Alpha self-absorption evaluation in radiometric filter material for the natural range of alpha energy (5-9 MeV)

In this paper, SRIM (The Stopping and Range of Ions in Matter) software package is used to simulate the interaction of alpha particles into the material of radiometric analytical filters. The effect of alpha particle self-absorption in alpha radiometric filters measurements is estimated, especially in the range of natural alpha energy (5-9 MeV, Radon and Thoron alpha energy). Software package SRIM allows to calculate the parameters of the ions interaction with target material using a Monte Carlo simulation method based on a quantum mechanical treatment of ion-atom collisions. The effect of the radiometric analytical filter material on the transmitted efficiency of alpha energy is discussed. As the energy increases the self-absorption in analytical filter material is decreased but still has a clear effect. In this case, the filter material and the space distance between the filter and the detector window decrease the number of alpha particles which reach to the detector window. © 2019 RAD Association. All rights reserved

Effect of electronic cigarette (EC) aerosols on particle size distribution in indoor air and in a radon chamber

Particle size distribution is an important factor governing whether aerosols can be deposited in various respiratory tract regions in humans. Recently, electronic cigarette (EC), as the alternative of tobacco cigarette, has become increasingly popular all over the world. However, emissions from ECs may contribute to both indoor and outdoor air pollution; moreover, comments about their safety remain controversial, and the number of users is increasing rapidly. In this investigation, aerosols were generated from ECs and studied in the indoor air and in a chamber under controlled conditions of radon concentration. The generated aerosols were characterized in terms of particle number concentrations, size, and activity distributions by using aerosol diffusion spectrometer (ADS), diffusion battery, and cascade impactor. The range of ADS assessment was from 10 -3 μm to 10 μm. The number concentration of the injected aerosol particles was between 40 000 and 100 000 particles/cm 3 . The distribution of these particles was the most within the ultrafi ne particle size range (0-0.2 μm), and the other particle were in the size range from 0.3 μm to 1 μm. The surface area distribution and the mass size distribution are presented and compared with bimodal distribution. In the radon chamber, all distributions were clearly bimodal, as the free radon decay product was approximately 1 nm in diameter, with a fraction of ~0.7 for a clean chamber (without any additional source of aerosols). The attached fraction with the aerosol particles from the ECs had a size not exceeding 1.0 μm. © 2019 H. N. Khalaf, M. Y. A. Mostafa & M. Zhukovsky

Water Absorption Enhancement Of Sodium Poly Acrylate And Poly(2-Acrylamido-2-Methylpropane Sulphonic Acid) Based Hydrogel Mixtures

Introduction: Hydrogels are hydrophilic polymers which are cross-linked to form three-dimensional structures, which can absorb, swell and retain huge amounts of water or aqueous fluids. Objective: This paper reports the preparation and characterization of Poly (2-Acrylamido-2-Methylpropane Sulphonic Acid) (PAMPS) hydrogel with different crosslinking intensities. Methodology: 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) monomer was purchased from Alfa Aesar Company as reagent grade. It was used as received (\u3e98% purity) without any further purification. PAMPS hydrogel was prepared by free radical crosslinking solution polymerization of AMPS in water at room temperature under a nitrogen blanket in cylindrical glass tubes. The characteristics of the obtained PAMPS hydrogel were compared with those of commercial sodium polyacrylates hydrogel. Results: It was found that decreasing the crosslinker weight improved the absorbance capacity but to a limit. The suggested reasons were discussed. The mixture showed higher absorbance rate than PAMPS, and bigger absorbance capacity than sodium polyacrylates. Conclusion: This paper investigates the effect of crosslinker ratio on the swelling capacity of PAMPS. It was found that as the crosslinking ratio decreases, the porosity of the hydrogel increases, thus improving the swelling capacity

A study of annexin-V labeled-lymphocytes apoptosis in pediatric-onset systemic lupus erythematosus in comparison to juvenile rheumatoid arthritis

