66 research outputs found
Differentiation of definitive endoderm from human induced pluripotent stem cells on hMSCs feeder in a defined medium
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
A checking method for probabilistic seismic-hazard assessment: case studies on three cities
The conventional Cornell's source-based approach of probabilistic seismic-hazard assessment (PSHA) has been employed all around the world, whilst many studies often rely on the use of computer packages such as FRISK (McGuire FRISK-a computer program for seismic risk analysis. Open-File Report 78-1007, United States Geological Survey, Department of Interior, Washington 1978) and SEISRISK III (Bender and Perkins SEISRISK III-a computer program for seismic hazard estimation, Bulletin 1772. United States Geological Survey, Department of Interior, Washington 1987). A "black-box" syndrome may be resulted if the user of the software does not have another simple and robust PSHA method that can be used to make comparisons. An alternative method for PSHA, namely direct amplitude-based (DAB) approach, has been developed as a heuristic and efficient method enabling users to undertake their own sanity checks on outputs from computer packages. This paper experiments the application of the DAB approach for three cities in China, Iran, and India, respectively, and compares with documented results computed by the source-based approach. Several insights regarding the procedure of conducting PSHA have also been obtained, which could be useful for future seismic-hazard studies. © 2010 The Author(s).published_or_final_versionSpringer Open Choice, 21 Feb 201
STABILITY IMPROVEMENT OF IMMOBILIZED ALKALINE PHOSPHATASE USING CHITOSAN NANOPARTICLES
Abstract -Enzyme engineering via immobilization techniques is a suitable approach for improving enzyme function and stability and is superior to the other chemical or biological methods. In this study chitosan nanoparticles were synthesized using the Ionic Gelation method and were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Alkaline phosphatase was successfully immobilized on the chitosan nanoparticles in optimum conditions. Chitosan nanoparticles were used because of their special properties for enzyme immobilization. This study indicated that the immobilized enzyme has improved function at high temperature and during storage. Immobilization resulted in an increased range of optimum pH and temperature, and reusability of enzyme. Furthermore, the binding efficiency calculation indicated that the immobilized alkaline phosphatase conserved 71% of its native activity. Kinetic parameter studies indicated no significant difference between the immobilized and free enzymes
The Impact of Entrepreneurship Education in Higher Education: A Systematic Review and Research Agenda
Using a teaching model framework, we systematically review empirical evidence on the impact of entrepreneurship education (EE) in higher education on a range of entrepreneurial outcomes, analyzing 159 published articles from 2004 to 2016. The teaching model framework allows us for the first time to start rigorously examining relationships between pedagogical methods and specific outcomes. Reconfirming past reviews and meta-analyses, we find that EE impact research still predominantly focuses on short-term and subjective outcome measures and tends to severely underdescribe the actual pedagogies being tested. Moreover, we use our review to provide an up-to-date and empirically rooted call for less obvious, yet greatly promising, new or underemphasized directions for future research on the impact of university-based entrepreneurship education. This includes, for example, the use of novel impact indicators related to emotion and mind-set, focus on the impact indicators related to the intention-to-behavior transition, and exploring the reasons for some contradictory findings in impact studies including person-, context-, and pedagogical model-specific moderator
A checking method for probabilistic seismic-hazard assessment: case studies on three cities
Decreased level of the anti-inflammatory adipokine, secreted frizzled-related protein 5, in patients with coronary artery disease
