Lead borate glasses and glass-ceramics singly doped with Dy3+ for white LEDs

In this paper, some series of lead borate glasses and glass ceramics singly doped with Dy3+ ions were prepared and then studied using spectroscopic techniques. Our research includes mainly studies of the luminescence properties of received materials for white light. The luminescence bands associated with the characteristic 4F9/2!6H15/2 (blue), 4F9/2!6H13/2 (yellow) and 4F9/2!6H11/2 (red) transitions of trivalent dysprosium in lead borate systems are well observed. In particular, the Commission Internationale de I’Eclairage (CIE) chromaticity coordinates (x, y) were calculated in relation to potential applications for white light-emitting diodes (W-LEDs). Their values depend on the relative B2O3/PbO ratios and PbX2 contents (where X = Cl, F, Br) in glass composition. For glass-ceramics, the chromaticity coordinates are changed significantly under di erent excitation wavelengths

Optical characterization of nano- and microcrystals of EuPO4 created by one-step synthesis of antimony-germanate-silicate glass modified by P2O5

Technology of active glass-ceramics (GC) is an important part of luminescent materials engineering. The classic method to obtain GC is based on annealing of parent glass in proper temperature and different time periods. Generally, only the bulk materials are investigated as a starting host for further applications. However, the effect of an additional heat-treatment process on emission and structural properties during GC processing is omitted. Here, we focus on the possibility of obtaining transparent glass-ceramic doped with europium ions directly with a melt-quenching method. The influence of phosphate concentration (up to 10 mol %) on the inversion symmetry of local environment of Eu3+ ions in antimony-germanate-silicate (SGS) glass has been investigated. The Stark splitting of luminescence spectra and the local asymmetry ratio estimated by relation of (5D0→7F2)/(5D0→7F1) transitions in fabricated glass confirms higher local symmetry around Eu3+ ions. Based on XRD and SEM/EDX measurements, the EuPO4 nano- and microcrystals with monoclinic geometry were determined. Therefore, in our experiment, we confirmed possibility of one-step approach to fabricate crystalline structures (glass-ceramic) in Eu-doped SGS glass without additional annealing process

Spectroscopic properties of erbium-doped oxyfluoride phospho-tellurite glass and transparent glass-ceramic containing BaF2 nanocrystals

The ErF3-doped oxyfluoride phospho-tellurite glasses in the (40-x) TeO2-10P2O5-45 (BaF2-ZnF2) -5Na2O-xErF3 system (where x = 0.25, 0.50, 0.75, 1.00, and 1.25 mol%) have been prepared by the conventional melt-quenching method. The effect of erbium trifluoride addition on thermal, structure, and spectroscopic properties of oxyfluoride phospho-tellurite precursor glass was studied by differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), and Raman spectroscopy as well as emission measurements, respectively. The DSC curves were used to investigate characteristic temperatures and thermal stability of the precursor glass doped with varying content of ErF3. FTIR and Raman spectra were introduced to characterize the evolution of structure and phonon energy of the glasses. It was found that the addition of ErF3 up to 1.25 mol% into the chemical composition of phospho-tellurite precursor glass enhanced 2.7 µm emission and upconversion. By controlled heat-treatment process of the host glass doped with the highest content of erbium trifluoride (1.25 mol%), transparent erbium-doped phospho-tellurite glass-ceramic (GC) was obtained. X-ray diffraction analysis confirmed the presence of BaF2 nanocrystals with the average 16 nm diameter in a glass matrix. Moreover, MIR, NIR, and UC emissions of the glass-ceramic were discussed in detail and compared to the spectroscopic properties of the glass doped with 1.25 mol% of ErF3 (the base glass)

Changing patterns in the surgical treatment of perforated duodenal ulcer : single centre experience

