Search results for: hepatic stellate cell

Authors: Marco Avila Lopez, Hasnae Ait-Douchi, Silvia De Los Santos, Badr Eddine Lebrouhi, Pamela Ramírez Vidal

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In the context of the energy transition, fuel cell technology has emerged as a solution for harnessing hydrogen energy and mitigating greenhouse gas emissions. An in-depth study was conducted on a PEMFC-type fuel cell, with an initiation of an analysis of its operational principles and constituent components. Subsequently, the modelling of the fuel cell was undertaken using the Python programming language, encompassing both steady-state and transient regimes. In the case of the steady-state regime, the physical and electrochemical phenomena occurring within the fuel cell were modelled, with the assumption of uniform temperature throughout all cell compartments. Parametric identification was carried out, resulting in a remarkable mean error of only 1.62% when the model results were compared to experimental data documented in the literature. The dynamic model that was developed enabled the scrutiny of the fuel cell's response in terms of temperature and voltage under varying current conditions.

Keywords: fuel cell, modelling, dynamic, thermal model, PEMFC

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Authors: Misa Nakao, Yuta Kurashina, Chikahiro Imashiro, Kenjiro Takemura

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The Research Goal: With the growing demand for regenerative medicine, an effective mass cell culture process is required. In a repetitive subculture process for proliferating cells, preparing single cell suspension which does not contain any cell aggregates is highly required because cell aggregates often raise various undesirable phenomena, e.g., apoptosis and decrease of cell proliferation. Since cell aggregates often occur in cell suspension during conventional subculture processes, this study proposes a single cell sorter driven by a resonance vibration of a cell culture substrate. The Method and the Result: The single cell sorter is simply composed of a cell culture substrate and a glass pipe vertically placed against the cell culture substrate with a certain gap corresponding to a cell diameter. The cell culture substrate is made of biocompatible stainless steel with a piezoelectric ceramic disk glued to the bottom side. Applying AC voltage to the piezoelectric ceramic disk, an out-of-plane resonance vibration with a single nodal circle of the cell culture substrate can be excited at 5.5 kHz. By doing so, acoustic radiation force is emitted, and then cell suspension containing only single cells is pumped into the pipe and collected. This single cell sorter is effective to collect single cells selectively in spite of its quite simple structure. We collected C2C12 myoblast cell suspension by the single cell sorter with the vibration amplitude of 12 µmp-p and evaluated the ratio of single cells in number against the entire cells in the suspension. Additionally, we cultured the collected cells for 72 hrs and measured the number of cells after the cultivation in order to evaluate their proliferation. As a control sample, we also collected cell suspension by conventional pipetting, and evaluated the ratio of single cells and the number of cells after the 72-hour cultivation. The ratio of single cells in the cell suspension collected by the single cell sorter was 98.2%. This ratio was 9.6% higher than that collected by conventional pipetting (statistically significant). Moreover, the number of cells cultured for 72 hrs after the collection by the single cell sorter yielded statistically more cells than that collected by pipetting, resulting in a 13.6% increase in proliferated cells. These results suggest that the cell suspension collected by the single cell sorter driven by the resonance vibration hardly contains cell aggregates whose diameter is larger than the gap between the cell culture substrate and the pipe. Consequently, the cell suspension collected by the single cell sorter maintains high cell proliferation. Conclusions: In this study, we developed a single cell sorter capable of sorting and pumping single cells by a resonance vibration of a cell culture substrate. The experimental results show the single cell sorter collects single cell suspension which hardly contains cell aggregates. Furthermore, the collected cells show higher proliferation than that of cells collected by conventional pipetting. This means the resonance vibration of the cell culture substrate can benefit us with the increase in efficiency of mass cell culture process for clinical applications.

Keywords: acoustic radiation force, cell proliferation, regenerative medicine, resonance vibration, single cell sorter

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Authors: Assia Haif, Djelloul Achouri, Zineddine Soualili

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Introduction: Laparoscopic treatment of liver echinococcosis cyst has become popular. In parallel, the diagnostic approach of cystic liver lesions is based on the number of lesions and their distribution. The etiologies of cystic masses in children are different, and the role of imaging in their characterization and pre-therapeutic evaluation is essential. The main differential diagnoses of hepatic hydatid cysts can be discovered intraoperatively by minimally invasive surgery. Methods: The clinical data contained seven patients with hepatic cystic who underwent laparoscopic surgery in the Department of Pediatric Surgery, SETIF, Algeria, from 2015 to 2022. Results: Of reported seven patients, five are male, and the remaining two are female. Abdominal pain was the most frequent clinical signs. Biological parameters were within normal limits, Abdominal ultrasound, practiced in all cases, completed by abdominal computed tomography (CT), showed a hydatid cystic. For all patients, surgical procedures were performed under laparoscopy. Total cystectomy in four patients, fenestration or subtotal cystectomy in three patients, respectively. A histopathological feature confirmed the nature of the cysts. During the follow-up period, there was no recurrence. Conclusions: Laparoscopic liver surgery is a safe and effective approach, it is an alternative to conventional surgery and a reproducible method. Laparoscopic surgery approach should follow the same principals with those of open surgery. This surgical technique can rectify the diagnosis of hydatid cyst, the histopathological examination confirms the nature of the cystic lesion.

