mohsen shayesteh

Nuclear emergency management prioritizes minimizing radioactive releases to protect public health and environmental systems. Radiological incidents can cause widespread ecosystem contamination with multi-generational consequences. This study employs predictive modeling to assess risks across all incident phases using computational tools and analytical methods.This study evaluates a hypothetical accident scenario involving a one-hour atmospheric release of 137Cs from a Russian KLT-40S small modular reactor (SMR) during peak operation in the Chabahar region. Utilizing the RASCAL computational code, a regulatory-endorsed tool for radiological emergency response, the research analyzes the isotope's dispersion dynamics over nine hours.This paper provides both a methodology for identifying hazard zones and a decision-support resource for emergency management officials during incident response. Implementation of fundamental protective actions, based on established protocols and real-time incident conditions, remains the responsibility of local authorities according to quantified risk levels.

This research simulated the natural circulation in a mini-loop using numerical calculations performed with a FORTRAN code and CFD simulations via Ansys Fluent. A stability map of the loop was derived, and the impact of the loop’s inclination angle on this stability map was examined. The findings indicate that at low power levels, particularly functional powers, the loop’s inclination angle does not significantly affect the stability map. The results of the numerical calculations were compared with Vijayan's experimental corrections for this mini-loop, showing good agreement within its functional power range. Additionally, a comparison was made between the numerical calculations and the Ansys Fluent simulation results, which also demonstrated a good agreement, thereby confirming the accuracy of the calculations. Two significant thermo-hydraulic parameters -the mass flow rate and temperature difference at the two heater heads- were calculated and compared for different loop inclinations. It was observed that increasing the inclination angle results in a decrease in the fluid’s mass flow rate and an increase in the temperature difference at the ends of the heat source. Notably, it was determined that achieving a specific temperature difference across the heat source does not necessarily require adjusting the power levels; simply changing the inclination angle is sufficient. Another important result of this research is that by making a series of straightforward assumptions, one-dimensional computations can be solved very precisely, thereby saving computation time.

Performing Monte Carlo simulation calculations for the neutron imaging system of the Tehran Research Reactor (TRR) as a complex system is usually very time-consuming. By using variance reduction methods, this time can be reduced to obtain results with sufficient accuracy. Each of the variance reduction techniques has its own advantages, problems, and characteristics, so the user is responsible for choosing the proper variance reduction method. In this research, the effect of using the variance reduction method of DXTRAN spheres in calculating the neutron and gamma dose rate at a point located in the neutron imaging system of the TRR has been selected and its results have been analyzed. For this purpose, by using the results of simulation with MCNPX code and calculation of neutron flux and dose at the E beam tube of TRR and simulating the imaging chamber, neutron dose rate and gamma rays using Tally F4 in two analog and non-analog ways were calculated. Also, for each mode, the Figure of Merit (FOM) for the number of different histories was compared. The results show that the use of this technique helps to reduce the calculation time until an acceptable variance is reached, although the effect of this method is not the same in the case of calculations related to neutrons and gamma, as well as increasing the FOM. This method also resulted in a significant increase in FOM in both neutron and gamma cases.

Dose evaluation of radioactive materials is one of the main safety categories of reactors and nuclear facilities. The spread of radioactive materials, which may be caused by an accident in a nuclear facility, can cause radiation hazards to humans and the environment, in such a situation, the dose should be evaluated and, if necessary, appropriate control measures should be taken into account. In this article, it is assumed that the ABV reactor, which is a small modular reactor, has been installed in order to supply energy to industrial facilities around Mobarake city, located in Isfahan province. The main goal of this research is to investigate the atmospheric release of cesium-134 and cesium-137 caused by a hypothetical core meltdown incident in this reactor. The amount of cesium-134 and 137 radioisotopes present in the reactor core at the time of the accident, which was calculated in the previous works of the authors, is assumed as a radiation source. Then, using RASCAL software and assuming that the release time of these two radioisotopes is one hour, their atmospheric distribution has been investigated in two days after the accident and up to a radius of 80 km. In this research, total effective dose of TEDE, thyroid dose, inhaled CEDE, as well as the surface pollution of these two isotopes have been calculated and their distribution pattern up to 80 km distance from the accident site has been drawn.

