Search results for: oxide nanoparticles
414 5-HT2CR Deficiency Causes Affective Disorders by Impairing E/I Balance through Augmenting Hippocampal nNOS-CAPON Coupling
Authors: Hu-Jiang Shi, Li-Juan Zhu
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The implication of 5-hydroxytryptamine 2C receptor (5-HT2CR) in affective behaviors is a topic of debate, and the underlying mechanisms remain largely unclear. Here, we elucidate that the interaction between hippocampal neuronal nitric oxide synthase (nNOS) and carboxy-terminal PDZ ligand of nNOS (CAPON) contributes to the disruption of hippocampal excitation-inhibition (E/I) balance, which is responsible for the anxiety- and depressive-like behaviors caused by chronic stress-related 5-HT2CR signaling deficiency. In detail, activation or inhibition of 5-HT2CR by CP809101 or SB242084 modulates nNOS-CAPON interaction by influencing intracellular Ca²⁺ release. Notably, the dissociation of nNOS-CAPON abolishes SB242084-induced anxiety- and depressive-like behaviors, as well as the reduction in extracellular signal-regulated kinase (ERK)/cAMP-response element binding protein (CREB)/synapsin signaling and SNARE complex assembly. Furthermore, nNOS-CAPON blockers restore the impairments caused by SB242084, including the reduction in SNARE assembly-mediated γ-aminobutyric acid (GABA) vesicle release and a consequent shift of the E/I balance toward excitation in CA3 pyramidal neurons. Conclusively, our findings disclose the regulatory role of 5-HT2CR in anxiety- and depressive-like behaviors and highlight the hippocampal nNOS-CAPON coupling-triggered E/I imbalance as a pivotal cellular event underpinning the behavioral consequences of 5-HT2CR inhibition.Keywords: 5-HT2CR, anxiety, depression, nNOS-CAPON coupling, excitation-inhibition balance, neurotransmitter release
Procedia PDF Downloads 57413 A Study of Laminar Natural Convection in Annular Spaces between Differentially Heated Horizontal Circular Cylinders Filled with Non-Newtonian Nano Fluids
Authors: Behzad Ahdiharab, Senol Baskaya, Tamer Calisir
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Heat exchangers are one of the most widely used systems in factories, refineries etc. In this study, natural convection heat transfer using nano-fluids in between two cylinders is numerically investigated. The inner and outer cylinders are kept at constant temperatures. One of the most important assumptions in the project is that the working fluid is non-Newtonian. In recent years, the use of nano-fluids in industrial applications has increased profoundly. In this study, nano-Newtonian fluids containing metal particles with high heat transfer coefficients have been used. All fluid properties such as homogeneity has been calculated. In the present study, solutions have been obtained under unsteady conditions, base fluid was water, and effects of various parameters on heat transfer have been investigated. These parameters are Rayleigh number (103 < Ra < 106), power-law index (0.6 < n < 1.4), aspect ratio (0 < AR < 0.8), nano-particle composition, horizontal and vertical displacement of the inner cylinder, rotation of the inner cylinder, and volume fraction of nanoparticles. Results such as the internal cylinder average and local Nusselt number variations, contours of temperature, flow lines are presented. The results are also discussed in detail. From the validation study performed it was found that a very good agreement exists between the present results and those from the open literature. It was found out that the heat transfer is always affected by the investigated parameters. However, the degree to which the heat transfer is affected does change in a wide range.Keywords: heat transfer, circular space, non-Newtonian, nano fluid, computational fluid dynamics.
