Exploring beam size measurement based on the Talbot effect at BEPCII.

Vertical beam size measurements were carried out at Beijing Electron-Positron Collider II (BEPCII) using a phase grating and an absorption grating based on the Talbot effect. The transverse coherence of synchrotron radiation is closely related to beam size. Due to the partial coherence of the synchrotron radiation source, the coherence length can be calculated by measuring the visibility decay of interferograms recorded at different distances behind the gratings. A vertical beam size of 68.19 ± 2 µm was obtained based on the relationship between the coherence length and beam size at the 3W1 beamline of BEPCII. A comparison of the vertical emittance derived from the grating Talbot method and the synchrotron radiation visible light interferometer method was presented. The vertical emittances from the two methods are 1.41 nm rad and 1.40 nm rad, respectively. The 0.1% difference indicates that the grating Talbot method for beam size measurement is reliable. This technique has great potential for small beam size measurement of fourth-generation synchrotron radiation light sources, considering its small diffraction limitation and simple experimental setups.

Anesthesia management for tracheoesophageal fistula closed with a new gastrointestinal occluder device: a case report.

BACKGROUND: Tracheoesophageal fistula (TEF) is a rare but life-threatening complication after esophagectomy. A new gastrointestinal occluder device provides treatment for TEF patients. However, TEF-related pneumonia and respiratory failure increase the difficulty of anesthesia management, especially in airway management. CASE PRESENTATION: A 64-year-old man with thoracic esophageal cancer underwent esophagectomy and gastric tube reconstruction one year ago. The patient presented with recurrent cough and sputum after surgery. Gastroscopy revealed a fistula between the esophagogastric anastomotic site and membrane of the trachea. Therefore, the patient received implantation of a new gastrointestinal occluder device under gastroscopy combined with tracheoscopy. Airway management under general anesthesia was discussed with an interdisciplinary decision, and cuffed endotracheal tube with an inner diameter of 5.5 mm was chosen. This airway management ensured adequate oxygenation during the operation and provided sufficient space for the operation of the tracheoscope in the trachea. Finally, the TEF disappeared after the operation, and the patient was administered an oral diet on the first postoperative day. CONCLUSIONS: The implantation of a new gastrointestinal occluder device under gastroscopy combined with tracheoscopy provides a new treatment for TEF patients. This case report suggests that it is important to select an endotracheal tube with an appropriate inner diameter that can not only meet the requirements of ventilation but also does not affect the operation of tracheoscopy in the trachea.