Radiation shielding performance of metal oxides/EPDM rubber composites using Geant4 simulation and computational study

Abstract This paper aimed to evaluate the shielding performance of ethylene propylene diene monomer (EPDM) rubber composites filled with 200 phr of different metal oxides (either Al2O3, CuO, CdO, Gd2O3, or Bi2O3) as protective materials against gamma and neutron radiations. For this purpose, different shielding parameters, including the linear attenuation coefficient (μ), mass attenuation coefficient (μ/ρ), mean free path (MFP), half value layer (HVL), and tenth value layer (TVL), were calculated in the energy range between 0.015 and 15 MeV by using the Geant4 Monte Carlo simulation toolkit. The simulated μ/ρ values were validated by the XCOM software to examine the precision of the simulated results. The maximum relative deviation between the Geant4 simulation and XCOM was not greater than 1.41%, confirming the accuracy of the simulated results. Based on μ/ρ values, other significant shielding parameters such as effective atomic number (Zeff), effective electron density (Neff), equivalent atomic number (Zeq), and exposure buildup factor (EBF) were also computed to explore the potential usage of the proposed metal oxide/EPDM rubber composites as radiation protective materials. The study demonstrates that the gamma-radiation shielding performance of the proposed metal oxide/EPDM rubber composites are increasing in the order of EPDM < Al2O3/EPDM < CuO/EPDM < CdO/EPDM < Gd2O3/EPDM < Bi2O3/EPDM. Furthermore, three sudden increases in the shielding capability in some composites occur at 0.0267 MeV for CdO/EPDM, 0.0502 MeV for Gd2O3/EPDM, and 0.0905 MeV for Bi2O3/EPDM composites. This increase in the shielding performance is due to the K absorption edges of Cd, Gd, and Bi, respectively. Regarding the neutron shielding performance, the macroscopic effective removal cross-section for fast neutrons (ƩR) was evaluated for the investigated composites using MRCsC software. The highest ƩR is obtained for Al2O3/EPDM, while the lowest ƩR is obtained for EPDM rubber with no metal oxide content. According to the obtained results, the investigated metal oxide/EPDM rubber composites can be employed as comfortable clothing and gloves designed for workers in radiation facilities

Determination of loop length, tightness factor and porosity of single jersey knitted fabric

After fabric relaxation, there is a reduction in wale and course density due to a reduction in loop length and this actually will affect the fabric properties. Then, it is useful to find a relation between loop length and courses and wales per unit length as well as the yarn thickness because wales and courses per unit length can be easily measured at any state while it is difficult to measure the loop length in the knitted fabrics. Therefore, it is required to find an equation, through which the value of loop length can be easily calculated from the measured values of courses and wales per unit length at any state after the knitting process. In this work estimated equations to calculate the knitted loop length for open to normal structure and for normal to compact structure are developed. By comparing the value of the loop length predicted from this work with the other mentioned models, it was found that the calculated values are very near to the L value of the case study; so the developed equations are acceptable. The tightness factor and the porosity of single jersey fabrics were also calculated theoretically

Radiation attenuation properties of chemically prepared MgO nanoparticles/HDPE composites

Abstract Sheets of high-density polyethylene (HDPE) loaded with magnesium oxide in micro and nano were synthesized with different weight percentages of micro-MgO (0,5,10,20 and 30% by weight) and nano-MgO (5 and 30%) and shaped in form of disc and dog bone shape. The morphological, mechanical, and attenuation characteristics of each concentration were determined. The linear attenuation coefficients (LAC) of the prepared discs were calculated using a well-calibrated scintillation detector and five standard gamma-ray point sources (241Am, 133Ba, 137Cs, 60Co and 152Eu). The LAC was theoretically calculated for HDPE/micro-MgO composites using XCOM software. A good agreement between the theoretical and experimental results was observed. The comparison between micro and nano-MgO as a filler in HDPE was evaluated. The results proved that the loaded nano-MgO in different proportions of HDPE produced greater attenuation coefficients than its micro counterpart. The addition of nano MgO with different weight percentage led to a significant improvement in the mechanical properties of HDPE, the ultimate force and ultimate stress increased as the concentration of nano MgO increased, and the young modulus of HDPE also increased with increasing concentration of micro and nano MgO

