Portable Triboelectric Electrostatic Tweezer for External Manipulation of Droplets within a Closed Femtosecond Laser-Treated Superhydrophobic System.

Controllable droplet manipulation has diverse applications; however, limited methods exist for externally manipulating droplets in confined spaces. Herein, we propose a portable triboelectric electrostatic tweezer (TET) by integrating electrostatic forces with a superhydrophobic surface that can even manipulate droplets in an enclosed space. Electrostatic induction causes the droplet to be subjected to an electrostatic force in an electrostatic field so that the droplet can be moved freely with the TET on a superhydrophobic platform. Characterized by its high precision, flexibility, and robust binding strength, TET can manipulate droplets under various conditions and achieve a wide range of representative fluid applications such as droplet microreactors, precise self-cleaning, cargo transportation, the targeted delivery of chemicals, liquid sorting, soft droplet robotics, and cell labeling. Specifically, TET demonstrated the ability to manipulate internal droplets from the outside of a closed system, such as performing cell labeling experiments within a sealed Petri dish without opening the culture system.

Active Droplet Transport Induced by Moving Meniscus on a Slippery Magnetic Responsive Micropillar Array.

Intelligent droplet manipulation plays a crucial role in both scientific research and industrial technology. Inspired by nature, meniscus driving is an ingenious way to spontaneously transport droplets. However, the shortages of short-range transport and droplet coalescence limit its application. Here, an active droplet manipulation strategy based on the slippery magnetic responsive micropillar array (SMRMA) is reported. With the aid of a magnetic field, the micropillar array bends and induces the infusing oil to form a moving meniscus, which can attract nearby droplets and transport them for a long range. Significantly, clustered droplets on SMRMA can be isolated by micropillars, avoiding droplet coalescence. Moreover, through adjusting the arrangement of the micropillars of SMRMA, multi-functional droplet manipulation such as unidirectional droplet transport, multi-droplet transport, droplet mixing, and droplet screening can be achieved. This work provides a promising approach for intelligent droplet manipulation and unfolds broad application prospects in microfluidics, microchemical reaction, biomedical engineering, and other fields.

Geometry-Gradient Magnetocontrollable Lubricant-Infused Microwall Array for Passive/Active Hybrid Bidirectional Droplet Transport.

Manipulation of droplets has increasingly garnered global attention, owing to its multifarious potential applications, including microfluidics and medical diagnostic tests. To control the droplet motion, geometry-gradient-based passive transport has emerged as a well-established strategy, which induces a Laplace pressure difference based on the droplet radius differences in confined state and transport droplets with no consumption of external energy, whereas this transportation method has inevitably shown some critical limitations: unidirectionality, uncontrollability, short moving distance, and low velocity. Herein, a magnetocontrollable lubricant-infused microwall array (MLIMA) is designed as a key solution to this issue. In the absence of a magnetic field, droplets can spontaneously travel from the tip toward the root of the structure as a result of the geometry-gradient-induced Laplace pressure difference. When the subject of an external magnetic field, the microwalls bend and overlap sequentially, ultimately resulting in the formation of a continuous slippery meniscus surface. The formed meniscus surface can exert sufficient propulsive force to surmount the Laplace pressure difference of the droplet, thereby effectuating active transport. Through the continuous movement of the microwalls, droplets can be actively transported against the Laplace pressure difference from the root to the tip side of the MLIMA or continue to actively move to the root after finishing the passive self-transport. This work demonstrates passive/active hybrid bidirectional droplet transport capabilities, validates its feasibility in the accurate control of droplet manipulation, and exhibits great potential in chemical microreactions, bioassays, and the medical field.

Meniscus-Induced Directional Self-Transport of Submerged Bubbles on a Slippery Oil-Infused Pillar Array with Height-Gradient.