Procedia PDF Downloads 412412 Pharmacokinetic and Tissue Distribution of Etoposide Loaded Modified Glycol Chitosan Nanoparticles
Authors: Akhtar Aman, Abida Raza, Shumaila Bashir, Mehboob Alam
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The development of efficient delivery systems remains a major concern in cancer chemotherapy as many efficacious anticancer drugs are hydrophobic and difficult to formulate. Nanomedicines based on drug-loaded amphiphilic glycol chitosan micelles offer potential advantages for the formulation of drugs such as etoposide that may improve the pharmacokinetics and reduce the formulation-related adverse effects observed with current formulations. Amphiphilic derivatives of glycol chitosan were synthesized by chemical grafting of palmitic acid N-hydroxysuccinimide and quaternization to glycol chitosan backbone. To this end, a 7.9 kDa glycol chitosan was modified by palmitoylation and quaternization, yielding a 13 kDa amphiphilic polymer. Micelles prepared from this amphiphilic polymer had a size of 162nm and were able to encapsulate up to 3 mg/ml etoposide. Pharmacokinetic results indicated that the GCPQ micelles transformed the biodistribution pattern and increased etoposide concentration in the brain significantly compared to free drugs after intravenous administration. AUC 0.5-24h showed statistically significant difference in ETP-GCPQ vs. Commercial preparation in liver (25 vs.70, p<0.001), spleen (27 vs.36, p<0.05), lungs (42 vs.136,p<0.001),kidneys(25 vs.70,p< 0.05),and brain(19 vs.9,p<0.001). ETP-GCPQ crossed the blood-brain barrier, and 4, 3.5, 2.6, 1.8, 1.7, 1.5, and 2.5 fold higher levels of etoposide were observed at 0.5, 1, 2, 4, 6, 12, and 24hrs; respectively suggesting these systems could deliver hydrophobic anticancer drugs such as etoposide to tumors but also increased their transport through the biological barriers, thus making it a good delivery systemKeywords: glycol chitosan, micelles, pharmacokinetics, tissue distribution
Procedia PDF Downloads 99411 Comparison of Effect of Promoter and K Addition of Co₃O₄ for N₂O Decomposition Reaction
Authors: R. H. Hwang, J. H. Park, K. B. Yi
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Nitrous oxide (N2O) is now distinguished as an environmental pollutant. N2O is one of the representative greenhouse gases and N2O is produced by both natural and anthropogenic sources. So, it is very important to reduce N2O. N2O abatement processes are various processes such as HC-SCR, NH3-SCR and decomposition process. Among them, decomposition process is advantageous because it does not use a reducing agent. N2O decomposition is a reaction in which N2O is decomposed into N2 and O2. There are noble metals, transition metal ion-exchanged zeolites, pure and mixed oxides for N2O decomposition catalyst. Among the various catalysts, cobalt-based catalysts derived from hydrotalcites gathered much attention because spinel catalysts having large surface areas and high thermal stabilities. In this study, the effect of promoter and K addition on the activity was compared and analyzed. Co3O4 catalysts for N2O decomposition were prepared by co- precipitation method. Ce and Zr were added during the preparation of the catalyst as promoter with the molar ratio (Ce or Zr) / Co = 0.05. In addition, 1 wt% K2CO3 was doped to the prepared catalyst with impregnation method to investigate the effect of K on the catalyst performance. Characterizations of catalysts were carried out with SEM, BET, XRD, XPS and H2-TPR. The catalytic activity tests were carried out at a GHSV of 45,000 h-1 and a temperature range of 250 ~ 375 ℃. The Co3O4 catalysts showed a spinel crystal phase, and the addition of the promoter increased the specific surface area and reduced the particle and crystal size. It was exhibited that the doping of K improves the catalytic activity by increasing the concentration of Co2+ in the catalyst which is an active site for catalytic reaction. As a result, the K-doped catalyst showed higher activity than the promoter added. Also, it was found through experiments that Co2+ concentration and reduction temperature greatly affect the reactivity.Keywords: Co₃O4, K-doped, N₂O decomposition, promoter
Procedia PDF Downloads 164410 Aluminum Based Hexaferrite and Reduced Graphene Oxide a Suitable Microwave Absorber for Microwave Application
Authors: Sanghamitra Acharya, Suwarna Datar
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Extensive use of digital and smart communication createsprolong expose of unwanted electromagnetic (EM) radiations. This harmful radiation creates not only malfunctioning of nearby electronic gadgets but also severely affects a human being. So, a suitable microwave absorbing material (MAM) becomes a necessary urge in the field of stealth and radar technology. Initially, Aluminum based hexa ferrite was prepared by sol-gel technique and for carbon derived composite was prepared by the simple one port chemical reduction method. Finally, composite films of Poly (Vinylidene) Fluoride (PVDF) are prepared by simple gel casting technique. Present work demands that aluminum-based hexaferrite phase conjugated with graphene in PVDF matrix becomes a suitable candidate both in commercially important X and Ku band. The structural and morphological nature was characterized by X-Ray diffraction (XRD), Field emission-scanning electron microscope (FESEM) and Raman spectra which conforms that 30-40 nm particles are well decorated over graphene sheet. Magnetic force microscopy (MFM) and conducting force microscopy (CFM) study further conforms the magnetic and conducting nature of composite. Finally, shielding effectiveness (SE) of the composite film was studied by using Vector network analyzer (VNA) both in X band and Ku band frequency range and found to be more than 30 dB and 40 dB, respectively. As prepared composite films are excellent microwave absorbers.Keywords: carbon nanocomposite, microwave absorbing material, electromagnetic shielding, hexaferrite