Breast cancer involvement of the nipple-areola complex and implications for nipple-sparing mastectomies: a retrospective observational study in 137 patients

Abstract Introduction Nipple-sparing mastectomy (NSM) has gained much attention by enhancing the aesthetic outcome in breast carcinoma patients. The aim of this study was to assess the prevalence of malignant affection of the nipple-areola complex (NAC) in breast carcinoma patients and its correlation with prognostic factors for breast cancer. Patients and methods This study included 137 female patients diagnosed with breast carcinoma at different disease stages who were admitted to our surgical oncology unit at Suez Canal University Hospital from June 15, 2014 to January 25, 2017. We excluded patients with evidence of nipple involvement as ulceration or patients with previous breast surgery with periareolar incisions. This study was designed to test the hypothesis that the NAC can be spared in certain selected patients. All studied participants provided a full history and underwent general and local clinical examinations, pre-operative laboratory tests, and radiological and pathological evaluations. Results The mean age of the study population was 47.39 ± 8.01 years. Among the patients, the NAC was affected in 12 (11.40%) patients. Patients with NAC involvement showed a significantly larger tumor size of more than 4 cm and a shorter tumor-nipple distance of less than 2 cm (p = 0.000). Lymph node metastasis was associated with NAC involvement (p = 0.001), with increased risk when more than 10 lymph nodes were involved (p = 0.007). Lymphovascular invasion was a significant predictor of NAC involvement (p = 0.014). Multifocal as well as multicentric tumors were significantly associated with NAC involvement (p = 0.016 and 0.003, respectively). NAC involvement was more likely in Estrogen receptor (ER) and Progesterone receptor (PR) patients than in ER+ and PR+ patients (p = 0.000), while Human epidermal receptor (HER+) patients were more likely to have NAC involvement than HER patients (p = 0.000). Additionally, stage ΙΙΙ cancer was significantly associated with NAC involvement (p = 0.041), and histological grade III disease carried a greater risk than grade I disease of NAC involvement (p = 0.008). Conclusion The incidence of NAC affection among breast carcinoma patients who underwent mastectomy and axillary clearance was associated with important parameters, such as tumor size, areola edge-tumor distance, lymph node affection, hormonal receptor status and lymphovascular invasion. Accordingly, NAC-preserving surgeries could be tailored to patients with favourable tumor characteristics

Bronchoscopic electrocauterization versus argon plasma coagulation as a palliative management for patients with bronchogenic carcinoma

AbstractOne of the main indications for therapeutic endoscopic treatment is palliation of advanced cancerous lesions. The main purpose is the relief of dyspnea due to central airway obstruction, and the pre-operative evaluation to confirm that the lung beyond the obstruction is viable and that dyspnea is effectively related to the obstruction (Wahidi et al., 2007) [1].This study was carried out in the Chest Department at Tanta and Zagazig University Hospitals from May 2012 to December 2012 on 20 cases with endobronchial tumor present in the proximal main or lobar bronchi and proved to be Non-Small Cell Lung Carcinoma (NSCLC) by histopathological examination of stage IIIA or IIIB according to the AJCC staging (Rami-Porta et al. (2011) [2]).This study aimed to compare the clinical, functional and radiological outcome of electrocauterization and argon plasma coagulation as a palliative treatment for bronchogenic carcinoma.Patients were classified into 2 groups: Group 1: Included 10 patients and they were managed by palliative electrocautery. Group 2: Included 10 patients and they were managed by palliative argon plasma coagulation. The number of therapy sessions was ranged from one to four sessions (15–40min each), with one week interval between each session.After application of bronchoscopic electrocautery on patients in group I, and argon plasma coagulation on patients in group II, there was more significant control of hemoptysis in group I compared to group II. Both groups showed a significant improvement in ventilatory function tests and arterial oxygen tension PaO2 before and after bronchoscopic intervention. Also, there was no significant difference between the 2 groups as regards post treatment complications.It was concluded that, therapeutic bronchoscopic intervention either by electrocautery or argon plasma coagulation is a safe and effective method for palliative management of patients with central malignant airway obstruction