Using the experimental data in nuclear computing to verify the calculation methods and tools based on numerical and statistical methods has many benefits such as illustrating the quality, ensuring the capabilities, and computer codes validating. Simulation by computer tools is also applicable in the safety analysis of research reactors. In this research, the computer tool (MCNPX 2.7.0: 2011) was verified against the experimental data of neutron flux and spectrum on the sample position of the Tehran Research Reactor (TRR) neutron imaging system by the neutron activation method. To determine the benchmark specifications, the simulation of the system was done at the first step by considering a well-defined facility geometric, material specification and reactor core configuration, fuel elements, and radiation facility (beam tubes and collimator, reactor core, and neutron imaging components). Then the flux and neutron spectrum at the sample position were calculated. In the second step, a set of In (bare and covered by cd) and Au foils and a set of Au, Ni, Ti, and Zr, were placed and exposed almost in front of the reactor E beam tube. The neutron energy spectrum was unfolded by calculating the saturation activity of each foil by SAND-II code, and the neutron flux was calculated. A comparison of the results obtained in two steps shows a relatively good and acceptable agreement (Max. 30% deviation) between the flux and the shape of the flux profile obtained from calculations and experimental data.

Guides play a key role in concentrating the neutron beam and increasing the flux for a neutron guide system. In this research, the role of a radius of curvature and length parameters on neutron intensity on the sample for the S-shape guide has been investigated and the results have been analyzed for three different types of geometry. In this work, the Monte Carlo simulation method is used with McStas software. The results show that at a constant radius with increasing length, the guide moves more towards bending and passes neutrons with less energy. Conversely, at a constant length with increasing radius, the guide gradually deviates from the curved state and it leads directly to the straight guide, all of the neutron energy spectra passes. A radius of curvature of 70 m and a length of 4 m were chosen for the S-shaped guide due to the passage of a larger range of thermal neutron fluxes. The guide radius can lead to a cut-off wavelength for neutrons. This guide can also eliminate fast neutrons and gamma rays..

Chemotherapy, biotherapy, and radiotherapy play a limited but important role in treating breast cancer. For more efficient treatment, combination therapy could be an appropriate option. In this study, radiotherapy using neutron radiation emitted from a 241Am-Be neutron source, as well as biotherapy using curcumin (80 μM) was combined to investigate the efficiency of treatment towards MCF-7 breast cancer in a 3D culture medium.

MTT, NR uptake assay, NO, GSH assay, catalase, cytochrome c, comet assay, and caspase-3 were used to determine the effect of neutron radiation and also neutron and curcumin combination on the viability of cancer cells.

The results of cytotoxicity test showed that neutron irradiation with or without curcumin at 5, 10, 15, and 20 h reduced the survival of tumor cells. Moreover, the rate of apoptosis due to the neutron effect at different irradiation times enhanced with the increasing time.

Due to the significant anticancer effect of curcumin in 3D culture, using this molecule before or after neutron therapy is recommended.

Prostate cancer is a major cause of disease and mortality among men. GNT is an isoflavone found naturally in legumes. Isoflavones, a subset of phytoestrogens, are structurally similar to mammalian estrogens. This study aimed to evaluate the anticancer and cytotoxic effects of GNT on PC3 cell line under 3D culture medium.

The 3D culture was created by encapsulating the PC3 cells in alginate hydrogel. MTT assay, neutral red uptake, comet assay, and cytochrome C assay were used to study the anticancer and cytotoxic effects of GNT at 120, 240, and 480 μM concentrations. Also, NO, catalase, and GSH levels were determined to evaluate the effect of GNT on the cellular stress. The culture medium was used as the negative control.

GNT reduced the production of cellular NO and increased the production of catalase and glutathione, confirming the results of the NO test. Evaluation of the toxicity effect of GNT at the concentrations of 120, 240, and 480 μM using comet assay showed that this chemical agent induces apoptosis in PC3 cells in a dose-dependent manner. As the level of cytochrome C in PC3 cells treated with different concentrations of GNT was not significantly different from that of the control, GNT could induce apoptosis in PC3 cells through the non-mitochondrial pathway. 

The findings of this study disclose that the anticancer effect of GNT on PC3 cells under 3D culture conditions could increase the effectiveness of treatment. Also, the cell survival rate is dependent on GNT concentration.

Breast cancer is the most common cancer among women. Information published by The Iranian Cancer Research Center in 2019 shows that one of every 10 to 15 women is afflicted with this cancer. As one of the active ingredients of turmeric, curcumin has a wide range of biological properties, such as antioxidant and anti-cancer activity. This study aimed to evaluate the anti-cancer effects of curcumin on breast cancer cells in 3-Dimensional (3D) culture conditions. To achieve a 3D environment, we used encapsulation of cells in alginate hydrogel. The anti-cancer effects of curcumin at concentrations of 20, 40, and 80 μM on MCF-7 breast cancer cells in 3D culture were evaluated by MTT, neutral red, comet assay, cytochrome c, Nitric Oxide (NO), catalase, and glutathione assays. The culture medium was used as the negative control and the cell-containing medium was used as the positive control. Data were analyzed by two-way ANOVA using GraphPad InStat software, and the significance was considered at the level of P<0.05. Curcumin reduces the production of cellular NO and increases the production of catalase and glutathione, which confirms the results of the NO test. In addition, the release of cytochrome c from Mitochondria from cells treated with different concentrations of curcumin compared to control cells are significant. The evaluation of the toxicity effect of curcumin at concentrations of 20, 40, and 80 μM using comet assay showed that this substance induces apoptosis in MCF-7 cells in a dose-dependent manner. The findings of this study showed that the anti-cancer effect of curcumin on MCF-7 cells under 3D culture conditions could increase the effectiveness of treatment. The Cell survival rate actually depended on curcumin concentration.