Background: In systemic lupus erythematosus (SLE), which is the prototype of autoimmune diseases, the autoimmune process seems to be antigen driven. Apoptosis is responsible for eliminating cells from the immune system that are autoreactive, and defects in apoptosis may contribute to autoimmune diseases such as SLE and juvenile rheumatoid arthritis (JRA). Objective: This work is aimed to study the apoptotic peripheral blood lymphocytes in patients with pediatric- onset SLE, to trace its correlations, if any, with the disease activity and clinical presentation, and to compare the apoptotic process to that in JRA, as an example of another rheumatologic disorder. Methods: The study was conducted on 32 patients with pediatric- onset SLE; their ages ranged between 5 and 25 years (mean + SD = 15.5 + 4.4). In addition to various laboratory investigations needed for diagnosis, assessment of different system involvement as well as disease activity, the percentage of early circulating apoptotic lymphocytes was measured by flowcytometry using Annexin –V. The results were compared to that of 20 age and sex matched clinically healthy children and adolescents as well as 10 JRA patients. Results: The percentage of circulating early apoptotic lymphocytes was significantly higher in SLE patients (mean ± SD = 7.02 ± 7.29 %) and JRA patients (mean ± SD=5.91± 6.00 %) as compared to healthy controls (mean ± SD = 1.89 ± 2.21 %; p=0.0003 and 0.023, respectively). The levels of apoptotic lymphocytes seemed higher in SLE patients than in JRA patients but the difference was statistically insignificant (p=0.58). There was no correlation between the percentage of circulating apoptotic lymphocytes and the disease activity markers (SLEDAI and ESR), different system involvement and the dose or duration of corticosteroids therapy. Conclusion: The general increase of circulating apoptotic lymphocytes seen in SLE patients may not be specific to SLE and could be seen with other autoimmune diseases. It seems that disturbance in the apoptotic process contributes more to the phenomenon of autoantigenicity rather than the prediction of the disease clinical activity or specific organ involvement.Keywords: SLE, apoptosis, annexin V, autoimmune diseases, JRA, PediatricEgypt J Pediatr Allergy Immunol 2003; 1(2): 118-2

HPGe-Detector as the base of radon concentration standard source

The purpose of this work is to introduce a simple and accurate system for calibrating radon measurement devices for monitoring the activity concentration of 222Rn in air. A high-purity germanium (HPGe) detector connected with 226Ra solid source to produce this simple prototype calibration system. A small emanation box was mounted on the HPGe detector for online gamma measurements. Inside this box, a solid 226Ra standard source was placed

One-Year Results of Simultaneous Topography-Guided Photorefractive Keratectomy and Corneal Collagen Cross-Linking in Keratoconus Utilizing a Modern Ablation Software

Purpose. To evaluate effectiveness of simultaneous topography-guided photorefractive keratectomy and corneal collagen cross-linking in mild and moderate keratoconus. Methods. Prospective nonrandomized interventional study including 20 eyes of 14 patients with grade 1-2 keratoconus that underwent topography-guided PRK using a Custom Ablation Transition Zone (CATz) profile with 0.02% MMC application immediately followed by standard 3 mw/cm2 UVA collagen cross-linking. Maximum ablation depth did not exceed 58 μm. Follow-up period: 12 months. Results. Progressive statistically significant improvement of UCVA from 0.83±0.37 logMAR preoperative, reaching 0.25±0.26 logMAR at 12 months (P<0.001). Preoperative BCVA (0.27±0.31 logMAR) showed a progressive improvement reaching 0.08±0.12 logMAR at 12 months (P=0.02). Mean Kmax reduced from 48.9±2.8 to 45.4±3.1 D at 12 months (P<0.001), mean Kmin reduced from 45.9±2.8 D to 44.1±3.2 D at 12 months (P<0.003), mean keratometric asymmetry reduced from 3.01±2.03 D to 1.25±1.2 D at 12 months (P<0.001). The safety index was 1.39 at 12 months and efficacy index 0.97 at 12 months. Conclusion. Combined topography-guided PRK and corneal collagen cross-linking are a safe and effective option in the management of mild and moderate keratoconus. Precis. To our knowledge, this is the first published study on the use of the CATz ablation system on the Nidek Quest excimer laser platform combined with conventional cross-linking in the management of mild keratoconus

Radiopharmaceutical dose distribution in different organs and tissues for Lu-177 with different carrier

177Lu refers to rare earth elements from a group of lanthanides. Relative to its short time span, 177Lu has virtually pervaded all areas of in vivo radionuclide therapy and becomes one of important keys for therapeutic radionuclides of choice for targeted radionuclide therapy. The rising interest in the use of 177Lu in targeted molecular therapies has primarily developed from recent unmatched advances in molecular and cell biology, which include the use of peptides targeted to cell surface receptors, which are overexpressed on the surface of tumour cells. Therefore, the use of 177Lu-labelled radiopharmaceuticals have been the major factors evoking excitement among researchers and capturing the imagination of the clinical community thanks to advances in molecular and cellular biology. In this work, radiopharmaceutical comparison for 177Lu absorbed dose in health human organs and tissues is presented. The comparison between unlabelled 177Lu (ionic form) and labelled with 177Lu-MDP (methylenediphosphonate) and 177Lu-MAb (monoclonal antibodies). The biokinetic model in each case are described and presented. The absorbed dose in health human organs and tissues are simulated with two recommended programs WinAct and IDAC 2.1(Internal Dose Assessment by Computer) software. The distribution of absorbed dose in the main organs nearly the same with different in the value for the ionic form and 177Lu-MDP. The absorption in the case of ionic form is high. The distribution is completely change while 177Lu-MAb is used. The most absorbed dose fraction goes to spleen and liver unlike bone surface absorb nearly 50 % of dose. © 2019 Author(s)