Nitric AcidBurns, ChemicalEsophageal StenosisCorrosionSpectrophotometry, AtomicNeodymiumLyeDecalcification TechniqueHydrofluoric AcidEsophagusTrapidilDilatationSulfuric AcidsTrace ElementsHydrochloric AcidEsophagoscopyNitratesUpper Gastrointestinal TractEsophageal PerforationMicrowavesEsophageal DiseasesCalibrationAcidsEnvironmental Monitoring