As an important species of the Martian thermosphere, NO is chemically and radiatively active. However, its abundance is poorly constrained due to difficulties in both remote sensing and in situ ...measurements. In this study, we use the Neutral Gas and Ion Mass Spectrometer measurements made onboard the Mars Atmosphere and Volatile Evolution to derive the N(4S), N(2D), and NO abundances in the Martian thermosphere based on time‐dependent odd N chemistry. At a reference altitude of 160 km, our calculations suggest that the NO abundance is maximized in the afternoon whereas the N(4S) and N(2D) abundances maximized in the morning, both driven by the variation of the ambient N2 mixing ratio. The difference in chemical loss time scale implies a strong diurnal variation for NO and N(2D) but a weak variation for N(4S).
Plain language summary
NO is usually regarded as a good tracer of energy input into the upper atmospheres of terrestrial planets. On Mars, NO is mainly produced via the reaction of atomic N in the excited state with ambient CO2 and lost via the reaction with atomic N in the ground state. Existing investigations of NO abundance in the Martian upper atmosphere are extremely limited due to difficulties in both remote sensing and in situ measurements. In this study, we propose a useful approach to determine the NO abundance on both the dayside and nightside of Mars by combining our knowledge of the odd N chemistry with available neutral and ion density measurements of relevant chemical reactants. On the dayside, we find the NO abundance to be maximized late in the afternoon, which is driven by the variation of N2 mixing ratio in the background atmosphere. Our analysis also allows the diurnal variation of NO to be explored for the first time, revealing a strong day‐night difference by 3 orders of magnitude. This is caused by the fast depletion of NO on the nightside where its production source drops to a minimum level in the absence of solar radiation.
Key Points
The odd N abundances at 160 km in the Martian thermosphere are calculated with time‐dependent chemistry
The NO abundance is maximized in the afternoon whereas the N(4S) and N(2D) abundances maximized in the morning
A strong diurnal variation is present for NO and N(2D) but a weak diurnal variation present for N(4S)
This article reports the surgical resection of clinically benign tumours in the maxillomandibular deep lobe of the parotid gland via sternocleidomastoid muscle–parotid space (SPS) approach. The use ...of maxillary–mandibular planes to subdivide the deep lobe of the parotid gland in order to establish the tumour location and accessibility is introduced. This approach, which does not raise a skin flap, may preserve the superficial lobe. Ten patients with clinically benign tumours in the maxillomandibular deep lobe of the parotid gland were treated via the SPS approach. The patients were followed up for 3–5 years and the surgical outcomes were analysed. All tumours were completely enucleated via the SPS approach with an optimal aesthetic outcome. No permanent facial weakness or tumour recurrence was identified during the 3–5 years of follow-up. The SPS approach to surgical resection is an ideal option for clinically benign tumours in the maxillomandibular deep lobe of the parotid gland and demonstrates good results.
A measurement of electron antineutrino oscillation by the Daya Bay Reactor Neutrino Experiment is described in detail. Six 2.9-GWth nuclear power reactors of the Daya Bay and Ling Ao nuclear power ...facilities served as intense sources of ν¯e’s. Comparison of the ν¯e rate and energy spectrum measured by antineutrino detectors far from the nuclear reactors (∼1500–1950 m) relative to detectors near the reactors (∼350–600 m) allowed a precise measurement of ν¯e disappearance. More than 2.5 million ν¯e inverse beta-decay interactions were observed, based on the combination of 217 days of operation of six antineutrino detectors (December, 2011–July, 2012) with a subsequent 1013 days using the complete configuration of eight detectors (October, 2012–July, 2015). The ν¯e rate observed at the far detectors relative to the near detectors showed a significant deficit, R=0.949±0.002(stat)±0.002(syst). The energy dependence of ν¯e disappearance showed the distinct variation predicted by neutrino oscillation. Analysis using an approximation for the three-flavor oscillation probability yielded the flavor-mixing angle sin22θ13=0.0841±0.0027(stat)±0.0019(syst) and the effective neutrino mass-squared difference of |Δmee2|=(2.50±0.06(stat)±0.06(syst))×10−3 eV2. Analysis using the exact three-flavor probability found Δm322=(2.45±0.06(stat)±0.06(syst))×10−3 eV2 assuming the normal neutrino mass hierarchy and Δm322=(−2.56±0.06(stat)±0.06(syst))×10−3 eV2 for the inverted hierarchy.
Summary
The purpose of this study was to investigate the effects of long‐term treatment with dexamethasone (DEX) on the antioxidation and nutrition metabolism in broiler chickens. Broilers were ...placed on a high‐nutrient diet for 41 days, and half were given orally DEX‐supplemented water at 20 mg/L every other day from 19 to 41 days of age. DEX treatment downregulated superoxide dismutase activity as well as the mRNA expression of CuZn‐superoxide dismutase and glutathione peroxidase with a decrease in GSH/GSSG ratio and an increase in malondialdehyde level in the liver of broilers. DEX treatment aggravated oxidative damage in the liver and, therefore, increased the sensitivity of broilers to ascites syndrome with higher mortality and reduced growth performance. Serum metabolomics analysis showed that DEX treatment significantly increased the levels of glucose, intermediates in protein metabolism (valine, proline, serine, threonine and urea) and lipid metabolism‐related products (palmitic acid, stearic acid and cholesterol) while decreasing the levels of β‐hydroxy butyric acid, succinic acid and malic acid, demonstrating that DEX treatment inhibited the Krebs cycle and the oxidation of fatty acids, and promoted the de novo synthesis of fatty acids as well as protein decomposition in the liver of broilers. Additionally, detection of metabolism‐related enzymes revealed that DEX treatment inhibited glycolysis and promoted glycogen decomposition. In summary, DEX treatment resulted in oxidative stress and glucose and lipid metabolism disorders in the broilers.
