Abstract
The Mn valence in thin film La
0.7
Sr
0.3
MnO
3
was studied as a function of film thickness in the range of 1–16 unit cells with a combination of non-destructive bulk and surface sensitive ...X-ray absorption spectroscopy techniques. Using a layer-by-layer valence model, it was found that while the bulk averaged valence hovers around its expected value of 3.3, a significant deviation occurs within several unit cells of the surface and interface. These results were supported by first principles calculations. The surface valence increases to up to Mn
3.7+
, whereas the interface valence reduces down to Mn
2.5+
. The change in valence from the expected bulk value is consistent with charge redistribution due to the polar discontinuity at the film-substrate interface. The comparison with theory employed here illustrates how this layer-by-layer valence evolves with film thickness and allows for a deeper understanding of the microscopic mechanisms at play in this effect. These results offer insight on how the two-dimensional electron gas is created in thin film oxide alloys and how the magnetic ordering is reduced with dimensionality.
The present work is a comprehensive study of the ionospheric vertical total electron content (vTEC) variations during the nighttime, based on data collected by ground‐based Global Navigation ...Satellite System (GNSS) receivers over the Latin American region. We provide a qualitative and quantitative analysis of the ionospheric vTEC trend at 21:00, 00:00, and 03:00 local time (LT), during geomagnetically undisturbed days of 2011 (ascending phase) and 2014 (maximum phase), which encompassed (a) the response to the solar flux variation, (b) the seasonal trend in different latitudes and longitudes, and (c) the interhemispheric asymmetry. One significant result of this study is the development of TEC maps for the Latin American region, which are used for the monitoring and forecasting of the ionosphere for space weather purposes. The nighttime vTEC variations showed a strong latitudinal dependence, especially in the Northern Hemisphere. For 2011, the semiannual anomaly was similar to that observed in daytime; however, in 2014, the receivers at midlatitude presented asymmetric behavior. Similarly, the nighttime winter anomaly (NWA) was very weak in both years. The Equatorial Ionospheric Anomaly (EIA) signature was absent from June to August, a period in which the hemispheric disparity in the vTEC values became more evident, suggesting a feeble interhemispheric circulation. The Midlatitude Summer Nighttime Anomaly (MSNA) was also identified in the Southern Hemisphere, during January and February of 2011 (moderate solar activity). Model approximations suggest that the equatorward winds and the EIA were involved in the formation of the MSNA.
Key Points
TEC maps for the Latin American region have been developed as a tool for analyzing the spatial and temporal nighttime ionosphere variations
The MSNA was analyzed in terms of downward plasma fluxes and equatorward winds registered during January and December
The seasonal variability of the ionosphere over this region, including the EIA and the MSNA, became no longer significant after midnight
Daytime Ionospheric TEC Weather Study Over Latin America Romero‐Hernandez, E.; Denardini, C. M.; Takahashi, H. ...
Journal of geophysical research. Space physics,
December 2018, 2018-12-00, 20181201, Letnik:
123, Številka:
12
Journal Article
Recenzirano
Odprti dostop
The present work is the first of a two‐part weather study of the ionospheric Total Electron Content (TEC), based on data collected by four ground‐based Global Navigation Satellite System networks ...that cover the whole Latin America from the Patagonia to the north of Mexico. From the best of our knowledge, the maps presented here are the first TEC maps obtained using ground‐based data that covers the entire Latin America region, which represent an advance to the space weather monitoring and forecasting of the ionosphere. This work provides a qualitative and quantitative daytime analysis of the ionospheric TEC variation, which encompasses: (a) the response of TEC to the solar flux at midday; (b) the seasonal variation of TEC in different latitudinal ranges; and (c) the North‐South asymmetry of TEC over Latin America. The response to the solar flux is based on day‐to‐day TEC variations during two periods of different solar activity conditions: 2011 (ascending phase) and 2014 (maximum). The approximations of meridional wind component derived from Horizontal Wind Model‐14 model and hmF2 obtained from International Reference Ionosphere model were used. Equinoctial asymmetries with an opposite configuration in high and moderate solar activity were identified in the TEC variation. For 2011, it was related to the solar flux change. However, in 2014, according to the hmF2 variation, the influence of neutral wind becomes dominant. Among the results, we highlight an absence of winter anomaly in the Northern Hemisphere in 2014 and a stronger annual anomaly for latitudes under −20∘.
Key Points
The response of TEC to solar flux over Latin America is investigated
The seasonal variation of TEC over Latin America during daytime is analyzed
North‐South asymmetries of TEC over Latin America during daytime are identified
sPHENIX is a new experiment under construction for the Relativistic Heavy Ion Collider at Brookhaven National Laboratory which will study the quark-gluon plasma to further the understanding of ...quantum chromodynamics (QCP) matter and interactions. A prototype of the sPHENIX electromagnetic calorimeter (EMCal) was tested at the Fermilab Test Beam Facility in Spring 2018 as experiment T-1044. The EMCal prototype corresponds to a solid angle of <inline-formula> <tex-math notation="LaTeX">\Delta \eta \times \Delta \phi = 0.2 \times 0.2 </tex-math></inline-formula> centered at pseudo-rapidity <inline-formula> <tex-math notation="LaTeX">\eta = 1 </tex-math></inline-formula>. The prototype consists of scintillating fibers embedded in a mix of tungsten powder and epoxy. The fibers project back approximately to the center of the sPHENIX detector, giving 2-D projectivity. The energy response of the EMCal prototype was studied as a function of position and input energy. The energy resolution of the EMCal prototype was obtained after applying a position-dependent energy correction and a beam profile correction. Two separate position-dependent corrections were considered. The EMCal energy resolution was found to be <inline-formula> <tex-math notation="LaTeX">\sigma (E)/\langle E\rangle = 3.5(0.1) \oplus 13.3(0.2)/\sqrt {E} </tex-math></inline-formula> based on the hodoscope position-dependent correction, and <inline-formula> <tex-math notation="LaTeX">\sigma (E)/\langle E\rangle = 3.0(0.1) \oplus 15.4(0.3)/\sqrt {E} </tex-math></inline-formula> based on the cluster position-dependent correction. These energy resolution results meet the requirements of the sPHENIX physics program.
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