In this study, thermal-hydraulic analysis of partial loss of coolant flow accident in supercritical pressure light water reactor (SCWR) with a new geometric design has been investigated. In the new design, the coolant and moderator circuits are separated. This analysis was performed using the development of a transient-state thermal-hydraulic code in which the equations of mass, momentum, and energy are solved. The porous Media approach is used to solve these equations. By extracting the results of transition modeling, it is observed that in the new geometric design, by separating the coolant and moderator circuits, the maximum fuel clad temperature is lower than the maximum fuel clad temperature value of the previous designs. As in the new design at the end of the transition, the maximum fuel clad temperature has decreased by about 37% compared to the initial state. The result of the calculations in this study shows that the new design, in which the coolant and moderator circuits are separated, has created more safety in a chosen transition.

Today, small modular reactors have received considerable attention in various countries. The ABV reactor is a PWR small modular reactor that has various applications. This reactor has been used silumin metal fuel with a 16.5% enrichment. In the present work, the efficiency of the conventional UO2 fuel with enrichment of less than 10% to be used as the main fuel of ABV reactor has been investigated, and four different patterns for the reactor core have been proposed. To perform the calculations, the ABV reactor is modeled using the PARCS neutronic code and the RELAP5 thermohydraulic code. Finally, using computational codes for the proposed patterns of the reactor core, various quantities including reactor cycle length, reactivity, burnup, power distribution, fuel, coolant temperature distribution, and feedback coefficients have been calculated.

‎The analysis deals with the assessment of best estimate code RELAP5/SCDAP mod3.4 in the simulation of double-ended loss coolant accident as a LBOCA‎, ‎4 in break as a SBLOCA an SBO accident with considering except accumulator water where no core cooling water systems are available‎. ‎The reference plant is SURRY nuclear power plant as a Westinghouse three-loop nuclear power plant‎. ‎In order to mitigation accident‎, ‎the in-vessel retention strategy was investigated for the prevention of lower plenum failure‎. ‎It has been concluded that during the SBLOCA‎, ‎LBLOCA conditions bottom of active fuel is uncovered at 6340 s and 2160 s‎, ‎respectively‎. It occurred for two times at 11650 s and 15608 s in SBO‎. ‎At 6792 s and 57002 s in the LBLOCA and SBO due to reaching melting point and in the SBLOCA at 15215 s due to lower plenum creep rupture‎, ‎failure of the reactor pressure vessel occurred‎. ‎The results show that hydrogen production in the SBO is more than the other two cases‎. ‎For the prevention of the lower plenum failure‎, ‎the in-vessel molten material retention strategy is investigated as a passive system‎. ‎The results show that lower plenum heat flux can be kept below the critical heat flux and its integrity is preserved in two cases of this analysis‎.

The Squat and Leg press exercises are methods that be used for lower limb muscular reinforcement. The aim of this study was to compare the effects of open versus closed kinetic chain exercise on the EMG activity of quadriceps femoris muscles during step descending.

Twenty healthy male students of between 20 - 28 years old were divided into two equal groups’ namely as squat group and leg press group. Squat and leg press groups underwent a 12 sessions of the Squat and Leg press exercises respectively. In synchronization with the EMG system, a Vicon motion analysis system (200 Hz) was used to separate the stance and swing phases. Measurements were repeated before and after the exercise program. Statistical analyses were done by independent and paired sample T tests.

In Squat group, after the exercise training, during stance phase, the EMG activity of the left vastus medialis muscle was decreased (P=0.040) significant. In Leg press group also, the EMG activity of the right vastus medialis in swing phase and the left vastus medialis muscle in both phases was decreased after the training program (p≤0.05). Range of reduction of vastus medialis muscular activity in Leg press group was higher than that in Squat group (p=0.050).

Leg press exercise showed better outcome than the Squat for the strengthening of the vastus medialis muscle measured in step descending task. It is suggested to use Leg press exercise with abducted hip for selective strengthening of vastus medialis muscle.

