939 research outputs found

    Differentiation of definitive endoderm from human induced pluripotent stem cells on hMSCs feeder in a defined medium

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    Background: The Definitive Endoderm (DE) differentiation using the undefined media and non-human feeders can cause contaminations in the generated cells for therapeutic applications. Therefore, generating safer and more appropriate DE cells is needed. This study compared five different methods to establish an appropriate method for inducing an efficient DE differentiation from Human Induced Pluripotent Stem Cells (hiPSCs) on an appropriate feeder in a more defined medium. Methods: Human Induced Pluripotent Stem Cells (hiPSCs) were cultured on inactivated feeders. Passaged hiPSCs, without feeder, were incubated for three days with Activin-A and different endodermal differentiation media including 1-FBS, 2-B27, 3- ITS and albumin fraction-V, 4-B27 and ITS and 5-like the third medium. The feeder cells in the first four methods were Mouse Embryonic Fibroblasts (MEFs) and in the fifth method were human adult bone marrow Mesenchymal Stem Cells (hMSCs). DE markers FOXA2, SOX17 and CXCR4 and also pluripotency marker OCT4 were evaluated using qRT-PCR, as well as FOXA2 by the immunocytochemistry. Results: QRT-PCR analysis showed that after three days, the expression levels of DE and pluripotency markers in the differentiated hiPSCs among all five groups did not have any significant differences. Similarly, the immunocytochemistry analysis demonstrated that the differentiated hiPSCs expressed FOXA2, with no significant differences. Conclusion: Despite this similarity in the results, the third differentiation medium has more defined and cost effective components. Furthermore, hMSC, a human feeder, is safer than MEF. Therefore, the fifth method is preferable among other DE differentiation methods and can serve as a fundamental method helping the development of regenerative medicine. © 2016, Avicenna Journal of Medical Biotechnology. All rights reserved

    The relationship between empowerment and effectiveness of staff (case study: national bank staff in Guilan province)

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    Effectiveness is one of the management concepts considered and studied always by management scientists and experts. The aim of this study was to investigate the effects of different dimensions of empowerment (servicing staff, staff monitoring, consulting staff, and training staff) on dimensions of effectiveness of staff (staff satisfaction and staff performance). This study is applied in terms of data collection and it is survey type of descriptive study in terms of data collection. The study population includes staff of National Bank branches in Guilan province, that their number is 1397 people. Cochran formula was used to determine sample size of study and 302 people were selected as minimum sample of study. Simple random sampling was used as method of sampling. Fir increased confidence, 360 questionnaires were distributed that 315 questionnaires were returned and analyzed. Method of data collection is using questionnaire distributed among samples of study after its validity and reliability were confirmed.SPSS software was used to analyze the data in descriptive statistics section and structural equation modeling using AMOS software was used in the inferential statistics using AMOS software to test the hypotheses of study. The results showed there is significant positive correlation between different dimensions of empowerment and dimensions of effectiveness of staff.Keywords: staff effectiveness, staff empowerment, staff training, staff performance, staff satisfactio

    Experimental investigation of the tire wear process using camera-assisted observation assessed by numerical modeling

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    This paper presents a novel experimental method to study the abrasion mechanism of car tires. It is based on the detection of microscopic movements associated with material damage (cracking) on the rubber tread. This is referred to as degrading layer relaxation. It correlates with the wear rate and, interestingly, the direction of the pattern's movement is opposite to the lateral forces during cornering. To measure and analyze the microscopic movements, a new camera-based method with feature point matching using video stabilization was developed. Besides extensive experimental investigation, the formation and propagation of microcracks are investigated using a simplified numerical model in which a phase field approach coupled with a viscoelastic constitutive behavior is implemented in a finite element framework

    Prazosin during threat discrimination boosts memory of the safe stimulus

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    The α-1 adrenoreceptor antagonist prazosin has shown promise in the treatment of post-traumatic stress disorder (PTSD) symptoms, but its mechanisms are not well understood. Here we administered prazosin or placebo prior to threat conditioning (day 1) and tested subsequent extinction (day 2) and reextinction (day 3) in healthy human participants. Prazosin did not affect threat conditioning but augmented stimulus discrimination during extinction and reextinction, via lower responding to the safe stimulus. These results suggest that prazosin during threat acquisition may have influenced encoding or consolidation of safety processing in particular, subsequently leading to enhanced discrimination between the safe and threatening stimuli

    Numerical and experimental investigation of multi-species bacterial co-aggregation

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    This paper deals with the mathematical modeling of bacterial co-aggregation and its numerical implementation in a FEM framework. Since the concept of co-aggregation refers to the physical binding between cells of different microbial species, a system composed of two species is considered in the modeling framework. The extension of the model to an arbitrary number of species is straightforward. In addition to two-species (multi-species growth) dynamics, the transport of a nutritional substance and the extent of co-aggregation are introduced into the model as the third and fourth primary variables. A phase-field modeling approach is employed to describe the co-aggregation between the two species. The mathematical model is three-dimensional and fully based on the continuum description of the problem without any need for discrete agents which are the key elements of the individual-based modeling approach. It is shown that the use of a phase-field-based model is equivalent to a particular form of classical diffusion-reaction systems. Unlike the so-called mixture models, the evolution of each component of the multi-species system is captured thanks to the inherent capability of phase-field modeling in treating systems consisting of distinct multi-phases. The details of numerical implementation in a FEM framework are also presented. Indeed, a new multi-field user element is developed and implemented in ANSYS for this multiphysics problem. Predictions of the model are compared with the experimental observations. By that, the versatility and applicability of the model and the numerical tool are well established

