Search results for: macular ganglion cell

Authors: Elena Petersen, Inna Kornienko, Svetlana Guryeva, Sergey Simakov

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In vitro organoid cultivation requires the simultaneous provision of necessary vascularization and nutrients perfusion of cells during organoid development. However, many aspects of this problem are still unsolved. The functionality of vascular network intergrowth is limited during early stages of organoid development since a function of the vascular network initiated on final stages of in vitro organoid cultivation. Therefore, a microchannel network should be created in early stages of organoid cultivation in hydrogel matrix aimed to conduct and maintain minimally required the level of nutrients perfusion for all cells in the expanding organoid. The network configuration should be designed properly in order to exclude hypoxic and necrotic zones in expanding organoid at all stages of its cultivation. In vitro vascularization is currently the main issue within the field of tissue engineering. As perfusion and oxygen transport have direct effects on cell viability and differentiation, researchers are currently limited only to tissues of few millimeters in thickness. These limitations are imposed by mass transfer and are defined by the balance between the metabolic demand of the cellular components in the system and the size of the scaffold. Current approaches include growth factor delivery, channeled scaffolds, perfusion bioreactors, microfluidics, cell co-cultures, cell functionalization, modular assembly, and in vivo systems. These approaches may improve cell viability or generate capillary-like structures within a tissue construct. Thus, there is a fundamental disconnect between defining the metabolic needs of tissue through quantitative measurements of oxygen and nutrient diffusion and the potential ease of integration into host vasculature for future in vivo implantation. A model is proposed for growth prognosis of the organoid perfusion based on joint simulations of general nutrient diffusion, nutrient diffusion to the hydrogel matrix through the contact surfaces and microchannels walls, nutrient consumption by the cells of expanding organoid, including biomatrix contraction during tissue development, which is associated with changed consumption rate of growing organoid cells. The model allows computing effective microchannel network design giving minimally required the level of nutrients concentration in all parts of growing organoid. It can be used for preliminary planning of microchannel network design and simulations of nutrients supply rate depending on the stage of organoid development.

Keywords: 3D model, consumption model, diffusion, spheroid, tissue organoid

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Authors: O. Gsib, U. Peirera, C. Egles, S. A. Bencherif

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In skin regenerative medicine, one of the critical issues is to produce a three-dimensional scaffold with optimized porosity for dermal fibroblast infiltration and neovascularization, which exhibits high mechanical properties and displays sufficient wound healing characteristics. In this study, we report on the synthesis and characterization of macroporous sequential interpenetrating polymer networks (IPNs) combining skin wound healing properties of fibrin with the excellent physical properties of polyethylene glycol (PEG). Fibrin fibers serve as a provisional biologically active network to promote cell adhesion and proliferation while PEG provides the mechanical stability to maintain the entire 3D construct. After having modified both PEG and Serum Albumin (used for promoting enzymatic degradability) by adding methacrylate residues (PEGDM and SAM, respectively), Fibrin/PEGDM-SAM sequential IPNs were synthesized as follows: Macroporous sponges were first produced from PEGDM-SAM hydrogels by a freeze-drying technique and then rehydrated by adding the fibrin precursors. Environmental Scanning Electron Microscopy (ESEM) and Confocal Laser Scanning Microscopy (CLSM) were used to characterize their microstructure. Human dermal fibroblasts were cultivated during one week in the constructs and different cell culture parameters (viability, morphology, proliferation) were evaluated. Subcutaneous implantations of the scaffolds were conducted on five-week old male nude mice to investigate their biocompatibility in vivo. We successfully synthesized interconnected and macroporous Fibrin/PEGDM-SAM sequential IPNs. The viability of primary dermal fibroblasts was well maintained (above 90%) after 2 days of culture. Cells were able to adhere, spread and proliferate in the scaffolds suggesting the suitable porosity and intrinsic biologic properties of the constructs. The fibrin network adopted a spider web shape that covered partially the pores allowing easier cell infiltration into the macroporous structure. To further characterize the in vitro cell behavior, cell proliferation (EdU incorporation, MTS assay) is being studied. Preliminary histological analysis of animal studies indicated the persistence of hydrogels even after one-month post implantation and confirmed the absence of inflammation response, good biocompatibility and biointegration of our scaffolds within the surrounding tissues. These results suggest that our Fibrin/PEGDM-SAM IPNs could be considered as potential candidates for dermis regenerative medicine. Histological analysis will be completed to further assess scaffold remodeling including de novo extracellular matrix protein synthesis and early stage angiogenesis analysis. Compression measurements will be conducted to investigate the mechanical properties.

Keywords: fibrin, hydrogels for dermal reconstruction, polyethylene glycol, semi-interpenetrating polymer network

Procedia PDF Downloads 237

Authors: H. Bouaziz, M. Sefi, J. de Lapuente, M. Borras, N. Zeghal

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Although arsenic trioxide has been the subject of toxicological research, in vitro cytotoxicity and genotoxicity studies using relevant cell models and uniform methodology are not well elucidated. Hence, the aim of the present study was to evaluate the cytotoxicity and genotoxicity induced by arsenic trioxide in human keratinocytes (HaCaT) using the MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and alkaline single cell gel electrophoresis (Comet) assays, respectively. Human keratinocytes were treated with different doses of arsenic trioxide for 4 h prior to cytogenetic assessment. Data obtained from the MTT assay indicated that arsenic trioxide significantly reduced the viability of HaCaT cells in a dose-dependent manner, showing a IC50 value of 34.18 ± 0.6 µM. Data generated from the comet assay also indicated a significant dose-dependent increase in DNA damage in HaCaT cells associated with arsenic trioxide exposure. We observed a significant increase in comet tail length and tail moment, showing an evidence of arsenic trioxide -induced genotoxic damage in HaCaT cells. This study confirms that the comet assay is a sensitive and effective method to detect DNA damage caused by arsenic.