This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 ...m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18) cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43) cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.
High arsenic (As) groundwater is frequently found in inland basins, yet the contributions of different processes to aqueous As distributions remain unresolved. In the Hetao Basin, a typical inland ...basin, groundwater As concentrations generally increased from the alluvial fan through the transition area to the flat plain. A geochemical process‐based reactive transport model was established to evaluate and quantify the processes of As mobilization in the northwestern Hetao Basin. Thirty‐six groundwater samples and eight sediment samples were collected from the alluvial fan to the flat plain to investigate the geochemical characteristics of the groundwater system. Along the approximate flow path, groundwater evolved from oxic‐suboxic conditions to anoxic conditions, with increasing concentrations of As, Fe (II), and NH4+, and decreasing Eh and SO42−/Cl−. Modeling results indicated that the observed concentrations of Fe (II) were caused by reductive dissolution of Fe (III) oxides and subsequent precipitation of mackinawite and siderite. Reductive dissolution of Fe (III) oxides was primarily driven by organic matter degradation (>75%), followed by H2S oxidation (<25%). More As was sequestered by mackinawite precipitation and adsorption than that released via abiotic reduction of Fe (III) oxides by H2S. Reductive dissolution of Fe (III) oxides was the dominant mechanism for liberating As in both the transition area and the flat plain (>70%), and As desorption under elevated pH and competitive adsorption by HCO3− and PO43− made an important contribution to As enrichment (up to 30%). Overall, this study provides an insight into the relative contributions of different geochemical processes to As enrichment in inland basins.
Plain Language Summary
Reductive dissolution of Fe (III) oxides via organic matter degradation and sulfide (H2S) oxidation, and As desorption induced by elevated pH and coexisting anions (e.g., HCO3− and PO43−) should be responsible for As mobility in anoxic aquifers in inland basins, where weakly alkaline pH and sulfidic conditions prevail. Quantifying these As mobility‐related processes and their relative importance may improve our understanding of the geochemical processes causing As enrichment in aquifer systems in inland basins. We established a 1‐D multicomponent redox process‐controlled reactive transport model to quantify As release‐related processes along an approximate flow path from the mountain to the flat plain in the Hetao Basin, China. The results showed that the reduction of Fe (III) oxides was mainly induced by organic matter degradation (>75%), followed by via H2S oxidation (<25%). Arsenic concentrations were depressed under sulfidic conditions due to As sequestration by mackinawite precipitation and adsorption, although abiotic H2S reduction of Fe (III) oxides contributed to the release of As. Overall, As was released through Fe (III) oxide reduction (>70%) and desorption under elevated pH and HCO3− and PO43− concentrations (<30%). This study provides an insight into the mechanisms of groundwater As mobilization in inland basins.
Key Points
Iron (III) oxides in inland aquifers were primarily reduced by organic matter degradation (>75%) and secondarily by H2S oxidation (<25%)
Reduction of Fe (III) oxides was the dominant mechanism of As enrichment (>70%), whereas As desorption contributed less than 30%
More As was sequestered by mackinawite precipitation than that released via abiotic H2S reduction of Fe (III) oxides in sulfidic conditions
“Free-standing” single wall carbon nanotube (SWNT) papers have been synthesised by simple filtration method via positive pressure. A conventional SWNT slurry coated electrode was fabricated to ...compare with the SWNT papers. The results show that the capacity of the “Free-standing” electrode was slightly lower than that of the conventional electrode, but the “Free-standing” electrode was produced without any binder, and metal substrate, so that the weight of electrode was reduced significantly. On the other hand, the procedures for SWNT electrode preparation were simplified, so the cost of the manufacturing could be reduced.
•Influence of printing angle on rate-sensitivity of FDM-fabricated PLA material.•Angle-dependent strut material causes anisotropy of lattices comprising octet and HS cells under impact.•A ...constitutive model of strut material with both rate and angle dependence factored in.•FE models incorporating the established constitutive model capture anisotropy of lattices observed.•Relationship between the change of cell deformation mode and anisotropy of lattices.
Additive manufacturing techniques facilitate fabrication of polymeric lattice structures comprising complex cell architectures, via the ability to fabricate component struts at specified angles. However, the inherent layer-wise fabrication process, especially for Fused Deposition Modelling (FDM), introduces angle-dependent properties depending on the orientation with respect to the printing bed. This results in lattices displaying different mechanical responses, depending on the direction of loading. The present study examines how the static and dynamic tensile material properties of cell strut material are influenced by the angle of printing. Specimens printed at various angles were subjected to quasi-static tensile loading, as well as dynamic extension using a tensile split Hopkinson bar device. It was found that the degree of rate-sensitivity depends on the printing angle. Octet and Hybrid Structure (HS) lattices were also fabricated and subjected to quasi-static and impact compression along the printing direction and transverse to it. The results show that the load-deformation responses and lattice crushing patterns differ significantly. Finite element models, incorporating both printing angle and rate dependent strut material and failure properties, were established, to analyse the deformation with respect to loading direction, at both lattice sample and cell-component levels.
In this study, we identified the ZmCLA4 gene, which is responsible for the qLA4-1 associated with leaf angle, by positional cloning, and parsed the genetic mechanism.
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