50 research outputs found

    Temporal Bisection Dynamics

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    Temporal bisection is a behavioral task used to study how we perceive time. However, it is not fully clear how time perception should be interpreted in different variations of this task. Moreover, it is not understood why the results of this task are often different for human and animal subjects. Understanding parameters of this task and making a connection between human and animal experiments may help researchers to understand how time is perceived in the brain and consequently disorders involving time perception. In this thesis, I propose a computational model that A) provides researchers with a framework to study the parameters of the temporal bisection task to design better experiments and B) gives researchers an insight into potential underlying reasons for differences between human and animal time perception in this task. This model mimics subjects\u27 learning and decision processes in making responses about the length of durations. By manipulating these processes, researchers should be able to verify how time perception is changed in different variations of the task. Additionally, this model helps researchers identify differences in learning and decision processes of human and animal subjects in temporal bisection, which could help explain more general differences in their time perception

    Factors Influencing Rural-Urban Migration from Mountainous Areas in Iran: A Case Study in West Esfahan

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    Migration of young people from rural areas reduces the rural development goals and increase social and economic problems in cities. This is an analysis of the causes of rural-urban migration from Esfahan Mountainous areas and guidelines for reducing migration from villages. Data were obtained using mixed methods approach comprising questionnaire surveys and key informant interviews. Study population are residents of 28 villages from Fereidan and Fereidunshahr counties. The population are 6300 people, who have migrated from these two counties. 362 persons were selected Using Cochran formula, as the sample size. Then, analysis was performed using SPSS v. 20 software. The study revealed that poverty, lack of jobs, insufficient educational facilities, education in the city, lack of public transportation systems, unsuitable mountain Road, cold weather , shortage of doctors, hospitals and health facilities are main factors of rural-urban migration from iran Mountainous areas. So It is recommended to eliminate the problems mentioned to reduce the rate of rural-urban migration for the rural residents

    Relationship of Anxiety and Depression in Patients with Chronic Periodontitis

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    Objectives Many researchers have attempted to link the current concepts of anxiety and depression to periodontal disease. This study aimed to compare the level of anxiety and depression in Iranian patients with chronic periodontitis (CP) and periodontally healthy controls.Methods Fifty CP patients and 50 periodontally healthy controls participated in this study according to our eligibility criteria. Periodontal clinical examination was performed using a Williams probe. The clinical attachment loss (CAL), pocket probing depth (PPD) and bleeding on probing (BOP) were recorded for all teeth except for third molars. In order to psychologically assess the individuals, the Beck’s Depression Inventory (BDI) and the Beck’s Anxiety Inventory (BAI) were used. The mean scores of BAI and BDI were compared between the two groups using the Student t-test.Results The mean age of participants was 44.86±8.07 years. The mean score of BDI was 13.58±8.35 in periodontally healthy controls and 25.62±13.01 in CP patients. The mean score of BAI was 9.9±5.65 in the control and 21.02±13.63 in the test group. The Student t-test revealed a significant difference between the two groups in total score of BDI and BAI (P<0.000). A significant correlation was noted between the BDI and age (P=0.027) but BAI had no significant correlation with age (P=0.245).Conclusion According to the results of this study, the level of anxiety and depression in CP patients was higher than that in periodontally healthy controls in our study populatio

    Strategic Environment Analysis Using DEMATEL Method Through Systematic Approach:

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    A combined model for Environmental Analysis (EA) in strategy formulation process is presented in this paper. EA is the critical element in strategic planning. Because of direct effect on quality of results, different quantitative or qualitative approaches have been developed. In this paper, steps of EA using values tools such as System Dynamics, expert panels, DEMATEL method, designed and explained in the integrated model. In first step, all different factors are identified and classified, and then using a questionnaire, related factors are listed. The causal model identifies the main causes and effects. DEMATEL method specifies priorities of each factor. By using the influenced-influencing matrix, key factors will be determined. In all stages, panel of experts plays complementary and approval role. Finally we applied this model in strategic planning processes of an energy research institute in Iran as a case study. Key words: Environmental Analysis; Systems Approach; Causal loop diagram; DEMATEL Method; Expert Panel

    Targeted delivery of silibinin via magnetic niosomal nanoparticles: potential application in treatment of colon cancer cells

