Survey on Relationship between Goal Orientation and Learning Strategies with Academic Stress in University Students

AbstractThis study examine the relationship between goal orientation and learning strategies with academic stress in university students(150 male and 150 female) which were selected among 4 college by cluster sampling method. Goal orientation questionnaire (Button, Mathieu and Zajac, 1996) and learning strategies questionnaire (Pintrich and Degroot, 1990) and academic stress questionnaire (Gadzella, 1991) were used as the research instrument. Finding show that there was a positive meaningful relationship between learning goal orientation with learning strategies (cognitive and met cognitive) and academic stress. Also there was negative meaningful correlation between performance goal orientation and learning strategies (cognitive and Meta cognitive). These finding also reveals that learning strategies (cognitive and Meta cognitive) have negative meaningful correlation with academic stress. Finally findings displays that academic stress is predictable through linear regression of goal orientation component and learning strategies. So totally these variables were explained 9/6 percent of the variance of academic stress

In Vitro Assessment of the Anti-Proliferative and Anti-Viability Effects of Salivary Gland Extracts from Hyalomma ticks (Acari: Ixodidae) on Human Colorectal Cancer Cells

Background: The saliva and salivary glands of ticks possess a wide range of immuno-pharmacologically active mole­cules that effectively modulate the activity of enzymes, antibodies, and amines that have a role in different biological processes. Derived components from saliva and salivary glands of hard ticks Ixodidae have been characterized as poten­tial natural sources for discovering promising anti-cancer drug candidates. Methods: The anti-cancer activity of salivary gland extracts (SGEs) from Hyalomma anatolicum, Hyalomma drome­darii, Hyalomma marginatum, and Hyalomma schulzei was assessed. MTT assays and flow cytometry were done on the HT-29 colorectal cancer cell line to evaluate the anti-viability and proliferative inhibition. Results: Based on the MTT assay results, the SGEs from Hy. dromedarii had the highest and lowest substantial anti-viability effects on the HT-29 cancer cell and human foreskin fibroblast (HFF) normal cell, respectively. The cytometric assessment revealed a significant increase in the apoptosis and necrosis ratio of the HT-29 cancer cells after treatment with Hy. dromedarii SGEs. Conclusion: The results demonstrated that Hy. dromedarii SGEs have significant anti-proliferative, anti-viability, and apoptotic potential. The result of this study suggests that Hy. dromedarii SGEs is an appropriate candidate for further investigations to identify and purify the mechanisms and molecules involved in the anti-cancer activity of the SGEs

A new O(m + kn log d) algorithm to Find the k shortest paths in acyclic digraphs

We give an algorithm, called T*, for finding the k shortest simplepaths connecting a certain pair of nodes, s and t, in a acyclic digraph.First the nodes of the graph are labeled according to the topologicalordering. Then for node i an ordered list of simple s − i paths iscreated. The length of the list is at most k and it is created by usingtournament trees. We prove the correctness of T* and show that itsworst-case complexity is O(m + kn log d) in which n is the number ofnodes and m is the number of arcs and d is the mean degree of thegraph. The algorithm has a space complexity of O(nk). An experimental evaluation of T*is presented which confirm the advantage of our algorithm comparedto the most efficient k shortest paths algorithms known so far

An adaptive MST-based topology connectivity control algorithm for wireless ad-hoc networks

Abstract: In this paper, an adaptive minimum spanning tree based topology control algorithm for mobile ad-hoc networks (MANETs) is presented. Logically, mobile nodes know their source, destination and trajectory. Therefore, every node can inform the nodes around it about its trajectory. Equipped with this knowledge, the node will then be able to compute the relocations of its neighbours and determines the time points at which it must adjust its transmission radius. At each time point, node u establishes a minimum spanning tree and considers the nodes which are its neighbours in the tree as its neighbours in the final topology. In contrast to the existing algorithms, we analytically prove that at each time point of network lifespan, connectivity is preserved. The algorithm can proactively adapt the network changes without relying on periodic beacons. In addition, message overhead is put to the network locally and occurs only if the nodes change their trajectories or lose/discover a neighbour(s). Simulation experiments are conducted to measure performance benefits with reference to three metrics, namely: node degree, transmission radius, packet loss ratio. Keywords: mobility; topology control; self adaptive; energy efficient. Reference to this paper should be made as follows: Kadivar, M., Shiri, M.E. and Dehghan, M. (2011) 'An adaptive MST-based topology connectivity control algorithm for wireless ad-hoc networks', Int

A study of graft possibility of human umbilical cord blood mononuclear cells into irradiated rat's bone marrow

