Synthesis and biological activity of multifunctional sensor/effector catalysts

Increased generation of reactive oxygen species (ROS) and an altered redox status have long been observed in several types of cancer. This biochemical property of cancer cells might be exploited for therapeutic benefits since it might be possible to preferentially eliminate these cells by pharmacological ROS insults. Compounds able to modulate the intracellular redox state of cells have been developed, which effectively, yet also selectively, appear to kill cancer cells. Among the various agents employed to modulate the intracellular redox state of cells, certain redox catalysts containing quinone and chalcogen moieties have shown considerable promise since they are non-toxic on their own yet develop an effective, often selective cytotoxicity. A simple synthetic method based on the Passerini and Ugi multicomponent reactions has been developed for the synthesis of multifunctional redox catalysts. This method allowed the synthesis of a representative set of agents combining two, three or even four redox centres in one molecule in a good yield. When incubated with cancer cells these multifunctional agents inhibited cell proliferation and induced both cell cycle delay and apoptotic cell death in low, often sub-micromolar concentrations. The cause was obviously OS, which was reflected by an enhanced ROS level together with a significant decrease in reduced glutathione. Interestingly, some of these redox active compounds showed quite low toxicity with normal human fibroblasts and endothelial cells, supporting the notion that such compounds might have a selective anticancer activity. Chemogenomic assays using a mutant library of Saccharomyces cerevisiae were used to look for chemical-genetic interactions. Analyzing the resulting chemical-genetic interaction profiles afforded a set of sensitive mutants. The corresponding knocked out genes of these mutants play a major role in the antioxidant defence system and are pivotal for the removal of toxic oxidants. Therefore, deletion of the respective genes might cause an OS sensitive phenotype of the mutant. These observations were in excellent agreement with the other cell-based assay performed as a part of this study. Finally, some of these compounds showed a potent antimicrobial activity evaluated against different fungal and bacterial strains.Seit langem wird in mehreren Krebsarten eine erhöhte Generierung von reaktiven Sauerstoffspezies (ROS) und ein veränderter Redox-Status beobachtet. Diese biochemische Eigenschaft von Krebszellen könnte für therapeutische Zwecke genutzt werden, indem diese Zellen durch eine weitere Erhöhung des ROS-Levels eliminiert werden können. Wirkstoffe, die den intrazellulären Redox-Status der Zellen modulieren, wurden hier entwickelt. Diese können effektiv aber auch selektiv Krebszellen abtöten. Von den verschiedenen untersuchten Substanzen sind vor allem Redoxkatalysatoren, die Quinone- und Chalcogenreste enthalten, Erfolg versprechend. Sie sind an sich nicht toxisch, zeigen aber eine effektive und selektive Zytotoxizität. Für die Synthese von solchen multifunktionalen Redoxkatalysatoren wurde eine einfache synthetische Methode basierend auf den Passerini und Ugi Multikomponenten Reaktionen entwickelt. Diese Methode ermöglicht die Synthese eines repräsentativen Satzes von Substanzen mit hoher Ausbeute. Diese Substanzen enthalten zwei, drei oder sogar vier Redox-Zentren in einem Molekül. Diese multifunktionalen Substanzen inhibieren die Zellproliferation in Krebszelllinien. Im niedrigen micromolaren Konzentrationsbereich hemmen sie den Zellzyklus und induzieren Apoptose. Diese Wirkung wurde durch oxidativen Stress (OS) vermittelt, was durch einen erhöhten ROS-Level zusammen mit einer deutlichen Abnahme von reduziertem Glutathion belegt werden konnte. Interessanterweise zeigen diese redox-aktiven Substanzen nur geringe toxische Effekte in primären humanen Fibroblasten sowie Endothelzellen, was die Annahme unterstützt, dass diese Substanzen einen selektiven Effekt auf Tumorzellen haben. Um chemo-genetische Wechselwirkungen dieser Stoffe zu identifizieren, wurden Experimente mit einer Bibliothek von Saccharomyces cerevisiae Mutanten durchgeführt. Dabei wurden mehrere Mutanten entdeckt, die sensitiv auf diese Stoffe reagieren. Die in diesen Mutanten deletierten Gene sind besonders bei der antioxidativen Kontrolle der Zellen von Bedeutung und spielen eine Schlüsselrolle bei der Beseitigung von toxischen Oxidantien. Die Deletion solcher Gene kann zu einem Phänotyp führen, der besonders empfindlich auf oxidativen Stress reagiert. Diese Ergebnisse stützen und bestärken die aus den zellbasierten Experimenten gewonnen Daten. Schließlich zeigen einige dieser Substanzen eine starke antimikrobielle Aktivität gegen verschiedene Pilz- und Bakterienstämme