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    Introduction: In recent years, various nanoparticles (NPs) have been discovered and synthesized for the targeted therapy of cancer cells. Targeted delivery increases the local concentration of therapeutics and minimizes side effects. Therefore, NPs-mediated targeted drug delivery systems have become a promising approach for the treatment of various cancers. As a result, in the current study, we aimed to design silibinin-loaded magnetic niosomes nanoparticles (MNNPs) and investigate their cytotoxicity property in colorectal cancer cell treatment.Methods: MNPs ferrofluids were prepared and encapsulated into niosomes (NIOs) by the thin film hydration method. Afterward, the morphology, size, and chemical structure of the synthesized MNNPs were evaluated using the TEM, DLS, and FT-IR techniques, respectively.Results and Discussion: The distribution number of MNNPs was obtained at about 50 nm and 70 nm with a surface charge of −19.0 mV by TEM and DLS analysis, respectively. Silibinin loading efficiency in NIOs was about 90%, and the drug release pattern showed a controlled release with a maximum amount of about 49% and 70%, within 4 h in pH = 7.4 and pH = 5.8, respectively. To investigate the cytotoxicity effect, HT-29 cells were treated with the various concentration of the drugs for 24 and 48 h and evaluated by the MTT as well as flow cytometry assays. Obtained results demonstrated promoted cell cytotoxicity of silibinin-loaded MNNPs (5-fold decrease in cell viability) compared to pure silibinin (3-fold decrease in cell viability) while had no significant cytotoxic effect on HEK-293 (normal cell line) cells, and the cellular uptake level of MNNPs by the HT-29 cell line was enhanced compared to the control group. In conclusion, silibinin-loaded MNNPs complex can be considered as an efficient treatment approach for colorectal cancer cells

    Measuring acute effects of subanesthetic ketamine on cerebrovascular hemodynamics in humans using TD-fNIRS

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    Quantifying neural activity in natural conditions (i.e. conditions comparable to the standard clinical patient experience) during the administration of psychedelics may further our scientific understanding of the effects and mechanisms of action. This data may facilitate the discovery of novel biomarkers enabling more personalized treatments and improved patient outcomes. In this single-blind, placebo-controlled study with a non-randomized design, we use time-domain functional near-infrared spectroscopy (TD-fNIRS) to measure acute brain dynamics after intramuscular subanesthetic ketamine (0.75 mg/kg) and placebo (saline) administration in healthy participants (n = 15, 8 females, 7 males, age 32.4 ± 7.5 years) in a clinical setting. We found that the ketamine administration caused an altered state of consciousness and changes in systemic physiology (e.g. increase in pulse rate and electrodermal activity). Furthermore, ketamine led to a brain-wide reduction in the fractional amplitude of low frequency fluctuations, and a decrease in the global brain connectivity of the prefrontal region. Lastly, we provide preliminary evidence that a combination of neural and physiological metrics may serve as predictors of subjective mystical experiences and reductions in depressive symptomatology. Overall, our study demonstrated the successful application of fNIRS neuroimaging to study the physiological effects of the psychoactive substance ketamine in humans, and can be regarded as an important step toward larger scale clinical fNIRS studies that can quantify the impact of psychedelics on the brain in standard clinical settings

    Acute effects of subanesthetic ketamine on cerebrovascular hemodynamics in humans: A TD-fNIRS neuroimaging study

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    Quantifying neural activity in natural conditions (i.e. conditions comparable to the standard clinical patient experience) during the administration of psychedelics may further our scientific understanding of the effects and mechanisms of action. This data may facilitate the discovery of novel biomarkers enabling more personalized treatments and improved patient outcomes. In this single-blind, placebo-controlled study with a non-randomized design, we use time-domain functional near-infrared spectroscopy (TD-fNIRS) to measure acute brain dynamics after intramuscular subanesthetic ketamine (0.75 mg/kg) and placebo (saline) administration in healthy participants (n= 15, 8 females, 7 males, age 32.4 ± 7.5 years) in a clinical setting. We found that the ketamine administration caused an altered state of consciousness and changes in systemic physiology (e.g. increase in pulse rate and electrodermal activity). Furthermore, ketamine led to a brain-wide reduction in the fractional amplitude of low frequency fluctuations (fALFF), and a decrease in the global brain connectivity of the prefrontal region. Lastly, we provide preliminary evidence that a combination of neural and physiological metrics may serve as predictors of subjective mystical experiences and reductions in depressive symptomatology. Overall, our studies demonstrated the successful application of fNIRS neuroimaging to study the physiological effects of the psychoactive substance ketamine and can be regarded as an important step toward larger scale clinical fNIRS studies that can quantify the impact of psychedelics on the brain in standard clinical settings
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