Background: Secreted frizzled-related protein 5 (SFRP5) is an anti-inflammatory adipokine that excreted by adipose tissue and functions to modulate metabolic and inflammatory dysregulations. The exact contribution of SFRP5 toward coronary artery disease (CAD) is largely unclear. Objectives: In the current study, the potential role of SFRP5, by particular focusing on its anti-inflammatory effects, was sought in CAD. Patients and Methods: Serum levels of SFRP5 and the inflammatory biomarkers, oxidized low-density lipoprotein (Ox-LDL), and high-sensitivity C-reactive protein (hsCRP), were measured in 40 CAD patients and 40 controls who were identified based on coronary angiography examinations. The status of CAD severity (in accord with Gensini score) and traditional CAD risk factors were also determined. Association of SFRP5 with Ox-LDL, hsCRP, CAD severity, and traditional CAD risk factors was analyzed. Results: Serum SFRP5 level in CAD patients was significantly decreased compared to controls (28.60 ng/mL 25.67-34.58 vs. 39.92 ng/mL 32.82-49.91, P = 0.000). The correlation of serum SFRP5 level with hsCRP, Ox-LDL, body mass index, and Gensini score was reveal to be significant and negative (P < 0.05). Serum SFRP5 level was independently and inversely associated with CAD (odds ratio, 0.28 95% confidence interval, 0.11-0.56, P = 0.001) and differentiated between CAD patients and controls (P = 0.01). Conclusions: Decreased level of serum SFRP5 is associated with CAD, highlighting its implication in CAD. It may also be a clinically useful biomarker for CAD
Evaluation of damping modification factors for seismic response spectra
Seismic response spectra with structural damping ratio other than nominal 5% (of critical damping) are essential for the design and evaluation of structures in performance-based seismic engineering. Such response spectra are also essential for the design and evaluation of structures with seismic isolation and energy dissipation systems. A number of formulations for damping modification factors (DMF) have been proposed in the literature for scaling the 5% damped response spectra. Dependence of the DMF on several ground motion parameters has also been identified. Few seismic design codes have already incorporated simplified DMF based on these studies. This paper critically reviews the available formulations for DMF for seismic response spectra. Analytical investigations on the ground motion response spectra at soil sites, based on a wide range of simulated ground motion records, have been carried out. It has been observed that the DMF for ground motion response spectra at soil sites is significantly dependent on site period, which has not been identified in previous studies. The influences of earthquake shaking level, earthquake source-site distance (nearfield and far-field events), soil plasticity index, and the rigidity of bedrock have also been investigated
Effects of curzerene and Smyrnium cordifolium Boiss. Extract on addiction withdrawal syndrome in mice
Introduction: The purpose of this study was evaluating the effect of Smyrnium cordifolium extract (SCE) and curzerene (Cur) on withdrawal syndrome in mice compared with clonidine. Methods: High-performance liquid chromatography (HPLC) was used to determine the active ingredients of S. cordifolium. To evaluate the effects of SCE and Cur, 64 mice were divided into 8 equal groups. Groups 1, 2 and 3 were treated Cur (0.03, 0.06, 0.12 mg/kg, respectively). Groups 4, 5 and 6 were treated with SCE (100, 200, 300 mg/kg, respectively). The seventh group received just morphine. Group 8 received morphine and clonidine (0.2 mg/kg). Results: The results of this study showed that Cur was the most important ingredient in the extract of the plant, and the hydroalcoholic extract yield of S. cordifolium was 17.55 (w/w). The dose of 100 mg/kg of extract (SCE100) and 0.03 mg/kg curzerene (Cur1) (P< 0.05), dose of 200 mg/kg of extract (SCE200) and dose of 0.06 mg/kg curzerene (Cur2), (P< 0.01), dose of 300 mg/kg of extract (SCE300) and dose of 0.12 mg/kg of curzerene (Cur3) (P< 0.001) decreased the symptoms compared to clonidine. Doses higher than 300 mg/kg of extract and 0.12 mg/ kg of Cur had fatal effects. All doses of SCE and Cur in comparison with the control group at significant level (P< 0.001) reduced the number of jumping, rearing and teeth chattering in morphine-dependent mice. Conclusion: The findings suggest that SCE and Cur are capable of reducing the symptoms of withdrawal syndrome and their effectiveness may be more than clonidine in reducing the addiction withdrawal syndrome, which may have human therapeutic potential. © Nickan Research Institute 2018. All rights reserved
Effects of abutment diameter, luting agent type, and re-cementation on the retention of implant-supported CAD/CAM metal copings over short abutments
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