Investigation of Dose Distribution in Mixed Neutron-Gamma Field of Boron Neutron Capture Therapy using N-Isopropylacrylamide Gel

AbstractGel dosimeters have unique advantages in comparison with other dosimeters. Until now, these gels have been used in different radiotherapy techniques as a reliable dosimetric tool. Because dose distribution measurement is an important factor for appropriate treatment planning in different radiotherapy techniques, in this study, we evaluated the ability of the N-isopropylacrylamide (NIPAM) polymer gel to record the dose distribution resulting from the mixed neutron-gamma field of boron neutron capture therapy (BNCT). In this regard, a head phantom containing NIPAM gel was irradiated using the Tehran Research Reactor BNCT beam line, and then by a magnetic resonance scanner. Eventually, the R2 maps were obtained in different slices of the phantom by analyzing T2-weighted images. The results show that NIPAM gel has a suitable potential for recording three-dimensional dose distribution in mixed neutron-gamma field dosimetry

Effect of humic acid foliar application on growth and quantity of corn in irrigation withholding at different growth stages

In order to study effect of humic acid foliar application and limited irrigation on growth and quantitative character¬istics of corn an experiment was conducted in research field of Varamin in Iran during 2012 growing season. The experimental design was laid out in a randomized complete block with a split plots arrangement of treatments in three replications. Main plots included three different levels of irrigation (complete irrigation, irrigation withhold¬ing at 8-leaf stage and irrigation withholding at staminate inflorescence) and four different concentration of humic acid foliar application (0, 150,300 and 450 ppm) was allocated to subplots were. The results showed that irrigation withholding conditions in different growth stages significantly decreased plant height, yield components, seed yield, biological yield and harvest index. Humic acid foliar application in irrigation with holding in different growth stages had positive effect on all attributes in this experiment. In general, the results of the present study indicate that usage of humic acid reduces the harmful effects of water deficit stress and increases resistance to drought stress in corn plant

Scram Incidence Statistic Survey in a Research Nuclear Reactor Considering System Hardware And Human Errors

ABSTRACT One of the major events in nuclear reactors is scram or immediate emergency shutdown. Qualitative and quantitative study of this event, as well as the main causative factors in evaluating reactor safety is an important point. In this study, safety of Tehran research reactor is assessed probabilistically and the human error possibility is evaluated using SPAR-H method. In this regard, scram fault tree associated with hardware failures and human errors are drawn by using SAPHIRE software. The calculated total scram possibility is found to be 1.0E-2

The Impact of High-Intensity Interval Training on Vascular Function in Adults: A Systematic Review and Meta-Analysis

Aim: We performed a systematic review and meta-analysis to investigate the effects of high-intensity interval training (HIIT) compared with moderateintensity continuous training (MICT) or with no exercise (CON) on vascular function in adults who were free of cardiometabolic diseases and those with cardiometabolic diseases. Methods: A search across three electronic databases including Scopus, PubMed, and Web of Science was conducted through February 2022 to identify the randomized trials evaluating HIIT vs. MICT and/or CON on vascular function as measured using brachial artery flow-mediated dilation (FMD) in adults. Separate analyses were conducted for HIIT vs. MICT and/or CON to calculate weighted mean differences (WMD) and 95% confidence intervals (95% CIs) using random or fixed models. Results: A total of 36 studies involving 1,437 participants who were either free of cardiometabolic diseases or had cardiometabolic diseases were included in the meta-analysis. HIIT effectively increased FMD when compared with MICT [1.59% (95% CI 0.87–2.31), p = 0.001] or CON [3.80% (95% CI 2.58–5.01), p = 0.001]. Subgroup analysis showed that HIIT increased FMD in participants with cardiovascular and metabolic diseases, but not in participants who were free of cardiometabolic diseases. In addition, HIIT effectively increased FMD regardless of age and body mass index. Conclusion: We confirm that HIIT is effective for improving vascular function in individuals with metabolic disorders and cardiovascular diseases and has a superior effect compared to MICT, demonstrating time efficiency. Systematic review registration: [https://www.crd.york.ac.uk/prospero], identifier [CRD42022320863]

A Review of Manufacturing Process of Polyethylene Pipe and Connectors for Applying in High-Pressure Natural Gas Pipelines