INTRODUCTION: Although the surgical treatment of patients with perforated duodenal ulcer is the method of choice, the introduction of effective pharmacotherapy has changed the surgical strategy. Nowadays less extensive procedures are chosen more frequently. The introduction of laparoscopic procedures had a significant impact on treatment results. AIM: To present our experience in the treatment of perforated duodenal ulcer in two periods, by comparing open radical anti-ulcer procedures with laparoscopic ulcer repair. MATERIAL AND METHODS: The analysis covered patients operated on for perforated duodenal ulcer. Two groups of patients were compared. Group 1 included 245 patients operated on in the period 1980–1994 with a traditional method (pyloroplasty + vagotomy) before introduction of proton pump inhibitors (PPI). Group 2 included 106 patients treated in the period 2000–2014 with the laparoscopic technique supplemented with PPI therapy. Groups were compared in terms of patients’ demographic structure, operative time, complication rate and mortality. RESULTS: The mean operative time in group 1 was shorter than in group 2 (p < 0.0001). Complications were noted in 57 (23.3%) patients in group 1 and 14 (13.5%) patients in group 2 (p = 0.0312). Reoperation was necessary in 13 (5.3%) cases in group 1 and in 5 cases in group 2 (p = 0.8179). The mortality rate in group 1 was significantly higher than in group 2 (10.2% vs. 2.8%, p = 0.0192). In group 1, median length of hospital stay was 9 days and differed significantly from group 2 (6 days, p < 0.0001). CONCLUSIONS: Within the last 30 years, significant changes in treatment of perforated peptic ulcer (PPU) have occurred, mainly related to abandoning routine radical anti-ulcer procedures and replacing the open technique with minimally invasive surgery. Thus it was possible to improve treatment results by reducing complication and mortality rates, and shortening the length of hospital stay. Although the laparoscopic operation is longer, it improves outcomes. In the authors’ opinion, in each patient with suspected peptic ulcer perforation, laparoscopy should be the method of choice

Structure and luminescence properties of transparent germanate glassceramics co-doped with Ni2+/Er3+ for near-infrared optical fiber application

An investigation of the structural and luminescent properties of the transparent germanate glass-ceramics co-doped with Ni2+/Er3+ for near-infrared optical fiber applications was presented. Modification of germanate glasses with 10–20 ZnO (mol.%) was focused to propose the additional heat treatment process controlled at 650 C to obtain transparent glass-ceramics. The formation of 11 nm ZnGa2O4 nanocrystals was confirmed by the X-ray diffraction (XRD) method. It followed the glass network changes analyzed in detail (MIR—Mid Infrared spectroscopy) with an increasing heating time of precursor glass. The broadband 1000–1650 nm luminescence ( exc = 808 nm) was obtained as a result of Ni2+: 3T2(3F) ! 3A2(3F) octahedral Ni2+ ions and Er3+: 4I13/2 ! 4I15/2 radiative transitions and energy transfer from Ni2+ to Er3+ with the efficiency of 19%. Elaborated glass–nanocrystalline material is a very promising candidate for use as a core of broadband luminescence optical fibers

Investigation of the TeO2/GeO2 Ratio on the Spectroscopic Properties of Eu3+-Doped Oxide Glasses for Optical Fiber Application

This study presented an analysis of the TeO2/GeO2 molar ratio in an oxide glass system. A family of melt-quenched glasses with the range of 0–35 mol% of GeO2 has been characterized by using DSC, Raman, MIR, refractive index, PLE, PL spectra, and time-resolved spectral measurements. The increase in the content of germanium oxide caused an increase in the transition temperature but a decrease in the refractive index. The photoluminescence spectra of europium ions were examined under the excitation of 465 nm, corresponding to 7F0 → 5D2 transition. The PSB (phonon sidebands) analysis was carried out to determine the phonon energy of the glass hosts. It was reported that the red (5D0 → 7F2) to orange (5D0 → 7F1) fluorescence intensity ratio for Eu3+ ions decreased from 4.49 (Te0Ge) to 3.33 (Te15Ge) and showed a constant increase from 4.58 (Te20Ge) to 4.88 (Te35Ge). These optical features were explained in structural studies, especially changes in the coordination of [4]Ge to [6]Ge. The most extended lifetime was reported for the Eu3+ doped glass with the highest content of GeO2. This glass was successfully used for the drawing of optical fiber