Cytoprotective and Antioxidants in Peroxisomal Neurodegenerative Diseases

Several of the peroxisomal neurodegenerative disorders are the consequence of a specific deficiency of an enzyme or a transporter involved in peroxisomal beta-oxidation of very long chain fatty acids [1,2]. One of the hallmarks in these peroxisomal rare neurodegenerative diseases and in other common demyelinating disorders is the accompanying oxidative damage and neuroinflammation [3]. Compelling data indicates that oxidative stress can activate microglia leading to the overproduction of pro-inflammatory molecules [4,5]. Thus, targeting oxidative stress to limit neuroinflammation may open a new pharmacological therapy window for these still incurable devastating peroxisomal diseases. Here, we present different natural (resveratrol) [6] and synthetic (organoselenides) [7] antioxidant compounds for their capacity of scavenging oxidative stress and in the perspective therapeutic use against oxidative damage in peroxisomal disorders

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

I. The keteniminium ion: a convenient synthetic intermediate / II. Redox reactions: metal-free redox transformations for C-C and C-N bond construction

Kapitel I zeigt eine kurze Diskussion von Keteniminium-Intermediaten. Basierend auf diesen reaktiven Intermediaten, die in situ aus Amiden oder Inamiden hergestellt werden, wurden erfolgreich diverse Reaktionen entwickelt. Das erste Bespiel präsentiert die Herstellung von Pyridinderivaten durch eine hochselektive [2+2+2] Cycloaddition. Die α-Arylierung von Amiden mit Hydroxamsäuren durch eine [3,3] sigmatrope Umlagerung ist ebenso dokumentiert. Zusätzlich werden auch die α-Umpolung von Amiden und die Dimerisierung von Inamiden präsentiert und diskutiert. Kapitel II fasst unsere neuesten Redoxreaktionen zusammen. Hydrazine können die Reduktion von Diazoniumsalzen zu den entsprechenden Radikalen katalysieren. Die Radikale reagieren weiter und bilden neue C-C Bindungen aus. Bei stöchiometrischer Verwendung von Hydrazine wurden Hydrazone als Reaktionsprodukte erhalten. Außerdem konnten wir zeigen, dass ein Photokatalysator (Eoisn Y) die Herstellung von Bisindol-Derivaten erfolgerich orchestriert. Der Mechanismus dieser Reaktion verläuft über einen 1,5-Wasserstoff-Shift.Chapter I presents a brief discussion on keteniminium intermediates. These reactive intermediates, which are usually generated in situ from amides or ynamides have been successfully utilised in a range of reactions. The first example concerns the synthesis of penta-substituted pyridines by means of a [2+2+2] cycloaddition reaction of activated ynamides and cyanoalkanes. Also documented is the α-arylation of amides with hydroxamic acids via [3,3] sigmatropic rearrangements. Additionally, α-umpolung reactivity of amides and the hydrative dimerisation of ynamides is presented and discussed (Scheme I). Chapter II summarises our recent redox reactions. The use of hydrazine derivatives to promote the reduction of diazonium salts into the corresponding aryl radicals and engaging them in a variety of transformations for C-C bond formation is presented. Hydrazines acted in dual role when used in stoichiometric quantities leading to the formation of hydrazone moieties. In addition, a visible light photo-catalysed formation of bis-indole derivatives via 1,5 hydrogen migration was also achieved

Synthese und biologische Aktivität von Multifunktionssensor/Effektor Katalysatoren

