In this study, SrGd2O4: xSm3+ (x = 0%, 0.5%, 1%, 2%, 3%, 4%, and 5%) phosphors were synthesized using solid state reaction method. X-ray diffraction (XRD) measurements confirmed a orthorhombic ...structure (space group Pnam (62)) of synthesized compounds. Following irradiation with 10 Gy beta dose, the sample doped with 0.5% Sm exhibited the highest integrated thermoluminescence (TL) intensity with the IRSL-TL wideband blue filter. In order to evaluate dose-response, samples were irradiated with beta radiation for 0.1–10 Gy. The Hoogenstraaten’s method, the initial rise method, combined with the TM-Tstop experiment, and glow curve fitting package were employed to determine the number of peaks, the trap structure, and the kinetic parameters of the thermoluminescence glow curve of Sm doped SrGd2O4. Based on the glow curve deconvolution obtained using software package, the component TL glow peaks present in the complex glow curve are composed of well-isolated five overlapping glow peaks.
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•SrGd2O4:Sm3+ phosphor is synthesized by solid state reaction method.•Thermoluminescence properties were conducted.•Activation energies were calculated using IR, VHR and CGCD method.
Different milling conditions, such as wet or dry, and use of different grinding media have a great impact on the flotation performance of sulphide minerals. In the present study, the effects of wet ...and dry grinding and the use of different grinding media, such as mild steel (MS) and stainless steel (SS), were investigated on a Cu-sulphide ore. The samples were ground as dry and wet with both grinding media, to a P80 value of −75 µm, and then flotation was carried out under the same conditions. The obtained data from flotation were evaluated in terms of solid/water recovery, chalcopyrite/pyrite recovery and separation efficiency. The effects of different milling conditions were discussed with the measured chemical parameters such as redox potential and dissolved oxygen level together with the flotation rate of chalcopyrite. The redox potential of the dry ground ore, irrespective of the type of milling media, was measured considerably higher than the wet grinding conditions. With SS media flotation, the rate of Cu was high for dry grinding, resulting in a higher selective concentrate in terms of grade. However, Cu recovery was lower due to the instability of the froth structure. Separation efficiency pointed out that the best flotation performance could be obtained using a wet grinding condition with MS balls.
In this work, SrGd2O4 phosphors incorporated with Eu3+ at various dopant concentrations are synthesized via solid state reaction method. An X-ray diffraction (XRD) and thermoluminescence (TL) ...technique were used to examine the structural and thermoluminescent properties of as-prepared phosphors. Orthorhombic phase formation of Eu3+ doped samples was confirmed by XRD. The influence of impurity concentration and heating rates on the glow curves was also investigated. Anomalous heating rate pattern was observed in the sample with Eu3+ additive. A model of semi-localized transition was used to explain this behaviour. The TL glow curves of beta irradiated SrGd2O4:Eu3+ (0.25 mass %) reveal three well-resolved peaks at 105, 189, and 245 °C. Various heating rates, TM–Tstop, initial rise, and computerized glow curve deconvolution techniques were employed to detect the overlapping peak numbers and establish the kinetic parameters of SrGd2O4:Eu3+ (0.25 mass %). When the trap numbers and comparable energy values are considered, the findings of the approaches are very similar. For the dose ranges between 0.1 and 8 Gy, SrGd2O4:Eu3+ (0.25 mass %) samples exhibited linear behaviour, and high reproducibility, indicating their applicability for TL dosimetry applications.
•Eu doped SrGd2O4 phosphors were synthesized using solid state reaction method.•The effect of impurity concentration on the TL response of the samples were studied.•The effect of irradiation with different doses on the glow curves of the sample were investigated.•Kinetic parameters are estimated using VHR, Tm-Tstop and CGCD.
The aim of this work was to develop a new lithium tetraborate luminophore with impurities that are strong co-activators for Optically Stimulated Luminescence (OSL) and to investigate its dosimetric ...properties using OSL method. Li2B4O7:Ag,Gd phosphor consisting of polycrystalline powder was synthesized using Solution Combustion Synthesis method. The structural characterization of the synthesized phosphor was performed using X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) methods. OSL dosimetry properties as a function of step-annealing procedure, radiation dose response, reproducibility of response and loss of stored signal in dark were investigated. Thermoluminescence (TL) glow curve of Li2B4O7:Ag,Gd phosphor consists of two separated glow peaks located at ∼80 and ∼210 °C with a heating rate of 2 °C/s. The traps responsible for these two TL peaks in Li2B4O7:Ag,Gd phosphor were found to be optically sensitive. Li2B4O7:Ag,Gd exhibits high OSL sensitivity and a good OSL signal reproducibility to ionizing radiation. The beta dose-response was performed in the range from 0.1 Gy to 500 Gy. The time-integrated total OSL signal intensity increases linearly with increasing dose from ∼6 Gy to 500 Gy. The minimum detectable dose was found to be ∼17.1 ± 0.9 μGy. The stored energy increased ∼6 % within 4 weeks following a strong fading value of 27 % of the initial OSL intensity after 24 h. Indeed, the X-ray Luminescence (XL) emission spectra are the characteristic of the expected f-f transitions. Luminescence spectrum of Gd doped Li2B4O7 exhibits major red emissions (590 nm, 607 nm, 621 nm) and a weak blue emission (450 nm) along with the emission bands from undoped Li2B4O7. These results strongly suggest that the luminescence properties of Li2B4O7:Ag,Gd deserves more attention as possible dosimeter material. Explanations of many TL/OSL phenomena observed in the study of Li2B4O7:Ag,Gd phosphor and improvements based on the better knowledge in the mechanism of TL/OSL in Li2B4O7:Ag,Gd, a boron-based compound were achieved by this study.
