Spontaneous motion of droplet in tubes: The effects of surface wettability and segment length

This work studies the spontaneous droplet flow in tubes with different wettability gradient and number of segments by using a particle-based numerical method, many-body dissipative particle dynamics (MDPD). The study aims to understand how the different contact angle sets (gradient contact angle distribution along with different segments of a tube) and the number of segments could affect the droplet flow velocity and time to reaching a stable state. Simulation results show that even with the same wettability gap, a contact angle set with higher values of contact angle along the tube segments can drive the droplet to flow faster in the tubes; moreover, with the same contact angle set and tube length, the tubes with fewer segments can allow a faster flow of droplet, thus a shorter time to reaching the stable state. The numerical findings in this work can provide a new idea and direction for the design of droplet-based microfluidic systems.

Spontaneous polarization and cell guidance on asymmetric nanotopography

Asymmetric nanotopography with sub-cellular dimensions has recently been demonstrated to be able to provide a unidirectional bias in the migration of cells. The details of this guidance depend both on the type of cell studied and the design of the nanotopography. This behavior is not yet well understood, so there is a pressing need for a predictive description of cell migration on such nanotopography that captures both the initiation of migration and the manner in which cell migration evolves. Here, we employ a three-dimensional, physics-based model to study cell guidance on asymmetric nanosawteeth. In agreement with experimental data, our model predicts that asymmetric sawteeth lead both to spontaneous motion and changes in motion phenotypes. Our model demonstrates that asymmetric nanosawteeth induce a unidirectional bias in guidance direction that is dependent upon the actin polymerization rate and the sawtooth dimensions. Motivated by this model, an analysis of previously reported experimental data indicates that the degree of guidance by asymmetric nanosawteeth increases with the cell velocity.

Solitons in spin-tensor–momentum-coupled Bose–Einstein condensates

Recently spin-tensor–momentum coupling (STMC) has been proposed to realize in the Bose–Einstein condensate (BEC). Here, we study the bright soliton in spin-1 three components BEC with STMC. The properties of the bright solitons are discussed by the analytical solutions and numerical solutions. In addition, we also study its dynamic evolution and discover the spontaneous motion, which is different from the spin-orbit-coupled solitons.

Exploring source/goal asymmetries in spontaneous and caused motion expression in Yuhup

The aim of this paper is to explore the asymmetry in the expression of Goal and Source in spontaneous and caused motion events in Yuhup (Makú/Naduhup family). We examine the asymmetries at the semantic, morphological and syntactic levels. As this language does not have a specialized system of nominal morphology that distinguishes the ground constituents representing the Source or the Goal of a movement, an asymmetrical treatment of Source and Goal is not evident. However, verbal semantics make more distinctions for Goal than for Source, ground constituents are more frequent in the expression of motion to(wards) the Goal than the one (away) from the Source, and structural variety and complexity differentiate between Source and Goal expression. Also, the Goal bias is stronger in the descriptions of caused motion than in the ones of spontaneous motion. The data were collected using tools designed for elicitation of spontaneous and caused motion events.

Expression of spontaneous motion events in Stieng

This study investigates the expression of Source and Goal in spontaneous motion events in Stieng (Cambodia, Vietnam). The analysis is based on data collected in Cambodia, using the Trajectoire video kit (Ishibashi et al. 2006). Regardless the type of Ground, Stieng data includes a wide range of constructions in describing motion events, combining lexical and grammatical tools (verbs and adnominals). While morphosyntactic resources available to express Source and Goal are formally similar, Stieng data shows that the Goal tends to be privileged compared to the Source, at the semantic, morphosyntactic, and syntactic levels. However, Source and Goal tend to be symmetrical with respect to the semantic distinctions of the verbs, and potential (a)symmetries with respect to the discourse level remain to be clarified. Instances of asymmetries in favor of the Goal tend to support previous studies that postulated a tendency for languages to privilege the Goal in the linguistic expression.

Asymmetries in Path expression in Ye’kwana

Ye’kwana is an Amazonian language of the Cariban family spoken by a group of about 8,700 people in Venezuela and Brazil. This paper explores the expression of Path in spontaneous motion events based on spoken data collected for the documentation and description of the language including data collected with the Trajectoire elicitation material (Ishibashi et al. 2006). In Ye’kwana, Path is mainly expressed by postpositional and adverbial stems: there is a rich inventory of 80 postpositions all compatible with locative and either allative or perlative uses and 29 spatial adverbs, most of deictic nature. Source is expressed with a dedicated suffix (-nno) which combines with almost all the spatial postpositions and adverbs. The data show that the asymmetries in the expression of Path are not only found between Source and Goal but also need to include the expression of Medium for which the language has dedicated forms.