Keywords: arsenic trioxide, cytotoxixity, genotoxicity, HaCaT

Procedia PDF Downloads 257

Authors: Kuan Yin Hsiao, Shyh Ming Kuo, Yi Jhen Wu, Chin Wen Chuang, Chuen-Fu Lin, Wei-qing Yang, Han Hsiang Huang

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Anti-tumor effects of natural products, like compounds from marine sponges and soft corals, have been investigated for decades. Polymeric nanoparticles prepared from biodegradable and biocompatible molecules, such as Hyaluronan (HA), Chitosan (CHI) and gelatin have been widely studied. Encapsulation of anti-cancer therapies by the biopolymeric nanoparticles in drug delivery system is potentially capable of improving the therapeutic effects and attenuating their toxicity. In the current study, the anti-bladder cancer effects of heteronemin extracted from the sponge Hippospongia sp. with or without HA and CHI nanoparticle encapsulation were assessed and evaluated in vitro. Results showed that IC50 (half maximal inhibitory concentration) of heteronemin toward T24 human bladder cancer cell viability is approximately 0.18 µg/mL. Both plain and HA nanoparticles-encapsulated heteronemin at 0.2 and 0.4 µg/mL significantly reduced T24 cell viability (P<0.001) while HA nanoparticles-encapsulated heteronemin showed weaker viability-inhibitory effects on L929 fibroblasts compared with plain heteronemin at the identical concentrations. HA and CHI nanoparticles-encapsulated heteronemin exhibited significantly stronger inhibitory effects against migration of T24 human bladder cancer cell than those exerted by plain heteronemin at the same concentrations (P<0.001). The flow cytometric results showed that 0.2 µg/mL HA and CHI nanoparticles-encapsulated heteronemin induced higher early apoptosis rate than that induced by plain heteronemin at the same concentration. These results show that HA and CHI nanoparticle encapsulation is able to elevate anti-migratory and apoptosis-inducing effects exerted by heteronemin against bladder cancer cells in vitro. The in vivo anti-bladder cancer effects of the compound with or without HA/CHI nanoparticle encapsulation will be further investigated and examined using murine tumor models. The data obtained from this study will extensively evaluate of the anti-bladder cancer effects of heteronemin as well as HA/CHI-encapsulated heteronemin and pave a way to develop potential bladder cancer treatment.

Keywords: heteronemin, nanoparticles, hyaluronan, chitosan, bladder cancer

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Authors: Gebregziabher Brhane Berhe, Wei-Nien Su, Bing Joe Hwang

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A new lithium-ion battery is configured by coupling sulfurized carbon anode and high voltage LiNi₀.₅Mn₁.₅O₄ (LNMO) cathode. The anode is derived from sulfurized polyacrylonitrile (S-C(PAN)). Severe capacity fading usually becomes unavoidable due to the oxidative decomposition of solvents, primarily when a conventional carbonate electrolyte with 1 M lithium hexafluorophosphate (LiPF6) is employed. Fluoroethylene carbonate (FEC), ethyl methyl carbonate (EMC), and 1, 1, 2, 2-Tetrafluoroethyl-2, 2, 3, 3-tetrafluoropropyl ether (TTE) are formulated as the best electrolyte (3:2:5 in vol. ratio) for this new high-voltage lithium-ion battery to mitigate this capacity fading and improve the adaptability of the S-C(PAN) and LNMO. The discharge capacity of a full cell made with 1 M lithium hexafluorophosphate (LiPF6) in FEC/EMC/TTE (3:2:5) electrolyte reaches 688 mAh g⁻¹ at a rate of 2 C, while 19 mAh g⁻¹ for the control electrolyte. X-ray photoelectron spectroscopy (XPS) results confirm that the fluorinated electrolyte effectively stabilizes both surfaces of S-C(PAN) and LNMO in the full cell. Compared to the control electrolyte, the developed electrolyte enhances the cyclic stability and rate capability of both half cells (Li//S-C(PAN and Li//LiNi₀.₅Mn₁.₅O₄) and S-C(PAN)//LiNi₀.₅Mn₁.₅O₄ full cells.

Keywords: fluorinated electrolyte, high voltage, lithium-ion battery, polyacrylonitrile

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Authors: Lindy Adoma Dampare, Marina Aferiba Tandoh

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Sickle cell disease (SCD) is an inherited blood disorder that mostly affects individuals in sub-Saharan Africa. Nutritional deficiencies have been well established in SCD patients. In Ghana, studies have revealed the prevalence of malnutrition, especially amongst children with SCD and hence the need to develop an evidence-based comprehensive nutritional therapy for SCD to improve their nutritional status. The aim of the study was to develop and assess the effect of a nutrition education material on the nutritional status of SCD patients in Ghana. This was a pre-post interventional study. Patients between the ages of 2 to 60 years were recruited from the Tema General Hospital. Following a baseline nutrition knowledge (NK), beliefs, sanitary practice and dietary consumption pattern assessment, a twice-monthly nutrition education was carried out for 3 months, followed by a post-intervention assessment. Nutritional status of SCD patients was assessed using a 3-days dietary recall and anthropometric measurements. Nutrition education (NE) was given to SCD adults and caregivers of SCD children. Majority of the caregivers (69%) and SCD adult (82%) at baseline had low NK. The level of NK improved significantly in SCD adults (4.18±1.83 vs. 10.00±1.00, p<0.001) and caregivers (5.58 ± 2.25 vs.10.44± 0.846, p<0.001) after NE. Increase in NK improved dietary intake and dietary consumption pattern of SCD patients. Significant increase in weight (23.2±11.6 vs. 25.9±12.1, p=0.036) and height (118.5±21.9 vs. 123.5±22.2, p=0.011) was observed in SCD children at post intervention. Stunting (10.5% vs. 8.6%, p=0.62) and wasting (22.1% vs. 14.4%, p=0.30) reduced in SCD children after NE although not statistically significant. Reduction (18.2% vs. 9.1%) in underweight and an increase (18.2% vs. 27.3%) in overweight SCD adults was recorded at post intervention. Fat mass remained the same while high muscle mass increased (18.2% vs. 27.3%) at post intervention in SCD adult. Anaemic status of SCD patients improved at post intervention and the improvement was statistically significant amongst SCD children. Nutrition education improved the NK of SCD caregivers and adults hence, improving the dietary consumption pattern and nutrient intake of SCD patients. Overall, NE improved the nutritional status of SCD patients. This study shows the potential of nutrition education in improving the nutritional knowledge, dietary consumption pattern, dietary intake and nutritional status of SCD patients, and should be further explored.

Keywords: sickle cell disease, nutrition education, dietary intake, nutritional status

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Authors: Paul Hernandez-Herrera, Fernando Montoya, Juan Manuel Rendon, Alberto Darszon, Gabriel Corkidi

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Intracellular calcium ([Ca2+]i) regulates sperm motility. The analysis of [Ca2+]i has been traditionally achieved in two dimensions while the real movement of the cell takes place in three spatial dimensions. Due to optical limitations (high speed cell movement and low light emission) important data concerning the three dimensional movement of these flagellated cells had been neglected. Visualizing [Ca2+]i in 3D is not a simple matter since it requires complex fluorescence microscopy techniques where the resulting images have very low intensity and consequently low SNR (Signal to Noise Ratio). In 4D sequences, this problem is magnified since the flagellum oscillates (for human sperm) at least at an average frequency of 15 Hz. In this paper, a novel approach to extract the flagellum’s center-line in 4D stacks is presented. For this purpose, an iterative algorithm based on the fast-marching method is proposed to extract the flagellum’s center-line. Quantitative and qualitative results are presented in a 4D stack to demonstrate the ability of the proposed algorithm to trace the flagellum’s center-line. The method reached a precision and recall of 0.96 as compared with a semi-manual method.

