Vapor-Induced Attraction of Floating Droplets

Droplets partially submersed in an immiscible liquid pool attract each other. We experimentally study the interaction of floating droplets containing aqueous solution of a volatile liquid. A droplet affects its neighbors by generating a vapor gradient to the surroundings and responds by evaporating asymmetrically over its exposed cap. We show that the induced asymmetric temperature distribution causes a surface tension gradient driving the attracting motion. We highlight that the attracting dynamics starts with an accelerating stage, followed by a decelerating stage. We finally provide a theoretical model that quantitatively captures the interactive forces between droplets and predicts essential features of the attracting motion

Hydrological responses of pine needle litter to rainfall erosional processes on Chinese karst hillslopes

The restoration of native vegetation like pines helps mitigate soil erosion, but the effects of pine needle litter on runoff, erosion, and hydrology in karst hillslopes are unclear. This study investigated these factors during the rainy season from June to August 2021 under six treatments (flat, gentle, and steep slopes with and without pine needle coverings). The results showed that pine needle litter significantly increased the soil water content, particularly on steeper slopes, by improving the water-holding capacity. It also substantially reduced runoff (by 23.8%) and soil erosion (by 92.5%). The critical rainfall threshold for generating runoff did not occur in the pine needle covering treatment, whereas it was 19.3 ± 8.8 mm in the bare soil treatment under wet conditions. These findings highlight the efficacy of pine needle cover in reducing runoff and erosion in karst areas, promoting it as a sustainable method for restoring degraded soil.</p

Plasma-Assisted Sulfur Doping of LiMn₂O₄ for High-Performance Lithium-Ion Batteries

Though considered as one of the most promising materials for rechargeable Li-ion batteries, spinel LiMn₂O₄ suffers from fast capacity fading during cycling due to the structural instability, Jahn–Teller distortion, and Mn dissolution into the electrolyte. In order to improve the electrochemical performance, in this work, we, for the first time, realize the sulfur doping by the plasma-assisted method in LiMn₂O₄. Physical properties of the synthesized materials LiMn₂O_4–<i>x</i>S_<i>x</i> are measured by XRD, SEM, and EDS, which confirm that S atoms have been successfully doped into the structure of LiMn₂O₄ (LiMn₂O_4–<i>x</i>S_<i>x</i>) with the high crystalline and uniform morphology. Compared to the pristine LiMn₂O₄ prepared by the conventional method (800 °C, 8 h), the LiMn₂O_4–<i>x</i>S_<i>x</i> prepared by the plasma-assisted method shows superior performance with higher capacity (125.3 mAh·g^–1) and significantly improved cycling stability (maintaining 97.76% of its initial discharge capacity after 60 cycles). In addition, the sulfur-doped LiMn₂O₄ demonstrates dramatically enhanced reversibility and stability even at the elevated temperature due to the improved structural stability and the suppressed Mn dissolution into the electrolyte by the doping of S. The sulfur doping into LiMn₂O₄ by the plasma-assisted method offers a new strategy for efficient modification of electrode materials for energy storage devices

Connectivity graphs of wake and sleep state.

<p>The networks represent binary connections, locally organized by a layout algorithm implemented in the Pajek software package. The yellow nodes represent the neocortical system, the green nodes represent the paralimbic-limbic cortex and the red nodes represent the centrencephalic structure. (Left:wake, Right:sleep)</p

Graph Theoretical Analysis of BOLD Functional Connectivity during Human Sleep without EEG Monitoring

<div><p>Background</p><p>Functional brain networks of human have been revealed to have small-world properties by both analyzing electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) time series.</p><p>Methods & Results</p><p>In our study, by using graph theoretical analysis, we attempted to investigate the changes of paralimbic-limbic cortex between wake and sleep states. Ten healthy young people were recruited to our experiment. Data from 2 subjects were excluded for the reason that they had not fallen asleep during the experiment. For each subject, blood oxygen level dependency (BOLD) images were acquired to analyze brain network, and peripheral pulse signals were obtained continuously to identify if the subject was in sleep periods. Results of fMRI showed that brain networks exhibited stronger small-world characteristics during sleep state as compared to wake state, which was in consistent with previous studies using EEG synchronization. Moreover, we observed that compared with wake state, paralimbic-limbic cortex had less connectivity with neocortical system and centrencephalic structure in sleep.</p><p>Conclusions</p><p>In conclusion, this is the first study, to our knowledge, has observed that small-world properties of brain functional networks altered when human sleeps without EEG synchronization. Moreover, we speculate that paralimbic-limbic cortex organization owns an efficient defense mechanism responsible for suppressing the external environment interference when humans sleep, which is consistent with the hypothesis that the paralimbic-limbic cortex may be functionally disconnected from brain regions which directly mediate their interactions with the external environment. Our findings also provide a reasonable explanation why stable sleep exhibits homeostasis which is far less susceptible to outside world.</p></div

Small-world property σ during sleep states as compared to the wake state.

<p>Small-world property σ during sleep states as compared to the wake state.</p

Group results of …

<p>(A) local efficiency, Eloc, and (B) global efficiency, Eglob, for sleep group (green dots) and wake group (blue dots) as a function of degree. Error bars correspond to standard error of the mean. Black dots above indicate significant group difference (p<0.05, FDR corrected).</p

fMRI Scanning Process.

<p>fMRI Scanning Process.</p

Group results of …

<p>(A) clustering coefficient, C_net, and (B) characteristic path length, L_net, for sleep group (green dots) and wake group (blue dots) as a function for degree. Error bars correspond to standard error of the mean. Black dots above indicate significant group difference (p<0.05, false discovery rate (FDR) corrected).</p

Schematic diagram of wake and sleep state.

<p>The yellow node represents the neocortical system, the green node represents the paralimbic-limbic cortex and the red node represents the centrencephalic structure. The size of the dot represents the value of the corresponding local efficiency. Dotted line represents connections reduced in number.</p