Barium

The sulfate contents of the LJ fucoidan were measured as described previously [36 (link)]. The LJ fucoidan was hydrolyzed with 10 mg of 2 M TFA in a screw-cap vial and kept for 2 h at 121 °C. The barium-gelatin solution was prepared by adding 0.75 g of gelatin (Sigma-Aldrich) in 250 mL of boiling water, cooling and mixing with 10 g of barium chloride (BaCl₂·2H₂O, Sigma-Aldrich). The barium-gelatin solution and 0.5 N of hydrochloric acid (Sigma-Aldrich) were mixed in a 1:1 ratio. The mixture (50 µL) and hydrolyzed sample (250 µL) were added into a microtiter plate and determined the absorbance at 450 nm. The standard curve was generated using a serial dilution of anhydrous sodium sulfate (Na₂SO₄). The experiments were performed in triplicate.

Polyclonal anti-KCC1 antibody was purchased from Alomone Labs, Israel. Bumetanide, amiloride, benzamil, barium, glibenclamide, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), CFTR(inh)-172, and forskolin were obtained from Sigma while GlyH 101 was from Calbiochem. All stock solutions were prepared in DMSO. Normal salt diet and low salt diet were purchased from Harlan Teklad. Ringer solution contains (in mM) 140.8 Na⁺, 5.2 K⁺, 123.5 Cl^-, 25 HCO₃^-, 1.25 Ca²⁺, 1.25 Mg²⁺ and 5 glucose, pH 7.4. Cl^--free Ringer solution contains HCO₃^- (25 mM) with no Cl^-. HCO₃^--free Ringer solution contains Cl^- with no HCO₃^-. Na⁺-free Ringer solution contains no Na⁺. In these solutions, isethionate was used in place of anion Cl^- and HCO₃^- and N-Methyl-D-glucamine (NMDG) was used as a substitute for Na⁺. HCO₃^--containing solutions were gassed with 95% O₂-5% CO₂; HCO₃^--free solution was gassed with 100% O₂.

BSO and LSO thin films were grown in a Veeco GEN10 MBE system. Separate effusion cells containing barium (99.99% purity, Sigma‐Aldrich), SnO₂ (99.996% purity, Alfa Aesar), lanthanum (99.996% purity, Ames Lab), and scandium (99.9% purity, Alfa Aesar) were heated. The fluxes of the resulting molecular‐beams emanating from the effusion cells were measured by a quartz crystal microbalance (QCM) before growth. A commercial ozone generator was used to produce the oxidant molecular beam source (≈10% ozone + 90% oxygen). The BSO film was grown in an adsorption‐controlled regime by supplying an excess SnO_x‐flux.^[19] The background pressure of the oxidant, 10% O₃ + 90% O₂, was held at a constant ion gauge pressure of 1.0 × 10⁻⁶ Torr. Subsequently, LSO was grown on top of the BSO film using a layer‐by‐layer growth method. The fluxes of the La and Sc molecular beams were roughly calibrated by a QCM and then more precisely calibrated by growing La₂O₃ and Sc₂O₃ binary oxide films and measuring the growth rate using both X‐ray reflectivity and in situ reflection high‐energy electron diffraction (RHEED) oscillations.^[47] For the growth of both the BSO and LSO layers the substrate temperature was maintained between 830 and 850 °C, as measured by an optical pyrometer operating at a wavelength of 1550 nm.