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Photon-photon coincidence counting is a primary standardization technique used for the absolute activity measurement of short half-life radionuclides. In this study, a coincidence spectrometer based on digital signal processing was developed for the absolute standardization of 125I seed Brachytherapy. The spectrometer includes a waveform digitizer that samples at the preamplifier signals directly from two similar 2ʺ × 2ʺ NaI (Tl) detectors. The sampled signals were shaped into trapezoidal signals for pulse height analysis. These detected signals were then recorded in a list file and the software was used to recognize coincidence events. Detailed discussions were included on the formulas for determining absolute activity measurement. The activity of a 125I seed was measured and showed good agreement with the reference values. This presented technique is a quick method for measuring the activity of 125I at nuclear hospitals. The standardized source can also serve as a tracer for measuring the activity of the 109Cd source

Due to the low cross-section to perform the reaction, muons are the earth's most common detectable cosmic rays. Like the other particles produced by the collision of energetic particles, muons are unstable and have a lifetime distribution spectrum. This paper measures the energy and lifetime of the muon cosmic radiation using a digital spectroscopy system. In the presented method, all the nuclear electronics modules are omitted, and the process of forming the signals is recorded in the software. To perform this measurement, radiation events were detected in coincidence mode using two NaI (Tl) detectors installed at the angle of 90° concerning the horizon line. The signals recorded in the pre-amplifier of the two detectors were sampled directly using a waveform digitizer and, after recording, stored as the list mode data. By programming on the data list, about 105 muon events were detected over two weeks. Their lifetime is extracted by measuring the time interval between events detected as muon radiation. By fitting the exponential function to the experimental data, the muon lifetime is determined to be 2.03 µs. The results show that this study's obtained lifetime for muon is consistent with the other experimental data. The transition from analog to digital nuclear electronics in muon radiation spectroscopy provides simplicity, high reliability, small size, light weight of the acquisition system, and the possibility to be installed on the research satellites.

Introduction: Workplaces often contain potential risks, such as exposure to toxic chemicals. Conducting a thorough health risk assessment helps employers recognize these dangers and implement necessary controls. In the 20th century, modern risk assessment frameworks began to be established with the rise of public health agencies. Material and Methods: The present study is a narrative review. In order to obtain necessary information, Persian and English texts were searched in Web of Science, PubMed, Scopus, SID and Magiran databases. Keywords such as “health risk assessment”, “chemicals” and “nanomaterials” were used in this study. Results: Both quantitative and qualitative health risk assessments play critical roles in occupational health, with each method providing different levels of depth and accuracy depending on the situation. EPA Model, Monte-Carlo Simulation, Physiologically Based Pharmacokinetic (PBPK) Modeling, Quantitative Structure-Activity Relationship (QSAR) Models, Probabilistic Risk Assessment (PRA), Life Cycle Impact Assessment (LCIA), and Biologically Based Dose-Response (BBDR) Models, are among the most important quantitative methods for assessing the health risk of chemicals. COSHH Model, ICCT Model, ICMM Model, Australian Model, and Romanian Model, are the most important qualitative methods for health risk assessment of chemicals. In addition to the quantitative and qualitative methods, semi-quantitative methods like Singapore Model, LEC Method, and SEP Model, have also been proposed for assessing the health risk of chemicals. The preference for qualitative over quantitative methods in the risk assessment of activities involving nanomaterials stems from substantial uncertainties, limited data availability, and the unique and complex behaviors of nanomaterials in the workplaces. Conclusion: Overall, the evolution of health risk assessment methods reflects a continuous drive towards greater accuracy, reliability, and relevance. As we continue to innovate and expand our knowledge, the field is well-positioned to address the complex and evolving landscape of chemical and material risks, ensuring the protection of human health and the environment.

Abstract Aim This study aimed to investigate the effect of circadian rhythm stability and amplitude on musculoskeletal disorder prevalence and work–family conflict among nurses. Design This cross‐sectional study was conducted on 386 nurses working in three hospitals, in Shahroud, Iran. Method The data were collected using the Circadian Rhythm Inventory, Nordic Musculoskeletal Disorders, and Carlson Work‐Family Conflict questionnaires. Results The highest prevalence of musculoskeletal disorders was reported in the lower back (68.4%), upper back (65.5%) and shoulders (53.6%), respectively. No significant relation was found between circadian rhythm stability and amplitude, and musculoskeletal disorders prevalence. The nurses who could not overcome drowsiness reported more Work Interference with Family (WIF), Family Interference with Work (FIW) (time‐based) and FIW (strain‐based) compared to the nurses who overcame drowsiness. In addition, the appropriate nurses for shift work experienced less WIF, FIW (behavioural‐based) and WIF (strain‐based) compared to the nurses who could not work overtime or at night.

