Deposition and re-entrainment of 1.1 microm microspheres were examined in packed glass beads and quartz sand under both favorable and unfavorable conditions for deposition. Experiments were performed at environmentally relevant ionic strengths and flow rates in the absence of solution chemistry and flow perturbations. Numerical simulations of experimental data were performed using kinetic rate coefficients to represent deposition and re-entrainment dynamics. Deposition rate coefficients increased with increasing flow rate under favorable deposition conditions (in the absence of colloid-grain surface electrostatic repulsion), consistent with expected trends from filtration theory. In contrast, under unfavorable deposition conditions (where significant colloid-grain surface electrostatic repulsion exists), the deposition rate coefficients decreased with increasing flow rate, suggesting a mitigating effect of hydrodynamic drag on deposition. Furthermore, the re-entrainment rate was negligible under favorable conditions but was significant under unfavorable conditions and increased with increasing flow rate, demonstrating that hydrodynamic drag drove re-entrainment under unfavorable conditions. The drag torque resulting from hydrodynamic drag was found to be 1 order of magnitude or more lower than the adhesive torque based on pull-off forces from atomic force microscopy measurements. This result indicates that hydrodynamic drag was insufficient to drive re-entrainment of microspheres that were associated with the grain surface via the primary energy minimum and suggests that hydrodynamic drag drove re-entrainment of secondary-minimum-associated microspheres.

Isoprene and monoterpenes are important precursors of secondary organic aerosols (SOA) in continents. However, their contributions to aerosols over oceans are still inconclusive. Here we analyzed SOA tracers from isoprene and monoterpenes in aerosol samples collected over oceans during the Chinese Arctic and Antarctic Research Expeditions. Combined with literature reports elsewhere, we found that the dominant tracers are the oxidation products of isoprene. The concentrations of tracers varied considerably. The mean average values were approximately one order of magnitude higher in the Northern Hemisphere than in the Southern Hemisphere. High values were generally observed in coastal regions. This phenomenon was ascribed to the outflow influence from continental sources. High levels of isoprene could emit from oceans and consequently have a significant impact on marine SOA as inferred from isoprene SOA during phytoplankton blooms, which may abruptly increase up to 95 ng/m3 in the boundary layer over remote oceans.

Abstract. Extended tailing of low bacterial concentrations following breakthrough at the Narrow Channel focus area was observed for 4 months. Bacterial attachment and detachment kinetics associated with breakthrough and extended tailing were determined by fitting a one-dimensional transport model to the field breakthrough-tailing data. Spatial variations in attachment rate coefficient (k f) were observed under forced gradient conditions (i.e., kf decreased as travel distance increased), possibly because of decreased bacterial adhesion with increased transport distance. When pore water velocity decreased by an order of magnitude at 9 days following injection, apparent bacterial attachment rate coefficients did not decrease with velocity as expected from filtration theory, but, instead, increased greatly for most of the wells. The coincidence of the increase in apparent attachment rate coefficient with the occurrence of protist blooms suggested that the loss of bacteria from the aqueous phase during the protist blooms was not governed by filtration but rather was governed by predation. Simulations were performed to examine the transport distances achieved with and without detachment, using attachment and detachment rate coefficients similar to those obtained in this field study. Simulations that included detachment showed that transport distances of bacteria may significantly increase because of detachment under the conditions examined. The relationship between the attachment rate and pore wa-2687 Introduction Bacterial transport in the subsurface is influenced by advec-

Biomass burning is known to affect air quality, global carbon cycle, and climate. However, the extent to which biomass burning gases/aerosols are present on a global scale, especially in the marine atmosphere, is poorly understood. Here we report the molecular tracer levoglucosan concentrations in marine air from the Arctic Ocean through the North and South Pacific Ocean to Antarctica during burning season. Levoglucosan was found to be present in all regions at ng/m3 levels with the highest atmospheric loadings present in the mid-latitudes (30°–60° N and S), intermediate loadings in the Arctic, and lowest loadings in the Antarctic and equatorial latitudes. As a whole, levoglucosan concentrations in the Southern Hemisphere were comparable to those in the Northern Hemisphere. Biomass burning has a significant impact on atmospheric Hg and water-soluble organic carbon (WSOC) from pole-to-pole, with more contribution to WSOC in the Northern Hemisphere than in the Southern Hemisphere.

