Ce 3+ -doped Ba 2 Ln(BO 3 ) 2 Cl (Ln ¼ Gd, Y) phosphors were synthesized through a conventional hightemperature solid state method in CO atmosphere. Structural and spectroscopic characterizations of the samples have been performed by X-ray diffraction and photoluminescence spectra measurements. The phosphors can be efficiently excited by near ultraviolet (n-UV) light resulting in blue emission. The optimal Ce 3+ dopant concentrations in both compounds were determined, and the concentration quenching mechanisms were also discussed. The photoluminescence excitation (PLE) and emission (PL) spectra, and decay curves at liquid helium temperature were measured to analyze the crystallographic occupancy sites of Ce 3+ in the Ba 2 Ln(BO 3 ) 2 Cl (Ln ¼ Gd, Y) hosts. The thermal stabilities of the phosphors Ba 2 Ln(BO 3 ) 2 Cl:Ce 3+ (Ln ¼ Gd, Y) were studied using the dependence of the luminescence intensities on temperature (300-500 K), and their luminescence quenching temperatures and thermal activation energies were also determined. The results indicate that the phosphor Ba 2 Gd(BO 3 ) 2 Cl:Ce 3+ offers excellent optical properties as a potential blue-emitting phosphor candidate for n-UV LEDs, such as a higher thermal stability and a stronger luminescence intensity, than those of the phosphor Ba 2 Y(BO 3 ) 2 Cl:Ce 3+ .

Photoluminescence and cathode-luminescence of Eu 3+doped NaLnTiO 4 (Ln = Gd and Y) phosphors3

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Background Delayed gastric emptying and the resultant “full stomach” is the most important risk factor for perioperative pulmonary aspiration. Using point-of-care gastric sonography, we aimed to investigate the prevalence of full stomach and its risk factors in elective surgical patients with type 2 diabetes. Methods Type 2 diabetic and non-diabetic elective surgical patients were included from July 2017 to April 2018 in a 1:1 ratio. The study was retrospectively registered at July 2017, after enrollment of the first participant. Gastric ultrasound was performed 2 h after ingesting clear fluid or 6 h after a light meal. Full stomach was defined by the presence of gastric content in both semi-recumbent and right lateral decubitus positions. For patients with full or intermediate stomach, consecutive ultrasound scan was performed until empty stomach was detected. Logistic regression analyses were used to identify risk factors associated with full stomach. Results Fifty-two type 2 diabetic and fifty non-diabetic patients were analyzed. The prevalence of full stomach was 48.1% (25/52) in diabetic patients, with 44.0% for 2-h fast after clear fluid and 51.9% for 6-h fast after a light meal, significantly higher than 8% (4/50) in non-diabetic patients (P = 0.000). The average time to empty stomach in diabetic patients was 146.50 ± 40.91 mins for clear liquid and 426.50 ± 45.25 mins for light meal, respectively. Further analysis indicated that presence of diabetes-related eye disease was an independent risk factor of full stomach in diabetic patients (OR = 4.83, P = 0.010). Conclusions Almost half of type 2 diabetic patients have a full stomach following the current preoperative fasting guideline. Preoperative ultrasound assessment of gastric content in type 2 diabetic patients is suggested, especially for those with diabetes -related eye disease. Trial registration The trial was registered at www.clinicaltrials.gov with registration number NCT03217630. Retrospectively registered on 14th July 2017.

A series of Eu3+ ions doped Ba2Ln(BO3)2Cl (Ln = Gd, Y) orange-red emitting phosphors were prepared by solid state reaction method. The structure and optical properties were characterized by the X-ray diffraction and photoluminescence spectra. The samples could be excited efficiently by charge transfer band (CTB) centered at 254 nm and n-UV light (350–410 nm) from the 4f6 electron configuration transition. The orange-red emission peaked at 593 nm from the magnetic dipole transition dominates the emission spectra. Crystallographic sites of Eu3+ ions, the structure defect and charge compensation mechanism were discussed. The spectra properties were investigated according to the symmetry of crystallography of Eu3+ ion occupancy. The electric dipole transitions become stronger with the increase of Eu3+ ions concentration, and the optimal compositions of the Ba2Ln(BO3)2Cl:Eu3+ (Ln = Gd, Y) phosphors were also determined.

Background Delayed gastric emptying and the resultant “full stomach” is the most important risk factor for perioperative pulmonary aspiration. Using point-of-care gastric sonography, we aimed to investigate the prevalence of full stomach and its risk factors in elective surgical patients with type 2 diabetes. Methods Type 2 diabetic and non-diabetic elective surgical patients were included from July 2017 to April 2018 in a 1:1 ratio. The study was retrospectively registered at July 2017, after enrollment of the first participant. Gastric ultrasound was performed 2h after ingesting clear fluid or 6h after a light meal. Full stomach was defined by the presence of gastric content in both semi-recumbent and right lateral decubitus positions. For patients with full or intermediate stomach, consecutive ultrasound scan was performed until empty stomach was detected. Logistic regression analyses were used to identify risk factors associated with full stomach. Results Fifty-two type 2 diabetic and fifty non-diabetic patients were analyzed. The prevalence of full stomach was 48.1% (25/52) in diabetic patients, with 44.0% for 2-hour fast after clear fluid and 51.9% for 6-hour fast after a light meal, significantly higher than 8% (4/50) in non-diabetic patients (P=0.000). The average time to empty stomach in diabetic patients was 146.50±40.91 mins for clear liquid and 426.50±45.25 mins for light meal, respectively. Further analysis indicated that presence of diabetes-related eye disease was an independent risk factor of full stomach in diabetic patients (OR=4.83, P=0.010). Conclusions Almost half of type 2 diabetic patients have a full stomach following the current preoperative fasting guideline. Preoperative ultrasound assessment of gastric content in type 2 diabetic patients is suggested, especially for those with diabetes -related eye disease. Key words : type 2 diabetes mellitus; gastric emptying; regurgitation and aspiration; ultrasonography

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