Keywords: children, cyst, echinococcosis, laparoscopic, liver

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Authors: Ezaldin A. M. Mohammed, Youssef K. H. Abdalhafid, Masoud. M. Zatout

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The study aims to clarify the toxic effect of plant hormones, which are widely used in agriculture. One of these is the plant hormones (indole acetic acid); has been ٳata hormone to rats at 100 ppm salt solution of 0.2 per day after day for a period of forty days before conception until the fourteenth day or sixteenth or childbirth. Treatment brought about a marked shortage in the rate of increase in the weight of mice., And a percentage of the weight of the liver there was a distinct increase in the relative weight of the liver. As well as the increase in pathological changes and increase the size of the nuclei and Kupffer cell, as noted widespread and dense clusters of inflammatory cells accompanied by about the erosion of liver tissue and blood ٳrchah. Biochemical analyzes showed a marked decrease of the liver in antioxidant enzymes and an increase in the rate of free radicals. It was also noted an increase in cases of abortion. The owner of so many birth defects. It was also noted the lack of body weight in fetuses and increase the absorption rate of embryos in fetuses of mothers treatment compared to the control group. Showed microscopic examinations of the liver of mice born in the transaction and the decay in the presence of hepatic cells and edema, blood vessels and increase the rate of cell death.

Keywords: indol acetic acid, liver, pathological changes, albino rats

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Authors: So Young Kim, Eun-Young Kwon, Bora Choi, Mi Kyeong Yu, Seon Jeong Lee, Myung-Sook Choi

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Lemon (Citrus limon) has various beneficial effect. Eriocitrin (eriodictyol 7-rutinoside) is the main ingredient of lemon fruit and is known to have antioxidative effects. However, there has been little research about the effects of eriocitrin on obesity and regulation of lipid profiles levels. In the present study, we investigated the anti-obesity and lipid-lowering effects of eriocitrin in mice fed high-fat diet (HFD). The 4 week-old male C57BL/6 mice were randomly divided into two groups and were fed HFD (20% fat, w/w) and HFD supplemented with eriocitrin (0.005%, w/w, EC) for 16 weeks. Food intake, body weight and white adipose tissue weight (WAT) were measured and plasma free fatty acid (FFA), apolipoprotein (Apo) B100 level and hepatic enzyme activity were analyzed. No differences were shown between the HFD and EC groups in body weight and food intake. However EC supplementation significantly reduced the weights of epididymal, subcutaneous and total WAT. In addition, the levels of plasma FFA and Apo B100 were significantly decreased in the EC group compared with the HFD group. Moreover, the activities of glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME) related to fatty acids synthesis were significantly lower in the EC group than in the HFD group in liver. Therefore, this study indicates that eriocitrin has beneficial effects on adiposity and nonalcholic fatty liver diseases by modulating hepatic lipid-regulating enzyme activities and plasma lipid profile.

Keywords: antiobesity, eriocitrin, high fat diet, lipid lowering

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Authors: Abdolamir Allameh, Shahnaz Esmaeili, Mina Allameh, Safoura Khajeniazi

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Stem cells with therapeutic applications can be isolated from human placenta/umblical cord blood (UCB) as well as the cord tissue (UC). Stem cells in culture are vulnerable to oxidative stress, particularly when subjected to differentiation process. The aim of this study was to examine the chnages in the rate of oxidation that occurs to cellular macromolecules during hepatic differentiation of mononuclear cells (MSCs). In addition, the impact of the hepatic differentiation process of MSC on cellular and biological activity of the cells will be undertaken. For this purpose, first mononuclear cells (MNCs) were isolated from human UCB which was obtained from a healthy full-term infant. The cells were cultured at a density of 3×10⁵ cells/cm² in DMEM- low-glucose culture media supplemented with 20% FBS, 2 mM L-glutamine, 100 μg/ml streptomycin and 100 U/ml penicillin. Cell cultures were then incubated at 37°C in a humidified 5% CO₂ incubator. After removing non-adherent cells by replacing culture medium, fibroblast-like adherent cells were resuspended in 0.25% trypsin-EDTA and plated in 25 cm² flasks (1×10⁴/ml). Characterization of the MSCs was routinely done by observing their morphology and growth curve. MSCs were subjected to a 2-step hepatocyte differentiation protocol in presence of hepatocyte growth factor (HGF), dexamethazone (DEX) and oncostatin M (OSM). The hepatocyte-like cells derived from MSCs were checked every week for 3 weeks for changes in lipid peroxidation, protein carbonyl formation and DNA oxidation i.e., 8-hydroxy-2'-deoxyguanosine (8-OH-dG) assay. During the 3-week differentiation process of MSCs to hepatocyte-like cells we found that expression liver-specific markers such as albumin, was associated with increased levels of lipid peroxidation and protein carbonyl formation. Whereas, undifferentiated MSCs has relatively low levels of lipid peroxidation products. There was a significant increase ( p < 0.05) in lipid peroxidation products in hepatocytes on days 7, 14, and 21 of differentiation. Likewise, the level of protein carbonyls in the cells was elevated during the differentiation. The level of protein carbonyls measured in hepatocyte-like cells obtained 3 weeks after differentiation induction was estimated to be ~6 fold higher compared to cells recovered on day 7 of differentiation. On the contrary, there was a small but significant decrease in DNA damage marker (8-OH-dG) in hepatocytes recovered 3 weeks after differentiation onset. The level of 8-OHdG which was in consistent with formation of reactive oxygen species (ROS). In conclusion, this data suggest that despite the elevation in oxidation of lipid and protein molecules during hepatocyte development, the cells were normal in terms of DNA integrity, morphology, and biologically activity.