Increased generation of reactive oxygen species (ROS) and an altered redox status have long been observed in several types of cancer. This biochemical property of cancer cells might be exploited for therapeutic benefits since it might be possible to preferentially eliminate these cells by pharmacological ROS insults. Compounds able to modulate the intracellular redox state of cells have been developed, which effectively, yet also selectively, appear to kill cancer cells. Among the various agents employed to modulate the intracellular redox state of cells, certain redox catalysts containing quinone and chalcogen moieties have shown considerable promise since they are non-toxic on their own yet develop an effective, often selective cytotoxicity. A simple synthetic method based on the Passerini and Ugi multicomponent reactions has been developed for the synthesis of multifunctional redox catalysts. This method allowed the synthesis of a representative set of agents combining two, three or even four redox centres in one molecule in a good yield. When incubated with cancer cells these multifunctional agents inhibited cell proliferation and induced both cell cycle delay and apoptotic cell death in low, often sub-micromolar concentrations. The cause was obviously OS, which was reflected by an enhanced ROS level together with a significant decrease in reduced glutathione. Interestingly, some of these redox active compounds showed quite low toxicity with normal human fibroblasts and endothelial cells, supporting the notion that such compounds might have a selective anticancer activity. Chemogenomic assays using a mutant library of Saccharomyces cerevisiae were used to look for chemical-genetic interactions. Analyzing the resulting chemical-genetic interaction profiles afforded a set of sensitive mutants. The corresponding knocked out genes of these mutants play a major role in the antioxidant defence system and are pivotal for the removal of toxic oxidants. Therefore, deletion of the respective genes might cause an OS sensitive phenotype of the mutant. These observations were in excellent agreement with the other cell-based assay performed as a part of this study. Finally, some of these compounds showed a potent antimicrobial activity evaluated against different fungal and bacterial strains.Seit langem wird in mehreren Krebsarten eine erhöhte Generierung von reaktiven Sauerstoffspezies (ROS) und ein veränderter Redox-Status beobachtet. Diese biochemische Eigenschaft von Krebszellen könnte für therapeutische Zwecke genutzt werden, indem diese Zellen durch eine weitere Erhöhung des ROS-Levels eliminiert werden können. Wirkstoffe, die den intrazellulären Redox-Status der Zellen modulieren, wurden hier entwickelt. Diese können effektiv aber auch selektiv Krebszellen abtöten. Von den verschiedenen untersuchten Substanzen sind vor allem Redoxkatalysatoren, die Quinone- und Chalcogenreste enthalten, Erfolg versprechend. Sie sind an sich nicht toxisch, zeigen aber eine effektive und selektive Zytotoxizität. Für die Synthese von solchen multifunktionalen Redoxkatalysatoren wurde eine einfache synthetische Methode basierend auf den Passerini und Ugi Multikomponenten Reaktionen entwickelt. Diese Methode ermöglicht die Synthese eines repräsentativen Satzes von Substanzen mit hoher Ausbeute. Diese Substanzen enthalten zwei, drei oder sogar vier Redox-Zentren in einem Molekül. Diese multifunktionalen Substanzen inhibieren die Zellproliferation in Krebszelllinien. Im niedrigen micromolaren Konzentrationsbereich hemmen sie den Zellzyklus und induzieren Apoptose. Diese Wirkung wurde durch oxidativen Stress (OS) vermittelt, was durch einen erhöhten ROS-Level zusammen mit einer deutlichen Abnahme von reduziertem Glutathion belegt werden konnte. Interessanterweise zeigen diese redox-aktiven Substanzen nur geringe toxische Effekte in primären humanen Fibroblasten sowie Endothelzellen, was die Annahme unterstützt, dass diese Substanzen einen selektiven Effekt auf Tumorzellen haben. Um chemo-genetische Wechselwirkungen dieser Stoffe zu identifizieren, wurden Experimente mit einer Bibliothek von Saccharomyces cerevisiae Mutanten durchgeführt. Dabei wurden mehrere Mutanten entdeckt, die sensitiv auf diese Stoffe reagieren. Die in diesen Mutanten deletierten Gene sind besonders bei der antioxidativen Kontrolle der Zellen von Bedeutung und spielen eine Schlüsselrolle bei der Beseitigung von toxischen Oxidantien. Die Deletion solcher Gene kann zu einem Phänotyp führen, der besonders empfindlich auf oxidativen Stress reagiert. Diese Ergebnisse stützen und bestärken die aus den zellbasierten Experimenten gewonnen Daten. Schließlich zeigen einige dieser Substanzen eine starke antimikrobielle Aktivität gegen verschiedene Pilz- und Bakterienstämme

