Lead oxide

Postmortem angiography was performed by injecting the contrast medium as previously described^{22 (link)}. Gelatine (20 g, type A, Sigma, MO, USA) was dissolved in 100 ml of 50 °C distilled water with continuous steering. Afterward, 100 g of lead oxide (Sigma, MO, USA) was added and mixed well. Animals were anaesthesized and anticoagulated, and the aorta was cannulated. Subsequently, the animals were bled and immersed in water warmed to 50 °C. Then, the contrast medium was infused at a pressure of 150–180 mmHg until filling of the distal femoral stump was observed. The animals were immediately placed on crushed ice, and the contrast medium was allowed to harden under continuous pressure. X-ray images were taken in an X-ray chamber (model DHF-155H, Tokyo Japan, HITACHI MEDICAL CORPORATION) exposed to 50 KV and 100 mA for 30 mS. Images were acquired and transferred to a computer, which was used to identify and quantify the collateral arteries.

Oleic acid (OA, 90%), 1-octadecene (ODE, 90%), lead oxide (PbO, 99.999%), Bis(trimethylsilyl) sulfide ((TMS)₂S, 95%), and hexane (95%, anhydrous) were purchased from Sigma-Aldrich. Ethanol (99.9%, anhydrous) was purchased from Daejung.
Synthesis of PbS QDs followed the previous method with slight modification. Briefly, 0.47 g of PbO, 23 ml of ODE, and 2 ml of OA were loaded in a 3-neck flask. The mixture was degassed at 110℃ for 1 h under vacuum. Then, the reaction flask was switched to N₂ and heated up to 120℃. Once the PbO fully dissolved, the reaction flask was stabilized at 80℃. Meanwhile, a 21 μl (TMS)₂S/1 ml pre-degassed ODE solution was prepared in a nitrogen-filled glove box. After removing the heating mantle, 5 ml of (TMS)₂S precursor was swiftly injected into the reaction flask. The reaction flask was slowly cooled to room temperature. The as-synthesized PbS QDs solution was transferred into a glove box to prevent air exposure. Then, the solution was purified with hexane and ethanol twice. Finally, purified PbS QDs were redispersed in octane (50 mg/ml) and stored in a glove box until further use.

Cesium carbonate (Cs₂CO₃, 99.995% trace-metal basis), lead oxide (PbO, 99.999% trace-metal
basis), lead(II) bromide (PbBr₂, 98%), oleic acid (OA,
technical grade 90%), oleylamine (OAm, technical grade 70%), 1-octadecene
(ODE, technical grade 90%), toluene (anhydrous, 99.8%), and hexane
(95%) were received from Sigma-Aldrich. Hydrobromic acid (HBr, 48%)
was purchased from VWR Chemicals BDH. OA and OAm were dried with molecular
sieves under an argon atmosphere before use. Other chemicals were
used as received.

Lead oxide (PbO, 99%), Methylammonium chloride (CH₃NH₃Cl, 99%), 2-(1-Cyclohexenyl)ethylamine (C₆H₉C₂H₄NH₂⁺, ≥ 98%), Hydriodic acid (HI, 57 wt % in H₂O), hypophosphorous acid (H₃PO₂, 50 wt.% in H₂O), N,N-dimethylformamide (DMF, anhydrous, 99.8%), were used as received from Sigma-Aldrich.

Methylammonium chloride (MACl), 50% aqueous
H₃PO₂, lead oxide (PbO, 99.999%), phenethylamine
(99%), n-butylamine (>99%), 57% stabilized hydroiodic
acid (HI), lead iodide (PbI₂, 98%), dimethyl sulfoxide
(DMSO, anhydrous), n-butylammonium bromide
((BA)Br, ≥98%)), phenethylammonium bromide ((PEA)Br,
≥98%), and lead bromide (PbBr₂, ≥98%) were
purchased from Sigma-Aldrich.