Keywords: flagellum, minimal path, segmentation, sperm

Procedia PDF Downloads 285

Authors: Christopher R. Triggle, Hong Ding, Khaled Machaca, Gnanapragasam Arunachalam

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The antidiabetic drug, metformin, has been in clinical use for over 50 years and remains the first choice drug for the treatment of type two diabetes. In addition to its effectiveness as an oral anti-hyperglycaemic drug metformin also possesses vasculoprotective effects that are assumed to be secondary to its ability to reduce insulin resistance and control glycated hemoglobin levels; however, recent data from our laboratory indicate that metformin also has direct vasoprotective effects that are mediated, at least in part, via the anti-ageing gene, SIRT1. Diabetes is a major risk factor for the development of cardiovascular disease (CVD) and it is also well established that tobacco use further enhances the risk of CVD; however, it is not known whether treatment with metformin can offset the negative effects of diabetes and tobacco use on cardiac function. The current study was therefore designed to investigate 1: the effects of hyperglycaemia (HG) either alone or in the presence of elevated fatty acids (palmitate) and nicotine on the protein expression levels of the deacetylase sirtuin 1 (the protein product of SIRT1), anti-apoptotic Bcl-2, pro-apoptotic BIM and the pro-apoptotic, tumour suppressor protein, acetylated p53 in cardiomyocytes. 2: the ability of metformin to prevent the detrimental effects of HG, palmitate and nicotine on cardiomyocyte survival. Cell culture protocols were designed using a rat cardiomyocyte cell line, H9c2, either under normal glycaemic (NG) conditions of 5.5mM glucose, or hyperglycaemic conditions (HG) of 25mM glucose with, or without, added palmitate (250μM) or nicotine (1.0mM) for 24h. Immuno-blotting was used to detect the expression of sirtuin 1, Bcl-2, BIM, acetylated (Ac)-p53, p53 with β-actin used as the reference protein. Exposure to HG, palmitate, or nicotine alone significantly reduced expression of sirtuin1, Bcl-2 and raised the expression levels of acetylated p53 and BIM; however, the combination of HG, palmitate and nicotine had a synergistic effect to significantly suppress the expression levels of sirtuin 1 and Bcl-2, but further enhanced the expression of Ac-p53, and BIM. The inclusion of 1000μM, but not 50μM, metformin in the H9c2 cell culture protocol prevented the effects of HG, palmitate and nicotine on the pro-apoptotic pathways. Collectively these data indicate that metformin, in addition to its anti-hyperglycaemic and vasculoprotective properties, also has direct cardioprotective actions that offset the negative effects of hyerglycaemia, elevated free fatty acids and nicotine on cardiac cell survival. These data are of particular significance for the treatment of patients with diabetes who are also smokers as the inclusion of metformin in their therapeutic treatment plan should help reduce cardiac-related morbidity and mortality.

Keywords: apoptosis, cardiac muscle, diabetes, metformin, nicotine

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Authors: Saman Khan, Imrana Naseem

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Copper is an essential trace element required for pro-angiogenic co-factors including vascular endothelial growth factor (VEGF). Elevated levels of copper are found in various types of cancer including prostrate, colon, breast, lung and liver for angiogensis and metastasis. Therefore, targeting copper via copper-specific chelators in cancer cells can be developed as effective anticancer treatment strategy. In continuation of our pursuit to design and synthesize copper chelators, herein we opted for a reaction to incorporate di-(2-picolyl) amine in 3-(bromoacetyl) coumarin (parent backbone) for the synthesis of complex 1. We evaluated lipid peroxidation, protein carbonylation, ROS generation, DNA damage and consequent apoptosis by complex 1 in exogenously added Cu(II) in human peripheral lymphocytes (simulate malignancy condition). Results showed that Cu(II)-complex 1 interaction leads to cell proliferation inhibition, apoptosis, ROS generation and DNA damage in human lymphocytes, and these effects were abrogated by cuprous chelator neocuproine and ROS scavengers (thiourea, catalase, SOD). This indicates that complex 1 cytotoxicity is due to redox cycling of copper to generate ROS which leads to pro-oxidant cell death in cancer cells. To further confirm our hypothesis, using the rat model of diethylnitrosamine (DEN) induced hepatocellular carcinoma; we showed that complex 1 mediates DNA breakage and cell death in isolated carcinoma cells. Membrane permeant copper chelator, neocuproine, and ROS scavengers inhibited the complex 1-mediated cellular DNA degradation and apoptosis. In summary, complex 1 anticancer activity is due to its copper chelation capability. These results will provide copper chelation as an effective targeted cancer treatment strategy for selective cytotoxic action against malignant cells without affecting normal cells.

Keywords: cancer treatment, copper chelation, ROS generation, DNA damage, redox cycling, apoptosis

Procedia PDF Downloads 292

Authors: Fahimeh Palizban, Farshad Noravesh, Amir Hossein Saeidian, Mahya Mehrmohamadi

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In the recent decade, the emergence of liquid biopsy has significantly improved cancer monitoring and detection. Dying cells, including those originating from tumors, shed their DNA into the blood and contribute to a pool of circulating fragments called cell-free DNA. Accordingly, identifying the tissue origin of these DNA fragments from the plasma can result in more accurate and fast disease diagnosis and precise treatment protocols. Open chromatin regions are important epigenetic features of DNA that reflect cell types of origin. Profiling these features by DNase-seq, ATAC-seq, and histone ChIP-seq provides insights into tissue-specific and disease-specific regulatory mechanisms. There have been several studies in the area of cancer liquid biopsy that integrate distinct genomic and epigenomic features for early cancer detection along with tissue of origin detection. However, multimodal analysis requires several types of experiments to cover the genomic and epigenomic aspects of a single sample, which will lead to a huge amount of cost and time. To overcome these limitations, the idea of predicting OCRs from WGS is of particular importance. In this regard, we proposed a computational approach to target the prediction of open chromatin regions as an important epigenetic feature from cell-free DNA whole genome sequence data. To fulfill this objective, local sequencing depth will be fed to our proposed algorithm and the prediction of the most probable open chromatin regions from whole genome sequencing data can be carried out. Our method integrates the signal processing method with sequencing depth data and includes count normalization, Discrete Fourie Transform conversion, graph construction, graph cut optimization by linear programming, and clustering. To validate the proposed method, we compared the output of the clustering (open chromatin region+, open chromatin region-) with previously validated open chromatin regions related to human blood samples of the ATAC-DB database. The percentage of overlap between predicted open chromatin regions and the experimentally validated regions obtained by ATAC-seq in ATAC-DB is greater than 67%, which indicates meaningful prediction. As it is evident, OCRs are mostly located in the transcription start sites (TSS) of the genes. In this regard, we compared the concordance between the predicted OCRs and the human genes TSS regions obtained from refTSS and it showed proper accordance around 52.04% and ~78% with all and the housekeeping genes, respectively. Accurately detecting open chromatin regions from plasma cell-free DNA-seq data is a very challenging computational problem due to the existence of several confounding factors, such as technical and biological variations. Although this approach is in its infancy, there has already been an attempt to apply it, which leads to a tool named OCRDetector with some restrictions like the need for highly depth cfDNA WGS data, prior information about OCRs distribution, and considering multiple features. However, we implemented a graph signal clustering based on a single depth feature in an unsupervised learning manner that resulted in faster performance and decent accuracy. Overall, we tried to investigate the epigenomic pattern of a cell-free DNA sample from a new computational perspective that can be used along with other tools to investigate genetic and epigenetic aspects of a single whole genome sequencing data for efficient liquid biopsy-related analysis.