Keywords: adult stem cells, DNA integrity, free radicals, hepatic differentiation

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Authors: Celso Afonso Klein Jr., Henrique Cantarelli, Fernando Portella, Keiichi Hosaka, Eduardo Reston, Fabricio Collares, Roberto Zimmer

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TTo evaluate the influence of preheating self-adhesive cement at 39ºC on cell migration, cytotoxicity and degree of conversion. RelyX U200, Set PP and MaxCem Elite were subjected to a degree of conversion analysis (FTIR-ATR). For the cytotoxicity analysis, extracts (24 h and 7 days) were placed in contact with NIH/3T3 cells. For cell migration, images were captured of each sample until the possible closure of the cleft occurred. In the results of the degree of conversion, preheating did not improve the conversion of cement. For the MTT, preheating did not improve the results within 24 hours. However, it generated positive results within 7 days for the Set PP resin cement. For cell migration, high rates of cell death were found in all groups. It is concluded that preheating at 39ºC caused a positive effect only in increasing the cell viability of the Set PP resin cement and that both materials analyzed are highly cytotoxic.

Keywords: dental cements, resin cements, degree of conversion, cytotoxicity, cell migration assays

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Authors: Mehran Fadaeinasab, Hamed Karimian, Najihah Mohd Hashim, Hapipah Mohd Ali

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In this study, three indole alkaloids namely; rauvolfine B, macusine B, and isoreserpiline have been isolated from the dichloromethane crude extract of Rauvolfia reflexa bark (Apocynaceae). The structural elucidation of the isolated compounds has been performed using spectral methods such as UV, IR, MS, 1D, and 2D NMR. Rauvolfine B showed anti proliferation activity on HCT-116 cancer cell line, its cytotoxicity induction was observed using MTT assay in eight different cell lines. Annexin-V is serving as a marker for apoptotic cells and the Annexin-V-FITC assay was carried out to observe the detection of cell-surface Phosphatidylserine (PS). Apoptosis was confirmed by using caspase-8 and -9 assays. Cell cycle arrest was also investigated using flowcytometric analysis. rauvolfine B had exhibited significantly higher cytotoxicity against HCT-116 cell line. The treatment significantly arrested HCT-116 cells in the S phase. Together, the results presented in this study demonstrated that rauvolfine B inhibited the proliferation of HCT-116 cells and programmed cell death followed by cell cycle arrest.

Keywords: apocynacea, indole alkaloid, apoptosis, cell cycle arrest

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Authors: Gizaw Mamo Gebeyehu, Marianna Pap, Geza Makkai, Tibor Z. Janosi, Shima Rashidian, Tibor A. Rauch

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Sepsis poses a significant global health threat, necessitating extensive exploration of indicators tied to its pathological mechanisms and multi-organ dysfunction. While murine studies have shed light on sepsis, the intricate cellular and molecular landscape in human sepsis remains enigmatic. Exploring the influence of activated monocyte-derived exosomes in sepsis sheds light on a promising pathway for understanding the intricate cellular and molecular mechanisms involved in this condition in humans. In sepsis, exosome-borne mRNA and miRNA orchestrate immune response gene expression in recipient cells. Yet, the specifics of exosome-mediated cell-to-cell communication, especially how mRNA cargoes modulate gene expression in recipient cells, remain poorly understood. This study aims to elucidate the precise molecular pathways through which exosomal mRNA cargo, particularly MAFB, contributes to the developing sepsis-induced molecular aberrations in liver tissues, employing rigorously defined cell culture conditions. THP-1 cells were treated with LPS to induce changes in exosomal RNA profiles. Exosomes were isolated and characterized using microscopy and mass spectrometry. RNA was extracted from exosomes and sequenced. The most abundant exosomal mRNAs were subjected to GO analysis for functional annotation analysis and KEGG database analysis to identify the involved enriched pathways. PCR (Polymerase Chain Reaction), RNA sequencing, and Western blotting were involved to analyze changes in gene expression, protein levels, and signaling pathways within the liver cells( HepG2) after exposure to exosomal MAFB. This study pinpoints exosomal MAFB as a potential key regulator linked to liver cell damage during sepsis, along with associated genes (miR155HG, H3F3A, and possibly JARD2) forming a crucial molecular pathway contributing to liver cell injury, Together, these elements indicate a vital molecular pathway that plays a significant role in the emergence of liver cell injury during sepsis.. These findings suggest the importance of further research on these components for potential therapeutic interventions in managing acute liver damage in sepsis.