Neutron focusing with specific energy and intensity distribution from neutron source plays an important role in various applications. In this paper, the effect of straight and elliptical guide systems for focusing on the neutron intensity on the target has been investigated for a neutron source as a Maxwell distribution in the range of wavelength from 0.5 to 5 angstroms. The simulations were performed using the Monte Carlo simulation code McStas and the effects of different parameters of straight and elliptical neutron guides on the neutrons intensity have been obtained. Then, the results of straight and elliptical guide systems are also compared. Studying the role of the straight and elliptical guide's length shows that increasing the guide length, the output intensity increases and after an optimal length, it decreases. The results show that for the straight guide, optimization of the distance between the source to the guide has the greatest effect on the intensity of the output neutrons versus wavelength, while for the elliptic guide, optimization of the source radius has the greatest effect. Finally, the results show that the performance of the elliptical guide is better than the straight guide.

Traumatic dental injuries (TDI) are unpleasant experiences for children and necessitate to be treated as soon as possible. The aim of this cross-sectional study was to assess the general dental practitioners (GDPs) knowledge and attitude regarding the emergency management of TDI in Ahvaz, Iran, in 2014-2015.
Subjects and

In this study a two-part questionnaire was distributed among 100 GDPs. Part 1 focusing on demographic information and part 2 asked questions about different dental injuries. One score was dedicated to each correct answer; the total score of 10 to 30 was considered as low knowledge and attitude, while scores 30-50, 50-70 and up to 70 were assigned as moderate, good and high knowledge and attitude, respectively. The data were analyzed using variance analysis and t-test.

With regards to the level of GDPs knowledge, the mean score was 59/2% , out of a total of 100, 51% of the dentists showed a good level of knowledge. A significant association was found between knowledge and attitude of GDPs in their practice that were encountered and treated TDI (P=0.001).

The overall knowledge of GDPs about the management of TDI in the selected community was good. ►Please cite this paper as: Basir L, Shayesteh M, Atiyeh Heydari M, Imani Z, Mammadi Kartalaee M. General Dental Practitioners Knowledge and Attitude Regarding Management of Dental Trauma in Children of Ahvaz City.

In order to gain the neutron spectrum with proper components specification for BNCT¡ it is necessary to design a Beam Shape Assembling (BSA)¡ including moderator¡ collimator¡ reflector¡ gamma filter and thermal neutrons filter¡ in front of the initial radiation beam from the source. According to the result of MCNP4Csimulation¡ the Northwest beam tube has the most optimized neutron flux between three north beam tubes of Tehran Research Reactor (TRR). So¡ it has been chosen for this purpose. Simulation of the BSA was done in four above mentioned phases. In each stage¡ ten best configurations of materials with different length and width were selected as the candidates for the next stage. The last BSA configuration includes: 78 centimeters of air as an empty space¡ 40 centimeters of Iron plus 52 centimeters of heave-water as moderator¡ 30 centimeters of water or 90 centimeters of Aluminum-Oxide as a reflector¡ 1 millimeters of lithium (Li) as thermal neutrons filter and finally 3 millimeters of Bismuth (Bi) as a filter of gamma radiation. The result of Calculations shows that best neutron flux and spectrum will be achieved for BNCT by using this BSA configuration for TRR Northwest beam tube.

In order to investigate the possibility of using the T.R.R beam tubes in BNCT, it is necessary to select the best one from three north beam tubes. This beam tube should have more flux and better spectrum compared to others. So, after simulation of the last configuration of reactors core (NO.55) by MCNP4C code, the neutron flux and spectrum were calculated at the start, middle, and end of each three north beam tubes (B1, B2, B3). Because of the relation between these parameters and the state of core, this calculation was done in three different situations of reactors core: BOC, MOC and EOC. The analyses of results showed that the neutron spectrum is almost the same in all of the beam tubes, but the neutron flux in northwest beam tube is better than the others .So, this beam tube is more proper to be used in BNCT.

This study aimed to compare the subcutaneous tissue responses to MTAD (mixture of a tetracycline isomer, an acid, and a detergent), 17% EDTA, and 2.6% NaOCl. Thirty-six Wistar albino rats were used for this study. Test solutions were injected subcutaneously into predetermined areas on the animal dorsum. The rats were then randomly divided into three groups of twelve each and sacrificed at 2 hours, 2 days, and 2 weeks. The severity of inflammation induced by each irrigant at different time intervals was assessed histologically. The data were analyzed using Kruskal-Wallis and Friedman tests. The difference in severity of inflammatory reactions induced by tested irrigants at the different time intervals was statically significant (P<0.05). There was no significant difference between the severity of inflammation induced by MTAD and 2.6% NaOCl at the various time intervals (P>0.05). Subcutaneous tissue responses to MTAD were not different from those observed in 17% EDTA specimens at 2-hour and 2-day intervals (P>0.05). Under the conditions of this study, MTAD has the same toxicity as 2.6% NaOCl