Procedia PDF Downloads 172409 Nitrogen, Phosphorus, Potassium (NPK) Hydroxyapatite Nano-Hybrid Slow Release Fertilizer
Authors: Tinomuvonga Manenji Zhou, Eubert Mahofa, Tatenda Crispen Madzokere
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The nanostructured formulation can increase fertilizer efficacy and uptake ratio of the soil nutrients in agriculture production and save fertilizer resources. Controlled release modes have properties of both release rate and release pattern of nutrients, for fertilizers that are soluble in water might be correctly controlled. Nanoparticles can reduce the rate at which fertilizer nutrients are in the soil by leaching. A slow release NPK-hydroxyapatite nano hybrid fertilizer was synthesized using exfoliated bentonite as filler material. A simple, scalable method was used to synthesize the nitrogen-phosphorus hydroxyapatite nano fertilizer, where calcium hydroxide, phosphoric acid, and urea were used as precursor material, followed by the incorporation of potassium through a liquid grinding method. The product obtained was an NPK-hydroxyapatite nano hybrid fertilizer. A quantitative analysis was done to determine the percentage of nitrogen, phosphorus, and potassium in the hybrid fertilizer. AAS was used to determine the percentage of potassium in the fertilizer. An accelerated water test was conducted to compare the nutrient release behavior of nutrients between the synthesized NPK-hydroxyapatite nano hybrid fertilizer and commercial NPK fertilizer. The rate of release of Nitrogen, phosphorus, and potassium was significantly lower in the synthesized NPK hydroxyapatite nano hybrid fertilizer than in the convectional NPK fertilizer. The synthesized fertilizer was characterized using XRD. NPK hydroxyapatite nano hybrid fertilizer encapsulated in exfoliated bentonite thus prepared can be used as an environmentally friendly fertilizer formulation which could be extended to solve one of the major problems faced in the global fertilization of low nitrogen, phosphorus, and potassium use efficiency in agriculture.Keywords: NPK hydroxyapatite nano hybrid fertilizer, bentonite, encapsulation, low release
Procedia PDF Downloads 89408 ZnS and Graphene Quantum Dots Nanocomposite as Potential Electron Acceptor for Photovoltaics
Authors: S. M. Giripunje, Shikha Jindal
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Zinc sulphide (ZnS) quantum dots (QDs) were synthesized successfully via simple sonochemical method. X-ray diffraction (XRD), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM) analysis revealed the average size of QDs of the order of 3.7 nm. The band gap of the QDs was tuned to 5.2 eV by optimizing the synthesis parameters. UV-Vis absorption spectra of ZnS QD confirm the quantum confinement effect. Fourier transform infrared (FTIR) analysis confirmed the formation of single phase ZnS QDs. To fabricate the diode, blend of ZnS QDs and P3HT was prepared and the heterojunction of PEDOT:PSS and the blend was formed by spin coating on indium tin oxide (ITO) coated glass substrate. The diode behaviour of the heterojunction was analysed, wherein the ideality factor was found to be 2.53 with turn on voltage 0.75 V and the barrier height was found to be 1.429 eV. ZnS-Graphene QDs nanocomposite was characterised for the surface morphological study. It was found that the synthesized ZnS QDs appear as quasi spherical particles on the graphene sheets. The average particle size of ZnS-graphene nanocomposite QDs was found to be 8.4 nm. From voltage-current characteristics of ZnS-graphene nanocomposites, it is observed that the conductivity of the composite increases by 104 times the conductivity of ZnS QDs. Thus the addition of graphene QDs in ZnS QDs enhances the mobility of the charge carriers in the composite material. Thus, the graphene QDs, with high specific area for a large interface, high mobility and tunable band gap, show a great potential as an electron-acceptors in photovoltaic devices.Keywords: graphene, heterojunction, quantum confinement effect, quantum dots(QDs), zinc sulphide(ZnS)
Procedia PDF Downloads 148407 Water Vapor Oxidization of NiO for a Hole Transport Layer in All Inorganic QD-LED
Authors: Jaeun Park, Daekyoung Kim, Ho Kyoon Chung, Heeyeop Chae