Directional manipulation of submerged bubbles is fundamental for both theoretical research and industrial production. However, most current strategies are limited to the upward motion direction, complex surface topography, and additional apparatuses. Here, we report a meniscus-induced self-transport platform, namely, a slippery oil-infused pillar array with height-gradient (SOPAH) by combining femtosecond laser drilling and replica mold technology. Owing to the unbalanced capillary force and Laplace pressure difference, bubbles on SOPAH tend to spontaneously transport along the meniscus gradient toward a higher elevation. The self-transport performances of bubbles near the pillars depend on the complex meniscus shape. Significantly, to understand the underlying transport mechanism, the 3D meniscus profile is simulated by solving the Young-Laplace equation. It is found that the concave valleys formed between the adjacent pillars can change the gradient direction of the meniscus and lead to the varied transport performances. Finally, by taking advantage of a water electrolysis system, the assembled SOPAH serving as a bubble-collecting device is successfully deployed. This work should not only bring new insights into the meniscus-induced self-transport dynamics but also benefit potential applications in the field of intelligent bubble manipulation.

Influence of flavor information on visual search: Attentional capture by and suppression of flavor-associated colors.

Numerous studies have demonstrated the impact of flavor cues on visual search, yet the underlying mechanisms remain elusive. In this experiment, we used event-related potentials (ERPs) to examine whether, and if so, how flavor information could lead to attentional capture by, and suppression of, flavor-associated colors. The participants were asked to taste certain flavored beverages and subsequently complete a shape-based visual search task, while their neural activities were simultaneously recorded. The behavioral results revealed that the participants made slower responses when a distractor in the flavor-associated color (DFAC) was present, suggesting an attentional bias toward the flavor-associated color. The ERP results revealed that the N2pc was detected if the target and the DFAC were shown in the same visual field (e.g. both target and DFCA on the right side of the screen), when the pairings between flavor cues and target colors were incongruent. However, the N2pc was not observed if the target and the DFAC were shown in the opposite visual fields (e.g. target on the right and DFCA on the left side of the screen) for the incongruent color-flavor pairings. Moreover, the distractor positivity (Pd) was observed if the target and the DFAC were shown in the opposite visual field for the congruent color-flavor pairings. These results suggest that both attentional capture and suppression are involved in the influence of flavor information on visual search. Collectively, these findings provide initial electrophysiological evidence on the mechanisms of the crossmodal influence of flavor cues on visual search.

Chinese character unitization enhances recollection-based associative recognition: Evidence from fMRI.

Previous research has suggested that familiarity can enhance associative memory after unitization, but the cognitive mechanisms underlying unitization remain debated. To explore the neural mechanisms of associative memory after unitization in the absence of semantic relations, we used Chinese characters as stimuli and recorded participants' blood oxygen level-dependent signals during recognition. Behavioral results showed that after Chinese character unitization, not only the associative performance of recognition (Pr, hit rate minus false alarm rate) and general Pr but also the hit rate and correct rejection rate increased. Neuroimaging results revealed activation of the hippocampus and parahippocampal gyrus during associative recognition in both the unitized and the non-unitized condition, and hippocampal activation increased after unitization. However, activation of the perirhinal cortex was not observed in either condition. These findings, in contrast to those from previous studies on unitization, suggest that Chinese character unitization enhances recollection-based, rather than familiarity-based, associative recognition. This suggests that the encoding of semantic relations during unitization is critical for subsequent familiarity-based associative recognition.

Femtosecond-laser-patterned origami Janus membrane toward enhanced water fog harvesting.

Fog harvesting is an effective way to relieve water shortages in arid regions; thus, improving the efficiency of fog harvesting is urgently needed for both academic research and practical applications. Here, we report an origami patterned Janus (O-P-Janus) membrane using laser-ablated copper foams inspired by origami handcraft and traditional Chinese architecture. Compared to the planar fully ablated Janus membrane, our O-P-Janus membrane, with selectively ablated rectangular areas, exhibits an exceptional water collection rate (WCR) of approximately 267%. The underlying physical mechanism of WCR enhancement is revealed and attributed to the enhanced fog adsorbing capacity on the upper superhydrophobic origami structures and the accelerated removal of accumulated droplets beneath the lower superhydrophilic V-shaped tips. This O-P-Janus membrane with excellent fog collection performance should open up a new avenue for both device designs and potential applications toward structuring-enhanced fog collection and microfluidic control platforms.

Self-Driving Underwater "Aerofluidics".