•Li2B4O7:Ag, Gd was prepared using solution combustion technique.•Structure, x-ray luminescence and OSL properties were characterized.•Source of OSL signal was studied.•The effect of OSL stimulation times on the RTL glow peaks intensity was studied.•Dose-response, dark fading and reproducibility were performed.
In this paper we describe the thermoluminescence (TL) characteristics of 0.8 mol% Tm3+ doped ZnB2O4phosphors prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of ...three peaks located at 181 °C, 213 °C and 351 °C. The glow peak TL temperature (Tm) at which the TL glow peak occurs shifts toward the higher temperature side whilst the heating ramp rate increases and also the peak TL intensity (Im) decreases. The TL glow curves are characterized by evaluating various dosimetric characteristics of scrutinized samples. The Tm−Tstopinvestigations on regenerated TL signals revealed that there are five different traps in the phosphor with energy values in the range of 0.61–1.71 eV. The dose responses increased in a linear way for 3 peaks with the beta-ray exposure in the dose range of 0.11–60 Gy. The process of applying 10 Gy dose was repeated for ten successive irradiation cycles to check reproducibility and the maximum variation was found to be less than 1% from the average value. These results provide valuable knowledge for use of the characteristics of Tm doped ZnB2O4 in dosimetry research.
•ZnB2O4:Tm3+ phosphors were successfully prepared by a wet chemical method.•The TL glow curves of the samples were analysed.•The trap parameters were calculated by IR method combined with Tm−Tstop
Background
Skin testing has a limited role in the diagnosis of non‐immediate beta‐lactam hypersensitivity in children. The aim of this study was to report the results of oral provocation tests ...performed without skin tests in children with non‐immediate mild cutaneous reactions without systemic symptoms caused by beta‐lactam antibiotics.
Methods
Oral provocation tests with suspected antibiotics were performed to patients with non‐immediate mild cutaneous reactions without systemic symptoms caused by beta‐lactam antibiotics. Skin tests were not performed before provocation tests. A total of five doses were administered with half‐an‐hour intervals in increasing doses. Provocation was continued for 5 days.
Results
A total of 119 patients with a median age of 4.3 (IQR: 2–7.5) years, of whom 58% were males, were included in the study. Amoxicillin–clavulanic acid was the most frequently responsible agent in 87 (73.1%) patients, and most common type of rash was maculopapular in 74 (62.2%) patients. Four patients (3.4%) had an urticarial reaction during the provocation test.
Conclusion
We did not experience any severe reactions during oral provocation test without previous skin tests performed to children with non‐immediate mild cutaneous reactions without systemic symptoms. Omitting skin tests before oral provocation test in this group of children can help decreasing the burden of allergy clinics and alleviating the discomfort of children.
The dietary protein proctocolitis, also known as allergic proctocolitis (AP), is characterized by the presence of mucoid, frothy, and bloody stools in an otherwise healthy infant. The aim of this ...study was to describe a group of children with AP, diagnosed according to the criterion-standard method, food challenge to provide clinicians with more information on typical presentation, and an overview on nutritional management strategies and prognosis.
We collected data on infants with AP in our allergy and gastroenterology outpatient clinics. Any other conditions that may cause bloody diarrhea were ruled out. Skin prick tests and atopy patch tests were performed for diagnosis, and patients were studied for resolution. To the patients whose rectal bleeding did not recover with oligoantigenic maternal diet in addition to amino acid-based formula, endoscopic evaluation was performed to confirm the diagnosis and to exclude other reasons of rectal bleeding.
Sixty patients were diagnosed as having AP. The age of onset was 1.7 ± 1.32 months. All of the patients were triggered by milk, 6.6% with milk and egg, 3.3% with milk and chicken, 1.7% with milk and wheat, 1.7% with milk and potato, and 3.3% had multiple food allergy. 53.3% (n = 32) acquired tolerance by age 1, 25.0% (n = 15) by 2 years, 5% (n = 3) by 3, and 1.7% (n = 1) by 4 years.
Milk was a triggering factor for all of the patients. Resolution of AP is usually within 1 year but symptoms of some patients may continue even longer. An extension of the follow-up period is required according to our study.
In this paper we describe the thermoluminescence (TL) characteristics of 0.8 mol% Tm
doped ZnB
O
phosphors prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of ...three peaks located at 181 °C, 213 °C and 351 °C. The glow peak TL temperature (T
) at which the TL glow peak occurs shifts toward the higher temperature side whilst the heating ramp rate increases and also the peak TL intensity (I
) decreases. The TL glow curves are characterized by evaluating various dosimetric characteristics of scrutinized samples. The T
-T
investigations on regenerated TL signals revealed that there are five different traps in the phosphor with energy values in the range of 0.61-1.71 eV. The dose responses increased in a linear way for 3 peaks with the beta-ray exposure in the dose range of 0.11-60 Gy. The process of applying 10 Gy dose was repeated for ten successive irradiation cycles to check reproducibility and the maximum variation was found to be less than 1% from the average value. These results provide valuable knowledge for use of the characteristics of T
doped ZnB
O
in dosimetry research.