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Quantum dots light-emitting diodes (QD-LEDs) have been considered as the next generation display and lighting devices due to their excellent color purity, photo-stability solution process possibility and good device stability. Currently typical quantum dot light emitting diodes contain organic layers such as PEDOT:PSS and PVK for charge transport layers. To make quantum dot light emitting diodes (QD-LED) more stable, it is required to replace those acidic and relatively unstable organic charge transport layers with inorganic materials. Therefore all inorganic and solution processed quantum dot light emitting diodes can potentially be a solution to stable and cost-effective display devices. We studied solution processed NiO films to replace organic charge transport layers that are required for stable all-inorganic based light emitting diodes. The transition metal oxides can be made by various vacuum and solution processes, but the solution processes are considered more cost-effective than vacuum processes. In this work we investigated solution processed NiOx for a hole transport layer (HTL). NiOx, has valence band energy levels of 5.3eV and they are easy to make sol-gel solutions. Water vapor oxidation process was developed and applied to solution processed all-inorganic QD-LED. Turn-on voltage, luminance and current efficiency of QD in this work were 5V, 1800Cd/m2 and 0.5Cd/A, respectively.Keywords: QD-LED, metal oxide solution, NiO, all-inorganic QD-LED device
Procedia PDF Downloads 744406 Anti-diabetic Potential of Olive (Olea Europaea) Leaves Extract: In Vitro and in Vivo Evaluation
Authors: Sobhy El-Sohaimy, Abduvali Toshev, Hanem Mansour
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(1) Objective: The main objective of the current study was to evaluate in an In Vitro and In Vivo, the potential activity of olive leaves extract (OLE) in the treatment and/or preventing the diabetes mellitus type II and related implications; (2) Methodology: Five groups of male rats were used in the current study: group (1)- negative control (normal); group (2)- positive control, streptozotocin (STZ) induced rats; group (3)-diabetic rats treated with metformin (200 mg/kg) plus OLE (200 mg/kg); group 4- diabetic rats treated with metformin (200 mg/kg); group 5- diabetic rats treated with OLE (200 mg/kg). A four-week regime of oral treatment was administered once daily; (3) Results: Diabetic rats treated with metformin + OLE clearly showed normal blood glucose level (121.67 ± 5.49 mg/dl), and glycated hemoglobin (HbA1c) (3.70 ± 0.10%). The combination of metformin + OLE obviously showed a superior improvement in the lipid profile (TG, TC, HDL and LDL) compared to both metformin and OLE individually. The histological examination revealed that the combination of metformin + Olive leaves extract successfully repaired of the liver, kidneys, and pancreatic tissues in diabetic rats to be near to the normal status; (4) Conclusion: Finally, it can be concluded that, the combination of metformin and OLE exhibited a superior improvement than metformin and OLE individually which emphasized the promising adjuvant role of the OLE in the treatment protocol of diabetes mellitus type II.Keywords: olive (olea europaea) leaves extracts, hypoglycemic agents, cytotoxicity, nitic oxide scavenging activity, α-glucose oxidase inhibitor
Procedia PDF Downloads 70405 Reorientation of Anisotropic Particles in Free Liquid Microjets
Authors: Mathias Schlenk, Susanne Seibt, Sabine Rosenfeldt, Josef Breu, Stephan Foerster
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Thin liquid jets on micrometer scale play an important role in processing such as in fiber fabrication, inkjet printing, but also for sample delivery in modern synchrotron X-ray devices. In all these cases the liquid jets contain solvents and dissolved materials such as polymers, nanoparticles, fibers pigments or proteins. As liquid flow in liquid jets differs significantly from flow in capillaries and microchannels, particle localization and orientation will also be different. This is of critical importance for applications, which depend on well-defined homogeneous particle and fiber distribution and orientation in liquid jets. Investigations of particle orientation in liquid microjets of diluted solutions have been rare, despite their importance. With the arise of micro-focused X-ray beams it has become possible to scan across samples with micrometer resolution to locally analyse structure and orientation of the samples. In the present work, we used this method to scan across liquid microjets to determine the local distribution and orientation of anisotropic particles. The compromise wormlike block copolymer micelles as an example of long flexible fibrous structures, hectorite materials as a model of extended nanosheet structures, and gold nanorods as an illustration of short stiff cylinders to comprise all relevant anisotropic geometries. We find that due to the different velocity profile in the liquid jet, which resembles plug flow, the orientation of the particles which was generated in the capillary is lost or changed into non-oriented or bi-axially orientations depending on the geometrical shape of the particle.Keywords: anisotropic particles, liquid microjets, reorientation, SAXS
Procedia PDF Downloads 331404 Anethum graveolens Prevents Liver and Kidney Injury, Oxidative Stress and Inflammation in Mice Exposed to Nicotine Perinatally
Authors: Saleh N. Maodaa
