531 research outputs found
The effect of resveratrol on the expression of MDR1 gene in leukemic lymphoblast's of acute lymphoblastic leukemia patients
Background: Chemotherapy plays a very important role in the treatment of leukemia but the resistance properties of the lymphoblasts limit the effect of chemotherapy. One of the main mechanisms of resistance to chemotherapy is the increased expression of MDR1 gene. The aim of this study was to explore the effect of resveratrol on the expression of MDR1 gene in leukemic lymphoblast of new cases of acute lymphoblastic leukemia (ALL) patients in vitro. Methods: Separation of lymphoblasts of 5 new case ALL patients from peripheral blood was performed by ficoll density gradient centrifugation. Lymphoblasts were cultured in RPMI 1640 medium. Lymphoblasts were treated with 50μmol/L resveratrol for 48 h. Total RNA was extracted with guanidine isothiocyanate. RNA was converted to cDNA. Real time PCR was used to detect mRNA expression of MDR1. Results: The results of gene detection showed that the expression of MDR1 did not change significantly in the patients however, in one patient expression of MDR1 increased upon treatment with resveratrol. Conclusion: The results of this study did not support resveratrol as a compound to reverse multidrug resistance in leukemic lymphoblasts
A phenomenological study of the process of ICT-competence of Iranian teachers with the purpose of presenting a native model
Background and Objectives: Research findings about the application of information and communication technologies in classroom has shown that despite the efforts had been done and the large amount of costs spent for empowering teachers' computer skills, but these activities have not been able to create desired changes in the role and activity of teachers in schools. Therefore, the purpose of the present study was to study the phenomenological process of Iranian teachers' ICT competence in order to present a native model. Methods: This was a qualitative phenomenological research, because the lived experiences of teachers in achieving technological competence in the classroom have been used to explore the objectives of the study. The statistical population of this qualitative study were all teachers in Urmia city. 22 teachers (13 females and 9 males) were selected by non-probability purposeful sampling method with considering the desired characteristics and theoretical saturation based-rule. Participants who engaged in 17 different schools including public, board of trustees, smart, nonprofit, and rural schools, were selected. The data collection tool was semi-structured interview. Voice recording and note-taking (with emphasis on voice recording), as Two techniques for gathering data, were used. George's (1970) four-step coding approach were used to analyze the data. The coding process was performed in MAXQDA10 software. Findings:The findings of the qualitative analysis indicated that the process of teachers ICT-competence can be organized into five components, including; 1) motivation/ tendency/ interest in teachers including the following sub-components: “Changing in teacher’s salary”, “Changing teachers’ position”, “Create need”, “Classification of teachers based on the prior knowledge”, “Pay attention to the timing of the courses” , “Changing the look to the teaching profession” and “Choosing the right professor”; 2) planning, including the following sub-components: “Teachers Rating (Needs Assessment)” , “Determining curriculum (educational topics)”, “Choosing the right professor”, “Locate the right place” and “Determine the right time”; 3) beginning of the learning process including the following components: “Hardware training”, “Software training”, “Problem-solving training”, “Information literacy training”, “Facilitate access to educational resources” and “Support”; 4) implementation of the learning process including the following sub-components: “In-service preparation courses”, “In-service training courses”, “Specialized school courses”, and “Out-of-school courses” and 5) " institutionalization of technology competence " including the following sub-components: “Problem-solving training’, “Formalize collaboration between teachers” and ‘Formalize follow-up courses for teaching and learning”. Conclusion: This model is presented by looking at the needs of teachers, the conditions and Organizational structure of education, the facilities of schools, the status of courses, the cooperation between teachers, and so on. In this model, all the influential factors in the process of acquiring information and technology competence by teachers have been included and based on the content of the interviews, each of them has been considered in the relevant step. Although it could be organized these components or steps in hierarchical or step-by-step structure, but in many places it is possible to go back and start from the previous step. It is hoped that this model will be a step towards developing an appropriate model in the field of staff technology competence for the Education Organization and other organizations.
