Photon and Fast Neutron Transmission Parameters of Metakaolin Doped Concrete

Radiation-shielding properties of metakaolin doped concrete samples wereinvestigated in this report. The gamma photon mass attenuation coefficientsand exposure buildup factor of the samples were determined theoreticallyusing WinXcom and EXABCal software respectively for the energyrange of 15 keV - 15 MeV and fast neutron removal cross section for theconcrete sample was evaluated. Results indicated that, oxides of silicon,aluminum, calcium and iron determined through the energy dispersiveX-ray fluorescence spectrometric analysis constitute more than 85% ofthe chemical composition of the concrete samples. The oxides contribute85.46, 86.47, 87.55, 88.75, and 86.15 % of the total chemical oxides inMK00, MK05, MK10, MK15, and MK20 respectively. Densities of theprepared MK doped concrete were in the range of 2.575-2.667 g/cm3 .Compressive stress of prepared MK doped concretes increased consistentlywith the curing period for each concrete sample. CS grew from 8.71 -10.63, 8.84 - 10.83, 9.44 - 11.22, 10.89 - 11.53, and 10.76 - 11.43 MPafor MK00, MK05, MK10, MK15, and MK20 respectively as the periodextends from 7 to 28 days. Mass attenuation coefficient decrease steadilywith an increase in energy up to about 0.1 MeV and the decrease becomesmaller beyond this energy with increasing energy for all the mixtures. Fastneutron removal cross section results indicate that MK10 (0.07693 cm-1)has the highest value of ΣR followed by MK15 (0.07628 cm-1) and MK20(0.07537 cm-1) while MK00 (0.07380 cm-1) and MK05 (0.07404 cm-1)have approximately the same value. It was found that MK10 concrete hasthe best gamma radiation and fast neutron shielding ability among the MKdoped concrete under study

High Energy X-Ray Dosimetry Using (ZnO)0.2(TeO2)0.8 Thin Filmbased Real-time X-Ray Sensor

This study reports the dosimetric response of a (ZnO)0.2(TeO2)0.8 thin film sensor irradiated with high-energy X-ray radiation at various doses. The spray pyrolysis method was used for the film deposition on soda-lime glass substrate using zinc acetate dehydrate and tellurium dioxide powder as the starting precursors. The structural and morphological properties of the film were determined. The I-V characteristics measurements were performed during irradiation with a 6 MV X-ray beam from a Linac. The results revealed that the XRD pattern of the AS-deposited thin film is non-crystalline (amorphous) in nature. The FESEM image shows the non-uniform shape of nanoparticles agglomerated separately, and the EDX spectrum shows the presence of Te, Zn, and O in the film. The I-V characteristics measurements indicate that the current density increases linearly with X-ray doses (0-250 cGy) for all applied voltages (1-6 V). The sensitivity of the thin film sensor has been found to be in the range of 0.37-0.94 mA/cm2 /Gy. The current-voltage measurement test for fading normalised in percentage to day 0 was found in the order of day 0 > day 15 > day 30 > day 1 > day 2. These results are expected to be beneficial for fabricating cheap and practical X-ray sensors

A comprehensive study on optical features, gamma photon buildup factors and neutron shielding capability of B2O3-SB2O3-LI2O-BI2O3 glasses

ABSTRACT. Linear, nonlinear optical properties, photon buildup factors, and neutron shielding capability of glasses with chemical composition (65-x)B2O3-10Sb2O3-25Li2O-xBi2O3, where x = 0 (BSLB0) – 20 (BSLB20) mol% with steps of 4 mol% were examined. Molar refractivity (Rmolar) and molar polarizability (αmolar) were increased as Bi2O3 content mol% increase in the examined BSLB-glasses. The values of metallization criterion (Mcriterion) confirmed that the BSLB-glasses were non-metallic materials. The static (εstatic) and optical (εoptical) dielectric constants having the same trend of the refractive index (noptical). Values of optical electronegativity (χ*) were reduced from 0.825 for BSLB0 (Bi2O3 = 0 mol%) glasses to 0.758 for BSLB20 (Bi2O3 = 20 mol%) glasses. The linear electric/dielectric susceptibility (χ(1)) increased from 0.370 to 0.397. The nonlinear optical susceptibility (χ3) and nonlinear refractive index n2optical were enhanced by increasing Bi2O3 content in the BSLB-glasses. The BSLB20 glasses presented the least exposure and energy absorption build-up factors (EBF and EABF) at all considered thickness. BSLB20 sample achieved the best fast neutron removal cross section ( ) shield among all glasses. The total stopping powers (TSP) follows the trend (TSP)BSLB0 < (TSP)BSLB4 < (TSP)BSLB8 < (TSP)BSLB12 < (TSP)BSLB16 < (TSP)BSLB20. The electron absorbing and hence shielding capacity of the BSLB-glasses improves as their Bi2O3 content increase.     KEY WORDS: Antimony lithium-borate glasses, Optical properties, Buildup factors, Neutron shielding   Bull. Chem. Soc. Ethiop. 2022, 36(4), 949-962.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i4.19                                                     &nbsp