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Perinatal exposure to nicotine imbalances the redox status in newborns. This study investigated the effect of Anethum graveolens (dill) extract on oxidative stress and tissue injury in the liver and kidney of mice newborns exposed to nicotine perinatally. Pregnant mice received nicotine (0.25 mg/kg) on gestational day 12 to day 5 after birth and/or A. graveolens extract on a gestational day 1 to day 15 after birth. Newborn mice exposed to nicotine showed multiple histopathological alterations in the kidney and liver, including inflammatory cell infiltration and degenerative changes. Nicotine exposure increased hepatic and renal reactive oxygen species (ROS), lipid peroxidation, tumor necrosis factor (TNF-_), interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS) (p < 0.001), and decreased antioxidant defenses (p < 0.001). A. graveolens supplementation significantly prevented liver and kidney injury, suppressed ROS generation (p < 0.001), lipid peroxidation (p < 0.001), and inflammatory response (p < 0.001), and enhanced antioxidant defenses. In addition, A. graveolens upregulated hepatic and renal Nrf2 and HO-1 mRNA and increased HO-1 activity in normal and nicotine-exposed mice. In conclusion, A. graveolens protects against perinatal nicotine-induced oxidative stress, inflammation, and tissue injury in the liver and kidney of newborn mice. A. graveolens upregulated hepatic and renal Nrf2/HO-1 signaling and enhanced antioxidant defenses in mice.Keywords: dill, oxidative stress, cytokines, nicotine
Procedia PDF Downloads 73403 The Effect of Magnetite Particle Size on Methane Production by Fresh and Degassed Anaerobic Sludge
Authors: E. Al-Essa, R. Bello-Mendoza, D. G. Wareham
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Anaerobic batch experiments were conducted to investigate the effect of magnetite-supplementation (7 mM) on methane production from digested sludge undergoing two different microbial growth phases, namely fresh sludge (exponential growth phase) and degassed sludge (endogenous decay phase). Three different particle sizes were assessed: small (50 - 150 nm), medium (168 – 490 nm) and large (800 nm - 4.5 µm) particles. Results show that, in the case of the fresh sludge, magnetite significantly enhanced the methane production rate (up to 32%) and reduced the lag phase (by 15% - 41%) as compared to the control, regardless of the particle size used. However, the cumulative methane produced at the end of the incubation was comparable in all treatment and control bottles. In the case of the degassed sludge, only the medium-sized magnetite particles increased significantly the methane production rate (12% higher) as compared to the control. Small and large particles had little effect on the methane production rate but did result in an extended lag phase which led to significantly lower cumulative methane production at the end of the incubation period. These results suggest that magnetite produces a clear and positive effect on methane production only when an active and balanced microbial community is present in the anaerobic digester. It is concluded that, (i) the effect of magnetite particle size on increasing the methane production rate and reducing lag phase duration is strongly influenced by the initial metabolic state of the microbial consortium, and (ii) the particle size would positively affect the methane production if it is provided within the nanometer size range.Keywords: anaerobic digestion, iron oxide, methanogenesis, nanoparticle
Procedia PDF Downloads 135402 Tuning Nanomechanical Properties of Stimuli-Responsive Hydrogel Nanocomposite Thin Films for Biomedical Applications
Authors: Mallikarjunachari Gangapuram
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The design of stimuli-responsive hydrogel nanocomposite thin films is gaining significant attention in these days due to its wide variety of applications. Soft microrobots, drug delivery, biosensors, regenerative medicine, bacterial adhesion, energy storage and wound dressing are few advanced applications in different fields. In this research work, the nanomechanical properties of composite thin films of 20 microns were tuned by applying homogeneous external DC, and AC magnetic fields of magnitudes 0.05 T and 0.1 T. Polyvinyl alcohol (PVA) used as a matrix material and elliptical hematite nanoparticles (ratio of the length of the major axis to the length of the minor axis is 140.59 ± 1.072 nm/52.84 ± 1.072 nm) used as filler materials to prepare the nanocomposite thin films. Both quasi-static nanoindentation, Nano Dynamic Mechanical Analysis (Nano-DMA) tests were performed to characterize the viscoelastic properties of PVA, PVA+Hematite (0.1% wt, 2% wt and 4% wt) nanocomposites. Different properties such as storage modulus, loss modulus, hardness, and Er/H were carefully analyzed. The increase in storage modulus, hardness, Er/H and a decrease in loss modulus were observed with increasing concentration and DC magnetic field followed by AC magnetic field. Contact angle and ATR-FTIR experiments were conducted to understand the molecular mechanisms such as hydrogen bond formation, crosslinking density, and particle-particle interactions. This systematic study is helpful in design and modeling of magnetic responsive hydrogel nanocomposite thin films for biomedical applications.Keywords: hematite, hydrogel, nanoindentation, nano-DMA
Procedia PDF Downloads 186401 Study on the Effect Cabbage (Brassica oleracea) and Ginger (Zingiber officinale) Extracts on Rat Liver Injuries Induced by Carbon tetrachloride (CCl4)
Authors: Asmaa F. Hamouda, Randa M Shrourou
