272 research outputs found
A study of professional radiation hazards in CT scan and nuclear medicine workers using GTG-banding and solid stain
Background: CT scan and nuclear medicine exams deliver a great part of medical exposures. This study examined professional radiation hazards in CT scan and nuclear medicine workers. Methods: In a cross sectional study 30 occupationally exposed workers and 7 controls (all from personnel of a laboratory) were selected. Physical dosimetry was performed for exposed workers. Blood samples were obtained from the experimental and control groups. Three culture mediums for each one were prepared in due to routine chromosome analysis using G-banding and solid stain. Results: There were significant increased incidence of chromatid gap (ctg) and chromatid break (ctb) with mean±SD frequencies of 3±0.84 and 3.1±1.40 per 100 cells respectively in the nuclear medicine workers versus controls with mean±SD frequencies of 1.9±0.69 and 1.3±0.84 for ctg and ctb, respectively. Chromosome gaps (chrg) were higher significantly in the nuclear medicine population (2.47±0.91) than in controls (1.4±0.9) (p< 0.05). In CT scan group the ctg and ctb were increased with a mean±SD frequency of 2.7±0.79 and 2.6±0.91 per 100 cells respectively compared with control group. The mean±SD frequencies of the chrb were 2.0±0.75 and 0.86±0.690 per 100 cells for exposed workers and control group, respectively. Conclusion: This study showed chromosome aberrations in peripheral lymphocytes using solid stain method are reasonable biomarker reflecting personnel radiation damage
Investigating the Underlying Psychiatric Disorders Leading to Suicide among Patients Hospitalized in Poisoning Center in Emam Reza Educational, Research and Treatment Center in Mashhad, 2015
Background: One of the most common causes of mortality in countries are drug induced suicide, the identification of underlying risk factors of which can play an important role in reducing its incidence as well as providing practical solutions.Methods: All poisoned patients referred to poisoning treatment center in Imam Reza hospital (MUMS) were studied in a descriptive cross-sectional study in 2015 and based on selection criteria and using a researcher- developed questionnaire. Moreover, results were analyzed using SPSS21 and Exactly Fisher test.Results: Among a total of 824 patients half of whom were men and the other half were women and with an average age of 27 years for men and 20 years for women, the most common underlying psychological factors in patients were holding under diploma, diploma, and above, impaired communication skills, depression, and Type B personality. Moreover, the most important types of impaired communication skills were poor stress and problem-solving management. Also, the drug-stimulant use was somehow associated with the same impaired inter-personal communications.Conclusion: Before providing the necessary and sufficient training to children who inevitably need time, chronological age, bitter and sweet experiences in their lives, it is essential to avoid entrusting heavy responsibilities on them
On the inter-area optimal voltage and reactive power control
Scheduling voltage and reactive power is one of the major problems and concerns of the Transmission System Operators (TSOs) especially after deregulation of power market. Due to locally provision of the reactive power resources, each TSO has developed its own specific method. Hence, the voltage and reactive power coordination in the interconnected system has got less attention. In this respect, current practices of different TSOs in Europe and North America, as examples of interconnected power systems, are investigated in this paper. Afterwards, it focuses on the inter-area optimization of the voltage and reactive power. Instead of performing the studies around one particular optimization, different aspects of the mathematical formulation of the optimization problem in the interconnected power system, including objective function, constraints and appropriate modeling of neighboring areas, are revisited more in depth. Various possible implementations of coordinated approaches, including centralized and decentralized structures, as well as non-coordinated approach in collaborative and non-collaborative environments are studied. In this respect, new contributions are proposed in this paper by using the distributed slack bus model and the limitation of the voltage and reactive power in the interconnections links. The comparative analysis between the available and proposed methods are discussed in terms of sub-optimality and time to convergence. The discussions are based on New England 39 bus system and the presented results in the literatures
Maximum Voltage Stability Margin Problem With Complementarity Constraints for Multi-Area Power Systems
This paper studies the multi-area voltage and reactive power management regarding the voltage stability. In this respect, the maximization of effective reactive power reserve is proposed using centralized and decentralized implementations. The proposed formulations benefit from the detailed modeling of generators reactive power limits as well as the distributed slack bus model for the compensation of active power imbalances. In addition, the generator switch between the constant terminal voltage and the constant reactive power output is modeled by the complementarity constraints. The simulation results demonstrate that the well-known decentralized implementation does not converge whenever there are PV generators at border buses. It is illustrated that this problem occurs when the complementarity constraints are considered. Appropriate modifications are proposed for the formulation of the decentralized optimization in order to consider the effect of the complementarity constraints at border buses. The effectiveness of the proposed formulation to handle such optimization problems is evaluated using the New England 39-bus system with three areas
Optical coherence tomography angiography in intermediate uveitis-related cystoid macular edema
Background: Cystoid macular edema (CME) is the leading cause of permanent visual impairment in patients with uveitis, particularly in patients with intermediate uveitis (IU). This study was aimed at comparing the changes in the macular microvasculature in patients with IU with uveitic non-responsive CME and without macular edema.