Keywords: open chromatin regions, cancer, cell-free DNA, epigenomics, graph signal processing, correlation clustering

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Authors: Sang-Myung Jung, Jeong Hyun Ju, Gwang Heum Yoon, Hwa Sung Shin

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Central nervous system (CNS) consists of neuronal cell and supporting cells. Astrocytes are the most common supporting cells and play roles in metabolism between neurons and blood vessel. For this function, engineered astrocytes have been studied as a therapeutic source for CNS injury. In neural tissue engineering, nanofiber has been suggested as an effective scaffold for providing structure and mechanical properties influencing physiology. Cellulose acetate (CA) has been investigated for material to fabricate scaffold because of its biocompatibility, biodegradability and fine thermal stability. In this research, CA nanofiber was modified via heat treatment and its effect on astrocyte activity was evaluated. Adhesion and viability of astrocyte were increased in proportion to stiffness. Additionally, expression of GFAP, a marker of astrocyte activation, was increased via stiffness of scaffold. This research suggests a simple modification method to change stiffness of CA nanofiber and shows cellular behavior affecting stiffness of three-dimensional scaffold independently. For the results, we highlight that the stiffness is a factor to regulate astrocyte activity.

Keywords: astrocyte, cellulose acetate, cell therapy, stiffness of scaffold

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Authors: A. Alvaredo , R. Guzman De Villoria, P. Castell, Juan P. Fernandez-Blazquez

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Since graphene was discovered in 2004, has been considered as superb material, due to its outstanding mechanical, electrical and thermal properties. Graphene has been incorporated as reinforcement in several high performance polymers in order to obtain a good balance of properties and to get new properties as thermal or electric conductivity. As well known, the properties of semicrystalline polymer and its composites depends heavily on degree of crystallinity. In this context, our research group has studied the crystallization behavior from amorphous state of PEEK/GNP composites. The monitoring of cold crystallization processes studied by time-resolved simultaneous wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS). These techniques allowed to get an extremely relevant information about the evolution of the morphology of the PEEK/GNP composites. In addition, the thermal evolution of cold crystallization was followed by differential scanning calorimetry (DSC) as well. The experimental results showed changes in crystallization kinetics and c parameter unit cell when adding graphene. The main aim of this work is to produce PEEK/GNP composites and characterize their morphology, unit cell parameters and crystallization kinetic.

Keywords: PEEK, graphene, synchrotron, cold crystallization

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Authors: M. Yadegari, M. Nourbakhsh, N. Arbabzadeh

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The skeletal system injuries are of major importance. In addition, it is recommended to use materials for hard tissue repair in open or closed fractures. It is important to use complex minerals with a beneficial effect on hard tissue repair, stimulating cell growth in the bone. Materials that could help avoid bone fracture inflammatory reaction and speed up bone fracture repair are of utmost importance in the treatment of bone fractures. Similar to minerals, the inner eggshell membrane consists of carbohydrates, lipids, proteins with the high pH, high calcium absorptive capacity and with faster bone fracture repair ability. In the present radiographic survey, eggshell-derived bone graft substitutes were used for bone defect repair in 8 dog tibia, measuring bone density on the day of implant placement and 30 and 60 days after placement. In fact, the result of this study shows the difference in bone growth and misshapen bones between treatment and control sites. Cell growth was adequate in treatment sites and misshapen bones were less frequent here than in control sites.

Keywords: bone repair, eggshell powder, implant, radiography

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Authors: Edgar Ochoa, G. Torres-Villasenor

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Superplastic deformation is shown by materials with a fine grain size, usually less than 10 μm, when they are deformed within the strain rate range 10-5 10-1 s-1 at temperatures greater than 0.5Tm, where Tm is the melting point in Kelvin. According to the constitutive equation for superplastic flow, refinement of the grain size would be expected to increase the optimum strain rate and decrease the temperature required for superplastic flow. Ribbons of eutectic Ag-Cu and Bi-Cd alloys were manufactured by using a single roller melt-spinning technique to obtain a fine grain structure for later test in superplastic regime. The eutectics ribbons were examined by scanning electron microscopy and X-Ray diffraction, and the grain size was determined using the image analysis software ImageJ. The average grain size was less than 1 μm. Tensile tests were carried out from 10-4 to 10-1 s-1, at room temperature, to evaluate the superplastic behavior. The largest deformation was shown by the Bi-Cd eutectic ribbons, Ɛ=140 %, despite that these ribbons have a hexagonal unit cell. On the other hand, Ag-Cu eutectic ribbons have a minor grain size and cube unit cell, however they showed a lower deformation in tensile test under the same conditions than Bi-Cd ribbons. This is because the Ag-Cu grew in a strong cube-cube orientation relationship.

Keywords: eutectic ribbon, fine grain, superplastic deformation, cube-cube orientation

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Authors: Yi Sun, George Ed Rainger, Steve P. Watson

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Background: Beyond the classical roles in haemostasis and thrombosis, platelets are important in the initiation and development of various thrombo-inflammatory diseases. In atherosclerosis and deep vein thrombosis, for example, platelets bridge monocytes with endothelium and form heterotypic aggregates with monocytes in the circulation. This can alter monocyte phenotype by inducing their activation, stimulating adhesion and migration. These interactions involve cell surface receptor-ligand pairs on both cells. This list is likely incomplete as new interactions of importance to platelet biology are continuing to be discovered as illustrated by our discovery of PEAR-1 binding to FcεR1α. Results: We have developed a highly sensitive avidity-based assay to identify novel extracellular interactions among 126 recombinantly-expressed platelet cell surface and secreted proteins involved in platelet aggregation. In this study, we will use this method to identify novel platelet-monocyte interactions. We aim to identify ligands for orphan receptors and novel partners of well-known proteins. Identified interactions will be studied in preliminary functional assays to demonstrate relevance to the inflammatory processes supporting atherogenesis. Conclusions: Platelet-monocyte interactions are essential for the development of thromboinflammatory disease. Up until relatively recently, technologies only allow us to limit our studies on each individual protein interaction at a single time. These studies propose for the first time to study the cell surface platelet-monocyte interactions in a systematic large-scale approach using a reliable screening method we have developed. If successful, this will likely to identify previously unknown ligands for important receptors that will be investigated in details and also provide a list of novel interactions for the field. This should stimulate studies on developing alternative therapeutic strategies to treat vascular inflammatory disorders such as atherosclerosis, DVT and sepsis and other clinically important inflammatory conditions.