Keywords: sepsis, exososome, exosomal MAFB, LPS-induced THP-1 cells, RNA profiles, sepsis-triggered liver injury

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Authors: Bing-Fang Lee, Srinivasan Periasamy, Ming-Yie Liu

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Shift work sleep disorder is a common problem in industrialized world. It is a type of circadian rhythmic sleep disorders characterized by insomnia and sleep deprivation. Lack of sleep in workers may lead to poor health conditions such as hepatic dysfunction. Melatonin is a hormone secreted by the pineal gland to alleviate insomnia. Moreover, it is a powerful antioxidant and may prevent acute liver injury. Therefore, workers take in melatonin to deal with sleep-related health is an important issue. The aim of this study was to investigate the effect of melatonin on an acute hepatic injury model sinusoidal obstruction syndrome (SOS) in mice. Male C57BL/6 mice were injected with a single dose (500 mg/kg) of monocrotaline (MCT) to induce SOS. Melatonin (1, 3, 10 and 30 mg/kg) was injected 1 h before MCT treatment. After 24 h of MCT treatment, mice were sacrificed. The blood and liver were collected. Organ damage was evaluated by serum biochemistry, hematology analyzer, and histological examination. Low doses of melatonin (1 and 3 mg/kg) had no protective effect on SOS. However, high doses (10 and 30 mg/kg) exacerbated SOS. In addition, it not only increased serum glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) and extended liver damage indicated by histological examination but also decreased platelet levels, lymphocyte ratio, and glutathione level; it had no effect on malondialdehyde and nitric oxide level in SOS mice. To conclude, melatonin may exacerbate MCT-induced SOS in mice. Furthermore, melatonin might have a synergistic action with SOS. Usage of melatonin for insomnia by people working in long shift must be cautioned; it might cause acute hepatic injury.

Keywords: acute liver injury, melatonin, shift work, sleep deprivation

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Authors: Deepak Mohan, Sushma Sharma

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Diclofenac sodium, a member of the acetic acid family of non-steroidal anti-inflammatory drugs, is used to retard inflammation, arthritis pain and ankylosing spondylitis. The drug is known to cause severe injury in different tissues due to formation of reactive oxygen species. The present study is focused on the effect of different doses of diclofenac (4 mg/kg/body weight and 14 mg/kg/body weight on histoarchitecture of the liver from 7-28 days of the investigation. Diclofenac administration resulted in distorted hepatic degeneration and formation of wide areas in the form of sinusoidal gaps. Hepatic fibrosis noticed in different stages of investigation could be attributed to chronic inflammation and reactive oxygen species which results in deposition of extracellular matrix proteins. The abrupt degenerative changes observed during later stages of the experiment showed maximum damage to the liver, and there was enlargement of sinusoidal gaps accompanied by maximum necrosis in the tissues.

Keywords: arthritis, diclofenac, histoarchitecture, sinusoidal

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Authors: Ben Nadler

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Cell adhesion plays a vital role in many cell activities. The motivation to model cell adhesion is to study important biological processes, such as cell spreading, cell aggregation, tissue formation, and cell adhesion, which are very challenging to study by experimental methods alone. This study provides important insight into cell adhesion, which can lead to improve regenerative medicine and tissue formation techniques. In this presentation the biological cells adhesion is mediated by receptors–ligands binding and the diffusivity of the receptor on the cell membrane surface. The ability of receptors to diffuse on the cell membrane surface yields a very unique and complicated adhesion mechanism, which is exclusive to cells. The phospholipid bilayer, which is the main component in the cell membrane, shows fluid-like behavior associated with the molecules’ diffusivity. The biological cell is modeled as a fluid-like membrane with negligible bending stiffness enclosing the cytoplasm fluid. The in-plane mechanical behavior of the cell membrane is assumed to depend only on the area change, which is motivated by the fluidity of the phospholipid bilayer. In addition, the presence of receptors influences on the local mechanical properties of the cell membrane is accounted for by including stress-free area change, which depends on the receptor density. Based on the physical properties of the receptors and ligands the attraction between the receptors and ligands is modeled as a charged-nonpolar which is a noncovalent interaction. Such interaction is a short-range type, which decays fast with distance. The mobility of the receptor on the cell membrane is modeled using the diffusion equation and Fick’s law is used to model the receptor–receptor interactions. The resultant interaction force, which includes receptor–ligand and receptor–receptor interaction, is decomposed into tangential part, which governs the receptor diffusion, and normal part, which governs the cell deformation and adhesion. The formulation of the governing equations and numerical simulations will be presented. Analysis of the adhesion characteristic and properties are discussed. The roles of various thermomechanical properties of the cell, receptors and ligands on the cell adhesion are investigated.

