Surface-swimming nano- and micromotors hold significant potential for on-chip mixing, flow generation, sample manipulation, and microrobotics. Here we describe rotating microrods magnetized nearly orthogonally to their long axes. When actuated near a solid surface, these microrods demonstrate precessing motion, with rods describing a double cone similar to the motion of a kayaker's paddle. The precessing motion induces translation. At 1 kHz, these "microkayaks" move at translational velocities of ≈14 μm s and generate advective flows up to 10 μm s.

Writing is no longer an individual activity but an interactive process through which social abilities of the learners are reinforced. To promote interaction in the writing class, collaboration has been suggested to be advantageous. The present study aimed to examine the impact of practicing in pairs on the writing fluency of Iranian EFL learners. To this end, an OPT test was administered to female EFL learners according to which 90 homogenous learners at an intermediate level comprised the research sample. Afterwards, the participants were randomly divided into two groups including a control group of 30 students, each producing a written text individually and an experimental group of 60 learners working in pairs. Since each pair produced a single text, the numbers of texts rather than the number of participants was considered. In order to compare the data collected from two groups, a t- test was used. The results obtained from the essays written in the first session of the writing phase revealed that pairs produced less fluent texts than the individual writers. More specifically, the average number of words, T-units, and clauses in individual essays was less than that of pairs.  The essays written in the last session revealed that there was a considerable improvement in the use of T-units and clauses produced by pairs; however, the fluency of the written texts was not noticeably significant in comparison with the fluency of essays produced by the individuals. The findings also revealed that practicing in pairs did improve the overall quality of the learners' writing productions even though the fluency of written texts did not change significantly

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Nanostructured biomaterials have great potential in the field of biomedical engineering. Efforts for treatment of cardiovascular diseases focused on introducing vascular substitutes that are nonthrombogenic and have long-term patency, but still there is not any perfect replacement for clinical use. In this study, nanostructure tubes of a commonly known biocompatible polymer, polyethylene terephthalate (PET), were prepared via electrospinning process using small diameter mandrel as a collector with two different speeds. The nanofibers (NFs) morphologies' physical and mechanical properties were investigated according to scanning electron microscope (SEM), water contact angle (WCA), porosity measurement, differential scanning calorimetry (DSC), and tensile test. Finer NFs, more percentage of crystallinity, and superior mechanical properties were observed for samples prepared by higher speed mandrel. Since both samples stimulated platelet adhesion and activation, further surface modification with sodium nitrate as nitric oxide (NO) donor was done using two different approaches: dip-coating and electrospraying. The modified NFs were evaluated via SEM, WCA, tensile test, platelets, and cell adhesion. The results showed more hydrophilicity, reduction in platelet adhesion, and improved blood compatibility for eNO-HS (electrosprayed NO for higher collector speed) compared with other samples implying the promising potential of this fabrication and modification technique for improving PET-based cardiovascular substitutes.

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