investigation into the potential applicability of gel dosimeters for dosimetry in boron neutron capture therapy

The aim of this work was to establish how well gel dosimeters performed, as substitutes for brain tissue compared with standard phantom materials such as water, polymethyl-methacrylate [or PMMA], A150 plastic and TE- liquid phantom material for dosimetry of neutron beams in boron neutron capture therapy. Thermal neutron fluence, photon dose and epithermal neutron dose distributions were computed for the epithermal neutron beam of the optimized linac based BNCT. Amongst all investigated phantom materials, TE-liquid was shown to be a better substitute for brain tissue than other phantom materials. The differences between TE- liquid and brain at the depth of 6.1 cm for thermal neutron fluence, gamma dose and epithermal neutron dose distributions was calculated 2.80%, 2.40% and -13.87%, respectively. In comparison with the other gel dosimeters, LMD2 provided a better simulation of radiation transport in the brain. It's results differed from the real brain, at the depth of 6.1 cm, for thermal neutron fluence, gamma dose and epithermal neutron dose distributions, by -1.27%, 4.20% and 21.05% respectively. Even though, in gamma dose distribution the LMD2 has large deviation from brain tissue distribution, the deviation is approximately independent of depth, so the results can be multiplied by a constant coefficient to be more consistent with reality. Even though, TE- liquid showed satisfactory results for brain tissue substitution in BNCT, but some properties of gel dosimeters such as three dimensionality, make LMD2 a potentially good dosimeter for dosimetric verification in BNCT

[Serum protein alterations in goats naturally infected with Babesia ovis]

This study was conducted to determine the electrophoretic pattern of serum protein in goats infected with Babesia ovis. Serum total protein was calculated and serum electrophoresis from 15 goats naturally infected with B. ovis as well as same number of healthy goats was performed. Microscopic examination of Giemsa-stained peripheral blood smears revealed B. ovis infection. The parasitological diagnosis was confirmed using polymerase chain reaction [PCR] assay by using a pair of B. ovis-specific primers. Mean values total protein and alpha and gama globulin fractions in infected goats were significantly higher [P<0.05] than those observed in the healthy group

Treatment of low-strength industrial wastewater using anaerobic baffled reactor

The performance of an anaerobic baffled reactor at the pilot scale, with a 100-L volume and six compartments, that is used to treat low-strength industrial wastewater [671.5 +/- 49.9 mg COD/L, 350.1 +/- 36.8 mg BOD[5]/L and 443.8 +/- 60.7 mg SO[4][-2]/L] was studied. The reactor was started with a hydraulic retention time [HRT] of 25 h at 35 °C, which was gradually reduced to 3.33 h. The best reactor performance was observed with an organic loading rate [OLR] and a sulfate loading rate [SLR] of 4.45 g COD/L.d and 3.32 g SO[4][-2]/L.d, which was obtained at a HRT of 4 h. The COD and SO4-2 removal efficiencies were 78.6% and 89.2%, respectively. Additionally, the majority of the COD and SO[4][-2] removal occurred in the first compartment, up to 51.2% and 69.1%, respectively. Moreover, the pH in the first compartment was also the lowest. Subsequently, when the temperature was reduced to 20 °C at a HRT of 4 h, the maximum removal efficiencies for COD and SO[4][-2] decreased to 59.4% and 66.1%, respectively. In this case, the highest COD and SO[4][-2] removal efficiencies were observed in the third and fourth compartments, respectively, and these compartments had lower pH values. This phenomenon indicates that decrease in temperature causes transference of the acidogenic phase toward subsequent reactor compartments. In addition, these findings further show the potential for sulfate removal of the acidogenic phase

new approach to contrast enhancement in MAGICA gel dosimeter image with MRI technique

Sensitivity and resolution are two main parameters that have to be measured in gel dosimetry. However, the resolution in gel is strongly dependant on gel composition. Selection of optimum method in dose response readout and proper values of parameters can result in noise reduction as well as improvement of contrast, and spatial resolution considerably. MAGICA polymer gel dosimeters were manufactured and irradiated to different doses using a 60Co therapy unit. Imaging was performed in a 0.5T MRI with 8 echoes in air and water as a hydrogenous environment. Imaging condition was kept constant, as much as possible, in both imaging modalities. Images obtained from these two procedures were compared quantitatively. R2- dose curves have three different sections, sensitivity obtained in these three sections were 1.039, 1.671, 1.260 Gy[-1]S[-1] and 1.032, 1.729, 1.37 Gy[-1]S[-1] for water and air respectively. Calibration errors were investigated and graphically were compared in two different methods. Imaging in water medium for doses lower than 17 Gy led to a small reduction in spatial resolution was exchanged to a considerable increase of contrast in R2 map. For doses higher than17 Gy, imaging in water or air was preferred depending on the importance of contrast or spatial resolution