Keywords: membrane proteins, large-scale screening, platelets, recombinant expression

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Authors: Ali Bayram, Remzi Yiğiter

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Objective: Alzheimer's disease (AD), the most common cause of dementia, is a progressive neurodegenerative disease. At present, diagnosis of AD is rather late in the disease. Therefore, we attempted to find peripheral biomarkers for the early diagnosis of AD. Herein, we conducted a study to investigate the unc-51 like autophagy activating kinase-1 (ULK1) mRNA expression levels in human peripheral blood mononuclear cells from patients with Alzheimer's disease. Method: To determine whether ULK1 gene expression are altered in AD patients, we measured their gene expression in human peripheral blood cell in 50 patients with AD and 50 age and gender matched healthy controls by quantitative real-time PCR technique. Results: We found that both ULK1 gene expression in peripheral blood cell were significantly decreased in patients with AD as compared with controls (p <0.05). Lower levels of ULK1 gene expression were significantly associated with the increased risk for AD. Conclusions: Serine/threonine-protein kinase involved in autophagy in response to starvation. Acts upstream of phosphatidylinositol 3-kinase PIK3C3 to regulate the formation of autophagophores, the precursors of autophagosomes. Part of regulatory feedback loops in autophagy: acts both as a downstream effector and negative regulator of mammalian target of rapamycin complex 1 (mTORC1) via interaction with RPTOR. Activated via phosphorylation by AMPK and also acts as a regulator of AMPK by mediating phosphorylation of AMPK subunits PRKAA1, PRKAB2, and PRKAG1, leading to negatively regulate AMPK activity. May phosphorylate ATG13/KIAA0652 and RPTOR; however such data need additional evidences. Plays a role early in neuronal differentiation and is required for granule cell axon formation. Alzheimer is the most common neurodegenerative disease. Our results provide useful information that the ULK1 gene expression is decreased in the neurodegeneration and AD patients with, indicating their possible systemic involvement in AD.

Keywords: Alzheimer’s sisease, ULK1, mRNA expression, RT-PCR

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Authors: Hyunjung Lim, Jeonghun Nam, Hyuk Choi

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High-throughput separation is an essential technique for cancer research and diagnosis. Here, we propose a viscoelastic microfluidic device for sheathless, high-throughput isolation of circulating tumor cells (CTCs) from white blood cells. Here, we demonstrate a viscoelastic method for separation and concentration of CTCs using closed-loop microfluidics. Our device is a rectangular straight channel with a low aspect ratio. Also, to achieve high-efficiency, high-throughput processing, we used a polymer solution with low viscosity. At the inlet, CTCs and white blood cells (WBCs) were randomly injected into the microchannel. Due to the viscoelasticity-induced lateral migration to the equilibrium positions, large CTCs could be collected from the side outlet while small WBCs were removed at the center outlet. By recirculating the collected CTCs from the side outlet back to the sample reservoir, continuous separation and concentration of CTCs could be achieved with high separation efficiency (~ 99%). We believe that our device has the potential to be applied in resource-limited clinical settings.

Keywords: circulating tumor cell, closed-loop microfluidics, concentration, separation, viscoelastic fluid

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Authors: Dimitriya A. Mihaylova, Zlatka V. Valkova-Jarvis, Georgi L. Iliev

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One possible approach for maintaining the security of communication systems relies on Physical Layer Security mechanisms. However, in wireless time division duplex systems, where uplink and downlink channels are reciprocal, the channel estimate procedure is exposed to attacks known as pilot contamination, with the aim of having an enhanced data signal sent to the malicious user. The Shifted 2-N-PSK method involves two random legitimate pilots in the training phase, each of which belongs to a constellation, shifted from the original N-PSK symbols by certain degrees. In this paper, legitimate pilots’ offset values and their influence on the detection capabilities of the Shifted 2-N-PSK method are investigated. As the implementation of the technique depends on the relation between the shift angles rather than their specific values, the optimal interconnection between the two legitimate constellations is investigated. The results show that no regularity exists in the relation between the pilot contamination attacks (PCA) detection probability and the choice of offset values. Therefore, an adversary who aims to obtain the exact offset values can only employ a brute-force attack but the large number of possible combinations for the shifted constellations makes such a type of attack difficult to successfully mount. For this reason, the number of optimal shift value pairs is also studied for both 100% and 98% probabilities of detecting pilot contamination attacks. Although the Shifted 2-N-PSK method has been broadly studied in different signal-to-noise ratio scenarios, in multi-cell systems the interference from the signals in other cells should be also taken into account. Therefore, the inter-cell interference impact on the performance of the method is investigated by means of a large number of simulations. The results show that the detection probability of the Shifted 2-N-PSK decreases inversely to the signal-to-interference-plus-noise ratio.

Keywords: channel estimation, inter-cell interference, pilot contamination attacks, wireless communications

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Authors: K. J. Keerthi, Vasundhara Kamineni, A. Ravi Shanker, T. Rammurthy, A. Vijaya Lakshmi, Q. Hasan

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Pancreatic β-cells are the predominant insulin-producing cell types within the Islets of Langerhans and insulin is the primary hormone which regulates carbohydrate and fat metabolism. Apoptosis of β-cells or insufficient insulin production leads to Diabetes Mellitus (DM). Current therapy for diabetes includes either medical management or insulin replacement and regular monitoring. Replacement of β- cells is an attractive treatment option for both Type-1 and Type-2 DM in view of the recent paper which indicates that β-cells apoptosis is the common underlying cause for both the Types of DM. With the development of Edmonton protocol, pancreatic β-cells allo-transplantation became possible, but this is still not considered as standard of care due to subsequent requirement of lifelong immunosuppression and the scarcity of suitable healthy organs to retrieve pancreatic β-cell. Fetal pancreatic cells from abortuses were developed as a possible therapeutic option for Diabetes, however, this posed several ethical issues. Hence, in the present study Mesenchymal stem cells (MSCs) were differentiated into insulin producing cells which were isolated from Human Umbilical cord (HUC) tissue. MSCs have already made their mark in the growing field of regenerative medicine, and their therapeutic worth has already been validated for a number of conditions. HUC samples were collected with prior informed consent as approved by the Institutional ethical committee. HUC (n=26) were processed using a combination of both mechanical and enzymatic (collagenase-II, 100 U/ml, Gibco ) methods to obtain MSCs which were cultured in-vitro in L-DMEM (Low glucose Dulbecco's Modified Eagle's Medium, Sigma, 4.5 mM glucose/L), 10% FBS in 5% CO2 incubator at 37°C. After reaching 80-90% confluency, MSCs were characterized with Flowcytometry and Immunocytochemistry for specific cell surface antigens. Cells expressed CD90+, CD73+, CD105+, CD34-, CD45-, HLA-DR-/Low and Vimentin+. These cells were differentiated to β-cells by using H-DMEM (High glucose Dulbecco's Modified Eagle's Medium,25 mM glucose/L, Gibco), β-Mercaptoethanol (0.1mM, Hi-Media), basic Fibroblast growth factor (10 µg /L,Gibco), and Nicotinamide (10 mmol/L, Hi-Media). Pancreatic β-cells were confirmed by positive Dithizone staining and were found to be functionally active as they released 8 IU/ml insulin on glucose stimulation. Isolating MSCs from usually discarded, abundantly available HUC tissue, expanding and differentiating to β-cells may be the most feasible cell therapy option for the millions of people suffering from DM globally.