Keywords: cell adhesion, cell membrane, receptor-ligand interaction, receptor diffusion

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Authors: Lanlan Xiao, Yang Liu, Shuo Chen, Bingmei Fu

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Most cancer-related deaths are due to metastasis. Metastasis is a complex, multistep processes including the detachment of cancer cells from the primary tumor and the migration to distant targeted organs through blood and/or lymphatic circulations. During hematogenous metastasis, the emigration of tumor cells from the blood stream through the vascular wall into the tissue involves arrest in the microvasculature, adhesion to the endothelial cells forming the microvessel wall and transmigration to the tissue through the endothelial barrier termed as extravasation. The narrow slit between endothelial cells that line the microvessel wall is the principal pathway for tumor cell extravasation to the surrounding tissue. To understand this crucial step for tumor hematogenous metastasis, we used Dissipative Particle Dynamics method to investigate an individual cell passing through a narrow slit numerically. The cell membrane was simulated by a spring-based network model which can separate the internal cytoplasm and surrounding fluid. The effects of the cell elasticity, cell shape and cell surface area increase, and slit size on the cell transmigration through the slit were investigated. Under a fixed driven force, the cell with higher elasticity can be elongated more and pass faster through the slit. When the slit width decreases to 2/3 of the cell diameter, the spherical cell becomes jammed despite reducing its elasticity modulus by 10 times. However, transforming the cell from a spherical to ellipsoidal shape and increasing the cell surface area only by 3% can enable the cell to pass the narrow slit. Therefore the cell shape and surface area increase play a more important role than the cell elasticity in cell passing through the narrow slit. In addition, the simulation results indicate that the cell migration velocity decreases during entry but increases during exit of the slit, which is qualitatively in agreement with the experimental observation.

Keywords: dissipative particle dynamics, deformability, surface area increase, cell migration

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Authors: David Pettitt, Benjamin Davies, Georg Holländer, David Brindley

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Cellular based therapies, whose origins can be traced from the intertwined concepts of tissue engineering and regenerative medicine, have the potential to transform the current medical landscape and offer an approach to managing what were once considered untreatable diseases. However, despite a large increase in basic science activity in the cell therapy arena alongside a growing portfolio of cell therapy trials, the number of industry products available for widespread clinical use correlates poorly with such a magnitude of activity, with the number of cell-based therapeutics in mainstream use remaining comparatively low. This research serves to quantitatively assess the barriers to the clinical adoption of cell-based therapeutics through identification of unique barriers, specific challenges and opportunities facing the development and adoption of such therapies.

Keywords: cell therapy, clinical adoption, commercialization, translation

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Authors: Amberkar Mohanbabu Vittalrao, Avin, Meena Kumari Kamalkishore, Padmanabha Udupa, Vinaykumar Bavimane, Honnegouda

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Objective: To evaluate the hepato-protective activity of Tinospora cordiofolia (Tc) against paracetamol induced hepatic damage in rats. Methods: The plant stem (test drug) was procured locally, shade dried, powdered and extracted with water. Silymarin was used as standard hepatoprotective drugs and 2% gum acacia as a control (vehicle) against paracetamol (PCT) induced hepatotoxicity. Results and Discussion: The hepato-protective activity of aqueous stem extract was assessed by paracetamol induced hepatotoxicity preventive model in rats. Alteration in the levels of biochemical markers of hepatic damage like AST, ALT, ALP and lipid peroxides were tested in both paracetamol treated and untreated groups. Paracetamol (3g/kg) had enhanced the AST, ALT, ALP and the lipid peroxides in the serum. Treatment of silymarin and aqueous stem extract of Tc (200 and 400mg/kg) extract showed significant hepatoprotective activity by altering biochemical marker levels to the near normal. Preliminary phytochemical tests were done. Aqueous Tc extract showed presence of phenolic compound and flavonoids. Our findings suggested that Tc extract possessed hepatoprotective activity in a dose dependent manner. Conclusions: Tc was found to possess significant hepatoprotective property when treated with PCT. This was evident by decreasing the liver enzymes significantly when treated with PCT as compared to PCT only treated group (P < 0.05). Hence Tinospora cardiofolia could be a good, promising, preventive agent against PCT induced hepatotoxicity.

Keywords: Tinospora cardiofolia, hepatoprotection, paracetamol, silymarin

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Authors: Radia Chemlal, Salim Mehenni, Dahbia Leila Anes-boulahbal, Mohamed Kherat, Nabil Mameri

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The application of the electric field is considered to be a very promising method in cancer therapy. Indeed, cancer cells are very sensitive to the electric field, although the cellular response is not entirely clear. The tests carried out consisted in subjecting the RD cell line under the effect of the continuous electric field while varying certain parameters (voltage, exposure time, and cell concentration). The response surface methodology (RSM) was used to assess the effect of the chosen parameters, as well as the existence of interactions between them. The results obtained showed that the voltage, the cell concentration as well as the interaction between voltage and exposure time have an influence on the mortality rate of the RD cell line.

