scholarly journals Environmental Radiation: Natural Radioactivity Monitoring

2020 ◽  
Author(s):  
Isam Salih Mohamed Musa
Keyword(s):  
Natural Radioactivity ◽  
Environmental Radiation ◽  
Radioactivity Monitoring

Repair pathway choice for double-strand breaks

2020 ◽  
Vol 64 (5) ◽  
pp. 765-777 ◽  
Author(s):  
Yixi Xu ◽  
Dongyi Xu
Keyword(s):  
Cell Cycle ◽  
Double Strand Breaks ◽  
Homologous Region ◽  
Gene Repair ◽  
Repair Pathway ◽  
Dna Double Strand Breaks ◽  
Environmental Radiation ◽  
Strand Breaks ◽  
Dna End Resection ◽  
End Resection

Abstract Deoxyribonucleic acid (DNA) is at a constant risk of damage from endogenous substances, environmental radiation, and chemical stressors. DNA double-strand breaks (DSBs) pose a significant threat to genomic integrity and cell survival. There are two major pathways for DSB repair: nonhomologous end-joining (NHEJ) and homologous recombination (HR). The extent of DNA end resection, which determines the length of the 3′ single-stranded DNA (ssDNA) overhang, is the primary factor that determines whether repair is carried out via NHEJ or HR. NHEJ, which does not require a 3′ ssDNA tail, occurs throughout the cell cycle. 53BP1 and the cofactors PTIP or RIF1-shieldin protect the broken DNA end, inhibit long-range end resection and thus promote NHEJ. In contrast, HR mainly occurs during the S/G2 phase and requires DNA end processing to create a 3′ tail that can invade a homologous region, ensuring faithful gene repair. BRCA1 and the cofactors CtIP, EXO1, BLM/DNA2, and the MRE11–RAD50–NBS1 (MRN) complex promote DNA end resection and thus HR. DNA resection is influenced by the cell cycle, the chromatin environment, and the complexity of the DNA end break. Herein, we summarize the key factors involved in repair pathway selection for DSBs and discuss recent related publications.

Assessment of the Natural Radioactivity and its Radiological Hazards in Stream Sediments at Gulf of Al Aqaba, Sinai, Egypt.

2015 ◽  
Vol 32 (part 2) ◽  
pp. 62-75
Author(s):  
M. Ibrahim ◽  
N. Walley elDine ◽  
A. EL-Shershaby ◽  
S. EL-Bahi ◽  
N. Ali
Keyword(s):  
Natural Radioactivity ◽  
Stream Sediments ◽  
Radiological Hazards

The Natural Radioactivity in Food: A Comparison Between Different Feeding Regimes

2019 ◽  
Vol 15 (5) ◽  
pp. 493-499 ◽  
Author(s):  
Francesco Caridi ◽  
Santina Marguccio ◽  
Alberto Belvedere ◽  
Maurizio D`Agostino ◽  
Giovanna Belmusto
Keyword(s):  
Vegetable Oils ◽  
Natural Radioactivity ◽  
Specific Activity ◽  
Mean Value ◽  
Vegetable Food ◽  
Fish Samples ◽  
Feeding Regimes ◽  
Italian Origin ◽  
Dose Levels

Background: In this article a comprehensive study was carried out for the determination of natural radioactivity in animal and vegetable food (meat, fish, milk and derivates, legumes, cereals and derivates, fruit, hortalizas, vegetables, vegetable oils) typical of different feeding regimes, for the age category higher than 17 years. Methods: A total of eighty-five samples of Italian origin, coming from large retailers during the years 2014, 2015 and 2016, were analyzed through HPGe gamma spectrometry. Results: The specific activity of 40K was investigated and its mean value was found to be: (106.3 ± 6.9) Bq/kg for bovine, swine and sheep meat; (116.5 ± 9.7) Bq/kg for fish; (52.9 ± 3.1) Bq/kg for milk and derivates; (271.9 ± 16.7) Bq/kg for legumes; (67.2 ± 4.7) Bq/kg for cereals and derivates; (52.7 ± 4.4) Bq/kg for fruit; (72.9 ± 5.6) Bq/kg for hortalizas; (83.9 ± 6.5) Bq/kg for vegetables; lower than the minimum detectable activity for vegetable oils. For animal food the highest mean 40K activity concentration was found in fish samples; for vegetable food the highest one was detected in legumes. Conclusion: The evaluation of dose levels due to the food ingestion typical of Mediterranean, Vegetarian and Vegan diets was performed. The annual effective dose was found to be 0.16 mSv/y, 0.41 mSv/y and 0.54 mSv/y, respectively.

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