    Phytoremediation of heavy metals: A green technology

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    The environment has been contaminated with organic and inorganic pollutants. Organic pollutants are largely anthropogenic and are introduced to the environment in many ways. Soil contamination with toxic metals, such as Cd, Pb, Cr, Zn, Ni and Cu, as a result of worldwide industrialization has increased noticeably within the past few years. There are some conventional remediation technologies to clean polluted areas, specifically soils contaminated with metals. In spite of being efficient, these methods are expensive, time consuming, and environmentally devastating. Recently, phytoremediation as a cost effective and environmentally friendly technology has been developed by scientists and engineers in which biomass/microorganisms or live plants are used to remediate the polluted areas. It can be categorized into various applications, including phytofiltration, phytostabilization, phytoextraction, and phytodegradation. A brief review of phytoremediation of soils contaminated with heavy metals has been complied to provide an extensive applicability of this green technology.Key words: Phytoremediation, heavy metals, soil pollution, toxicity

    The effect of different degrees of feed restriction on heat shock protein 70, acute phase proteins, and other blood parameters in female broiler breeders

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    The aim of the current study was to determine the physiological response to feed restriction in female broiler breeders using a range of conventional and novel indicators. One hundred female breeders were subjected to one of five feeding regimens from d 28 to 42 as follows (i) ad libitum feeding (AL), (ii-v) 75, 60, 45, and 30% of ad libitum feed intake. Blood heterophil to lymphocyte ratio (HLR), and plasma circulating corticosterone (CORT), ghrelin (GHR), serotonin (5-HT), and dopamine (DA) and serum acute phase proteins (APP) concentrations together with brain heat shock protein (HSP) 70 level were measured. The results showed a significant effect of feed restriction on blood HLR and plasma CORT, GHR, 5-HT, DA, and brain HSP 70 levels. However, feed restriction had no effect on serum levels of APP of alpha-1 acid glycoprotein, ovotransferin, and ceruloplasmin. Serum levels of 5-HT and GHR varied curvilinearly with the feed restriction level. The relationship between brain HSP 70 and level of feed restriction was negligible. However, significant linear relationships between HLR, CORT, DA, and the level of feed restriction were noted. Thus, these 3 parameters appear to represent a straight forward relation with severity of feed restriction

    Stem cell-based approach for the treatment of Parkinson's disease

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    Parkinson's disease (PD) is the second most common neurodegenerative brain disorder which is around 1.5 times more common in men than in women. Currently, drug medications, surgery, and lifestyle changes are common approaches to PD, while all of them focused on reducing the symptoms. Therefore, regenerative medicine based on stem cell (SC) therapies has raised a promising hope. Various types of SCs have been used in basic and experimental studies relevant to PD, including embryonic pluripotential stem cells, mesenchymal (MSCs) and induced pluripotent SCs (iPSCs). MSCs have several advantages over other counterparts. They are easily accessible which can be obtained from various tissues such as bone marrow, adipose tissue, peripheral blood, etc. with avoiding ethical problems. Therefore, MSCs is attractive clinically because there are no related ethical and immunological concerns . Further studies are needed to answer some crucial questions about the different issues in SC therapy. Accordingly, SC-based therapy for PD also needed more complementary evaluation in both basic and clinical study areas

    cAMP-dependent and cholinergic regulation of the electrogenic intestinal/pancreatic Na+/HCO3- cotransporter pNBC1 in human embryonic kidney (HEK293) cells

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    <p>Abstract</p> <p>Background</p> <p>The renal (kNBC1) and intestinal (pNBC1) electrogenic Na<sup>+</sup>/HCO<sub>3</sub><sup>- </sup>cotransporter variants differ in their primary structure, transport direction, and response to secretagogues. Previous studies have suggested that regulatory differences between the two subtypes can be partially explained by unique consensus phosphorylation sites included in the pNBC1, but not the kNBC1 sequence. After having shown activation of NBC by carbachol and forskolin in murine colon, we now investigated these pathways in HEK293 cells transiently expressing a GFP-tagged pNBC1 construct. </p> <p>Results</p> <p>Na<sup>+</sup>- and HCO<sub>3</sub><sup>-</sup>-dependent pH<sub>i </sub>recovery from an acid load (measured with BCECF) was enhanced by 5-fold in GFP-positive cells compared to the control cells in the presence of CO<sub>2</sub>/HCO<sub>3</sub><sup>-</sup>. Forskolin (10<sup>-5 </sup>M) had no effect in untransfected cells, but inhibited the pH<sub>i </sub>recovery in cells expressing pNBC1 by 62%. After preincubation with carbachol (10<sup>-4 </sup>M), the pH<sub>i </sub>recovery was enhanced to the same degree both in transfected and untransfected cells, indicating activation of endogenous alkalizing ion transporters. Acid-activated Na<sup>+</sup>/HCO<sub>3</sub><sup>- </sup>cotransport via pNBC1 expressed in renal cells is thus inhibited by cAMP and not affected by cholinergic stimulation, as opposed to the findings in native intestinal tissue. </p> <p>Conclusion</p> <p>Regulation of pNBC1 by secretagogues appears to be not solely dependent on its primary structure, but also on properties of the cell type in which it is expressed.</p
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