Introduction: Considering the importance of cell migration in cell therapy protocols and the necessity to understand this issue better. This study was administred to evaluate the homing possibility of human umbilical cord blood mononuclear cells in the irradiated and non-irradiated rats’ bone marrow. Materials and Methods: Human umbilical cord blood was collected and after isolation and cell counting, 5 × 10 6 cells were injected to tail veins of 13 groups (1 healthy and 12 irradiated group) of adult rats. In defined time gaps after injection, transplanted rats were sacrificed and their bone marrow cells were collected. Then, the DNA of these collected cells was extracted and was amplified by PCR using specific primers for human STS. Finally, PCR products were analyzed on gel electrophoresis. Results: PCR results for irradiated and non-irradiated rats in all groups were negative which implied that human umbilical cord blood mononuclear cells did not home in bone marrow of transplanted rats. Conclusion: Our results suggest that human umbilical cord blood mononuclear cells are unable to home in rat's bone marrow after intra-venous injection. This might be the result of trapping of cells into other organs or unknown conditions of cells physiology for migration and homing

Effects of %1 acute hypoxia on gene expression of connexin43 and CXCR4 in human bone marrow derived mesenchymal stem cells

Introduction: Increased pressure of oxygen in cell culture condition in comparison with in vivo, leads tochanges in expression of some genes and subsequently abnormality in some functions of cells. The aim ofthis study was to investigate the effect of in vitro %1 acute hypoxia on the expression of connexin 43 andCXCR4 in human bone marrow derived mesenchymal stem cells.Materials and Methods: After culturing, a group of stem cells were treated under %1 acute hypoxia for4, 8, 16, 24 and 48 hours. In another group (Hypoxia/Re-oxygenation), the cells were exposed to normoxiacondition for 8 hours following mentioned hypoxia treatment. In each case, RNA was extracted andsubsequently cDNA synthesised and then the expression of connexin 43 and CXCR4 genes were comparedwith normoxia group using real-time PCR technique.Results: Connexin 43 gene expression significantly increased at 4, 8 and 16 hours of hypoxia. Thisincrease in CXCR4 expression was observed in only 16 hours hypoxia. In Hypoxia/Re-oxygenation group,although Connexin 43 gene expression was greatly increased at 4 and 8 hours, CXCR4 gene expressionshowed no significant change compared with normoxia group.Conclusion: Based on these results, O2 concentration, time of exposure to O2 and and type of it'sadministration play important roles in the expression of CXCR4 and Connexin 43 in human bone marrowderived mesenchymal stem cells. Regarding the main role of oxygen in expression of these genes, it wouldbe necessary to optimise the O2 concentration to reach the maximum expression in each gene in these cell

The Role of Academic Optimism, Academic Emotions and School Well-Being in Mathematical Performance of Students

The objective of the study was to explain the role of academic optimism, academic emotions and school well-being on the mathematical performance of girl and boy students. The research method was descriptive and correlation. A sample of 440 (109 boys and 331 girls) students was selected by cluster random sampling. The research instruments were Student Academic Optimism Scale (Tschannen-Moran, Bankole, Mitchell & Moore), Academic Emotions Questionnaire (Pekrun, Goetz & Frenzel), and School Well-being Questionnaire (Konu, Alanen, Lintonen, & Rimpela). A teacher- made questionnaire was also used to evaluate math scores. The data were analyzed by using descriptive statistics, Pearson correlation, stepwise multiple regression analysis and independent t- test. Findings showed that academic optimism, academic emotions and school well-being had significant positive correlation with math performance (0.20, 0.23, 0.16). The results showed academic well-being had significant positive relationship whit mathematic performance of girls and boys and predicts mathematic performance, too. Also, the results showed academic emotions had significant positive relationship with students mathematic performance in the girls and in combination with academic well-being explained %16 mathematic performance; but it was not the case in the boys. Academic optimism with academic well-being could explain %17 of boys mathematic performance, while in the girls there were not such explanation power

Isolation, Culture and Characterization of Human Synovium-Derived Mesenchymal Stem Cells

