Spectroscopic studies of Er3+-Yb3+ codoped multicomposition tellurite oxide glass

Multicomposition of Er3+-Yb3+ codoped tellurite oxide, TeO2-ZnO-PbO-TiO2-Na2O glass has been investigated. A detailed spectroscopic study of the Judd-Ofelt analysis has been performed from the measured absorption spectrum in order to obtain the intensity parameters Ωt (t=2, 4, 6). The calculated Ωt values were then utilized in the determination of transition probabilities, radiative lifetimes and branching ratios of the Er3+ transitions between the J(upper)-J’(lower) manifolds. Both visible upconversion and near-infrared spectra were characterized under the 980 nm laser diode excitation at room temperature

Physical, structural, optical and gamma radiation shielding properties of borate glasses containing heavy metals (Bi 2 O 3 /MoO 3 )

In an attempt to develop a novel gamma radiation shielding glasses, we prepared borate glasses contains a high concentration of heavy metals like Bi 2 O 3 and MoO 3 with the composition of 20MoO 3 -(80-x)B 2 O 3 -xBi 2 O 3 , were x varied from 30 to 45 mol% using tradition melt-quenching-annealing method. A structural investigation such as XRD and FTIR were characterized to confirm the amorphous structure of the prepared glasses and prove the availability of all chemicals included in these compositions after the melting process. Furthermore, optical studies on these glasses were investigated to prove the transparency of the fabricated glasses. Attenuation characteristics (mass attenuation coefficients, radiation protection efficiency, and half value layer) of the prepared glasses with respect to gamma photons (in the range of 0.356–1.33 MeV) were investigated. The mass attenuation coefficients and radiation protection efficiency results increased with increasing the Bi 2 O 3 content and this improves the attenuation ability for the prepared samples. The radiation protection efficiency also revealed that the glasses have the maximum capability in attenuation gamma photons at 0.356 MeV. The mean free path with the prepared glasses was compared with some concretes which is reported in the literature and with some commercial glasses to assess their potential for use in gamma radiation shielding products

An investigation on shielding properties of BaO, MoO3 and P2O5 based glasses using MCNPX code

In the present work, some radiation shielding quantities (mass attenuation coefficients, effective atomic number, effective electron density, half value layer and mean free path) for various BaO–MoO3–P2O5 ternary glass systems have been determined within the 0.015–15 MeV energy range, using WinXCom program. Additionally, the mass attenuation coefficients of all the investigated glasses have been calculated using MCNPX simulation code (version 2.6.0) and compared to those of WinXCom results. Among the studied glasses, BaMoP8 glass sample with MoO3 content of 70% mol is found to have superior gamma-ray shielding characteristics. Moreover, the glasses studied in this paper possess better radiation shielding properties by providing shorter half value layer (HVL) than RS-253 G18 commercial glass and some concrete samples namely ordinary, hematite-serpentine and ilmanite-limonite. Keywords: MoO3-based glass, Radiation shielding, Attenuation coefficients, WinXCom, MCNP

Vibrational, thermal features, and photon attenuation coefficients evaluation for TeO2-B2O3-BaO-ZnO-Na2O-Er2O3-Pr6O11 glasses as gamma-rays shielding materials

Sodium zinc barium borotellurite glass systems doped with singly Er, Pr, and Er/Pr-codoped ions were fabricated via melt quenching method to study their structural, thermal, and gamma radiation shielding features. Both FTIR and Raman spectroscopic results revealed that the glass network matrix is prevailingly formed by TeO4, TeO3 + 1, TeO3, BO3 and BO4 structural clusters. The characteristic temperatures (glass transition (Tg), onset crystallization (Tx), peak crystallization (Tc), and melting (Tm)) and thermal stabilities (ΔT) were determined by differential scanning calorimetry (DSC). An increase in ‘Tg’ and (ΔT) variation within the temperature range 123–164 °C with an addition of Er2O3, Pr6O11, and Er2O3/Pr6O11 oxides indicates that synthesized glasses possess good thermal stability. For selected glasses, mass attenuation coefficient (μ/ρ) values calculated using both XCOM software and MCNP5 simulation code in the 0.015–15 MeV photon energy range were matched well. Moreover, based on the (μ/ρ) values, various shielding parameters like effective atomic number (Zeff), electron density (Ne), mean free path (MFP) and half-value layer (HVL) are evaluated. Additionally, exposure buildup factor (EBF) values have been determined using Geometric Progression (G–P) fitting method in the energy range 0.015–15 MeV and up to a penetration depth of 40 mfp, and variation of all the shielding parameters is discussed for the effect of singly Er, Pr and doubly Er/Pr ions inclusion into the host glass. As an example, the prepared rare-earth (RE)-doped glasses show lower HVL values compared to 80TeO2-20MgO and 80TeO2-20MoO3 (mol %) glasses suggesting their potentiality as good gamma radiation shielding materials

Safety of hospital discharge before return of bowel function after elective colorectal surgery

Background: Ileus is common after colorectal surgery and is associated with an increased risk of postoperative complications. Identifying features of normal bowel recovery and the appropriateness for hospital discharge is challenging. This study explored the safety of hospital discharge before the return of bowel function. Methods: A prospective, multicentre cohort study was undertaken across an international collaborative network. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The main outcome of interest was readmission to hospital within 30 days of surgery. The impact of discharge timing according to the return of bowel function was explored using multivariable regression analysis. Other outcomes were postoperative complications within 30 days of surgery, measured using the Clavien\u2013Dindo classification system. Results: A total of 3288 patients were included in the analysis, of whom 301 (9\ub72 per cent) were discharged before the return of bowel function. The median duration of hospital stay for patients discharged before and after return of bowel function was 5 (i.q.r. 4\u20137) and 7 (6\u20138) days respectively (P < 0\ub7001). There were no significant differences in rates of readmission between these groups (6\ub76 versus 8\ub70 per cent; P = 0\ub7499), and this remained the case after multivariable adjustment for baseline differences (odds ratio 0\ub790, 95 per cent c.i. 0\ub755 to 1\ub746; P = 0\ub7659). Rates of postoperative complications were also similar in those discharged before versus after return of bowel function (minor: 34\ub77 versus 39\ub75 per cent; major 3\ub73 versus 3\ub74 per cent; P = 0\ub7110). Conclusion: Discharge before return of bowel function after elective colorectal surgery appears to be safe in appropriately selected patients