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

Application of deep neural network to the reconstruction of two-phase material imaging by capacitively coupled electrical resistance tomography

A convolutional neural network (CNN)-based image reconstruction algorithm for two-phase material imaging is presented and verified with experimental data from a capacitively coupled electrical resistance tomography (CCERT) sensor. As a contactless version of electrical resistance tomography (ERT), CCERT has advantages such as no invasion, low cost, no radiation, and rapid response for two-phase material imaging. Besides that, CCERT avoids contact error of ERT by imaging from outside of the pipe. Forward modeling was implemented based on the practical circular array sensor, and the inverse image reconstruction was realized by a CNN-based supervised learning algorithm, as well as the well-known total variation (TV) regularization algorithm for comparison. The 2D, monochrome, 2500-pixel image was divided into 625 clusters, and each cluster was used individually to train its own CNN to solve the 16 classes classification problem. Inherent regularization for the assumption of binary materials enabled us to use a classification algorithm with CNN. The iterative TV regularization algorithm achieved a close state of the two-phase material reconstruction by its sparsity-based assumption. The supervised learning algorithm established the mathematical model that mapped the simulated resistance measurement to the pixel patterns of the clusters. The training process was carried out only using simulated measurement data, but simulated and experimental tests were both conducted to investigate the feasibility of applying a multi-layer CNN for CCERT imaging. The performance of the CNN algorithm on the simulated data is demonstrated, and the comparison between the results created by the TV-based algorithm and the proposed CNN algorithm with the real-world data is also provided

Design of heat sinks for wearable thermoelectric generators to power personal heating garments: A numerical study

To mitigate climate change attributed to the built environments, there have been tremendous efforts to improve air conditioning systems in the buildings. The possibility of harvesting body heat as a renewable energy source to power a wearable personal heating system is investigated. The aim of this study is to integrate a wearable personal heating system with a thermoelectric generator (TEG) that harvests the body heat which is used to convert it into electricity. Moreover, the interaction between the TEG configuration and power output is studied. The power generation of TEG system is obtained by COMSOL Multiphysics software. The simulation results concluded that all the four proposed heat sink configurations can improve the power output of the wearable TEG at 1.4 m/s and 3m/s compared to that of the reference model. Furthermore, the perforated and trapezium shapes of heat sinks have a significantly better performance in comparison to conventional heat sinks

A Wideband Contactless Electrical Impedance Tomography System

This work focuses on the development of a wideband contactless electrical impedance tomography (EIT) system. The system is developed from the aspects of the multifrequency capacitively coupled electrical impedance tomography (CCEIT) hardware, the impedance calculation model and the system evaluation. The hardware includes a 12-electrode CCEIT sensor, 6 sensing modules, a data acquisition module, and a personal computer (PC). The impedance calculation model is established by combining the mechanism modeling of the integrated circuits (ICs) and the empirical modeling of the measurement data with the least squares (LS) method. Experiments were carried out to evaluate the developed system, including the signal-to-noise ratio (SNR), the impedance measurement accuracy and the imaging performance. Experimental results show that the system achieves an SNR above 65.00 dB for the frequencies up to 20 MHz. Impedance measurement results indicate that the system has good impedance measurement accuracy at frequencies below 10 MHz and acceptable impedance measurement accuracy at 10 MHz - 20 MHz. It has particularly good performance at several specific frequencies, which can also serve as a high-performance single-frequency contactless EIT device. Imaging results show that the spectroscopic images reconstructed by the developed system are consistent with the actual distributions. Few types of research on contactless multifrequency EIT systems have been reported. So, this work is of great significance for further development and practical application of the newly emerged contactless EIT technique

N-acetylcysteine compared to metformin, improves the expression profile of growth differentiation factor-9 and receptor tyrosine kinase c-kit in the oocytes of patients with polycystic ovarian syndrome