Keywords: continuous electric field, RD cancer cell line, RSM, voltage

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Authors: Abdullah A. Al Orainy

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Small cell backhaul solutions need to be cost-effective, scalable, and easy to install. This paper presents an overview of small cell backhaul technologies. Wireless solutions including TV white space, satellite, sub-6 GHz radio wave, microwave and mmWave with their backhaul characteristics are discussed. Recent research on issues like beamforming, backhaul architecture, precoding and large antenna arrays, and energy efficiency for dense small cell backhaul with mmWave communications is reviewed. Recent trials of 5G technologies are summarized.

Keywords: backhaul, small cells, wireless, 5G

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Authors: Souhila Boukli Hacene, Djamila Kherbouche, Abdelhak Chikhaoui

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In this work, we elucidate theoretically the effect of defects and temperature on the performance of the organic bulk heterojunction solar cell (BHJ) P3HT: PCBM. We have studied the influence of their parameters on cell characteristics. For this purpose, we used the effective medium model and the solar cell simulator (SCAPS) to model the characteristics of the solar cell. We also explore the transport of charge carriers in the device. It was assumed that the mixture is lightly p-type doped and that the band gap contains acceptor defects near the HOMO level with a Gaussian distribution of energy states at 100 and 50 meV. We varied defects density between 1012-1017 cm-3, from 1016 cm-3, a total decrease of the photovoltaic characteristics due to the increase of the non-radiative recombination can be noticed. Then we studied the effect of variation of the electron and the hole capture cross-section on the cell’s performance, we noticed that the cell obtains a better efficiency of about 3.6% for an electron capture cross section ≤ 10-15 cm2 and a hole capture cross section ≤ 10-19 cm2. On the other hand, we also varied the temperature between 120K and 400K. We observed that the temperature of the solar cell induces a noticeable effect on its voltage. While the effect of temperature on the solar cell current is negligible.

Keywords: organic solar cell, P3HT:PCBM, defects, temperature, SCAPS

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Authors: Majid Ali, Xinfang Jin, Victor Eniola, Henning Hoene

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The performance of proton exchange membrane (PEM) fuel cells is sensitive to several factors, including power fluctuations, hydrogen utilization, and the quality orientation of the fuel cell stack. In this study, we investigate the impact of these factors on the performance of a PEM fuel cell. We start by analyzing the power fluctuations that are typical in renewable energy systems and their effects on the 50 Watt fuel cell's performance. Next, we examine the hydrogen utilization rate (0-1000 mL/min) and its impact on the cell's efficiency and durability. Finally, we investigate the quality orientation (three different positions) of the fuel cell stack, which can significantly affect the cell's lifetime and overall performance. The basis of our analysis is the utilization of experimental results, which have been further validated by comparing them with simulations and manufacturer results. Our results indicate that power fluctuations can cause significant variations in the fuel cell's voltage and current, leading to a reduction in its performance. Moreover, we show that increasing the hydrogen utilization rate beyond a certain threshold can lead to a decrease in the fuel cell's efficiency. Finally, our analysis demonstrates that the orientation of the fuel cell stack can affect its performance and lifetime due to non-uniform distribution of reactants and products. In summary, our study highlights the importance of considering power fluctuations, hydrogen utilization, and quality orientation in designing and optimizing PEM fuel cell systems. The findings of this study can be useful for researchers and engineers working on the development of fuel cell systems for various applications, including transportation, stationary power generation, and portable devices.

Keywords: fuel cell, proton exchange membrane, renewable energy, power fluctuation, experimental

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Authors: Bouaziz H., Soudania N., Essafia M., Ben Amara I., Hakim A., Jamoussi K., Zeghal Km, Zeghal N.

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In this investigation, we have evaluated the effects of arsenic trioxide on hepatic function in pregnant and lactating Swiss albino mice and their suckling pups. Experiments were carried out on female mice given 175 ppm As2O3 in their drinking water from the 14th day of pregnancy until day 14 after delivery. Our results showed a significant decrease in plasma levels of total protein and albumin, cholesterol and triglyceride in As2O3 treated mice and their pups. The hyperbilirubinemia and the increased plasma total alkaline phosphatase activity suggested the presence of cholestasis. Transaminase activities as well as lactate deshydrogenase activity in plasma, known as biomarkers of hepatocellular injury, were elevated indicating hepatic cells’damage after treatment with As2O3. Exposure to arsenic led to an increase of liver thiobarbituric acid reactive substances level along with a concomitant decrease in the activities of superoxide dismutase, catalase and glutathione peroxidase and in glutathione.

Keywords: antioxidant status, arsenic trioxide, hepatotoxicity, mice, oxidative stress

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Authors: Ivan Tolj

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Water produced during electrochemical reaction in Proton Exchange Membrane (PEM) fuel cell can be used for internal humidification of reactant gases; hydrogen and air. On such a way it is possible to eliminate expensive external humidifiers and simplify fuel cell balance-of-plant (BoP). When fuel cell operates at constant temperature (usually between 60 °C and 80 °C) relatively cold and dry ambient air heats up quickly upon entering channels which cause further drop in relative humidity (below 20%). Low relative humidity of reactant gases dries up polymer membrane and decrease its proton conductivity which results in fuel cell performance drop. It is possible to maintain such temperature profile throughout fuel cell cathode channel which will result in close to 100 % RH. In order to achieve this, passive heat exchanger was designed using commercial CFD software (ANSYS Fluent). Such passive heat exchanger (with variable surface area) is suitable for small scale PEM fuel cells. In this study, passive heat exchanger for single PEM fuel cell segment (with 20 x 1 cm active area) was developed. Results show close to 100 % RH of air throughout cathode channel with increased fuel cell performance (mainly improved polarization curve) and improved durability.