Keywords: diabetes mellitus, human umbilical cord, mesenchymal stem cells, differentiation

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Authors: Mohanad Alhabo, Li Zhang, Naveed Nawaz

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In this paper, a non-cooperative game method is formulated where all players compete to transmit at higher power. Every base station represents a player in the game. The game is solved by obtaining the Nash equilibrium (NE) where the game converges to optimality. The proposed method, named Power Efficient Handover Game Theoretic (PEHO-GT) approach, aims to control the handover in dense small cell networks. Players optimize their payoff by adjusting the transmission power to improve the performance in terms of throughput, handover, power consumption and load balancing. To select the desired transmission power for a player, the payoff function considers the gain of increasing the transmission power. Then, the cell selection takes place by deploying Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS). A game theoretical method is implemented for heterogeneous networks to validate the improvement obtained. Results reveal that the proposed method gives a throughput improvement while reducing the power consumption and minimizing the frequent handover.

Keywords: energy efficiency, game theory, handover, HetNets, small cells

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Authors: Ahmed M. Hjazi, Bader M. Hjazi

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Protein 4.1 is a crucial component of complex interactions between the cytoskeleton and other junctional complex proteins. When the gene encoding this protein is altered, resulting in reduced expression, or when the protein is absent, the red cell undergoes a significant structural change. This research aims to achieve a deeper comprehension of the biochemical effects of red cell protein deficiency. A Tandem Mass Spectrometry Analysis (TMT-MS/MS) of patient cells lacking protein 4.1 compared to three healthy controls was achieved by the Proteomics Institute of the University of Bristol. The SDS-PAGE and Western blotting were utilized on the original patient sample and controls to partially confirm TMT MS/MS data analysis of the protein-4.1-deficient cells. Compared to healthy controls, protein levels in samples lacking protein 4.1 had a significantly higher concentration of proteins that probably originated from reticulocytes. This could occur if the patient has an elevated reticulocyte count. The increase in chaperone and reticulocyte-associated proteins was most notable in this study. This may result from elevated quantities of reticulocytes in patients with hereditary elliptocytosis.

Keywords: hereditary elliptocytosis, protein 4.1, red cells, tandem mass spectrometry data.

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Authors: Sam Weber, Deepak Mishra, Susan Wilde, Elizabeth Kramer

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The frequency and severity of cyanobacteria harmful blooms (CyanoHABs) have been increasing over time, with point and non-point source eutrophication and shifting climate paradigms being blamed as the primary culprits. Excessive nutrients, warm temperatures, quiescent water, and heavy and less regular rainfall create more conducive environments for CyanoHABs. CyanoHABs have the potential to produce a spectrum of toxins that cause gastrointestinal stress, organ failure, and even death in humans and animals. To promote enhanced, proactive CyanoHAB management, risk modeling using geospatial tools can act as predictive mechanisms to supplement current CyanoHAB monitoring, management and mitigation efforts. The risk maps would empower water managers to focus their efforts on high risk water bodies in an attempt to prevent CyanoHABs before they occur, and/or more diligently observe those waterbodies. For this research, exploratory spatial data analysis techniques were used to identify the strongest predicators for CyanoHAB blooms based on remote sensing-derived cyanobacteria cell density values for 771 waterbodies in the Georgia Piedmont and landscape characteristics of their watersheds. In-situ datasets for cyanobacteria cell density, nutrients, temperature, and rainfall patterns are not widely available, so free gridded geospatial datasets were used as proxy variables for assessing CyanoHAB risk. For example, the percent of a watershed that is agriculture was used as a proxy for nutrient loading, and the summer precipitation within a watershed was used as a proxy for water quiescence. Cyanobacteria cell density values were calculated using atmospherically corrected images from the European Space Agency’s Sentinel-2A satellite and multispectral instrument sensor at a 10-meter ground resolution. Seventeen explanatory variables were calculated for each watershed utilizing the multi-petabyte geospatial catalogs available within the Google Earth Engine cloud computing interface. The seventeen variables were then used in a multiple linear regression model, and the strongest predictors of cyanobacteria cell density were selected for the final regression model. The seventeen explanatory variables included land cover composition, winter and summer temperature and precipitation data, topographic derivatives, vegetation index anomalies, and soil characteristics. Watershed maximum summer temperature, percent agriculture, percent forest, percent impervious, and waterbody area emerged as the strongest predictors of cyanobacteria cell density with an adjusted R-squared value of 0.31 and a p-value ~ 0. The final regression equation was used to make a normalized cyanobacteria cell density index, and a Jenks Natural Break classification was used to assign waterbodies designations of low, medium, or high risk. Of the 771 waterbodies, 24.38% were low risk, 37.35% were medium risk, and 38.26% were high risk. This study showed that there are significant relationships between free geospatial datasets representing summer maximum temperatures, nutrient loading associated with land use and land cover, and the area of a waterbody with cyanobacteria cell density. This data analytics approach to CyanoHAB risk assessment corroborated the literature-established environmental triggers for CyanoHABs, and presents a novel approach for CyanoHAB risk mapping in waterbodies across the greater southeastern United States.

Keywords: cyanobacteria, land use/land cover, remote sensing, risk mapping

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Authors: Humayun Kabir, Amirul Hasan, Yu Miyaoka, Makiko Yamaguchi, Chisaki Kadota, Kazuaki Takehara

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From field isolates of Newcastle disease virus (NDV) in Japan, one avirulent strain, APMV/northern pintail/Japan/Aomori/2003 (dk-Aomori/03, NDV 261), was selected for its excellent thermostability, and the strain was heat-treated at 56℃ temperatures for 30 min with each passage into Vero cells to maintain thermostability and to adapt Vero cells. After serial 20 passages in Vero cells, it was named NDV Vero20. When growth curves were tested in Vero cells, NDV Vero20 grew well to compare the original NDV261. The HN gene was sequenced, and found motifs that show thermostability. The intracerebral pathogenicity index (ICPI) test score was 0. The thermostability of the virus was confirmed by storing it at different temperatures, including at 37°C. When susceptible chicks were inoculated with NDV Vero20 through eye drops, induced adequate levels of antibody were measured using a serum neutralization test. The results showed that NDV Vero20, a vaccine candidate strain is thermostable, Vero cell adapted, and has immunogenic potential, which would make as an alternative to the traditional embryonated chicken eggs-based vaccine.