Optimal management of Seawater intrusion in arid and semi-arid coastal aquifers

Freshwater aquifers in coastal zones are vulnerable to seawater intrusion (SWI). SWI is a natural and troublesome phenomenon that impairs the potability of groundwater. Moreover, impacts of population growth and climate change such as recharge variations, sea level rise (SLR), and land-surface inundation (LSI) associated with SLR may exacerbate this problem. Sea levels are expected to rise substantially due to climate change. It is widely assumed that this rise will adversely affect SWI processes in coastal aquifer. Mitigation measures can be either by changing the water resources management legislation or by implementing physical or hydraulic barriers. The focus of this project is on assessing the effectiveness of a novel hydraulic barrier as a mitigation measure, in addition to addressing the challenges of two hydraulic barriers to control SWI in coastal aquifers. The decision makers should be informed of the risks surrounding their decisions before implementing any mitigation measure. A decision support tool is developed to determine whether an investment is needed, and the associated degree of uncertainty. A generalized computationally efficient framework is proposed to analyze the predictive uncertainty of models. The novel components of the framework include efficient parameter space sampling using an optimized Latin hypercube sampling strategy, and applying the Null Space Monte Carlo method (NSMC) along with a developed filtering technique. The NSMC renders generated sample sets to calibrate the model while exploring the null space. This space contains parameter combinations that are not sufficiently supported by observations. The filtering technique omits low-potential parameter sets from undergoing model calibration. The framework is tested on the seawater intrusion (SWI) model of Wadi Ham aquifer, to investigate aquifer sustainability in 2050. It is concluded that, with a moderate to a high degree of certainty, SWI threatens the main pumping fields, and this would adversely affect the suitability of groundwater for irrigation. Therefore a managed aquifer recharge (MAR) scheme involving an infiltration pond is used in this study to mitigate SWI caused by future climate change in 2050. However, running a management model, based on variable-density groundwater flow and solute transport equations, is time-consuming. Besides, optimizing the model objectives would require several simulation runs. To reduce the computational burden, a surrogate-assisted simulation-optimization framework is developed, based on constrained multiobjective Bayesian optimization (BO) algorithm. BO is a data-efficient learning technique, which solves computationally expensive problems with few iterations. This algorithm is introduced to SWI management for the first time in this study. The proposed framework is applied to determine the optimal location and dimensions of an infiltration pond considering environmental and economic effectiveness. Since BO is newly introduced in this field, it was benchmarked against the widely used robust NSGA-II (Non-dominated Sorting Genetic Algorithm II) method. The results prove the effectiveness of BO in achieving the optimum design parameters of the mitigation measure in much fewer simulation runs. Mixed hydraulic barriers, as another mitigation measure, is optimally designed using the BO approach. Through evaluating several management scenarios, it is shown that the injection has a significant impact on the management, while the abstracted water provides an alternative source of water. A sensitivity analysis is conducted on the optimization problem to illustrate its efficiency by omitting the barriers one at a time and assessing impacts on the objective and constraint functions. A third novel mitigation measure is introduced in this research as an improvement for the potential loss in the available freshwater induced by the negative barriers in the mixed hydraulic barriers method. This measure combines the injection of reclaimed water with the use of groundwater circulation wells (GCW), which creates a sustainable solution (Inj_GCW mitigation measure). First, an illustrative simplified unconfined coastal aquifer is used to quantitatively evaluate the Inj_GCW's performance in controlling SWI. Using the findings from this aquifer, recommended design parameters are estimated for a field-scale case study of the Nile Delta aquifer in Egypt. The study adopts a 2100 future scenario that considers Sea Level Rise due to climate change and projected population growth. The results of implementing the Inj_GCW measure on the Nile Delta aquifer show retardation in the SWI compared to the expected intrusion in 2100, and a reduction in the aquifer salinity. At the well injection screen of the GCW, a brackish water bubble is formed acting as a hydraulic barrier

Synthesis, absorption and fluorescence spectra of new colorants based on pyrrolinone esters

