Synthesis, photo- and thermo-luminescent properties of Mg2P2O7:Tm3+ phosphors.

In this work, both undoped and Thulium (Tm3+) doped (0.3-10 mol%) magnesium pyrophosphate (Mg2P2O7) powders were synthesized by the solvent evaporation method to study their photo-and thermoluminescent properties. Two crystalline phases were observed in the powders by X-Ray diffraction (XRD), the main phase being Mg2P2O7 and the second one thulium phosphate (TmPO4). The superficial morphology was analyzed by scanning electron microscopy (SEM), which revealed that the powders are agglomerates with an undefined form and grains with non-uniform size distribution. The photoluminescence (PL) emission spectra of Tm3+ doped powders show the 1D2 → 3F4 transition, associated with Tm3+ ions, at 452 and 458 nm. The thermoluminescence (TL) properties were analyzed in the undoped and Tm3+ doped powders exposed to 90Sr beta source. The TL glow curve of Tm3+ doped powders exhibits three maxima at about ⁓64-66 °C, ⁓198-202 °C, and ⁓301 °C. The TL dose-response is sub-linear from 0.11 to 0.54 Gy, linear between 0.79 and 24.95 Gy, and supra-linear from 34.99 to 599.95 Gy. Acceptable repeatability with a coefficient of variation of ∼1% was obtained after ten cycles of irradiation and readout. At 63 d of storage, the powders show fading of 30%, and at 1.6 years (585 d), the integrated TL intensity decays by 47%. The kinetic parameters of activation energy and frequency factor were evaluated using the Initial Rise, Booth, Bohun, and Porfianovitch (BBP) and Hoogenstraaten methods and Glow Curve Deconvolution with a general order kinetic model.

Thermoluminescence properties and identification of irradiated cocoa beans during long-term storage.

This work reports on the thermoluminescence (TL) properties and detection of contaminating minerals isolated from Mexican cocoa beans irradiated with gamma radiation and stored for 4 years. Contaminating minerals isolated from cocoa beans consisting of quartz, diopside, plagioclase, albite, and iron oxide with irregular and rectangular grains and average length of 135 µm. Cocoa beans are detected as irradiated even after 4 years of storage using the shape and maximum temperature of the TL glow curve of contaminating minerals. The TL properties of dose-response, and fading of minerals were also analysed. The TL dose-response is linear from 5 to 100 Gy, supra-linear between 250 and 1000 Gy, and sub-linear above 1500 Gy. Based on the TL1/TL2 ratio the minerals are identified as irradiated from 250 Gy to 4500 Gy in the dose-response test and after different storage times in the darkness at room temperature. A continuum trap distribution can be associated with the TL glow curve of minerals using the Tm-Tstop method. First order kinetic peaks were used in the Glow Curve Deconvolution of natural and irradiated (1 and 10 kGy) TL curves.

Continuous-wave optically stimulated luminescence properties of Guajillo chilli polyminerals exposed to gamma radiation.

In this investigation, the Continuous-Wave Optically Stimulated Luminescence (CW-OSL) properties of polyminerals extracted from Mexican and Peruvian Guajillo chilli were studied using a source of cesium-137 (Cs-137) gamma radiation. The Guajillo chilli polyminerals were stimulated with blue light for 120 s, and their luminescence was detected in the UV region. The General Order Kinetics (GOK) deconvolution analysis of the CW-OSL curves was carried out using three individual components. The CW-OSL dose response from 10 to 5000 Gy was analysed in Guajillo chilli polyminerals. After different storage periods, the polyminerals show an increase in the CW-OSL intensity. A strong and moderate effect of the sunlight (60 min) and artificial (6 h) light is observed on the CW-OSL response. Therefore, the CW-OSL properties of polyminerals could be used in the identification of Mexican and Peruvian Guajillo chilli exposed to Cs-137 gamma radiation.

Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation.

In this work, the continuous wave - optically stimulated luminescence (CW-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The CW-OSL dose response of natural salt showed a linear range between 0.5Gy and 10Gy of gamma radiation of 60Co. Samples exposed at 3Gy exhibited good repeatability with a variation coefficient of 4.6%. The CW-OSL response as function of the preheating temperature (50-250°C) was analyzed. An increase of 15% of the CW-OSL response was observed in NaCl samples during storage period of 336h. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation.

Optically and thermally stimulated luminescence characteristics of LaAlO3:Pr3+ beta irradiated.

This paper reports on an investigation into the thermally stimulated luminescence (TL) and optically stimulated luminescence (OSL) characteristics of novel luminescent phosphor. A new Pr3+-doped, lanthanum aluminate (LaAlO3)-based luminescent phosphor is developed. Samples of LaAlO3:Pr3+ were irradiated to beta doses, in air, from 0.1Gy up to 50Gy and then were analyzed using both TL and continuous wavelength OSL (CW-OSL) techniques to determine their luminescent characteristics. This phosphor shows a TL glow curve, after its irradiation to beta radiation, with two TL peaks: one located around 160°C and a second at 300°C. CW-OSL response presented a fast decay into the first 20s of blue light stimulation. TL and CW-OSL response as a function of beta radiation dose were linear in the studied dose range. The high sensitivity of the CW-OSL and TL response will make this phosphor suitable for beta radiation detection. Finally, the kinetic parameters of activation energy, frequency factor and kinetic order were analyzed in the TL response using computerized glow curve deconvolution based on general order kinetic model.

Synthesis of ß-Ca2P2O7:Tb3+ to gamma radiation detection by thermoluminescence.