Keywords: Newcastle disease virus, thermostability, vaccine, Vero cell adaptability

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Authors: Caleb B. Sagwa, Tobias O. Okeno, Alexander K. Kahi

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Dairy cattle production plays an important role in the Kenyan economy. However, high incidences of mastitis is a major setback to the productivity in this industry. The current dairy cattle breeding objective in Kenya does not include mastitis resistance, mainly because the economic value of mastitis resistance has not been determined. Therefore this study aimed at estimating the economic value of mastitis resistance in dairy cattle in Kenya. Initial input parameters were obtained from literature on dairy cattle production systems in the tropics. Selection index methodology was used to derive the economic value of mastitis resistance. Somatic cell count (SCC) was used an indicator trait for mastitis resistance. The economic value was estimated relative to milk yield (MY). Economic values were assigned to SCC in a selection index such that the overall gain in the breeding goal trait was maximized. The option of estimating the economic value for SCC by equating the response in the trait of interest to its index response was considered. The economic value of mastitis resistance was US $23.64 while maximum response to selection for MY was US $66.01. The findings of this study provide vital information that is a pre-requisite for the inclusion of mastitis resistance in the current dairy cattle breeding goal in Kenya.

Keywords: somatic cell count, milk quality, payment system, breeding goal

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Authors: Ashagrie Getnet Flattie

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Line-of-sight (LOS) information, data rates, good quality, and flexible network service are limited by the fact that, for the duration of any given connection, they experience severe variation in signal strength due to fading and path loss. Wireless system faces major challenges in achieving wide coverage and capacity without affecting the system performance and to access data everywhere, all the time. In this paper, the cell coverage and edge rate of different Multiple-input multiple-output (MIMO) schemes in 20 MHz Long Term Evolution (LTE) system under Unmanned Air Vehicles (UAV) platform are investigated. After some background on the enormous potential of UAV, MIMO, and LTE in wireless links, the paper highlights the presented system model which attempts to realize the various benefits of MIMO being incorporated into UAV platform. The performances of the three MIMO LTE schemes are compared with the performance of 4x4 MIMO LTE in UAV scheme carried out to evaluate the improvement in cell radius, BER, and data throughput of the system in different morphology. The results show that significant performance gains such as bit error rate (BER), data rate, and coverage can be achieved by using the presented scenario.

Keywords: LTE, MIMO, path loss, UAV

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Authors: Md. Maksudur Rahman Khan, Chee Wai Woon, Huei Ruey Ong, Vignes Rasiah, Chin Kui Cheng, Kar Min Chan, E. Baranitharan

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The present work represents a preparation of non-precious iron-based electrocatalyst (FeN) for ORR in air-cathode microbial fuel cell by pyrolysis treatment. Iron oxalate which recovered from the industrial wastewater and Phenanthroline (Phen) were used as the iron and nitrogen precursors, respectively in preparing FeN catalyst. The performance of as prepared catalyst (FeN) was investigated in a single chambered air cathode MFC in which anaerobic sludge was used as inoculum and palm oil mill effluent as substrate. The maximum open circuit potential (OCV) and the highest power density recorded were 0.543 V and 4.9 mW/m2, respectively. Physical characterization of FeN was elucidated by using Brunauner Emmett Teller (BET), X-Ray Diffraction (XRD) analysis and Field Emission Scanning Electron Microscopy (FESEM) while the electrochemical properties were characterized by cyclic voltammetry (CV) analysis. The presence of biofilm on anode surface was examined using FESEM and confirmed using Infrared Spectroscopy and Thermogravimetric Analysis. The findings of this study demonstrated that FeN is electrochemically active and further modification is needed to increase the ORR catalytic activity.

Keywords: iron based catalyst, microbial fuel cells, oxygen reduction reaction, palm oil mill effluent

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Authors: Nonita Sarin, K.J.Singh, Anuj Kumar, Davinder Singh

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Polymeric 3D hydrogels have pivotal role in bone tissue regeneration applications. Hydrogels behave similar to the living tissues because they have large water imbibing capacity in swollen state and adjust their shape according to the tissues during tissue formation after implantation. On the other hand, hydrogels are very soft, fragile and lack mechanical strength. Incorporation of bioceramics can improve mechanical strength. Furthermore, bioceramics synthesized by sol gel technique may enhance the apatite formation and degradation rates which can lead to the increase in faster rates for new bone and tissue regeneration. Simulated body fluid (SBF) induces the poly-condensation of silanol groups which leads to formation of silica matrix and provide active sites for the precipitation of Ca2+ and PO43- ions to form apatite layer which is similar to mineral form of bone. Therefore, authors have synthesized bioceramic incorporated Polyacrylamide-carboxymethylcellulose hydrogels by free radical polymerization and bioceramic compositions of xSrO-(36-x)CaO-45SiO2-ySeO3-(12-y)P2O5-7MgO (where x=0,4 and y=0,2 mol%) were synthesized by sol gel technique. Bioceramics incorporated in polymer matrix induces quicker apatite formation during immersion in SBF by raising the pH with the release of alkaline ions during ion exchange process and the apatite formation takes place in alkaline medium. The behavior of samples PABC-0 (without bioceramics) and PABC-20 (with 20 wt% bioceramics) were evaluated by X-Ray Diffraction and FTIR. In term of bioactivity, it was observed that PABC-20 has shown hydroxyapatite (HA) formation on 1st day of immersion whereas, PABC-0 was shown apatite formation on 7th day of immersion in SBF. The rapid rate of HA growth on 1st day of immersion in SBF signifies easy regeneration of damaged bone tissues. Degradation studies have been undertaken in Phosphate Buffer Saline and PABC-20 exhibited slower degradation rate up to 9%as compared to PABC-0 up to 18%. Slower degradation rate is suitable for new tissue regeneration and cell attachment. Also, Zeta potential studies have been employed to check the surface charge and it has been observed that samples carry negative charge when immersed in SBF. In addition, the swelling test of the samples have been performed and relative swelling ratio % observed for PABC-0 is 607% and PABC-20 is 305%. This indicates that the incorporation of bioceramics leads to the filling up of the voids in between the polymer matrix which in result reduces porosity and increase the mechanical strength by filling the voids. The porosity of PABC-0 is 84% and PABC-20 is 72%. PABC-20 sample demonstrates that bioceramics incorporation reduce the porosity and improves mechanical strength. Also, maximum in vitro cell viability up to 98% with MG63 cell line has been observed which indicate that the bioceramic incorporated hydrogel(PABC-20) provide the alkaline medium which is suitable environment for cell growth.