pitted groove was found to have superior unidirectional liquid spreading effects to those of other cases. Finally, the mechanism of the unidirectional liquid spreading was investigated by the microgroove-induced capillary effect, and inclined arc pits induced a strong liquid-pinning effect.As a carnivorous plant, the peristome of N. alata possesses a marvelous function of unidirectional liquid spreading to form a wet slippery surface for capturing insects. [20,21] The structural characterization demonstrated that the unidirectional liquid spreading mainly results from its unique structural features, i.e., a sharp edge with an arch-shaped outline aligning at the bottom of the microgroove. Under the inspiration from N. alata, a microgroove with a pit array aligned at its bottom is critical for the unidirectional liquid spreading surface. To make clear the impact of the sharp edge and its arch-shaped outline, various pit shapes at the bottom of microgroove should be built for comparison, including an inclined square pitted groove, arc pitted groove, and inclined arc pitted groove. Here, we define the inclined pit extension direction and arc protruding direction as the front direction of the pitted groove surface structure, and its opposite direction as the rear direction. All these complicated surface structures were fabricated by the use of two-step UV lithography.The fabrication of the inclined pitted groove is composed of two successive steps of UV lithography. The first step is the inclined pit array fabrication. SU-8 photoresist was chosen for the construction of the thick structure and spin coated on the glass substrate. Mask-a with arc patterns ① and square patterns ② was used to expose the arc pit array and square pit array, as shown in Figure 1a. An inclined UV source with an angle Ω of 45° was shot from the rear to the front of the arc patterns to build the inclined pit array. [22] The second step is the fabrication of the overlaid microgrooves on the pit array. After the development of the photoresist, the inclined pit array was spin coated again with the same thickness of SU-8 as in the first step. A straight strip pattern with the same width as the pit array was used as Mask-b, as shown in Figure 1b. During the exposure, strips of Mask-b were carefully aligned to cover the inclined pit array, ensuring that the microgroove was well overlaid upon the pit array, and UV exposure was performed perpendicularly to Mask-b. After the second development, the inclined arc pitted groove and inclined square pitted groove were finally obtained. The arc pitted groove was built with an angle Ω of 0°, and a smooth groove was fabricated by the use of Mask-b with common UV lithography. Directional liquid spreading has gradually attracted worldwide attention owing to its potential applications in various fields, such as fog harvesting, [1][2][3] filtration, [4] and microfluidic devices. [5][6][7][8][9] Several anisotropic liquid spreading phenomena have been discovered on 1D thread-shaped natural systems, including water ...

No abstract

Graphene nanoribbons (GNRs) with atomically precise width and edge structures are a promising class of nanomaterials for optoelectronics, thanks to their semiconducting nature and high mobility of charge carriers. Understanding the fundamental static optical properties and ultrafast dynamics of charge carrier generation in GNRs is essential for optoelectronic applications. Combining THz spectroscopy and theoretical calculations, we report a strong exciton effect with binding energy up to ∼700 meV in liquid-phase-dispersed GNRs with a width of 1.7 nm and an optical band gap of ∼1.6 eV, illustrating the intrinsically strong Coulomb interactions between photogenerated electrons and holes. By tracking the exciton dynamics, we reveal an ultrafast formation of excitons in GNRs with a long lifetime over 100 ps. Our results not only reveal fundamental aspects of excitons in GNRs (strong binding energy and ultrafast exciton formation etc.) but also highlight promising properties of GNRs for optoelectronic devices.

The dysregulation of circular RNA (circRNA) expression is involved in the progression of several cancers, including non‐small cell lung cancer (NSCLC). However, the role and underlying molecular mechanisms of circRNA FGFR3 (circFGFR3) in NSCLC progression remains unknown. Here, we used quantitative real‐time polymerase chain reaction to validate that circFGFR3 expression was higher in NSCLC tissues than in the paratumor tissues. Furthermore, our study indicated that the forced circFGFR3 expression promoted NSCLC cell invasion and proliferation. Mechanistically, we found that circFGFR3 promoted NSCLC cell invasion and proliferation via competitively combining with miR‐22‐3p to facilitate the galectin‐1 (Gal‐1), p‐AKT, and p‐ERK1/2 expressions. Clinically, we revealed that the high circFGFR3 expression correlates with the poor clinical outcomes in patients with NSCLC. Together, these data provide mechanistic insights into the circFGFR3‐mediated regulation of both the AKT and ERK1/2 signaling pathways by sponging miR‐22‐3p and increasing Gal‐1 expression.