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Cabbage (Brassica oleracea) and Ginger (Zingiber officinale) constitute apportion of regular human diet. The effect of Cabbage(CE) and Ginger extracts(GE) separately on liver nitric oxide (NO), malondialdehyde (MDA), as well as serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, total cholesterol(TC), triglyceride(T.G), high density lipoprotein(HDL cholesterol), low density lipoprotein (LDL cholesterol), thyroid-stimulating hormone (TSH), Triiodothyronine (T3), Thyroxine (T4) in rats treated and untreated with carbon tetrachloride (CCl4) was studied. The levels of NO, MDA, as well as serum AST, ALT, total bilirubin, TC, T.G, LDLand TSH showed an elevation and decline in HDL, T3, and T4 in rats treated with CCl4 as compared to control. Treatment of rats with GE pre, during, and post CCl4 administration improved NO, MDA, as well as serum AST, ALT, total bilirubin, TC, T.G, HDL, LDL, TSH, T3, T4 as compared to CCl4, indicates that GE improve thyroid function and reduced oxidative stress as well as injuries induced by CCl4. Treatment of rats with CE pre, during, and post CCl4 administration did not improved in the thyroid hormones and lipid profile levels as compared to CCl4. These findings suggest that ginger treatment exerts a protective effect on metabolic disorders by decreasing oxidative stress.Keywords: liver injuries, carbon tetrachloride (CCl4), cabbage (Brassica oleracea), ginger (Zingiber officinale), thyroid function
Procedia PDF Downloads 261400 An Overview of Paclitaxel as an Anti-Cancer Agent in Avoiding Malignant Metastatic Cancer Therapy
Authors: Nasrin Hosseinzad, Ramin Ghasemi Shayan
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Chemotherapy is the most common procedure in the treatment of advanced cancers but is justsoberlyoperativeand toxic. Nevertheless, the efficiency of chemotherapy is restrictedowing to multiple drug resistance(MDR). Lately, plentiful preclinical experiments have revealedthatPaclitaxel-Curcumin could be an ultimateapproach to converse MDR and synergistically increase their efficiency. The connotationsamongst B-cell-lymphoma2(BCL-2) and multi-drug-resistance-associated-P-glycoprotein(MDR1) consequence of patients forecast the efficiency of paclitaxel-built chemoradiotherapy. There are evidences of the efficacy of paclitaxel in the treatment of surface-transmission of bladder-cell-carcinoma by manipulating bio-adhesive microspheres accomplishedthroughout measured release of drug at urine epithelium. In Genetically-Modified method, muco-adhesive oily constructionoftricaprylin, Tween 80, and paclitaxel group showed slighter toxicity than control in therapeutic dose. Postoperative chemotherapy-Paclitaxel might be more advantageous for survival than adjuvant chemo-radio-therapy, and coulddiminish postoperative complications in cervical cancer patients underwent a radical hysterectomy.HA-Se-PTX(Hyaluronic acid, Selenium, Paclitaxel) nanoparticles could observablyconstrain the proliferation, transmission, and invasion of metastatic cells and apoptosis. Furthermore, they exhibitedvast in vivo anti-tumor effect. Additionally, HA-Se-PTX displayedminor toxicity on mice-chef-organs. Briefly, HA-Se-PTX mightprogress into a respectednano-scale agentinrespiratory cancers. To sum up, Paclitaxel is considered a profitable anti-cancer drug in the treatment and anti-progress symptoms in malignant cancers.Keywords: cancer, paclitaxel, chemotherapy, tumor
Procedia PDF Downloads 124399 Pozzolanic Properties of Synthetic Zeolites as Materials Used for the Production of Building Materials
Authors: Joanna Styczen, Wojciech Franus
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Currently, cement production reaches 3-6 Gt per year. The production of one ton of cement is associated with the emission of 0.5 to 1 ton of carbon dioxide into the atmosphere, which means that this process is responsible for 5% of global CO2 emissions. Simply improving the cement manufacturing process is not enough. An effective solution is the use of pozzolanic materials, which can partly replace clinker and thus reduce energy consumption, and emission of pollutants and give mortars the desired characteristics, shaping their microstructure. Pozzolanic additives modify the phase composition of cement, reducing the amount of portlandite and changing the CaO/SiO2 ratio in the C-S-H phase. Zeolites are a pozzolanic additive that is not commonly used. Three types of zeolites were synthesized in work: Na-A, sodalite and ZSM-5 (these zeolites come from three different structural groups). Zeolites were obtained by hydrothermal synthesis of fly ash in an aqueous NaOH solution. Then, the pozzolanicity of the obtained materials was assessed. The pozzolanic activity of the zeolites synthesized for testing was tested by chemical methods in accordance with the ASTM C 379-65 standard. The method consisted in determining the percentage content of active ingredients (soluble silicon oxide and aluminum).in alkaline solutions, i.e. those that are potentially reactive towards calcium hydroxide. The highest amount of active silica was found in zeolite ZSM-5 - 88.15%. The amount of active Al2O3 was small - 1%. The smallest pozzolanic activity was found in the Na-A zeolite (active SiO2 - 4.4%, and active Al2O3 - 2.52). The tests carried out using the XRD, SEM, XRF and textural tests showed that the obtained zeolites are characterized by high porosity, which makes them a valuable addition to mortars.Keywords: pozzolanic properties, hydration, zeolite, alite
Procedia PDF Downloads 72398 Ovarian Hormones and Antioxidants Biomarkers in Dromedary Camels Synchronized with Controlled Intravaginal Drug Release/Ovsynch GPG Program during Breeding Season
Authors: Heba Hozyen, Ragab Mohamed, Amal Abd El Hameed, Amal Abo El-Maaty
