Cosmological viability conditions for f(T)f(T) dark energy models

Recently $f(T)$ modified teleparallel gravity where T is the torsion scalar has been proposed as the natural gravitational alternative for dark energy. We perform a detailed dynamical analysis of these models and find conditions for the cosmological viability of $f(T)$ dark energy models as geometrical constraints on the derivatives of these models. We show that in the phase space exists two cosmologically viable trajectory which (i) The universe would start from an unstable radiation point, then pass a saddle standard matter point which is followed by accelerated expansion de sitter point. (ii) The universe starts from a saddle radiation epoch, then falls onto the stable matter era and the system can not evolve to the dark energy dominated epoch. Finally, for a number of $f(T)$ dark energy models were proposed in the more literature, the viability conditions are investigated.Comment: 15 pages, 7 figures, Accepted for publication in JCAP (2012

High-levelexpression of functional recombinant human coagulation factor VII in insect cells

Abstract: Recombinant coagulation factor VII (FVII) is used as a potential therapeutic intervention in hemophilia patients who produce antibodies against the coagulation factors. Mammalian cell lines provide low levels of expression, however, the Spodoptera frugiperda Sf9 cell line and baculovirus expression system are powerful systems for high-level expression of recombinant proteins, but due to the lack of endogenous vitamin K-dependent carboxylase, expression of functional FVII using this system is impossible. In the present study, we report a simple but versatile method to overcome the defect for high-level expression of the functional recombinant coagulation FVII in Sf9 cells. This method involves simultaneous expression of both human γ-carboxylase (hGC) and human FVII genes in the host. It may be possible to express other vitamin K-dependent coagulation factors using this method in the future. Keywords: Baculovirus; γ-carboxylase; Coagulation FVII; Factor VII; Insect cel

Identification of valuable natural factors by the VPS Method from children’s points of view, in order to provide a framework for organizing the school yard space

Background and Objective: Addressing the issue of identifying elements of the nature are important to children and increase children's creativity. In such a way that these elements can be presented in a general framework so that designers and architects can rely on them, the most important concepts and items needed in the design, to consider these spaces and apply them. Of course, it should be noted that several environmental factors affect creativity. However, in this study, an attempt is made to identify the factors that have the most impact, so that the needs of children can be met in accordance with their activities and a general framework for designing children's spaces can be proposed. The main difference between this research and other researches is in prioritizing the effective factors in nature from the children's point of view and its effect on creativity and then presenting the results in the form of an overall design framework. Various research has been done on this subject, but in a one-dimensional way and in them only one factor is mentioned, such as the effect of creativity on learning, but none of them presents the effect of nature's role in increasing creativity. The purpose of this research is to determine which natural elements are important from children’s points of view and whether the use and presence of elements are possible in educational locations. This research seeks to find approaches to design school yards based on children’s points of view with regard to the role of nature in their education. Methods: The research method used in this qualitative study is content analysis. Based on the nature of the subject, a questionnaire and the image technique were used as the main method of data collection. The structure of the questionnaire is based on the measures and criteria derived from the subject literature and designed based on Likert scale. In the first stage, 120 questionnaires were provided to children of 7-12 age in the case study. Results of the questionnaires were obtained. To ensure that the results of the questionnaires are expanded, the researcher, in the second phase, provided some pictures relevant to questionnaires, so that the children could respond to questions based on their visual preferences. The researcher then obtained results based on visual content analysis. Findings: It was discovered that these two instruments of measurement are in line with each other and are appropriate to the environmental factors affecting children. Finally, a framework for organizing the school yard is presented. Conclusion: By creating an appropriate, responsive and purposeful framework in design, we can address the main goal of the research, which is to identify the effective factors in nature from the children's point of view by increasing their creativity, and finally, an appropriate framework by considering these factors to organize the space of the school yard. The necessity of presenting the framework can be expressed in such a way that the weakening of children's connection with outside the classroom is harmful for the child, on the other hand, an intellectual movement moves towards learning outdoors. The presence of natural elements or the same nature has a positive effect on children's creativity, discovers and flourishes the latent talent in children and creates a suitable environment for a bright future for children.   ===================================================================================== COPYRIGHTS  ©2019 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.  ====================================================================================

Nanoparticle-induced neuronal toxicity across placental barriers is mediated by autophagy and dependent on astrocytes

The potential for maternal nanoparticle (NP) exposures to cause developmental toxicity in the fetus without the direct passage of NPs has previously been shown, but the mechanism remained elusive. We now demonstrate that exposure of cobalt and chromium NPs to BeWo cell barriers, an in vitro model of the human placenta, triggers impairment of the autophagic flux and release of interleukin-6. This contributes to the altered differentiation of human neural progenitor cells and DNA damage in the derived neurons and astrocytes. Crucially, neuronal DNA damage is mediated by astrocytes. Inhibiting the autophagic degradation in the BeWo barrier by overexpression of the dominant-negative human ATG4BC74A significantly reduces the levels of DNA damage in astrocytes. In vivo, indirect NP toxicity in mice results in neurodevelopmental abnormalities with reactive astrogliosis and increased DNA damage in the fetal hippocampus. Our results demonstrate the potential importance of autophagy to elicit NP toxicity and the risk of indirect developmental neurotoxicity after maternal NP exposure

<i>F</i>(<i>G</i>) gravity models based on the ordinary and entropy-corrected holographic dark energy models

The ordinary and entropy-corrected versions of the holographic dark energy models in the spatially flat Friedmann–Robertson–Walker universe are considered. Then the F(G) modified gravity models as a candidates of dark energy are reconstructed according to the ordinary and entropy-corrected versions of the holographic dark energy models. The EoS parameters corresponding to the F(G) gravity models are obtained. The validity phantom or quintessence models in this framework of the modified gravity are investigated. </jats:p

Total phenolic and flavonoid contents and antioxidant activity of four medicinal plants from Hormozgan province, Iran

Background and objectives:Hormozgan province is located in the south of Iran, bordering waters of the Persian Gulf and Oman Sea. Due to the antioxidant potential of plants which might be responsible for their medicinal properties, the antioxidant properties of four medicinal plants of the region were evaluated. Methods: The antioxidant properties of Chrozophora obliqua, Daphne mucronata, Salvia aegyptiaca and Suaeda vermiculata were evaluated by four different methods: free radical scavenging using 2,2-diphenyl-1-picrylhydrazyl (DPPH), metal chelating activity, inhibition of lipid peroxidation by the ferric thiocyanate method, and total reduction capability. The flavonoid and phenolic content of the plants were also analyzed. Results: Amongst the species, C. obliqua showed the best result in metal chelating activity test, and S. vermiculata showed the best antioxidant activity in the three other assays, and S. vermiculata and S. aegyptiaca had the highest amount of phenolic and flavonoid contents. Conclusion: The acceptable antioxidant activity of S. vermiclata as a halophyte plant, could justify the medicinal properties of the plant