Here, the concept of "aerofluidics," in which a system uses microchannels to transport and manipulate trace gases at the microscopic scale to build a highly versatile integrated system based on gas-gas or gas-liquid microinteractions is proposed. A kind of underwater aerofluidic architecture is designed using superhydrophobic surface microgrooves written by a femtosecond laser. In the aqueous medium, a hollow microchannel is formed between the superhydrophobic microgrooves and the water environment, which allows gas to flow freely underwater for aerofluidic devices. Driven by Laplace pressure, gas can be self-transported along various complex patterned paths, curved surfaces, and even across different aerofluidic devices, with an ultralong transportation distance of more than 1 m. The width of the superhydrophobic microchannels of the designed aerofluidic devices is only ≈42.1 µm, enabling the aerofluidic system to achieve accurate gas transportation and control. With the advantages of flexible self-driving gas transportation and ultralong transportation distance, the underwater aerofluidic devices can realize a series of gas control functions, such as gas merging, gas aggregation, gas splitting, gas arrays, gas-gas microreactions, and gas-liquid microreactions. It is believed that underwater aerofluidic technology can have significant applications in gas-involved microanalysis, microdetection, biomedical engineering, sensors, and environmental protection.

Bioinspired magnetism-responsive hybrid microstructures with dynamic switching toward liquid droplet rolling states.

The functionality of tunable liquid droplet adhesion is crucial for many applications such as self-cleaning surfaces and water collectors. However, it is still a challenge to achieve real-time and fast reversible switching between isotropic and anisotropic liquid droplet rolling states. Inspired by the surface topography on lotus leaves and rice leaves, herein we report a biomimetic hybrid surface with gradient magnetism-responsive micropillar/microplate arrays (GMRMA), featuring dynamic fast switching toward different droplet rolling states. The exceptional dynamic switching characteristics of GMRMA are visualized and attributed to the fast asymmetric deformation between the two different biomimetic microstructures under a magnetic field; they endow the rolling droplets with anisotropic interfacial resistance. Based on the exceptional morphology switching surface, we demonstrate the function of classification and screening of liquid droplets, and thus propose a new strategy for liquid mixing and potential microchemical reactions. It is expected that this intelligent GMRMA will be conducive to many engineering applications, such as microfluidic devices and microchemical reactors.

A Biocompatible Vibration-Actuated Omni-Droplets Rectifier with Large Volume Range Fabricated by Femtosecond Laser.

High-performance droplet transport is crucial for diverse applications including biomedical detection, chemical micro-reaction, and droplet microfluidics. Despite extensive progress, traditional passive and active strategies are restricted to limited liquid types, small droplet volume ranges, and poor biocompatibilities. Moreover, more challenges occur for biological fluids due to large viscosity and low surface tension. Here, a vibration-actuated omni-droplets rectifier (VAODR) consisting of slippery ratchet arrays fabricated by femtosecond laser and vibration platforms is reported. Through the relative competition between the asymmetric adhesive resistance originating from the lubricant meniscus on the VAODR and the periodic inertial driving force originating from isotropic vibration, the fast (up to ≈60 mm s-1 ), programmable, and robust transport of droplets is achieved for a large volume range (0.05-2000 µL, Vmax /Vmin  ≈ 40 000) and in various transport modes including transport of liquid slugs in tubes, programmable and sequential transport, and bidirectional transport. This VAODR is general to a high diversity of biological and medical fluids, and thus can be used for biomedical detection including ABO blood-group tests and anticancer drugs screening. These strategies provide a complementary and promising platform for maneuvering omni-droplets that are fundamental to biomedical applications and other high-throughput omni-droplet operation fields.

Cloud-Based Commensality: Enjoy the Company of Co-diners Without Social Facilitation of Eating.

Previous research has associated frequently enforced solo dining with negative consequences on psychological well-being, but the problem of having to eat alone may be solved by seeking mealtime companions in the digital space by watching an eating broadcast (i.e., Mukbang) or videoconferencing with others (i.e., cloud-based commensality). We conducted the present study to compare the consequences of Mukbang-based, cloud-based, and in-person commensality. Ninety-five healthy Chinese young adults were instructed to rate images of eating scenarios and foods. The results revealed that they expected loneliness to be reduced by Mukbang-based or in-person commensality, but they were also aware of the risks of enhancing food intake and/or being shifted toward less healthy food choices in these two scenarios. By contrast, the participants expected cloud-based commensality to provide the benefits of reducing loneliness without the health-compromising risks of increasing food intake or unhealthy eating. Collectively, these findings suggest the beliefs of the participants that cloud-based commensality can provide an "alone but together" context to balance the need for social interactions with the strategic avoidance of a social context facilitating unhealthy eating. The findings also provide some novel insights into how the application of technologies for eating behavior can be used to integrate social factors and food pleasure, and shed light on the promising future of cloud-based commensality as a combination of the strengths of solitary and commensal eating.