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This study aimed to investigate the effect of CIDR and ovsynch (Gonadotropin-prostaglandine-gonadotropin GPG) protocols for synchronization of follicular waves of dromedary camels on ovarian hormones, oxidative stress and conception during breeding season. Twelve dark colored dromedary camels were divided into two equal groups. The first group was subjected to CIDR insertion for 7 days and blood samples were collected each other day from the day of CIDR insertion (day 0) till day 21. The other group was subjected to GPG system (Ovsynch) and blood samples were collected daily for 11 days. Progesterone (P4) and estradiol were assayed using commercial ELISA diagnostic EIA kits. Catalase (CAT), total antioxidants capacity (TAC), glutathione reduced (GHD), lipid peroxide product (malondialdehyde, MDA) and nitric oxide (NO) were measured colorimetrically using spectrophotometer. Results revealed that CIDR treated camels had significantly high P4 (P= 0.0001), estradiol (P= 0.0001), CAT (P= 0.034), NO (P= 0.016) and TAC (P= 0.04) but significantly low MDA (P= 0.001) and GHD (P= 0.003) compared to GPG treated ones. Camels inserted with CIDR had higher conception rate (66.7%) compared to those treated with GPG (33%). In conclusion, camels treated with CIDR had higher hormonal response and antioxidant capacity than those synchronized with GPG which positively reflected on their conception rate. The better response of camels to CIDR and the higher conception compared to GPG protocol recommends its use for future reproductive management in camels.Keywords: antioxidants, camel, CIDR, season, steroid hormones
Procedia PDF Downloads 284397 Nanoparticle Emission Characteristics during Methane Pyrolysis in a Laminar Premixed Flame
Authors: Mohammad Javad Afroughi, Farjad Falahati, Larry W. Kostiuk, Jason S. Olfert
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This study investigates the physical characteristics of nanoparticles generated during pyrolysis of methane in hot products of a premixed propane-air flame. An inverted burner is designed to provide a laminar premixed propane-air flame (35 SLPM) then introduce methane co-flow to be pyrolyzed within a closed cylindrical chamber (20 cm in diameter and 68 cm in length). The formed products are discharged through an exhaust with a sampling branch to measure emission characteristics. Carbon particles are sampled with a preheated nitrogen dilution system, and the size distribution of particles formed by pyrolysis is measured by a scanning mobility particle sizer (SMPS). Dilution ratio is calculated using simultaneously measured CO2 concentrations in the exhaust products and diluted samples. Results show that particle size distribution (PSD) is strongly affected by dilution ratio and preheating temperature. PSD becomes unstable at high dilution ratios (typically above 700 times) and/or low preheating temperatures (below 40° C). At a suitable dilution ratio of 55 and preheating temperature up to 70° C, the median diameter of PSD increases from 20 to 220 nm following the introduction of 0.5 SLPM of methane to the propane-air premixed flame. Furthermore, with pyrolysis of methane, total particle number concentration and estimated total mass concentration of particles in the size range of 14 to 700 nm, increase from 1.12 to 3.90 *107 cm-3 and from 0.11 to 154 µg L-1, respectively.Keywords: laminar premixed flame, methane pyrolysis, nanoparticle physical characteristics, particle mass concentration, particle number concentration, particle size distribution (PSD)
Procedia PDF Downloads 227396 Aerobic Exercise Increases Circulating Hematopoietic Stem Cells and Endothelial Progenitor Cells
Authors: Khaled A. shady, Fagr B. Bazeed, Nashwa K. Abousamra, Ihab H. Elberawe, Ashraf E. shaalan, Mohamed A. Sobh
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Physical activity activates a variety of adult stem cells which might be released into the circulation or might be activated in their organ-resident state. A variety of stimuli such as metabolic, mechanical, and hormonal stimuli might by responsible for the mobilization. This study was done to know the changes in hematopoietic stem cells and endothelial progenitor in athletes in the 24 hours following 30 min of aerobic exercise. Methods: Ten healthy male's athlete's (age 20.7± 0.61 y) performed moderate running with 30 min at 80% of velocity of The IAT. Blood samples taken pre-, and immediately, 30 min, 2h, 6h and 24h post-exercise were analyzed for hematopoietic stem cells (HSCs ), endothelial progenitor cells (EPCs(, vascular endothelial growth factor (VEGF), nitric oxide (NO), lactic acid (LA), and white blood cells . HSCs and EPCs were quantified by flow cytometry. Results: After 30min of aerobic exercise significant increases in HSCs, EPC, VEGF, NO, LA and WBCs (p ˂ 0.05). This increase will be at different rates according to the timing of taking blood sample and was in the maximum rate of increase after 30 min of aerobic exercise. HSCs, EPC, NO and WBCs were in the maximum rate of increase 2h post exercise. In addition, VEGF was in the maximum rate of increase immediately post exercise and LA concentration not affected after exercise. Conclusion: These data suggest that HSCs and EPCs increased after aerobic exercise due to increase of VEGF which play an important role in mobilization of stem cells and promotes NO increase which contributes to increase EPCs.Keywords: physical activity, hematopoietic stem cells, mobilization, athletes