Keywords: PEM fuel cell, passive heat exchange, relative humidity, thermal management

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Authors: Hsin-Ping Huang, Shyankay Jou

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Resistive switching of aluminum nitride (AlNx) thin film was demonstrated in a TaN/AlNx/TiN memory cell that was prepared by sputter deposition techniques. The memory cell showed bipolar switching of resistance between +3.5 V and –3.5 V. The resistance ratio of high resistance state (HRS) to low resistance state (HRS), RHRS/RLRS, was about 2 over 100 cycles of endurance test. Both the LRS and HRS of the memory cell exhibited ohmic conduction at low voltages and Poole-Frenkel emission at high voltages. The electrical conduction in the TaN/AlNx/TiN memory cell was possibly attributed to the interactions between charges and defects in the AlNx film.

Keywords: aluminum nitride, nonvolatile memory, resistive switching, thin films

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Authors: Hassane Ben Slimane, Dennai Benmoussa, Abderrachid Helmaoui

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We have theoretically calculated the photovoltaic conversion efficiency of a graded interface CdS/CIGS solar cell, which can be experimentally fabricated. Because the conduction band discontinuity or spike in an abrupt heterojunction CdS/CIGS solar cell can hinder the separation of hole-electron by electric field, a graded interface layer is uses to eliminate the spike and reduces recombination in space charge region. This paper describes the role of the graded band gap interface layer in decreasing the performance of the heterojunction cell. By optimizing the thickness of the graded region, an improvement of conversion efficiency has been observed in comparison to the conventional CIGS system.

Keywords: heterojunction, solar cell, graded interface, CIGS

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Authors: Bouzaki Mohammed Moustafa, Benyoucef Boumediene, Benouaz Tayeb, Benhamou Amina

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The ambient temperature and the defects density in the Hetero-junction with Intrinsic Thin layers solar cells (HIT) strongly influence their performances. In first part, we presented the bands diagram on the front/back simulated solar cell based on a-Si: H / c-Si (p)/a-Si:h. In another part, we modeled the following layers structure: ZnO/a-Si:H(n)/a-Si:H(i)/c-Si(p)/a-Si:H(p)/Ag where we studied the effect of the ambient temperature and the defects density in the gap of the crystalline silicon layer on the performance of the heterojunction solar cell with intrinsic layer (HIT).

Keywords: heterojunction solar cell, solar cell performance, bands diagram, ambient temperature, defect density

Procedia PDF Downloads 480

Authors: Hyo-Min Kim, Seokjin Ham, Mi-Joung Yoo, Minseon Kim, Tae-Young Roh

Abstract:

The gastrointestinal (GI) tract of most animals, including murine, is highly compartmentalized epithelia which also provide distinct different functions of its own tissue. Nevertheless, these epithelia share certain characteristics that enhance immune responses to infections and maintain the barrier function of the intestine. GI tract epithelia also undergo regeneration not only in homeostatic conditions but also in a response to the damage. A full turnover of the murine gastrointestinal epithelium occurs every 4-5 day, a process that is regulated and maintained by a minor population of Lgr5+ adult stem cell that commonly conserved in the bottom of crypts through GI tract. Maintenance of the stem cell is somehow regulated by epigenetic factors according to recent studies. Chromatin vacancy, remodelers, histone variants and histone modifiers could affect adult stem cell fate. In this study, Lgr5-EGFP reporter mouse was used to take advantage of exploring the epigenetic dynamics among Lgr5 positive mutual stem cell in GI tract. Cells were isolated by fluorescence-activated cell sorting (FACS), gene expression levels, chromatin accessibility changes and histone modifications were analyzed. Some notable chromatin structural related epigenetic variants were detected. To identify the overall cell-cell interaction inside the stem cell niche, an extensive genome-wide analysis should be also followed. According to the results, nevertheless, we expected a broader understanding of cellular niche maintaining stem cells and epigenetic barriers through conserved stem cell in GI tract. We expect that our study could provide more evidence of adult stem cell plasticity and more chances to understand each stem cell that takes parts in certain organs.