A set of azo dyes were prepared by diazotization of a series of electronically different substituted anilines and subsequent azo coupling of these diazonium salts with ethyl 4,5-dihydro-5-oxo-2-aryl(1H)pyrrole-3-carboxylate as a the coupling component. All of the dyes were confirmed as keto-hydrazone tautomers and were found as a mixtures of E- and Z- isomers with respect to the exocyclic C=N bond by 1H NMR spectroscopy. The absorption spectra are all similar irrespective of substituent and solvent. By comparison the fluorescence is strongly dependent on the electronic character of the substituents. All compounds fluoresce in a low temperature solvent glass and in the solid state except the ortho hydroxyl and ortho nitro derivatives and only the 4-cyanophenyl and 4-nitrophenyl derivatives show fluorescence in solution at room temperature. The spectroscopic behavior is explained in terms of competition between E/Z isomerisation and fluorescence after excitation. In the second part of this work short series of cobalt and chromium complex dyes based on pyrrolinone ring was prepared; the synthesis of these compounds was based on using pure hydrazone dyes as starting ligand. Multinuclear magnetic resonance spectroscopy (NMR) technique was very useful for proving the structure of prepared compounds. In contrast to the starting compounds existing ligands completely in hydrazone form, cobalt (III) complexes exist in (E)-azo configuration and cobalt atom is six-coordinated being bound to oxygens, which originate in hydroxyl and CONH groups and nitrogens from substituted anilines as starting material from two ligands. Spectral properties of these compounds were studied as well as photochemical isomerisation using absorption spectra.A set of azo dyes were prepared by diazotization of a series of electronically different substituted anilines and subsequent azo coupling of these diazonium salts with ethyl 4,5-dihydro-5-oxo-2-aryl(1H)pyrrole-3-carboxylate as a the coupling component. All of the dyes were confirmed as keto-hydrazone tautomers and were found as a mixtures of E- and Z- isomers with respect to the exocyclic C=N bond by 1H NMR spectroscopy. The absorption spectra are all similar irrespective of substituent and solvent. By comparison the fluorescence is strongly dependent on the electronic character of the substituents. All compounds fluoresce in a low temperature solvent glass and in the solid state except the ortho hydroxyl and ortho nitro derivatives and only the 4-cyanophenyl and 4-nitrophenyl derivatives show fluorescence in solution at room temperature. The spectroscopic behavior is explained in terms of competition between E/Z isomerisation and fluorescence after excitation. In the second part of this work short series of cobalt and chromium complex dyes based on pyrrolinone ring was prepared; the synthesis of these compounds was based on using pure hydrazone dyes as starting ligand. Multinuclear magnetic resonance spectroscopy (NMR) technique was very useful for proving the structure of prepared compounds. In contrast to the starting compounds existing ligands completely in hydrazone form, cobalt (III) complexes exist in (E)-azo configuration and cobalt atom is six-coordinated being bound to oxygens, which originate in hydroxyl and CONH groups and nitrogens from substituted anilines as starting material from two ligands. Spectral properties of these compounds were studied as well as photochemical isomerisation using absorption spectra.Ústav organické chemie a technologieZápis o obhajobě disertační práce Mgr. Tarek Aysha Syntéza, absorpční a fluorescenční spektra nových kolorantů na bázi pyrrolinonových esterů 14.11.2011 12:00 učebna 02031 Přítomni - viz Prezenční listina obhajoby celkem 7 členů komise Průběh obhajoby: prof. Hanika 12:00: představení komise obhajoby a představení Mgr. Tarek Aysha prof. Hanika 12:15 posudek školitele Mgr. Tarek Aysha prof. Hanika 12:30 posudek vedoucího pracoviště ÚOCHT závěr: Mgr. Tarek Aysha splnil požadavky na podání disertační práce (dále jen DP) - práce byla doporučena k obhajobě. Mgr. Tarek Aysha 12:45-13:15 prezentace výsledků DP. Posudky oponentů: prof. Hanika : posudek spolu s komentářem, komentář posudku Mgr. Aysha a odpovězení otázek oponenta z posudku DP. Na základě toho práce doporučena k obhajobě. prof. Nepraš: posudek spolu s komentářem, komentář posudku Mgr. Aysha a odpovězení otázek oponenta z posudku DP. Na základě toho práce doporučena k obhajobě. Diskuze k DP: prof. Nepraš Otázka: Jakým způsobem byly identifikovány vybrané deriváty. Odpověď Ayshy: NMR,MS, elementární analýza + vysvětlení spekter. prof. Hrdina: Vztah mezi strukturou a absorpčním spektrem připravených derivátů. doc. Burget: Vliv substituce a arozpouštědla na absorpčním spektrum. Ing. Halama: Syntéza pyrrolinonových esterů. Souvislost mezi publikacemi a DP: Výsledky dosažené v disertační práci byly publikovány v impaktovaných časopisech. Podíl studenta na jednotlivých publikacích: Podíl disertanta na překládaných publikacích byl významný a rozhodující. Zapsal Ing. Oldřich Machalický, Dr

Estimation of radioecological parameters of soil samples from a phosphatic area

The activity concentrations of natural radionuclides (226Ra, 232Th, and 40K) for a set of 31 agricultural soil samples from the Nile River banks in the area of El-Sebaiya city, Aswan Governorate, Egypt were measured by gamma-spectrometry. The study revealed that the average activity concentrations of natural radionuclides 226Ra, 232Th, and 40K were 23.2 ± 2.8Bq/kg, 21.1 ± 2.8 Bq/kg, and 218.6 ± 3.7 Bq/kg, respectively. The obtained results of the activity concentrations are within the range of values reported for neighbouring areas in Egypt. The values obtained for the hazard indices and the representative level index in all sampling sites were lower than unity, showing that there is no significant risk arising from the exposure to the soil in the studied area. The absorbed dose rate and annual effective dose in air outdoors and indoors were calculated from 226Ra, 232Th, and 40K in soil, the average values being 32.64 nGy/h, 40.06 µSv, and 160.25 µSv, respectively. The absorbed dose rate at the eastof El-Sebaiya city is higher than that obtained for the west because of higher concentrations of tri-calcium phosphate in the soil. The studied area is not significantly affected by the industrial activities, except for a few isolated spots