A New Environmentally Friendly Mortar from Cement, Waste Marble and Nano Iron Slag as Radiation Shielding

Improving mortar shielding properties to preserve environmental and human safety in radiation facilities is essential. Conventional cement mortars, composed of cement, water, and lime aggregate, are crucial for radiation shielding. Using recycled aggregates to produce new mortar and concrete compositions has attracted the attention of several researchers. In the current study, waste marble and iron slag as aggregates are used to create novel cement mortar compositions to study the aggregate’s impact on the radiation attenuation capability of the mortar. Three mortar groups, including a control mortar (CM-Ctrl), were prepared based on cement and waste marble. The other two groups (CM-MIS, CM-NIS), contained 25% iron slag at different particle sizes as a replacement for a waste marble. The study aims to compare iron slag in their micro and nano sizes to discuss the effect of particle size on the mortar radiation capability. For this purpose, the NaI scintillation detector and radioactive point sources (241Am, 133Ba, 137Cs, 60Co, and 152Eu) were utilized to measure several shielding parameters, such as the linear attenuation coefficient (LAC), mass attenuation coefficient (MAC), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP), for the produced mortars at different photon energies. Furthermore, the transmission electron microscope (TEM) is used to measure the particle size of the aggregates. In addition, a scanning electron microscope (SEM) is utilized to acquire the cross-section morphologies of the prepared mortars. According to our findings, mortars prepared with nano-iron slag and waste marble offered superior shielding capabilities than mortars containing natural sand or fine crushed stone. The nano iron slag mortar can be utilized in place of typical sand mortar for applications as rendering or plastering materials for building medical diagnostic and CT scanner rooms, due to its improved shielding abilities

[1] Ejaculation-preserving transurethral bipolar prostatectomy: Enucleation vs resection

Objective: To assess the feasibility and safety of a novel ejaculation-preserving transurethral bipolar resection of prostate (ep-TUBRP) and compare the resection technique to the enucleation technique. Methods: After obtaining local ethics approval, 100 consecutive patients with benign prostatic obstruction (BPO) and normal sexual activity were enrolled from June 2015 to June 2016. These patients were selectively randomised into two groups; 50 patients in each group. Group 1 underwent ejaculation-preserving transurethral bipolar enucleation of prostate (ep-TUBEP) and Group 2 underwent ep-TUBRP. All patients were evaluated pre- and postoperatively using the maximum urinary flow rate (Qmax); post-void residual urine volume (PVR); International Prostate Symptom Score (IPSS); and the five-item version of the International Index of Erectile Function (IIEF-5), including two additional questions evaluating ejaculation and orgasm. All patients were followed-up at 1, 3, and 6 months. Results: Overall, 100, 98 and 97 patients were evaluated at 1, 3 and 6 months, respectively. All preoperative parameters such as age, prostate-specific antigen (PSA), prostate volume, Qmax, PVR, IPSS, and IIEF-5 were comparable between the two groups (all P>0.05). At the 1-month follow-up, antegrade ejaculation was preserved in 88 of 100 (88%) (45 patients in Group 1 and 43 in Group 2). In addition, there were significant improvements in Qmax [from a mean (SD) of 6.54 (1.72) mL/s to 15.38 (3.02) mL/s], PVR [from a mean (SD) of 94.4 (41.85) mL to 25.04 (32.72) mL], and IPSS [from a mean (SD) of 21.7 (6.6) to 11.72 (2.39)] compared with the preoperative measurements. Moreover, these improvements were maintained at the 3- and 6-month follow-up visits (all P<0.001). No serious adverse events were reported. Conclusion: Ejaculation-preserving transurethral bipolar prostatectomy seems safe and effective for preservation of antegrade ejaculation with either the resection or the enucleation technique