655 research outputs found
Radiation exposure from diagnostic nuclear medicine examinations in golestan province
Introduction: The aim of present study was to estimate effective dose from most common procedures performed in nuclear medicine departments of Golestan province. Methods: Data of nuclear medicine procedures performed in 2 nuclear medicine departments in Golestan province were collected during 4 years. Effective dose, collective effective dose and effective dose per examination were calculated using standard dosimetry tables. Results: Based on the data of this study, results of 10437 nuclear medicine procedures performed during 4 years have lead to 3.97 mSv as average effective dose per examination and 10.37 human-Sv as mean collective effective dose. It was also revealed that Tc-99m was the main source of effective dose (98.3%), bone scan was the most common procedure (25.9%) and cardiac scan (MIBI-rest) has the highest collective effective dose (33.5%) during 4 years. Conclusion: Beside the cardiac scan which was the most common nuclear medicine procedure and the main contributor of effective dose in patients, due to geographical condition of the northeast of Iran, bone scan was the highest performed nuclear medicine examination in the Golestan province
A study of the time of hospital discharge of differentiated thyroid cancer patients after receiving iodine-131 for thyroid remnant ablation treatment
The aim of this study was to measure the radiation exposure rate from differentiated thyroid carcinoma (DTC) patients who had received iodine-131 (131I) treatment, and to evaluate hospital discharge planning in relation to three different sets of regulations. We studied 100 patients, 78 females and 22 males, aged 13 to 79 years (mean 44.40±15.83 years) with DTC, in three Groups who were treated with 3.7, 5.5 or 7.4GBq of 131I, respectively. The external whole-body dose rates following oral administration of 131I were measured after each one of the first three hospitalization days. A multivariant linear analysis was performed, considering exposure rates as dependent variables to the administered dose for treatment, age, gender, regional and/or distant metastases, thyroglobulin (Tg), antibodies to Tg and thyroid remnant in the three dose groups. We found that the exposure rates after each of the three first days of hospitalization were 30, 50 and 70μSvh-1 at 1m. All our DTC patients had an acceptable dose rate on days 2 and 3 that allowed their hospital discharge. After only 1 day of hospitalization, just 3/11 cases showed not permissible exposure rates above 70μSvh-1. In conclusion, it is the opinion of the authors that after measuring the exposure rates, most treated, DTC patients could be discharged after only one day of hospitalization, even some of those treated with high doses of 131I (7.4GBq). Patients, who received the higher doses of 131I, should not be released before their individual exposure rate is measured
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Particle Compression Test: A Key Step towards Tailoring of Feedstock Powder for Cold Spraying
Copyright © 2020 by the authors. Cold spray is on the way to becoming a mainstream technology for coating and additive manufacturing processes. While there have been many advances in various aspects of this technology, the question of tailoring the ‘ideal’ feedstock powder for cold spraying has remained open. In particular, the mechanical strength and its dependence on the particle size, which are amongst the most relevant properties of the feedstock powder for cold spraying, are rarely covered when reporting powder specifications. This is mainly because of the lack of standardised methods of characterisation for these specific properties. In the present case study, we demonstrate how compression tests of single Inconel 718 particles by using a modified nanoindenter can address this central question. Data analyses are supported by finite element modelling of particle compression for a range of plastic behaviours. The results of simulation are then stored in the form of a surrogate model for subsequent comparison with the experimental data. Thus, the ultimate tensile strength and the size of the examined particles are calculated directly from the measured force-displacement data. The paper will also discuss how this information can be used to optimise cold spraying, and so, unveils a key step towards the design and manufacturing of cold-spray-specific feedstock powder
Synthesis and Characterization of Some New 1-(3-(heterocyclic-2-yl)-4,5-dihydroisoxazol-5-yl)Pentane-1,2,3,4,5-Pentaol Derivatives from New Chalcone
The synthesis and characterization of some novel chalcone and isoxazole derivatives has been presented. Isoxazoles (D-F) have been prepared from chalcones (A-C) by treating with hydroxylamine hydrochloride . The structure of isoxazoles has been characterized by spectral analysis by FT-IRÂ and 1H NMR spectroscopy. Keywords: isoxazole chalcone, heterocyclic DOI: 10.7176/CMR/12-1-02 Publication date: January 31st 202
Chapter 6 Collapsible Soils in the UK
Metastable soils may collapse because of the nature of their fabric. Generally speaking, these soils have porous textures, high void ratios and low densities. They have high apparent strengths at their natural moisture content, but large reductions of void ratio take place upon wetting and, particularly, when they are loaded because bonds between grains break down upon saturation. Worldwide, there is a range of natural soils that are metastable and can collapse, including loess, residual soils derived from the weathering of acid igneous rocks and from volcanic ashes and lavas, rapidly deposited and then desiccated debris flow materials such as some alluvial fans; for example, in semi-arid basins, colluvium from some semi-arid areas and cemented, high salt content soils such as some sabkhas. In addition, some artificial non-engineered fills can also collapse. In the UK, the main type of collapsible soil is loess, though collapsible non-engineered fills also exist. Loess in the UK can be identified from geological maps, but care is needed because it is usually mapped as ‘brickearth’. This is an inappropriate term and it is suggested here that it should be replaced, where the soils consist of loess, by the term ‘loessic brickearth’. Loessic brickearth in the UK is found mainly in the south east, south and south west of England, where thicknesses greater than 1 m are found. Elsewhere, thicknesses are usually less than 1 m and, consequently, of limited engineering significance. There are four steps in dealing with the potential risks to engineering posed by collapsible soils: (1) identification of the presence of a potentially collapsible soil using geological and geomorphological information; (2) classification of the degree of collapsibility, including the use of indirect correlations; (3) quantification of the degree of collapsibility using laboratory and/or in situ testing; (4) improvement of the collapsible soil using a number of engineering options
Impact of Ramadan fasting on intraocular pressure, visual acuity and refractive errors
Introduction: Fasting evidently influences a variety
of physiological parameters that can impact the
ocular system. Among these modifications are
alterations in insulin secretion, sympathetic
activity, free fatty acids, lipid profile, melatonin,
cortisol, electrolytes and catecholamines. In this
study, we investigated the possible alterations
in intraocular pressure (10P), visual acuity and
refractive errors during Ramadan fasting.
Methods: 10P, visual acuity and refractive errors
of both eyes of volunteers were measured on the
first and last days of Ramadan (once in the morning
and evening). Body weight was measured so as to
estimate the amount of dehydration. Data from
the two examinations was analysed using one-way
analysis of variance. A p -value of less than 0.05 was
considered statistically significant.
Results: 58 healthy, fasting male volunteers with
a mean age of 40.7 +/- 7.1 years participated in
the study. Statistical analysis demonstrated no
difference in 10P, visual acuity or refractive errors
on the first and last days of Ramadan, or within a
single day (from morning to evening).
Conclusion: Our results reveal that Islamic
Ramadan fasting does not profoundly affect
physiological 10P, refractive error or visual acuity
values in healthy volunteers. However, more
detailed investigations using animal models should
be designed to evaluate whether fasting has a
pivotal influence on pathological conditions.
Keywords: body weight, intraocular pressure,
Ramadan fasting, refractive errors, visual acuit
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