Fluoroindate glass co-doped with Yb3+/Ho3+ as a 2.85 μm luminescent source for MID-IR sensing

This work reports on the fabrication and analysis of near-infrared and mid-infrared luminescence spectra and their decays in fluoroindate glasses co-doped with Yb3+/Ho3+. The attention has been paid to the analysis of the Yb3+ ! Ho3+ energy transfer processed ions in fluoroindate glasses pumped by 976 nm laser diode. The most effective sensitization for 2 um luminescence has been obtained in glass co-doped with 0.8YbF3/1.6HoF3. Further study in the midinfrared spectral range (2.85 um) showed that the maximum emission intensity has been obtained in fluoroindate glass co-doped with 0.1YbF3/1.4HoF3. The obtained efficiency of Yb3+ ! Ho3+ energy transfer was calculated to be up to 61% (0.8YbF3/1.6HoF3), which confirms the possibility of obtaining an efficient glass or glass fiber infrared source for a MID-infrared (MID-IR) sensing application

Germanate glasses co-doped with Ce3+/Ln3+ (Ln = Pr, Tb, Dy) for white light emitting diodes

Glasses doped with lanthanides ions may be good white light emitters due to their interesting physical and spectroscopic properties. In this paper, the optical spectroscopy of rare earths doped glasses with a special emphasis on application as white LED were presented. The luminescent glass materials containing Ln3+ (Ln = Pr, Tb, Dy) and Ce3+ ions were obtained. The glasses samples were prepared by a traditional melt-quenching technique. The optical properties of glasses containing various concentrations of rare earth ions were analyzed. It was observed that luminescence bands corresponding to characteristic transitions of Ln3+ and cerium ions are present on spectra measured under direct excitation of Ce3+. Therefore, it indicates that the energy transfer process between Ce3+ /Pr3+, Ce3+ /Tb3+, Ce3+ / Dy3+ ions in glasses occurs. Some parameters such as correlated color temperature (CCT) and chromaticity coordinates (CIE) that characterize white LEDs were analyzed and discussed in detail

The prevalence of, and risk factors for, Barretts oesophagus after sleeve gastrectomy

INTRODUCTION: Sleeve gastrectomy has become one of the most performed bariatric procedures. There is increasing evidence that sleeve gastrectomy patients suffer from gastroesophageal reflux disease and its sequelae such as erosive oesophagitis (EO) or Barret’s oesophagus (BO). AIM: To evaluate the incidence of EO and BO among patients with normal preoperative oesophagogastroduodenoscopy findings, who underwent sleeve gastrectomy, and investigate factors that may contribute to the development of EO and BO after the surgery. MATERIAL AND METHODS: We conducted a single-centre longitudinal study that included patients who underwent sleeve gastrectomy and completed 5 years of follow-up. Gastroscopies were performed in all patients at the end of the follow-up period. Patient- and treatment-related factors were used to search for risk factors of BO. RESULTS: From a total of 30 patients, symptomatic reflux was reported by 17 (56.7%) during the follow-up period. At EGD EO was found in 9 of those patients (30%), whereas BE was diagnosed in 8 (27%) patients. The median BMI at the end of the follow-up period was significantly higher among patients with BE than in the groups with EO and with no endoscopic changes: 40.91 ±6.32, 32.42 ±5.53, and 33.25 ±4.41, respectively (p = 0.04). CONCLUSIONS: The prevalence of BO in SG patients is considerable. The risk of BE increases in patients with poor bariatric outcome. Endoscopic surveillance should be considered as part of the follow-up, especially in patients with higher overall risk of BE