In this work, luminescent emissions of beta-calcium pyrophosphate doped with terbium ions (ß-Ca2P2O7:Tb3+) were studied. The Ca2P2O7:Tb3+ powders were prepared by precipitation and annealed at 900°C for 2h was applied on the powders to observe the beta phase. Radioluminescence measurements showed emission bands related with 5D3 (5D4)→7FJ transitions of Tb3+ ions. Three overlapped peaks at 126, 165 and 220°C were observed in thermoluminescence response. A linear TL dose-response in the range of 0.2-10Gy and an acceptable TL reproducibility were showed by the ß-Ca2P2O7:Tb3+ samples exposed to 60Co gamma radiation. The TL glow curves were analyzed by Initial Rise method and Computational Glow-Curve Deconvolution assuming a General Order Kinetic model to evaluate the kinetic parameters related with the TL peaks.

Luminescence detection and dose assessment of irradiated Yerba Mate (Ilex paraguariensis) tea leaves.

Imported commercial samples of Yerba Mate (Ilex paraguariensis) tea leaves were characterized by thermoluminescence (TL) and photoluminescence (PSL) physical methods. Samples of Yerba Mate were irradiated between 0.5-50Gy and 20Gy-5kGy gamma doses by using two different dose rates from (60)Co irradiators. The Electron Dispersive Analysis (EDS) shows that the inorganic fraction is mainly composed by quartz and Ca-feldspars minerals. These polyminerals show a good sensitivity to gamma radiation and to UV light (530nm). Linear dose-response curves were obtained between 0.5 and 12Gy at low dose-rate, and with 20 to 500Gy at high dose-rate of gamma radiation. At higher doses (600Gy) an apparent slow saturation effect was observed. Low fading of the TL signal was found. The detection limits of TL and PSL are 6Gy and 300Gy, respectively. Results show that luminescence emission (TL and PSL) is a reliable method for detection of irradiation Yerba Mate.

Effect of the chemical impurities on the luminescence emission of natural apatites.

This paper reports on both cathodoluminescence (CL) and blue thermoluminescence (TL) emission of well-characterized natural Spanish and Brazilian apatites [Ca5(PO4)3(OH, F, Cl)]. Chemical analyses performed by means of Electron Microprobe Analysis (EMPA) have shown the presence of trace elements that can induce CL bands. In this sense, the apatites shown emission bands peaked at 3.26, 2.86, 2.62, 2.14, 2.02 and 1.94eV are respectively linked to substitutional Ce(3+), Tb(3+), Dy(3+), Pr(3+), Sm(3+) and Mn(2+) in structural Ca(2+) positions. The 3.18eV emission band can be associated with intrinsic electron defects on oxygen of the phosphate group (PO4)(3-). The presence of (UO2)(2+) gives rise to an emission at 2.14eV. All the studied aliquots exhibit one single UV-blue TL peak that modifies the position from one sample to another (370, 256 and 268°C) probably due to (i) the variation in the crystallinity index (from 0.88 to 1.34) and (ii) successive chemical processes such as oxidation, dehydration, dehydroxylation, and fluorine ions losses due to the thermal readout.

Thermal and electron stimulated luminescence of natural bones, commercial hydroxyapatite and collagen.

The luminescence (cathodoluminescence and thermoluminescence) properties of natural bones (Siberian mammoth and adult elephant), commercial hydroxyapatite and collagen were analyzed. Chemical analyses of the natural bones were determined using by Electron Probe Micro-Analysis (EMPA). Structural, molecular and thermal characteristics were determined by X-ray Diffraction (XRD), Raman spectroscopy and Differential Thermal and Thermogravimetric analysis (DTA-TG). Cathodoluminescence (CL) spectra of natural bones and collagen showed similar intense broad bands at 440 and 490 nm related to luminescence of the tetrahedral anion [Formula: see text] or structural defects. A weaker luminescence exhibited at 310 nm could be attributed to small amount of rare earth elements (REEs). Four luminescent bands at 378, 424, 468 and 576 nm were observed in the commercial hydroxyapatite (HAP). Both natural bones and collagen samples exhibited natural thermoluminescence (NTL) with well-defined glow curves whereas that the induced thermoluminescence (ITL) only appears in the samples of commercial hydroxyapatite and collagen. Additional explanations for the TL anomalous fading of apatite, as a crucial difficulty performing dosimetry and dating, are also considered.

Coste directo de la epilepsia en Cuba. Estudio en consulta externa / The direct cost of epilepsy in Cuba. A study in outpatients

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Renal cell carcinoma and vaginal metastasis.

A case of left renal cell carcinoma which presented as vaginal bleeding from a vaginal metastasis is reported. Less than 60 cases of this occurrence have been described.

Bladder dysfunction after Schauta hysterectomy. One-year follow-up.

The purpose of this study was to determine the long-term effect of Schauta hysterectomy on bladder function as determined by serial cystometric studies. The maximum bladder capacity, resting pressure at maximum capacity, and volume of residual urine were determined preoperatively, postoperatively, at time of final catheter removal, and one or more years after surgery. A prior report showing that the bladder decreased in capacity, increased in tone, and, emptied poorly if at all postoperatively was confirmed. The mean duration of postoperative catheter drainage in 68 patients was 33 days. One year or more after surgery the mean maximum bladder capacity had returned to the preoperative volume; persistent elevation of the mean resting pressure was significant in the pooled but not in the paired data; the mean residual urine volume of 25 ml. was significantly elevated. The assumption was that maintenance of intrinsic detrusor muscle tone by prevention of overdistention preserved balanced bladder function. Many patients initiated and maintained micturition by voluntary straining or by use of Crede's maneuver although others voided relatively normally. Presumably these bladders are denervated to varying degrees, producing a spectrum of functional disturbance. The "bladder-conscious" patient can protect and preserve bladder function but these bladders appear to remain vulnerable to infection and overdistention, perhaps permanently.