Methods: In this case-control study, 55 eyes of patients with IU were assessed for macular microvascular structures, including vascular density, foveal avascular zone (FAZ) measurement, and vascular morphological changes, using spectral-domain optical coherence tomography angiography (OCT-A) with the AngioVue OCT-A system. We divided patients into the following two groups: the case group, including 30 eyes with IU-related non-responsive CME, and the control group, including 25 eyes with IU without macular edema.
Results: Participants in the case and control groups had comparable age (P = 0.753) and sex (P = 0.124) distributions. Superficial capillary plexus vessel density in the case group was significantly decreased in the whole image (P = 0.027) and the parafoveal area (P = 0.001) compared to the control group. However, there were no statistically significant differences between the two groups in terms of foveal superficial vessel density, deep capillary plexus vessel density, FAZ area, FAZ perimeter, FAZ acircularity index, or foveal vessel density in a 300-µm-wide annulus around the FAZ (all P > 0.05). Vascular morphological changes, such as the capillary tuft, telangiectatic vessels, or micro-aneurism, were not different in the overview images of the OCT-A printout between the two groups.
Conclusions: The mean superficial capillary plexus vessel density was lower in eyes with IU-related nonresponsive CME than in those without macular edema. We observed more cystoid spaces in SCP than in DCP. Microcystic changes in the inner retina and ischemia may be the underlying cause in eyes with nonresponsive CME. Future prospective longitudinal studies with healthy, matched controls are warranted to confirm our findings
The Inter-Structural Relationships between Early Maladaptive Schemas and Marital Commitment of Couples: The Mediating Role of Communication Patterns
Background: Marital commitment has been identified as one of the effective components in the development and stability of marital relationships. This study aimed to investigate the inter-structural relationships between early maladaptive schemas and marital commitment mediated by communication patterns in couples.
Methods: This correlational study was performed on married students of Mashhad Islamic Azad University with more than 3 years of marital life in 2019-2020. 300 people participated according to the research statistical method based on hidden variables. Data were collected using Adams and Jones Marital Commitment Questionnaire (1997), Young Early Maladaptive Schema Questionnaire (1998), and Christensen and Sullaway Communication Patterns Questionnaire (1984). Data analysis was performed by the structural equation method.
Results: The results of path coefficients revealed that the direct effect of early maladaptive schemas on communication patterns is positive and significant (P≤0.01, g=0.71) and its effect on marital commitment is negative and significant (Pvalue≤0.01, g=-0.45). Also, the direct effect of communication patterns on marital commitment is significant and negative (Pvalue≤0.01, ß=-0.41). Examining of standardized coefficients of indirect effects showed that the indirect effect of early maladaptive schemas on marital commitment is significant with the mediating role of communication patterns (Pvalue<0.01, IF=-0.51). The explained variance of marital commitment in terms of early maladaptive schemas and communication patterns was equal to 0.59.
Conclusions: According to the results, communication patterns act as a mediating variable in the relationship between early maladaptive schemas and marital commitment. Furthermore, two variables of communication patterns and early maladaptive schemas can predict marital commitment.
Keywords: Commitment, Early maladaptive schema, Communication, Marita
Discussion on uncertainty management in power systems
This discussion is deliberated regarding the presentations of the session on 'managing uncertainty in power systems' in 9th IREP Symposium 2013. © 2013 IEEE
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