TL glow curve and kinetic analysis of Na2SiO3:Pr3+ under beta radiation effect.

Ionizing radiation dosimetry with thermoluminescence (TL) materials based on silicon or glass can be interesting in its potential use in radiation monitoring as the solution to the constant looking of development of new radiation detectors. In this work, TL characteristics of sodium silicate exposed to beta radiation effects were studied. TL response beta irradiated exhibited a glow curve with two peaks centered at 398 K and 473 K. Samples showed linearity from 0.55 to 13.2 Gy. TL readings after 10 times showed a repeatability with an error of less than 1%. Remain information showed significant losses during the first 24 h, but its information was almost constant after 72 h of storage. The Tmax-Tstop method exhibited three peaks which were mathematically analyzed with a general order deconvolution finding kinetic orders close to the second order for the first peak, meanwhile the kinetic order for the second peak and third peak are close to second order. Finally, the VHR method showed anomalous TL glow curve behavior with an increasing intensity TL as the heating rate increased.

Thermoluminescent studies of GdAlO3 powders.

The increasing use of thermoluminescence (TL) materials as radiation detectors with application in different areas of ionizing radiation has motivated research on new materials with adequate luminescent characteristics. In this work, experimental results gadolinium aluminate (GdAlO3) analyzed by thermoluminescent phenomenon under beta irradiation effect are studied. To prepare GdAlO3 powders the coprecipitation method was used. TL glow curve and other luminescent characteristics were analyzed using an automatic Lexsig Smart TL/OSL luminescent reader. TL glow curve showed four peaks with three prominent and well-defined peaks centered at 140, 230, and 270 °C. TL response as a function of beta radiation dose was linearity in the range from 1.1 up to 44 Gy. Kinetic parameters such as activation energy (E), frequency factor (s), and order of kinetics after the deconvolution of the TL glow curve were also determined using Chen's peak shape method. Experimental results show GdAlO3 as a potential luminescent host material for TL studies.

Intraosseous epidermoid cyst in a horse.

A 21-year-old female American Saddle Horse with a prominent swelling on the ventral aspect of the right hemimandible and radiographic evidence of a bone cyst was examined. The cyst cavity was surgically explored and was found to contain mucinous fluid and sheets of keratin. Microscopically, the cyst was lined by well-differentiated squamous epithelium characterized by various degrees of hyperkeratosis and parakeratosis. The stromal component varied from scant areas in which epithelium was closely apposed to bone to wide regions of dense connective tissue that contained fragments of keratin surrounded by foreign-body giant cells. Histologic features were consistent with a diagnosis of intraosseous epidermoid cyst. After curettage of the cyst and repulsion of the second premolar tooth, drainage was established and iodine flushes were begun. Nine months after surgery, drainage was not detectable and size of the hemimandible had decreased by approximately a fourth.