Keywords: hydrogels, hydroxyapatite, MG63 cell line, zeta potential

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Authors: G. Eom, H. Kim, A. Hwang, T. Kang, B. Kim

Abstract:

Telomerase activity is overexpressed in over 85% of human cancers while suppressed in normal somatic cells. Telomerase has been attracted as a universal cancer biomarker. Therefore, the development of effective telomerase activity detection methods is urgently demanded in cancer diagnosis and therapy. Herein, we report a nanogap-rich Au nanowire (NW) surface-enhanced Raman scattering (SERS) sensor for detection of human telomerase activity. The nanogap-rich Au NW SERS sensors were prepared simply by uniformly depositing nanoparticles (NPs) on single-crystalline Au NWs. We measured SERS spectra of methylene blue (MB) from 60 different nanogap-rich Au NWs and obtained the relative standard deviation (RSD) of 4.80%, confirming the superb reproducibility of nanogap-rich Au NW SERS sensors. The nanogap-rich Au NW SERS sensors enable us to detect telomerase activity in 0.2 cancer cells/mL. Furthermore, telomerase activity is detectable in 7 different cancer cell lines whereas undetectable in normal cell lines, which suggest the potential applicability of nanogap-rich Au NW SERS sensor in cancer diagnosis. We expect that the present nanogap-rich Au NW SERS sensor can be useful in biomedical applications including a diverse biomarker sensing.

Keywords: cancer biomarker, nanowires, surface-enhanced Raman scattering, telomerase

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Authors: Ji-Young Choi, Jungjin Kim, Sang-Sun Yun, Sangmee Ahn Jo

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Intracellular adhesion molecule1 (ICAM1) is a mediator of inflammation and involved in adhesion and transmigration of leukocytes to endothelial cells, resulting in enhancement of brain inflammation. We hypothesized that increase of ICAM1 expression in endothelial cells is an early step in the pathogenesis of brain diseases such as Alzheimer’s disease. Here, we report that ICAM1 expression is regulated by pro-inflammatory cytokine TNFa in human microvascular endothelial cell (HBMVEC). TNFa significantly increased ICAM1 mRNA and protein levels at the concentrations showing no cell toxicity. This increase was also shown in micro vessels of mouse brain 24 hours after treatment with TNFa (8 mg/kg, i.v). We then investigated the epigenetic mechanism involved in the induction of ICAM1 expression. Chromatin immunoprecipitation assay revealed that TNFa reduced methylation of histone3K9 (H3K9-2me) and histone3K27 (H3K27-3me), well-known modification as gene suppression, with in the ICAM1 promoter region. However, acetylation of H3K9 and H3K14, well-known modification as gene activation, was not changed by TNFa. Treatment of BIX01294, a specific inhibitor of histone methyltransferase G9a responsible for H3K9-2me, dramatically increased in ICAM1 mRNA and protein levels and overexpression of G9a gene suppressed TNFa-induced ICAM1 expression. In contrast, GSK126, an inhibitor of histone methyltransferase EZH2 responsible for H3K27-3me and valproic acid, an inhibitor of histone deacetylase (HDAC) did not affect ICAM1 expression. These results suggested that histone3 methylation is involved in ICAM1 repression. Moreover, TNFa or BIX01294-induced ICAM induction resulted in both enhancements in adhesion and transmigration of leukocyte on endothelial cell. This study demonstrates that TNFa upregulates ICAM1 expression through H3K9-2me and H3K27-3me within the ICAM1 promoter region, in which G9a is likely to play a pivotal role in ICAM1 transcription. Our study provides a novel mechanism for ICAM1 transcription regulation in HBMVEC.

Keywords: ICAM1, TNFa, HBMVEC, H3K9-2me

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Authors: Zeyu Zhou, Ziyu Zhao, Xiaochen Yang, Ling AI, Heng Zhai, Stuart Holmes

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As a promising sustainable alternative to traditional fossil fuels, fuel cell technology is highly favoured due to its enhanced working efficiency and reduced emissions. In the context of high-temperature fuel cells (operating above 100 °C), the most commonly used proton exchange membrane (PEM) is the Polybenzimidazole (PBI) doped phosphoric acid (PA) membrane. Grafting is a promising strategy to advance PA-doped PBI PEM technology. The existing grafting modification on PBI PEMs mainly focuses on grafting phosphate-containing or alkaline groups onto the PBI molecular chains. However, quaternary ammonium-based grafting approaches face a common challenge. To initiate the N-alkylation reaction, deacidifying agents such as NaH, NaOH, KOH, K2CO3, etc., can lead to ionic crosslinking between the quaternary ammonium group and PBI. Polyvinylpyrrolidone (PVP) is another widely used polymer, the N-heterocycle groups within PVP endow it with a significant ability to absorb PA. Recently, PVP has attracted substantial attention in the field of fuel cells due to its reduced environmental impact and impressive fuel cell performance. However, due to the the poor compatibility of PVP in PBI, few research apply PVP in PA-doped PBI PEMs. This work introduces an innovative strategy to graft PVP onto PBI to form a network-like polymer. Due to the absence of quaternary ammonium groups, PVP does not pose issues related to crosslinking with PBI. Moreover, the nitrogen-containing functional groups on PVP provide PBI with a robust phosphoric acid retention ability. The nuclear magnetic resonance (NMR) hydrogen spectrum analysis results indicate the successful completion of the grafting reaction where N-alkylation reactions happen on both sides of the grafting agent 1,4-bis(chloromethyl)benzene. On one side, the reaction takes place with the hydrogen atoms on the imidazole groups of PBI, while on the other side, it reacts with the terminal amino group of PVP. The XPS results provide additional evidence from the perspective of the element. On synthesized PBI-g-PVP surfaces, there is an absence of chlorine (chlorine in grafting agent 1,4-bis(chloromethyl)benzene is substituted) element but a presence of sulfur element (sulfur element in terminal amino PVP appears in PBI), which demonstrates the occurrence of the grafting reaction and PVP is successfully grafted onto PBI. Prepare these modified membranes into MEA. It was found that during the fuel cell operation, all the grafted membranes showed substantial improvement in maximum current density and peak power density compared to unmodified one. For PBI-g-PVP 30, with a grafting degree of 22.4%, the peak power density reaches 1312 mW cm⁻², marking a 59.6% enhancement compared to the pristine PBI membrane. The improvement is caused by the improved PA binding ability of the membrane after grafting. The AST test result shows that the grafting membranes have better long-term durability and performance than unmodified membranes attributed to the presence of added PA binding sites, which can effectively prevent the PA leaching caused by proton migration. In conclusion, the test results indicate that grafting PVP onto PBI is a promising strategy which can effectively improve the fuel cell performance.

Keywords: fuel cell, grafting modification, PA doping ability, PVP

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