Catalytic pyrolysis and liquefaction behavior of microalgae for bio-oil production.

Microalgae bio-oil production is related to the sustainable use of world energy in the future. In the present work, catalytic pyrolysis and liquefaction behavior of microalgae for bio-oil production were investigated. The results show that the rare earth compounds as catalysts contributed to significantly accelerating the pyrolysis of microalgae via reducing the activation energy of pyrolysis process. Ce(II)/HZSM-5 presented the optimal catalytic pyrolysis and liquefaction effects by helping cut the microalgae molecule chains. The maximum bio-oil yield amounted to 49.71 wt% at the catalyst concentration of 5 wt%. The chemical components of the Spirulina bio-oil were composed of carboxylic acids, ketones, olefins, amides, ethers, esters, and partially cyclic N-containing compounds. Although the combustion performances of the Spirulina bio-oil are worse than those of the diesel fuel, it is superior to the reported rice husk bio-oil, suggesting a promising potential application prospect.

Examining the neural mechanism behind testing effect with concrete and abstract words.

The testing effect refers to the fact that testing enhances delayed memory more than restudying does. Previous studies revealed that the testing effect can be influenced by the delay period, the type of testing, and other factors. However, a few studies have focused on how the testing effect interacts with the properties of words, such as the concreteness effect. In an event-related potential study, we investigated how concreteness affects the testing effect. The behavioral results showed that concrete words benefited more from retrieval practice than the abstract words. The event-related potential amplitude of concrete words was significantly different between retrieval practice and restudying. Source analyses showed that only concrete words elicited activity in superior parietal lobule after being retrieved. We suggest that this difference is owing to the additional imaging during the encoding and retrieving of concrete words.

Dissociating neural correlates of retrieval practice and elaborative study in associative recognition memory.

Retrieval practice effect refers to better long-term retention enhanced by active retrieval compared to re-studying, which has been widely demonstrated. However, controversies remain as to whether the underlying mechanism of this effect could be attributed to semantic elaboration. We investigated whether retrieval practice and elaboration were equivalent by observing the underlying cognitive processes of the two conditions using corresponding event-related potentials measures of associative memory and item memory. Behavioral results showed that retrieval practice induced better associate memory performance than elaborative study. For event-related potential results, an early old/recombined effect (FN400) related to familiarity and a late old/recombined effect (late positive component) related to recollection emerged in the retrieval practice condition, while both were absent in the elaborative study condition. An early recombined/new effect (FN400) appeared in the elaborative study condition, which did not occur in the retrieval practice condition. It could be inferred that retrieval practice promoted the recollection of episodic contexts for later associative memory, while elaborative study strengthened the familiarity of individual item. These findings suggest that retrieval practice and elaboration are two distinctive processes.

[Trend of bone development of adolescent at 14 years old].

OBJECTIVE: To describe characteristic of hand-wrist bone development in adolescents of 14 years old in China, and to estimate trend of bone development of them. METHODS: A total of 109 adolescents of 14 years was selected as subjects (males: 53, females: 56). X-rays examination of their left hand-wrist bone were performed and analyzed. The development characteristics of each position in accordance with Gu's mapping of skeletal age were compared with Gu's results and ours. RESULTS: Compared with Gu's, osteoepiphysis of distal radius, the first metacarpal bone, the fourth proximal phalanx were more advanced in boys, osteoepiphysis of distal radius, the second-fifth metacarpal bones, the first-fifth proximal phalanxs, and the second-fifth middle phalanxs were more advanced in girls. CONCLUSION: The results suggested that a forward trend of 14 years old adolescents bone development currently exists in our country, especially in girls. As an important age of criminal responsibility, this forward trend of development of bones among adolescents currently should be kept in mind when estimating bone age of criminals.