Treatment of cancer patients requires high-sensitivity diagnostic techniques. Recently, the Society of Positron Annihilation Spectroscopy (PAS) has been working on hypoxia detection using positron lifetime and hopes to diagnose cancer at its initial phases. The accepted hypothesis for the use of positron as a biomarker of tumor hypoxia is that due to the distance between the blood vessels and the cancerous tissues, the oxygen concentration strongly decreases in cancerous tissues. The point that can put the PAS technique in the category of cancer diagnosis tools is its potential capability for oxygen-sensing in tissues. So, the partial pressure of oxygen in the patients tissues can be measured from the Positron Annihilation Lifetime Spectroscopy (PALS). However, before the positron lifetime imaging technique can be established, it is essential to verify the oxygen-sensing capability of the PALS in various chemical environments. In this paper, the mechanisms of positron annihilation in the deionized water and air-bubbled water samples were investigated via systematic experiments by our homemade Doppler Broadening Spectroscopy (DBS) and PALS spectrometer. Three mechanisms for positron annihilation in the investigated liquid samples including oxidation, Positronium conversion, and Positronium inhibition were described. The outcome of this investigation could advance the development of the PALS method for detecting tumors before metastasis, using the J-PET machine, which is still under development at Jagiellonian University. [ABSTRACT FROM AUTHOR]

Recently, malignant neoplasms have growingly caused human morbidity and mortality. Head and neck cancer (HNC) constitutes a substantial group of malignancies occurring in various anatomical regions of the head and neck, including lips, mouth, throat, larynx, nose, sinuses, oropharynx, hypopharynx, nasopharynx, and salivary glands. The present study addresses the phosphoinositide 3‐kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway as a possible therapeutic target in cancer therapy. Finding new multitargeting agents capable of modulating PI3K/Akt/mTOR and cross‐linked mediators could be viewed as an effective strategy in combating HNC. Recent studies have introduced phytochemicals as multitargeting agents and rich sources for finding and developing new therapeutic agents. Phytochemicals have exhibited immense anticancer effects, including targeting different stages of HNC through the modulation of several signaling pathways. Moreover, phenolic/polyphenolic compounds, alkaloids, terpenes/terpenoids, and other secondary metabolites have demonstrated promising anticancer activities because of their diverse pharmacological and biological properties like antiproliferative, antineoplastic, antioxidant, and anti‐inflammatory activities. The current review is mainly focused on new therapeutic strategies for HNC passing through the PI3K/Akt/mTOR pathway as new strategies in combating HNC. [ABSTRACT FROM AUTHOR]

Introduction: Nowadays, health, safety, and environment (HSE) management system is employed and implemented comprehensively in order to reduce accidents, create a safe environment and increase workers' productivity in workplaces. The aim of this study was to determine the condition of HSE at Shahroud University of Medical Sciences. Methods: This cross-sectional study evaluated the status of HSE at office environment from the perspective of 81 staffs and occupational hygienist .Data collection tools consisted of a self-made checklist adapted from the provided checklists by the authoritative organizations. Data were analyzed using SPSS16 statistical software through descriptive statistics and statistical tests including Pearson correlation and independent T-test. Results: HSE components' average from users and interviewers' perspectives were 0.51±0.15 and 0.6 ±0.15, respectively. Safety had the worst situation form participants' perspective with average 0.499±0.02 and 0.489±0.02, respectively. However, the best situation was attributed to the physical agents section with an average of 0.69±0.028 and 0.72±0.025, respectively. There was a significant relationship between users and interviewers' perspectives regarding Ergonomic and Physical agents. Conclusion: By taking into account the facts that HSE average score was low and the study was conducted in the one of the administrative units of universities affiliated to the Ministry of Health, which itself is part of the HSE trustee, further attention is required to the implement and establish the HSE management system

Measuring hydrogen concentration and determining its depth profile in different substrates has always been a major challenge for material science. Proton–proton scattering is a nondestructive technique for hydrogen analysis in thin samples. In this paper, the development of a 2D coincidence proton–proton spectroscopy was performed using a 3 MeV Van de Graaff accelerator. In the presented technique, the coincidence recording of the proton–proton scattering events by a waveform digitizer provides the sum‐difference energy spectrum of the correlated events. By determining the proton energy loss in the sample, the hydrogen depth profile was extracted. To correct the error in the counting efficiency due to the multiple scattering, the Monte Carlo simulation was performed using the Corteo code. The performance of the technique was tested by measuring the concentration of hydrogen on both sides of a thin layer of aluminum. The results confirmed that the established technique is sensitive enough to separate the hydrogen peaks of these two thin layers. [ABSTRACT FROM AUTHOR]