Keywords: adult stem cell, epigenetics, LGR5 stem cell, gastrointestinal tract

Procedia PDF Downloads 206

Authors: Vallisree Sivathanu, Kumaraswamidhas Lakshmi Annamalai, Trupti Ranjan Lenka

Abstract:

We report a tandem solar cell model with Silicon as the bottom cell absorber material and Cu₂BaSn(S, Se)₄(CBTSSe) as absorber material for the top cell. As a first step, the top and bottom cells were modelled and validated by comparison with the experiment. Once the individual cells are validated, then the tandem structure is modelled with Indium Tin Oxide(ITO) as conducting layer between the top and bottom cells. The tandem structure yielded better open circuit voltage and fill factor; however, the efficiency obtained is 7.01%. The top cell and the bottom cells are investigated with the help of electron-hole current density, photogeneration rate, and external quantum efficiency profiles. In order to minimize the various loss mechanisms in the tandem solar cell, the material parameters are optimized within experimentally achievable limits. Initially, the top cell optimization was carried out; then, the bottom cell is optimized for maximizing the light absorption, and upon minimizing the current and photon losses in the tandem structure, the maximum achievable efficiency is predicted to be 19.52%.

Keywords: CBTSSe, silicon, tandem, solar cell, device modeling, current losses, photon losses

Procedia PDF Downloads 80

Authors: Salvador Garcia Bernal, Chi Zheng, Keqi Zhang, Lei Mao

Abstract:

Circulating Tumor Cells (CTC) is used to detect tumoral cell metastases using blood samples of patients with cancer (lung, breast, etc.). Using an immunofluorescent method a three channel image (Red, Green, and Blue) are obtained. These set of images usually overpass the 11 x 30 M pixels in size. An aided tool is designed for imaging cell analysis to segmented and identify the tumorous cell based on the three markers signals. Our Method, it is cell-based (area and cell shape) considering each channel information and extracting and making decisions if it is a valid CTC. The system also gives information about number and size of tumor cells found in the sample. We present results in real-life samples achieving acceptable performance in identifying CTCs in short time.

Keywords: Circulating Tumor Cells (CTC), cell analysis, immunofluorescent, medical image analysis

Procedia PDF Downloads 190

Authors: Giuliano Raimondo, Jörg Wangemann, Peer Drechsel

Abstract:

In systems development involving Fuel Cells generators, it is important to have from an early stage of the project a dynamic model for the electrical behavior of the stack to be shared between involved development parties. It allows independent and early design and tests of fuel cell related power electronic. This paper presents an empirical Fuel Cell system model derived from characterization tests on a real system. Moreover, it is illustrated how the obtained model is used to build and validate a real-time Fuel Cell system emulator which is used for aerospace electrical integration testing activities.

Keywords: fuel cell, modelling, real time emulation, testing

Procedia PDF Downloads 310

Authors: Charlie Jeffkins

Abstract:

Sickle cell disease is a serious life-limiting condition which can reduce the quality of life for many patients. Public Health England (PHE), in partnership with the Sickle Cell Society (SCS), has created guidelines to prevent severe complications from sickle cell disease. Data was collected from Children’s Hospital for Wales between 15/03/21-26/03/21. Methods: A manual search of patient records for children under the care of Rocket Ward and a key term search of online records was used. Results: Penicillin prophylaxis was given at 90 days for 89%, 77% of TCDs scans were done at 2-3 years, and 72% have had a scan in the last year. 53% of patients have had discussions about hydroxycarbamide, whilst 65% have started it. PPV vaccination was documented for 19%. Conclusion: Overall, none of the four standards were reached; however, TCD uptake has improved. There is a need for better documentation of treatment and annual re-audits.

Keywords: paediatric, haematology, sickle cell, audit

Procedia PDF Downloads 196

Authors: Fumio Kasai, Noriko Hirayama, Jorge Pereira, Azusa Ohtani, Masashi Iemura, Malcolm A. Ferguson Smith, Arihiro Kohara

Abstract:

The VERO cell line was established in 1962 from normal tissue of an African green monkey, Chlorocebus aethiops (2n=60), and has been commonly used worldwide for screening for toxins or as a cell substrate for the production of viral vaccines. The VERO genome was sequenced in 2014; however, its cytogenetic features have not been fully characterized as it contains several chromosome abnormalities and different karyotypes coexist in the cell line. In this study, the VERO cell line (JCRB0111) was compared with one of the sublines. In contrast to 59 chromosomes as the modal chromosome number in the VERO cell line, the subline had two peaks of 56 and 58 chromosomes. M-FISH analysis using human probes revealed that the VERO cell line was characterized by a translocation t(2;25) found in all metaphases, which was absent in the subline. Different abnormalities detected only in the subline show that the cell line is heterogeneous, indicating that the subline has the potential to change its genomic characteristics during cell culture. The various alterations in the two independent lineages suggest that genomic changes in both VERO cells can be accounted for by progressive rearrangements during their evolution in culture. Both t(5;X) and t(8;14) observed in all metaphases of the two cell lines might have a key role in VERO cells and could be used as genetic markers to identify VERO cells. The flow karyotype shows distinct differences from normal. Further analysis of sorted abnormal chromosomes may uncover other characteristics of VERO cells. Because of the absence of STR data, cytogenetic data are important in characterizing animal cell lines and can be an indicator of their quality control.

Keywords: VERO, cell culture passage, chromosome rearrangement, heterogeneous cells

Procedia PDF Downloads 390