Vhx 500f

Body length from each specimen was measured as length from snout tip to vent (McDiarmid and Altig, 1999 ) and developmental stage was determined (Gosner, 1960 ). As oral structures, maximum oral disc width, number of denticles present in 2nd posterior denticle row and total number of oral papillae (McDiarmid and Altig, 1999 ) were determined. As intestinal structures, gut length (from the end of the Manicotto glandulare to the vent), average intestinal diameter (calculated from five measurements uniformly distributed over the length of the intestine), and Manicotto glandulare volume [calculated as (0.5×diameter Manicotto glandulare)²×π×length Manicotto glandulare]. Fixation in alcohol had the effect that the intestines turned rigid and broke into parts when dissecting. We carefully sorted (from anterior to posterior) and measured those parts for length and the other variables, and then added the measurements. All measurements were taken on a digital microscope (Keyence VHX-500F) using integrated measuring software tools. During measurements, tadpoles or dissected intestinal structures were placed in a wax bowl with a dark background. For measuring variables of the oral apparatus, a pin was inserted through the oral disc and pushed through the head to fixate and open the oral disc. Moreover, oral papillae were stained with Methylene Blue.

At stage 7, that fat body was dissected with the aid of a digital stereo-microscope (Keyence VHX-500F). During measurements, froglets or dissected fat bodies were placed in a wax bowl with dark background (Fig. 4A). Fat bodies were dabbed and their mass determined to the nearest 0.01 mg with an electronic balance (Sartorius A200 S). Relative fat body size was calculated from individual mass of fat body (mg) divided by individual body mass (mg) and expressed as mg × .

A ball-on-disc tribometer (MS-T3000, Lanzhou, China) was used to investigate the wear properties of the specimens under dry conditions. Each specimen was tested using a silicon nitride ceramic ball (Si₃N₄, φ6 mm), with the following parameters: a load of 5 N, a sliding speed of 200 rpm, and a test duration of 30 min. The friction coefficients were recorded, and the wear scars were observed using an ultra-depth 3D microscope (VHX-500F, Keyence, Osaka, Japan). Three duplicate specimens were tested for each group.

To determine the distribution and shape of calcium carbonate crystals in the gels, gels were cut into 1 mm thin slices using a microtome blade. The slices were subsequently investigated using an incident light microscope VHX-500 F (Keyence, Osaka, Japan).

The experimental setup for the measurement of the dependence of the electrical resistance of the liquid metal-based-strain sensor on the bending motion of a PBA used a digital multimeter (34,460A, Keysight Tech., Bucharest, Romania) in combination with data processing software (BenchVue). The relative resistance change ΔR/R₀ was measured and converted into bending angle θ.
The deformation of a microchannel for liquid metal-based-sensor with/without parylene C deposition was estimated by applying external pushing force using a positioning stage (KHE06008-C, SURUGA SEIKI CO., LTD., Sanda City, Hyogo, Japan.). The deformation of a microchannel by vertical pushing force was observed by a microscope (VHX 500F, Keyence, Bucharest, Romania). The repulsion force was measured by a load cell (LVS-5GA, Kyowa Electronic Instruments Co., Ltd. Tokyo, Japan).