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Positive emotion regulation strategies as mediators in depression and generalized anxiety disorder symptoms: A Transdiagnostic framework investigation
Positive emotion regulation (ER) strategies may contribute to the development and maintenance of generalized anxiety disorder (GAD) and depression; nonetheless, the underlying and transdiagnostic mechanisms are still unknown. To examine: 1) the mediating role of positive ER strategies in the relationship between ER deficits and experiential avoidance in GAD and depression symptoms; 2) differences in positive ER strategies among participants with elevated symptoms of GAD, depression, depression comorbid with GAD, and a nonclinical sample. 532 Tehran University students completed questionnaires assessing experiential avoidance, deficits in ER, positive ER strategies (dampening, positive rumination), and GAD and depression symptoms. Differences were assessed in four groups: GAD, depression, depression comorbid with GAD, and nonclinical. Data were analysed with path analysis and MANCOVA. Dampening and positive rumination mediated the relationship between deficits in ER and experiential avoidance in participants with depression and GAD symptoms. As for the between groups comparisons, the comorbid group obtained the highest scores on dampening and the nonclinical group the lowest. By contrast, nonclinical participants had the highest scores on positive rumination, whereas the comorbid group had the lowest. Positive ER strategies might be transdiagnostic variables. Dampening was more associated with psychopathology than positive rumination, suggesting that this strategy could be more clearly considered a transdiagnostic factor. Future studies with clinical samples must support this suggestion
Comparison of some biological aspects of Empoasca decipiens (Hom.: Cicadellidae) on four bean species
Some biological aspects of Emposaca decipiens Paoli were investigated on different bean species (Phaseolus vulgaris L., P. lunatus L., P. calcaratus Roxb. and Vigna sinensis L.) under field and laboratory conditions (26 ± 1ºC, RH: 70 ± 5% and a photoperiod of 16L: 8D h.). The species of the host plant had no significant effect on incubation period, but the nymphal instars, development time, adult longevity and life span were affected by host plant species significantly. The shortest and longest development time in the field condition were occurred on V. sinensis (22.58 ± 0.50) and P. calcaratus (27.17 ± 0.67), respectively. But in laboratory conditions these parameters were observed on V. sinensis (20.71 ± 0.57) and P. vulgaris (29.29 ± 1.00), respectively. Adult longevity on V. sinensis had the longest duration. In contrast, the shortest adult longevity was observed on P. vulgaris. Surface of the leaves inV. sinensis is smooth and without trichomes, but presence of the hoocked trichomes on three other host plants especially in P. vulgaris assumed as the most important reason of their unsuitability for the leafhopper
Real-Time Measurements of Photonic Microchips with Femtometer-Scale Spectral Precision and Ultra-High Sensitivity
Photonic integrated circuits (PICs) are enabling major breakthroughs in a
number of areas, including quantum computing, neuromorphic processors, wearable
devices, and more. Nevertheless, existing PIC measurement methods lack the
spectral precision, speed, and sensitivity required for refining current
applications and exploring new frontiers such as point-of-care or wearable
biosensors. Here, we present the Sweeping Optical Frequency Mixing Method
(SOHO), surpassing traditional PIC measurement methods with real-time
operation, 30 dB higher sensitivity, and over 100 times better spectral
resolution. Leveraging the frequency mixing process with a sweeping laser and
custom control software, SOHO excels in simplicity, eliminating the need for
advanced optical components and additional calibration procedures. We showcase
its superior performance on ultrahigh-quality factor (Q) fiber-loop resonators
(Q = 46M) as well as microresonators realized on a new optical waveguide
platform. An experimental spectral resolution of 19.1 femtometers is
demonstrated using an 85-meter-long unbalanced fiber Mach Zehnder
Interferometer, constrained by noise resulting from the extended fiber length,
while the theoretical resolution is calculated to be 6.2 femtometers, limited
by the linewidth of the reference laser. With its excellent performance
metrics, SOHO has the potential to become a vital measurement tool in
photonics, excelling in high-speed and high-resolution measurements of weak
