Search

This work investigates seasonal and interhemispheric variations of the afternoon auroral responses to the interplanetary magnetic field (IMF) By effects. The auroral observations are adopted from the global ultraviolet imager instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite during 2002–2007. The results show that in both summer and winter solstices, the stronger afternoon auroral intensity is associated with negative IMF By (By < 0) in the northern hemisphere, and with By > 0 in the southern hemisphere. This suggests stronger contributions from the upward field‐aligned currents (FACs), which can be induced by the By‐associated north‐south oriented electric field and the By‐associated flow shear in the ionosphere. In addition, the strongest afternoon aurora occurs in summer in each hemisphere. In summer, the absolute difference between the auroral peak intensity under the two By polarities is greater and occurs earlier than in winter, which may be related to changes in FACs and conductivity from winter to summer. Differently, in equinoxes stronger auroral intensity favors By conditions associated with more frequent occurrence of southward IMF Bz, such as By < 0 and By > 0 conditions in March and in September, respectively. Therefore, in equinoxes the effects of the favorable By, which were seen in solstices, are masked. We suggest that these are caused by the Russell‐McPherron effect, which leads to more southward Bz conditions, resulting in more energy deposited and subsequent stronger aurora in polar ionosphere. These results contribute to our deeper understanding of the asymmetrical phenomena in the Earth's magnetosphere‐ionosphere induced by IMF By. Plain Language Summary: Aurora is mainly controlled by coupling among the solar wind, magnetosphere and ionosphere. The afternoon aurora can vary with the change of the north‐south components (positive‐negative Bz) and east‐west components (positive‐negative By) of interplanetary magnetic field (IMF). Generally, compared with northward Bz, stronger afternoon aurora occurs when Bz is southward. It also has By orientation preference from case studies and statistics. In this study, quantitative and statistical analysis was performed on the afternoon aurora. We confirmed that in summer and winter of the northern hemisphere, the afternoon auroral intensity is stronger for negative By than that for positive By, while the opposite trend, that is, the stronger afternoon aurora under positive By, occurs in the southern hemisphere. This hemispheric change of the afternoon auroral response to By is most probably associated with the resultant field‐aligned currents. However, the afternoon auroral intensity is stronger for negative By in both hemispheres in March and is stronger for positive By in both hemispheres in September. In each equinox, the stronger afternoon auroral intensity prefers the By orientation that is associated with greater occurrence frequency of southward Bz. Key Points: In summer and winter solstices, the afternoon auroral responses to By polarities are opposite between the northern and southern hemispheresThe absolute difference in auroral peak intensity between different By polarities is greater and occurs earlier in summer than in winterIn equinoxes, stronger afternoon auroral intensity is mostly associated with the Russell‐McPherron effect, regardless of the hemisphere [ABSTRACT FROM AUTHOR]