Investigation of Er3+ Ions Reinforced Zinc-Phosphate Glasses for Ionizing Radiation Shielding Applications

Melt quenching technique is used for preparing glasses with chemical formula (70P2 O5)– (16 − x)CdO–(14ZnO)–(xEr2 O3), (x = 1–6 mol%). These glasses were named Er1, Er2, Er3, Er4, Er5, and Er6, respectively. Photon buildup factors, fast neutron absorption, and electron stopping of the prepared glasses were examined. Glasses’ density was varied from 3.390 ± 0.003 for the Er1 glass sample to 3.412 ± 0.003 for the Er6 glass sample. The Buildup factor (BUF) spectra have relatively higher values in the Compton Scattering (CS) dominated areas compared to both Photoelectric effect (PE), and Pair Production (PP) dominated energy regions. The highest BUF appeared at the Er atom K-absorption edge, whose intensity increases as the molar concentration of Er2 O3 in the glasses increases. The photon absorption efficiency (PAE) of the glasses increases according to the trend (PAE)Er1 < (PAE)Er2 < (PAE)Er3 < (PAE)Er4 < (PAE)Er5 < (PAE)Er6. Fast neutron removal cross-section, FNRC (ΣR) values of the glasses obtained via calculation varied from 0.1045–0.1039 cm−1 for Er1–Er6. Furthermore, the continuous slowing down approximation mode (CSDA) range enhances the kinetic energy of electrons for all glasses. Generally, results revealed that the investigated glasses could be applied for radiation shielding and dosimetric media. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Taif University Researchers Supporting Project number (TURSP-2020/23), Taif University, Taif Saudi Arabia. "The APC was covered by "Dunarea de Jos" University of Galati, Romania, through grant no. RF3621/2021

Abdominal ultrasonography in HIV/AIDS patients in southwestern Nigeria

<p>Abstract</p> <p>Background</p> <p>Though the major target of the HIV-virus is the immune system, the frequency of abdominal disorders in HIV/AIDS patients has been reported to be second only to pulmonary disease. These abdominal manifestations may be on the increase as the use of antiretroviral therapy has increased life expectancy and improved quality of life. Ultrasonography is an easy to perform, non invasive, inexpensive and safe imaging technique that is invaluable in Africa where AIDS is most prevalent and where sophisticated diagnostic tools are not readily available. Purpose: To describe the findings and evaluate the clinical utility of abdominal ultrasonography in HIV/AIDS patients in Ibadan, Nigeria</p> <p>Methods</p> <p>A Prospective evaluation of the abdominal ultrasonography of 391 HIV-positive patients as well as 391 age and sex-matched HIV-negative patients were carried out at the University College Hospital, Ibadan.</p> <p>Results</p> <p>Of the 391 cases studied, 260 (66.5%) were females; the mean age was 38.02 years, (range 15–66 years). The disease was most prevalent in the 4th decade with an incidence of 40.4%. Compared with the HIV-negative individuals, the HIV+ group of patients had a significantly higher proportion of splenomegaly (13.5% vs. 7.7%; p < 0.01), lymphadenopathy (2.0% vs. 1.3%; p < 0.70), and renal abnormalities (8.4% vs. 3.8%; p < 0.02). There were no differences in hepatic and pancreatic abnormalities between the HIV+ and HIV- groups. There were significantly fewer gallstones in the HIV+ group (1.4% vs. 5.1%; p < 0.01).</p> <p>Conclusion</p> <p>AIDS is a multi-systemic disease and its demographic and clinical pattern remains the same globally. Ultrasonography is optimally suited for its clinical management especially in Africa. Its accuracy and sensitivity may be much improved with clinico-pathologic correlation which may not be readily available in developing countries; further studies may provide this much needed diagnostic algorithms.</p

Hydrostatic Reduction of Intussusception under Ultrasound Guidance: An Initial Experience in a Developing Country

