Igor macros

Both SANS and USANS experiments were conducted at the NIST Center for Neutron Research (NCNR, Gaithersburg, MD, USA). 30 m SANS instrument (NGB-30) was used to obtain the SANS profiles^{33 (link)}. Scattering patterns from three detector positions were stitched together to access a full q-range between 1 × 10⁻³ and 0.45 Å⁻¹. Demountable titanium cells with quartz windows and a path length of 1 mm were used to hold the sample. The temperature of the sample environment was controlled by a Peltier module. USANS experiment was conducted on the USANS instrument at NCNR (BT-5), which covers a q-range of 3 × 10⁻⁵Å⁻¹ < q < 1 × 10⁻³ Å⁻¹. A circulation bath was hooked up to a multi-position sample changer (6CB) to regulate the temperature. Both the SANS and USANS results were reduced with Igor macros (Wavemetrics, Portland, OR, USA)^{34 (link)}.

Amperometric recordings were performed by using carbon fibers microelectrodes purchased from ALA Scientific Instrument Inc. (Westbury, NY, USA) and a HEKA EPC-10 amplifier (HEKA Elektronik GmbH, Reutlingen, Germany) [7 (link), 30 (link)]. Carbon fibers (5 μm diameter) were cut at an angle of 45°, polarized to + 800 mV, and positioned next to the cell membrane. Rat CCs were maintained in standard saline solution, containing (mM) 130 NaCl, 2 MgCl₂, 10 glucose, 10 HEPES, 2 CaCl₂, and 4 KCl. For the first 2 min of recordings, the cells were not stimulated and spontaneous exocytic activity was measured. Then the rat CCs were stimulated by using a KCl-enriched solution, containing (mM) 100 NaCl, 2 MgCl₂, 10 glucose, 10 HEPES, 10 CaCl₂, and 30 KCl. Amperometric currents were sampled at 4 kHz, low-pass filtered at 1 kHz, and monitored over 120 s. Finally, we analyzed the recordings by using IGOR macros (Wave-Metrics, Lake Oswego, OR, USA) as previously described [8 ].