Primary standardization of radioactivity is related to the direct measurement of activity in radioactive decay. A large variety of primary standardization techniques have been developed in the past years. The photon-photon coincidence counting is one of the methods for activity determination. This method is particularly applied for the standardization of I-125 using the detection of X-ray and gamma-ray coincident counting. In this paper, a 2D photon-photon coincidence digital system with two similar 2n × 2n NaI(Tl) detectors for absolute activity measurement is developed. The system is established based on a 100 MHz CAEN waveform digitizer (DT5724) which directly records the pre-amplifier output signals of the two NaI(Tl) detectors. The sampled signals was transformed to trapezoidal signals using pulse height analyzer firmware and coincidence events were recorded in a list file. The list file was analyzed offline using a Matlab code to realize correlated gama lines of Co-60 source. The Volkovitsky formulas were used for the activity calculation and the details of the experimental setup were also discussed. Standardization of the two Co-60 standard sources was performed using this system. Results are in good agreement with the reference activity of Co-60 sources. The presented formula can be modified for absolute calibration of the other medical radioisotopes. The technique can be generalized for absolute activity measurement of I-125 which uses for ophthalmic plaque radiation therapy. [ABSTRACT FROM AUTHOR]

Compton scattering events are the main source of error on the peak counting during the Neutron Activation Analysis (NAA). The Compton suppressor system in instrumental NAA reduces the detection limit of the technique and leads to a data with a higher degree of precision. In this paper, a two-dimensional coincidence Compton suppressor system is presented for the NAA technique. The system is established based on a CAEN digitizer which directly records the pre-amplifier output signals of the two HPGe detectors. The recorded events in the list mode file are analyzed offline by a Matlab code and the correlated photopeak events are realized. The performance of the system for Compton suppression is tested by measuring the gamma lines of Ba-133 and Cs-137 standard sources. The results show that the presented technique provides the peak to Compton ratio up to 104 and can be an alternative for conventional Compton suppressor systems. [ABSTRACT FROM AUTHOR]

A two-dimensional coincidence technique is carried out to suppress the background for exploring the contribution of positron annihilation with core electrons. The spectrometer is composed of two face-to-face HPGe detectors. To test the performance of the system, the Coincidence Doppler Broadening (CDB) ratio curve of pure well-annealed Copper is investigated. The quality of the annealing process is measured using Positron Annihilation Lifetime Spectroscopy (PALS). For comparison of the ratio curve of different laboratories, an Aluminum sample is considered as a reference due to its simple electronic structure. The element-specific CDBS signature of Copper shows the two peaks around 12.8 × 10-3 m0c and 19 × 10-3 m0c at the ratio curve which is dependent on the momentum of Fermi electrons. The presented ratio curve is compared with the reference measurement and simulation. Differences and the similarities in the reported ratio curves are discussed. The comparison shows that our result is more compatible with the theoretical calculations and can be considered as a new reference for future studies on the chemical environment of defects in alloys that include copper in their contents. [ABSTRACT FROM AUTHOR]

The potential biomedical application of Positron Annihilation Spectroscopy (PAS) for nonstructural characterization of normal and cancer cells was not thoroughly employed and researched. In this paper, the experimental investigation of the oxygen sensing ability of the PAS technique for tumor imaging is presented and discussed. This research is based on the validated hypothesis that tumor cells differ from the normal tissues in their value of oxygen concentrations. The components of Doppler Broadening and positron annihilation lifetime spectra are measured with our homemade spectrometer to determine the mechanism behind the positron annihilation in oxygen content tissue-equivalent samples. The analysis of PAS data shows that the Orbital Momentum Spectrum (OEMS) of the Coincidence Doppler Broadening Spectroscopy (CDBS) and the positronium lifetime components of Positron Annihilation Lifetime Spectroscopy (PALS) are sensitive to the presence of oxygen. The results are applicable in the development of a tumor imaging system based on the PAS technique. [ABSTRACT FROM AUTHOR]

Objectives. Occupational stress and workload are common risk factors among nurses that increase absenteeism, reduce the quality and quantity of patient care, increase care costs and increase the patient safety risk. The relation between these risk factors and oxidative stress levels has not been clearly defined. Methods. This study was conducted with 258 participants (126 nurses as the case group and 132 healthy adults as the control group). Information was collected using a demographic questionnaire, the nurses' occupational stress scale and the NASA task load index workload questionnaire. Blood samples were taken from the participants and then the levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase and total antioxidant capacity (TAC) were measured in the serum samples. Independent t tests and one-way analysis of variance were used for statistical analysis. Results. SOD and TAC were significantly higher and MDA was significantly lower among the case group compared to the control group. TAC levels significantly decreased with increased stress. MDA levels showed negative associations with stress and workload. Nurses experience high levels of occupational stress and workload. Conclusion. Biomarkers such as SOD, TAC and MDA are the most important predictors of work stress and overwork in this study. [ABSTRACT FROM AUTHOR]