Intussusception is one of the most common causes of acute intestinal obstruction in children. Hydrostatic reduction with barium enema is the widely accepted and preferredmode of treatment of uncomplicated intussuception. The aim of this study was to report our initial experiencewith hydrostatic reduction of intussusception. We present our initial experience in which 8 patients had ultrasound guided hydrostatic reduction of intussusception over a period of 2 years. All patients that presentedwithin 48hours of onset of symptoms were recruited into the study. Clinical diagnosis of intussusceptions was made in all of them while abdominal ultrasoundwas used to confirm the diagnosis. Half of the patients presented after 24 hours of onset of symptoms. Five patients (62.5%) had a successful reduction of their intussusception while three patients (37.5%) had incomplete reduction which was completed by surgery. There was only one (12.5%) recurrence and there was no peritonitis. Ultrasound guided hydrostatic reduction of intussusceptions in this environment is possible when patients present early with low risk of complication and low recurrence rate. Keywords: Intussusception, ultrasound guided, hydrostatic reduction, recurrence. African Journal of Paediatric Surgery Vol. 4 (2) 2007: pp. 68-7

Mechanical and Gamma Ray Absorption Behavior of PbO-WO3-Na2O-MgO-B2O3 Glasses in the Low Energy Range

The Makishima and Mackenzie model has been used to determine the mechanical properties of the PbO-WO3-Na2O-MgO-B2O3 glass system. The number of bonds per unit volume of the glasses (nb) increases from 9.40 × 1022 to 10.09 × 1022 cm−3 as the PbO content increases from 30 to 50 mol%. The Poisson’s ratio (σ) for the examined glasses falls between 0.174 and 0.210. The value of the fractal bond connectivity (d) for the present glasses ranges from 3.08 to 3.59. Gamma photon and fast neutron shielding parameters were evaluated via Phy-X/PSD, while that of electrons were calculated via the ESTAR platform. Analysis of the parameters showed that both photon and electron attenuation ability improve with the PbO content. The fast neutron removal cross section of the glasses varies from 0.094–0.102 cm−1 as PbO molar content reduced from 50–30 mol%. Further analysis of shielding parameters of the investigated glass system showed that they possess good potential to function in radiation protection applications

Effects of Index Client and Geo-targeting on HIV Case Identification: An Observational Study

Background Despite huge investments in HIV prevention, treatment, and care in sub-Saharan Africa, fewer than one in 10 individuals knows their HIV status, and 40% of individuals living with HIV are not cognisant of their positive status. Efforts to improve and strengthen HIV service delivery, particularly in HIV testing, are necessary to increase efficiency in HIV case finding and optimise service delivery. Standard approaches to HIV testing have not been effective in addressing this gap. Our objective was to evaluate a targeted approach for HIV case identification in a PEPFAR-supported HIV programme in Nigeria. Methods Between October, 2016, and June, 2017, we implemented a strategy that included index client testing, geo-targeted HIV testing, and provider-initiated counselling and testing in 14 local government areas in Akwa Ibom, southern Nigeria. The tests were administered in conjunction with the conventional method of testing and were in line with the PEPFAR impact agenda. We estimated the number of individuals who needed to be tested by each method in order to meet a benchmark of 8000 new diagnoses per quarter. We described dispersion using median and IQR. Findings Conventional methods in the 14 local government areas required testing of 600 000 individuals (median 50 000 [IQR 741 000]) whereas using our targeted approach, we met 60% of the benchmark in each quarter by testing 214 000 individuals on average (median 14 000 [IQR 12 000]). Interpretation We demonstrated that use of a targeted approach to HIV testing can increase the efficiency of case identification. This process can therefore help increase early initiation of treatment and retention of subjects diagnosed with HIV. Funding PEPFAR

Shielding Properties of Some Marble Types: A Comprehensive Study of Experimental and XCOM Results

In this work, some marble types were collected from Egypt, and their shielding characteristics were estimated. Their rigidity, in addition to their elegant shape, led us to consider their use as a protective shield, in addition to making the workplace more beautiful. The mass attenuation coefficient (μ/ρ) was calculated for three types of marble (Breshia, Galala, and Trista) experimentally, using a narrow gamma ray source and high pure germanium (HPGe). The results obtained were compared with the XCOM program and indicated a very good agreement between the two methods. The linear attenuation coefficient (μ) was evaluated to calculate the half and tenth value layers. The maximum μ value of 1.055, 1.041, and 1.024 cm−1 was obtained for Breshia, Galala, and Trista, respectively, at 0.06 MeV. The mean free path for studying the materials was compared with other shielding materials and showed good results at different energy scales. The energy absorption (EABF) and exposure buildup factors (EBF) were determined at different mean free paths. The fast neutron removal cross section ΣR was calculated and expresses the ability of the marbles to slow down fast neutrons through multiple scattering. This is the ability of the marbles to shield fast neutrons