Objective: It has been demonstrated that mesenchymal stem cells (MSCs), which are isolatedfrom various tissues, have different potential in differentiation and proliferation. Forthis reason it is necessary to isolate these cells from various sources in order to use them inclinical settings. The present study has been done to investigate the possibility of isolation,culture and characterization of human synovium-derived mesenchymal stem cells.Materials and Methods: Samples (200-300 mg) were provided from synovium tissue ofpatients who had knee surgery. Obtained samples were homogenized, enzymatically mincedwith collagenase D and passed through 70 μm nylon filters; separated cells were then cultured.Isolated cells were identified by morphological observations, differentiation tests, flowcytometry, immunocytochemistery studies and RT-PCR.Results: The isolated cells in this study showed fibroblast-like morphology and have a highproliferation capacity. In flow cytometry and immunocytochemical studies, they were positivefor CD73 and CD105 antigens. RT-PCR analysis and specific staining for differentiated cellstowards osteogenic and adipogenic lineages, showed that isolated cells were potent in differentiationinto the mentioned lineages.Conclusion: These results suggest that synovium tissue, which is discarded in most kneeoperations, can be used for cell therapy and tissue engineering protocols as an enrichmentsource of potent mesenchymal stem cells

Up-regulation of miR-21 and 146a expression and increased DNA damage frequency in a mouse model of polycystic ovary syndrome (PCOS)

Introduction: Polycystic ovary syndrome (PCOS), a multigenic endocrine disorder, is highly associated with low-grade chronic inflammation, however its etiology remains unclear. In this study, we employed dehydroepiandrosterone (DHEA)-treated mice to reveal the molecular mechanism of inflammation and its correlation with oxidative stress in PCOS patients. Methods: miR-21 and miR-146a expression levels were measured using quantitative real-time polymerase chain reaction (qRT-PCR). DNA strand breakage frequency was measured using the single cell gel electrophoresis (SCGE) assay (comet assay) and micronucleus test (MN). CRP levels were measured by ELISA method and ESR values were measured by means of Micro-Dispette (Fisher No: 02-675-256) tubes according to the manufacturer’s instructions. Data were analyzed using one-way ANOVA in SPSS 21.0 software. Results: Our results showed that miR-21 and miR-146a as inflammation markers were up-regulated in the sample group in comparison with control group. Erythrocyte sedimentation rate (ESR) and C- reactive protein (CRP) levels were also increased in mouse models of PCOS (p < 0.000). Micronucleated polychromatic erythrocyte (MNPCE) rates per 1000 polychromatic erythrocyte (PCE) significantly increased in DHEA treated mice (6.22 ± 3.28) in comparison with the controls (2.33 ± 2.23, p < 0.000). Moreover, mean arbitrary unit in DHEA treated animals (277 ± 92) was significantly higher than that in controls (184 ± 76, p = 0.005). Conclusion: To conclude, increased DNA strand breakage frequency and increased expression levels of miR-21 and miR-146a in DHEA administrated animals suggest that low grade chronic inflammation and oxidative stress can act as the main etiologies of PCOS

Optimization and Comparison of the PolyFect Gene Delivery Method in Three Different Kinds of Mesenchymal Stem Cell Types

Objective: The aim of this study was optimization of the PolyFect gene delivery methodof pcDNA3.1 expression vector transfected with the mouse pdx-1 gene in three differentkinds of mesenchymal stem cells and Hepa cells as well as comparison of transfectionefficiency leading to expression of the mentioned gene in the cell types used.Materials and Methods: Rat bone marrow-derived mesenchymal stem cells, C57 mousebone marrow-derived mesenchymal stem cells, human synovium derived mesenchymalstem cells and Hepa cells were used in this study. After culturing of the mentioned cells,mouse pdx-1 gene were transfected into them using the Qiagen PolyFect kit. 72 hourslater, the cells were treated with anti-mouse Pdx-1 antibody and immunocytochemicallyanalyzed using a fluorescent inverted microscope. Transfection conditions were optimizedin each of these cells by changing different lipofection parameters such as DNAconcentration, PolyFect reagent concentration and cell density.Results: The results demonstrated that for transfection of these cells, the best concentrationsof DNA and PolyFect reagent are 400 ng/μL and 6000 ng/μL respectively. For maximumtransfection efficiency, the best cell density in 12-well plates was 105 cells in Hepacells, 1.3×105 cells in rat bone marrow-derived mesenchymal stem cells, 1.5×105 cells inhuman synovium-derived mesenchymal stem cells and 105 cells in C57 mouse bone marrow-derived mesenchymal stem cells. Under the mentioned optimized conditions, the maximumefficiency of transfection was determined to be 50% for Hepa cells, 40% for rat bonemarrow-derived mesenchymal stem cells, 21% for human synovium-derived mesenchymalstem cells and 10% for C57 mouse bone marrow-derived mesenchymal stem cells.Conclusion: These findings implicate that the most important factor extremely influencingtransfection efficiency in mesenchymal stem cells is the cell derivation origin. Resultsof this study can be used in basic and clinical studies dealing with gene therapy in mesenchymalstem cells