Our preliminary investigation has identified the potential of serum fucosylated extracellular vesicles (EVs) miR-4732-5p in the early diagnosis of lung adenocarcinoma (LUAD) by a fucose-captured strategy utilizing lentil lectin (LCA)-magnetic beads and subsequent screening of high throughput sequencing and validation of real-time quantitative polymerase chain reaction (RT-qPCR). Considering the relatively complicated procedure, expensive equipment, and stringent laboratory condition, we have constructed an electrochemical biosensor assay for the detection of miR-4732-5p. miR-4732-5p is extremely low in serum, down to the fM level, so it needs to be detected by highly sensitive electrochemical methods based on the Mg2+-dependent DNAzyme splitting nucleic acid lock (NAL) cycle and hybridization chain reaction (HCR) signal amplification. In this study, signal amplification is achieved through the dual amplification reactions using NAL cycle in combination with HCR. In addition, hybridized DNA strands bind to a large number of methylene blue (MB) molecules to enhance signaling. Based on the above strategy, we further enhance our signal amplification strategies to improve detection sensitivity and accuracy. The implementation of this assay proceeded as follows: initially, miR-4732-5p was combined with NAL, and then Mg2+-dependent DNAzyme splitted NAL to release auxiliary DNA (S1) strands, which were subsequently captured by the immobilized capture probe DNA (C1) strands on the electrode surface. Following this, abundant quantities of DNA1 (H1) and DNA2 (H2) tandems were generated by HCR, and S1 strands then hybridized with the H1 and H2 tandems through base complementary pairing. Finally, MB was bonded to the H1 and H2 tandems through π–π stacking interaction, leading to the generation of a signal current upon the detection of a potential capable of inducing a redox change of MB by the electrode. Furthermore, we evaluated the performance of our developed electrochemical biosensor assay. The results demonstrated that our assay is a reliable approach, characterized by its high sensitivity (with a detection limit of 2.6 × 10−17 M), excellent specificity, good accuracy, reproducibility, and stability. Additionally, it is cost-effective, requires simple operation, and is portable, making it suitable for the detection of serum fucosylated extracellular vesicles miR-4732-5p. Ultimately, this development has the potential to enhance the diagnostic efficiency for patients with early-stage LUAD. [ABSTRACT FROM AUTHOR]

It can be expected that a moon shadow of solar eclipse can largely reduce the ionospheric electron density (Ne) during the obscuration. However, in this study, the total electron content (TEC) from the ground‐based Global Navigation Satellite System receivers recorded a significant Ne enhancement over the continental United States (CONUS) near the first contact of the total solar eclipse on 21 August 2017. The ionosonde observations of the F2‐layer peak density (NmF2) and its height (hmF2) over Idaho National Lab (43.81°N, 112.68°W, 99.6% obscuration), ID, and Boulder (40°N, 105.3°W, 93.1% obscuration), CO, verified the unexpected early enhancement. The ionospheric Ne starts to enhance at ∼1520 UT (before the obscuration) and increases by ∼25% to ∼80% at ∼1600 UT (near the first contact) in the F2 layer. The early enhancement reveals the ascension of the F2 layer that tilted east over the CONUS. Plain Language Summary: The moon shadow of a solar eclipse can largely reduce the atmospheric temperature and the ionospheric electron density as the umbra and penumbra cones are perpendicular to the Earth's surface. However, it is surprising to see that the ionospheric electron density increases significantly over the continental United States near the first contact of the total solar eclipse on 21 August 2017. The ground‐based Global Navigation Satellite System receivers and ionosondes comprehensively observed the pre‐ascension of the ionospheric F2 layer that could be attributed to the upward motion of plasma at midlatitude. Key Points: An unexpected Ne enhancement occurred near the first contact of the total solar eclipse on 21 August 2017 by comparing the data on 20th AugustThe total electron content and NmF2 increase by ∼10% and ∼25%–80%, respectively, near the first contact over the north and central area of CONUSThe early enhancement occurred mainly in the F2 layer [ABSTRACT FROM AUTHOR]

Modern nanofabrication technologies have propelled significant advancement of high-resolution and optically thin holograms. However, it remains a long-standing challenge to tune the complex hologram patterns at the nanoscale for temporal light field control. Here, we report femtosecond laser direct lithography of perovskites with nanoscale feature size and pixel-level temporal dynamics control for temporally programmable holograms. Specifically, under tightly focused laser irradiation, the organic molecules of layered perovskites (PEA) 2 PbI 4 can be exfoliated with nanometric thickness precision and subwavelength lateral size. This creates inorganic lead halide capping nanostructures that retard perovskite hydration, enabling tunable hydration time constant. Leveraging advanced inverse design methods, temporal holograms in which multiple independent images are multiplexed with low cross talk are demonstrated. Furthermore, cascaded holograms are constructed to form temporally holographic neural networks with programmable optical inference functionality. Our work opens up new opportunities for tunable photonic devices with broad impacts on holography display and storage, high-dimensional optical encryption and artificial intelligence., (© 2024. The Author(s).)