Early detection of noise induced hearing loss by extended high frequency audiometery

Surrounding noise, especially in industrial environments, is one of the most common etiologic factors of sensory-neural hearing loss [SNHL], which is not curable, but preventable. By industrialization of communities, the prevalence of the disease and its unfavorable socioeconomic outcome is growing up. Since the preventable defect, early diagnosis has the utmost importance. In recent years, the role of extended high frequency audiometry [EHFA] as a sensitive diagnostic tool for noise induced hearing loss has received much attention. This study deals with the role of EHFA in early diagnosis of this disorder. This was a retrospective cohort study during 2003-4 in Isfahan, Iran. A total number of 30 male labors, aged 20-50 years working in a noisy industrial environment, were compared with an equal number of controls with normal conventional audiometry, and no risk factor for other causes of SNHL according to their history and otoscopic examination. All 60 individuals underwent both types of conventional and extended high-frequency audiometry. Data were analyzed with SPSS software using t-test, paired t-test and correlation tests of Pearson and Spearman. There was no difference between the right and left ears. The exposed subjects had significantly worse hearing than the non exposed group, at all tested frequencies [especially at 16 KHz]. The age effect was notable in both groups. The correlation between high frequency threshold and duration of noise-exposure was significant only at 16, 18 and 20 KHz. The higher mean frequency threshold of the cases was predictable; the normal findings of conventional audiometry, reveal that EHFA can be useful in early diagnosis of acoustic injuries

[Evaluation of induced stress in PDL of anterior maxillary teeth by applying intrusive forces distal to the maxillary canine]

One of the precise methods for evaluating periodontal responses to orthodontic forces is finite element method. The aim of this study was to evaluate induced stresses in PDL of anterior teeth by application of intrusive forces distal to the canine. Solid works software was used to translate bidimentional images of the maxillary teeth [central, lateral, canine] into tridimentional images. PDL and alveolar bone around teeth were simulated and anterior teeth were positioned in an ideal arch with appropriate tip and torque, and rectangular wire was stablished rigidly on labial surfaces of the teeth. Models were modified to "Finite element model" by means of MSC-NASTRAN. Intrusive forces [35 gr] were applied on anterior wire distal to the canine and induced stresses were analyzed by means of MSC-PATRAN. By delivery of intrusive forces between the lateral and canine teeth, the maximum stress was concentrated in PDL of canine [8.38 x 10[-3] N/mm2] and the minimum stress was in PDL of central [7.6 x 10[-6] N/mm2]. Application of intrusive forces on the distal of canine teeth lead to un homogenous stress distribution in anterior area due to intrusive and unintended labiodistal movement. Therefore distal of canine is not an appropriate point for intrusive forces application

investigation on stress distribution of the anterior maxillary teeth PDL during the application of intrusive forces in midline

Finite element method is one of the highly precise methods to evaluate periodontal responses to orthodontic forces. The goal of the present study was to investigate the PDL response of anterior maxillary teeth [central, lateral, canine] during the application of intrusive forces using FEM. Solid works software was used to translate bidimensional images of the mentioned maxillary teeth into tridimensional ones. Then, PDL and alveolar bone were simulated around teeth and anterior teeth were positioned in an ideal arch with appropriate tip and torque and rectangular wire was placed rigidly on labial surfaces of teeth. These models were then modified to "Finite element model" by MSC-NASTRAN software. Intrusive forces were applied mesially on the anterior wire and induced stresses were analyzed by MSC-PATRAN. The maximum stress was observed in the PDL of lateral incisors [2.53x10[-3] N/mm[2]] and the minimum stress was in the PDL of canines [9.07.x10[-5] N/mm[2]]. Applying the intrusive forces in midline maximum stresses were focused on the apical part of lateral incisor and the minimum stresses were in the apically third of canine