In this article various pipes used for transporting of gas are introduced and pros and cons of each one are elucidated. The pipes are categorized in three different subgroups including metallic, polymeric and metallic-wire reinforced polymeric pipes. Metallic-wire reinforced polymeric pipes are nominated as the best option for usage in high pressure pipelines transporting natural gas. As a result, some information about major manufacturers of this kind of polymeric pipes, raw material, production process and metallic-wire orientation are presented. Finally, from economical point of view, some calculations are done to estimate required amount of polymer and metallic-wire to manufacture such pipes. It is also possible to compare their manufacturing cost with usual metallic and polymeric pipes

Interleukin-15 responses to acute and chronic exercise in adults: a systematic review and meta-analysis

PurposeInterlukin-15 (IL-15) is an inflammatory cytokine that plays a vital role in immunology and obesity-associated metabolic syndrome. We performed this systematic review and meta-analysis to investigate whether exercise promotes circulating IL-15 concentrations in adults.MethodsWe searched PubMed, Web of Science, and Scopus from inception to May, 2023 and identified original studies that investigated the effectiveness of acute and/or chronic exercise on serum/plasma IL-15 levels in adults. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated using random effect models. Subgroup analyses were performed based on type of exercise, and training status, health status and body mass indexes (BMI) of participants.ResultsFifteen studies involving 411 participants and 12 studies involving 899 participants were included in the acute and chronic exercise analyses, respectively. Our findings showed that acute exercise increased circulating IL-15 concentrations immediately after exercise compared with baseline [SMD=0.90 (95% CI: 0.47 to 1.32), p=0.001], regardless of exercise type and participants’ training status. Similarly, acute exercise was also associated with increased IL-15 concentrations even one-hour after exercise [SMD=0.50 (95% CI: 0.00 to 0.99), p=0.04]. Nevertheless, chronic exercise did not have a significant effect on IL-15 concentrations [SMD=0.40 (95% CI: -0.08 to 0.88), p=0.10].ConclusionOur results confirm that acute exercise is effective in increasing the IL-15 concentrations immediately and one-hour after exercise intervention, and thereby playing a potential role in improving metabolism in adults.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=445634, identifier CRD42023445634

The three dimensional map of dose components in a head phantom for boron neutron capture therapy

The in-phantom measurement of physical dose distribution and construction of a convenient phantom is very important for boron neutron capture therapy planning validation. In this study we have simulated a head phantom, suggested for construction in boron neutron capture therapy facilities, and calculated all relevant dose components inside of it using the Monte Carlo code MCNPX. A “generic” epithermal neutron beam with a broad neutron spectrum, similar to beams used for neutron capture therapy clinical trials, was used. The calculated distributions of all relevant dose components in brain tissue equivalent were compared with those in water. The results show that water is a suitable dosimetry material and that the simulated head phantom is a suitable design for producing accurate three-dimensional maps of dose components at enough points inside of the phantom for boron neutron capture therapy dosimetry measurements and the use of these dose maps in beam development and benchmarking of computer-based treatment codes

Development of An Embedded FPGA-Based Data Acquisition System Dedicated to Zero Power Reactor Noise Experiments

An embedded time interval data acquisition system (DAS) is developed for zero power reactor (ZPR) noise experiments. The system is capable of measuring the correlation or probability distribution of a random process. The design is totally implemented on a single Field Programmable Gate Array (FPGA). The architecture is tested on different FPGA platforms with different speed grades and hardware resources. Generic experimental values for time resolution and inter-event dead time of the system are 2.22 ns and 6.67 ns respectively. The DAS can record around 48-bit x 790 kS/s utilizing its built-in fast memory. The system can measure very long time intervals due to its 48-bit timing structure design. As the architecture can work on a typical FPGA, this is a low cost experimental tool and needs little time to be established. In addition, revisions are easily possible through its reprogramming capability. The performance of the system is checked and verified experimentally

A pragmatic approach towards designing a second shutdown system for Tehran research reactor

One second shutdown system is proposed for the Tehran Research Reactor to achieve the goal of higher safety in compliance with current operational requirements and regulations and improve the overall reliability of the reactor shutdown system. The proposed second shutdown system is a diverse, independent shutdown system compared to the existing rod based one that intends to achieve and maintain sub-criticality condition with an enough shutdown margin in many of abnormal situations. It is designed as much as practical based on neutron absorber solution injection into the existing core while the changes and interferences with the existing core structure are kept to a minimum. Core neutronic calculations were performed using MCNPX 2.6.0 and MTR_PC package for the current operational core equipped with the second shutdown system, and one experiment was conducted in the Tehran Research Reactor to test the neutronic calculations. A good agreement was seen between theoretical results and experimental ones. In addition, capability of the second shutdown system in the case of occurrence of design basis accident in the Tehran Research Reactor is demonstrated using PARET program