Background: Paracrine disruption of growth factors in women with polycystic ovarian syndrome (PCOS) results in production of low quality oocyte, especially following ovulation induction. The aim of this study was to investigate the effects of metformin (MET), N-acetylcysteine (NAC) and their combination on the hormonal levels and expression profile of GDF-9, BMP-15 and c-kit, as hallmarks of oocyte quality, in PCOS patients. Materials and Methods: This prospective randomized, double-blind, placebo controlled trial aims to study the effects of MET, NAC and their combination (MET+NAC) on expression of GDF-9, BMP-15 and c-kit mRNA in oocytes [10 at the germinal vesicle (GV) stage, 10 at the MI stage, and 10 at the MII stage from per group] derived following ovulation induction in PCOS. Treatment was carried out for six weeks, starting on the third day of previous cycle until oocyte aspiration. The expression of GDF9, BMP15 and c-kit were determined by quantitative real time polymerase chain reaction (RT-qPCR) and western blot analysis. Data were analyzed with one-way ANOVA. Results: The follicular fluid (FF) level of c-kit protein significantly decreased in the NAC group compared to the other groups. Significant correlations were observed between the FF soluble c-kit protein with FF volume, androstenedione and estradiol. The GDF-9 expression in unfertilized mature oocytes were significantly higher in the NAC group compared to the other groups (P<0.001). Similar difference was not observed between the MET, NAC+MET and control groups. The c-kit expression in unfertilized mature oocytes were significantly lower in the NAC group compared to the other groups (P<0.001). Similar difference was not observed between the MET, NAC+MET and control groups (Registration number: IRCT201204159476N1). Conclusion: We concluded that NAC can improve the quality of oocytes in PCOS. © 2017, Royan Institute (ACECR). All rights reserved

Void fraction measurement of gas-liquid two-phase flow with a 12-electrode contactless resistivity array sensor under different excitation patterns

This work focuses on the void fraction measurement of gas–liquid two-phase flow by a 12-electrode contactless resistivity array sensor. Such a sensor, which can realize different excitation patterns, is developed here. Five different excitation patterns (with 1, 2, 3, 4 or 5 electrodes) and three two-phase distributions (bubble flow, stratified flow and annular flow) are investigated. Two data processing approaches, the data average method and the principal component regression (PCR) method, are used to establish models of void fraction measurement and hence to implement it. Experiments on void fraction measurement are carried out with the 12-electrode contactless resistivity array sensor. The results show that the void fraction measurement performances are different under different excitation patterns. Among the five different excitation patterns studied, the one with five electrodes has the best performance and the absolute values of void fraction measurement errors of the three two-phase distributions are all less than 5.0% (using the data average method) and 3.0% (using the PCR method). Research results indicate that the 5-electrode excitation pattern + PCR combination is a new effective way to implement void fraction measurement of gas–liquid two-phase flow with the 12-electrode contactless resistivity array sensor.<br/

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

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

Neuroprotective Effects of Bone Marrow Mesenchymal Stem Cells on Bilateral Common Carotid Arteries Occlusion Model of Cerebral Ischemia in Rat

Cell therapy is the most advanced treatment of the cerebral ischemia, nowadays. Herein, we discuss the neuroprotective effects of bone marrow mesenchymal stem cells (BMSCs) on rat hippocampal cells following intravenous injection of these cells in an ischemia-reperfusion model. Adult male Wistar rats were divided into 5 groups: control, sham (surgery without blockage of common carotid arteries), ischemia (common carotid arteries were blocked for 30 min prior to reperfusion), vehicle (7 days after ischemia PBS was injected via the tail vein), and treatment (injections of BMSC into the tail veins 7 days after ischemia). We performed neuromuscular and vestibulomotor function tests to assess behavioral function and, finally, brains were subjected to hematoxylin and eosin (H&E), anti-Brdu immunohistochemistry, and TUNEL staining. The ischemia group had severe apoptosis. The group treated with BMSCs had a lower mortality rate and also had significant improvement in functional recovery (P<0.001). Ischemia-reperfusion for 30 min causes damage and extensive neuronal death in the hippocampus, especially in CA1 and CA3 regions, leading to several functional and neurological deficits. In conclusion, intravenous injection of BMSCs can significantly decrease the number of apoptotic neurons and significantly improve functional recovery, which may be a beneficial treatment method for ischemic injuries. © 2016 Bagher Pourheydar et al