optical signals
Fire resistance of a damaged building employing buckling restrained braced system
This study investigates the influence of buckling restrained brace systems (BRBs) on the overall structural stability against fire following a severe incident, which caused the failure of a column on the first storey of a steel building. A four-storey moment frame fitted with the inverted-V arrangement of braces is modelled, considering a multi-hazard approach. This technique concentrates on a structural plane frame that is designed to meet the progressive collapse criteria according to the U.S. Department of Defense guidelines and assumes that an extreme event damaged a first-storey centre column, before the exposure to an ensuing fire. The performance of BRBs in preventing the global collapse of the structure due to a post-event fire is compared with that of ordinary concentric brace systems (OCBs). The results indicate that BRBs offer a higher global collapse time to the building owing to the greater stiffness they provide to the structural frame. The fire resistance provided by BRBs is restricted to the participation of bracing elements and framing girders afterwards. In the case of OCBs, columns contribute to the structural resistance prior to the full capacity of braces used. To conclude, it is found that BRBs are more capable in maintaining the stability of a damaged building against fire resulting from an extreme event than OCBs. © 2018, Hong Kong Institute of Steel Construction
Survival analysis in gastric cancer: A multi-center study among Iranian patients
Background: Gastric cancer (GC) has been considered as the 5th most common type of cancer and the third leading cause of cancer-associated death worldwide. The aim of this historical cohort study was to evaluate the survival predictors for all patients with GC using the Cox proportional hazards, extended Cox, and gamma-frailty models. Methods: This historical cohort study was performed according to documents of 1695 individuals having GC referred to three medical centers in Iran from 2001 to 2018. First, most significant prognostic risk factors on survival were selected, Cox proportional hazards, extended Cox, gamma-frailty models were applied to evaluate the effects of the risk factors, and then these models were compared with the Akaike information criterion. Results: The age of patients, body mass index (BMI), tumor size, type of treatment and grade of the tumor increased the hazard rate (HR) of GC patients in both the Cox and frailty models (P < 0.05). Also, the size of the tumor and BMI were considered as time-varying variables in the extended Cox model. Moreover, the frailty model showed that there is at least an unknown factor, genetic or environmental factors, in the model that is not measured (P < 0.05). Conclusions: Some prognostic factors, including age, tumor size, the grade of the tumor, type of treatment and BMI, were regarded as indispensable predictors in patients of GC. Frailty model revealed that there are unknown or latent factors, genetic and environmental factors, resulting in the biased estimates of the regression coefficients. © 2020 The Author(s)
Barium effect on germination, plant growth, and antioxidant enzymes in Cucumis sativus L. plants
Barium (Ba) is a nonessential element that can cause several deleterious effects in
most organisms. Elevated Ba concentrations can be toxic for plants and may affect
growth and disturbances in homeostasis. This study aimed to evaluate the Ba stress,
the plant-tolerance limits, and the detoxification strategy adopted by Cucumis sativus
L. The effect of Ba on seed's germination and vegetative development of this species
was evaluated. For germination test, different Ba concentrations were used (0, 200,
500, 1,000, and 2,000 μM). Results showed that germination was stimulated with
500 and 2,000 µM of Ba. The toxicity effect on plant development was studied by
treating the plants with increasing doses of Ba (100, 200, 300, and 500 μM) during
45 days. Shoot and root dry biomass production decreased significantly with elevated
Ba concentrations, although water content enhanced in the roots. The concentration
of Ba, 500 µM, induced high Ba accumulation in shoots and roots (9 times higher
than in the control plants). Moreover, results showed that catalase, guaiacol peroxidase, and ascorbate peroxidase activities were stimulated in the different tissues of
cucumber plants which highlight the occurring of an oxidative damage through Ba
treatments and the involvement of the plant enzymatic antioxidant defense system
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