Af micro nikkor 60 mm f 2.8d

The incubator (201 × 124 × 50 mm) was fitted with six glass tubes. To ensure equal image quality and background a LED flood light aperture (15,000 lux) (Aputure Amaran AL-528W) covering the whole field of view (238 × 190 mm) was installed behind the incubator. A time lapse image series of intestines were captured during the experiment using a camera (Nikon DS-Fi3) with a macro lens (Nikon, AF Micro-Nikkor 60 mm f/2.8D), at a resolution of 1,024 × 768 pixels. The capture of the time lapse series was controlled with the NIS-Elements Confocal 4.51.01 software and captured 3.5 frames s⁻¹ for the duration of 50 min. for Experiment 1 and 35 min. for Experiment 2. Six intestines were processed in parallel in each video (Figure 1).

A charge coupled device (CCD) camera (WAT-902H ULTIMATE, WATEC, Japan) connected with a micro lens (AF Micro-NIKKOR 60 mm f/2.8D, Nikon, Japan) was used for recording, with 30 of the frame rate, and 250 × 250 of resolution for the clips in supplementary movies. The ability of the microrobot to mix chemicals in the blood was evaluated by Eq. (1) through the intensity of pixels (m_i), average intensity of an image to measure the fluid uniformity ( $\overline{m}$ ) and (n) represents the total number of pixels in an image. The acquisitions of information of images including pixel numbers and intensity were achieved with image processing software, ImageJ. $$\mathrm{Mixing}\mathrm{effeciency}\left(\%\right)=(1-\frac{1}{\overline{m}}\sqrt{\frac{\sum _i^n({m_i-\overline{m})}^2}{n}})\times 100.$$

Worm lengths in P₁ and R were measured by imaging worms on 50 mm, bacteria-free NGM plates. After pelleting by settlement (5 min at -20 C) worms were transferred to the plates in 2–5 μL aliquots until the desired number of worms was obtained (usually, 3–6 aliquots per plate). Prior to measurement, worms were allowed to disperse for 5–10 min., a process sometimes accelerated by puffs of air from a rubber bulb. Typically, all worms on 4–6 plates were imaged per experiment. Worms were immobilized by flowing C0₂ through a transparent chamber inverted over the plate. Worms were imaged at 5.64 μm/pixel using a macro lens (AF Micro-Nikkor 60 mm f/2.8D, Nikon, Japan). A series of still images tiling the entire surface of the plate was captured using a microscope camera (HDMI 1080P HD212, AmScope, Irvine, CA, USA). Images were combined into a single image stack which was submitted to WormLab software (MBF Bioscience, Williston, VT, USA) for automated length measurements. Length measurements excluded the worm’s tail which was not resolved in the images.

The video recording of the droplets was performed by a camera (Edmund Optics Inc., Singapore). It used an adjustable lens (AF Micro Nikkor 60 mm f/2.8D, Nikon, Tokyo, Japan). A horizontal shot was needed to capture the merging and mixing of the droplets. A direct capture using the camera proved to be difficult. This was due to the refraction of light from the PMMA holder. In order to mitigate this problem, a 45° prism was employed, as shown in Figure 1. The yellow dotted line represents the “line of sight” between the camera and the droplets through the prism. The camera lens was set in the “face down” position by attaching it to a PMMA slab (not shown in Figure 1). This slab was in turn clamped to the lab jack. The camera was connected to the PC through a USB port. The camera software (uEye cockpit, IDS, Ettlingen, Germany) set the video recording at 39.2 frames per second and at 82 MHz pixel clock. The image processing of the captured movie is explained in Section 2.4. Three sampled movies are provided as supplementary files S1, S2 and S3.
For the temperature recording, the data logger (Picolog USB TC-08, Pico Technology Limited., St Neots, UK) documented the temperature readings throughout the duration of the experiment. Temperature data were sampled every 1 ms. The video recording and the temperature data acquisition ran simultaneously.