Procedia PDF Downloads 94395 Modification of Electrical and Switching Characteristics of a Non Punch-Through Insulated Gate Bipolar Transistor by Gamma Irradiation
Authors: Hani Baek, Gwang Min Sun, Chansun Shin, Sung Ho Ahn
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Fast neutron irradiation using nuclear reactors is an effective method to improve switching loss and short circuit durability of power semiconductor (insulated gate bipolar transistors (IGBT) and insulated gate transistors (IGT), etc.). However, not only fast neutrons but also thermal neutrons, epithermal neutrons and gamma exist in the nuclear reactor. And the electrical properties of the IGBT may be deteriorated by the irradiation of gamma. Gamma irradiation damages are known to be caused by Total Ionizing Dose (TID) effect and Single Event Effect (SEE), Displacement Damage. Especially, the TID effect deteriorated the electrical properties such as leakage current and threshold voltage of a power semiconductor. This work can confirm the effect of the gamma irradiation on the electrical properties of 600 V NPT-IGBT. Irradiation of gamma forms lattice defects in the gate oxide and Si-SiO2 interface of the IGBT. It was confirmed that this lattice defect acts on the center of the trap and affects the threshold voltage, thereby negatively shifted the threshold voltage according to TID. In addition to the change in the carrier mobility, the conductivity modulation decreases in the n-drift region, indicating a negative influence that the forward voltage drop decreases. The turn-off delay time of the device before irradiation was 212 ns. Those of 2.5, 10, 30, 70 and 100 kRad(Si) were 225, 258, 311, 328, and 350 ns, respectively. The gamma irradiation increased the turn-off delay time of the IGBT by approximately 65%, and the switching characteristics deteriorated.Keywords: NPT-IGBT, gamma irradiation, switching, turn-off delay time, recombination, trap center
Procedia PDF Downloads 153394 Development of Bioactive Medical Textiles by Immobilizing Nanoparticles at Cotton Fabric
Authors: Munir Ashraf, Shagufta Riaz
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Personal protective equipment (PPE) and bioactive textiles are highly important for the health care of front line hospital workers, patients, and the general population to be safe from highly infectious diseases. This was even more critical in the wake of COVID-19 outbreak. Most of the medical textiles are inactive against various viruses and bacteria, hence there is a need to wash them frequently to avoid the spread of microorganisms. According to survey conducted by the world health organization, more than 500 million people get infected from hospitals, and more than 13 million died due to these hospitals’ acquired deadly diseases. The market available PPE are though effective against the penetration of pathogens and to kill bacteria but, they are not breathable and active against different viruses. Therefore, there was a great need to develop textiles that are not only effective against bacteria, fungi, and viruses but also are comfortable to the medical personnel and patients. In the present study, waterproof breathable, and biologically active textiles were developed using antiviral and antibacterial nanomaterials. These nanomaterials like TiO₂, ZnO, Cu, and Ag were immobilized at the surface of cotton fabric by using different silane coupling agents and electroless deposition that they retained their functionality even after 30 industrial laundering cycles. Afterwards, the treated fabrics were coated with a waterproof breathable film to prevent the permeation of liquid droplets, any particle or microorganisms greater than 80 nm. The developed cotton fabric was highly active against bacteria and viruses. The good durability of nanomaterials at the cotton surface after several industrial washing cycles makes this fabric an ideal candidate for bioactive textiles used in the medical field.Keywords: antibacterial, antiviral, cotton, durable
Procedia PDF Downloads 168393 Effect of Barium Doping on Structural, Morphological, Optical, and Photocatalytic Properties of Sprayed ZnO Thin Films
Authors: Halima Djaaboube, Redha Aouati, Ibtissem Loucif, Yassine Bouachiba, Mouad Chettab, Adel Taabouche, Sihem Abed, Salima Ouendadji, Abderrahmane Bouabellou
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Thin films of pure and barium-doped zinc oxide (ZnO) were prepared using spray pyrolysis process. The films were deposited on glass substrates at 450°C. The different samples are characterized by X-ray diffraction (XRD) and UV-Vis spectroscopy. X-ray diffraction patterns reveal the formation of a single ZnO Wurtzite structure and the good crystallinity of the films. The substitution of Ba ions influences the texture of the layers and makes the (002) plane a preferential growth plane. At concentrations below 6% Ba, the hexagonal structure of ZnO undergoes compressive stresses due to barium ions which have a radius twice of the Zn ions. This result leads to the decrees of a and c parameters and therefore the volume of the unit cell. This result is confirmed by the decrease in the number of crystallites and the increase in the size of the crystallites. At concentrations above 6%, barium substitutes the zinc atom and modifies the structural parameters of the thin layers. The bandgap of ZnO films decreased with increasing doping, this decrease is probably due to the 4d orbitals of the Ba atom due to the sp-d spin-exchange interactions between the band electrons and the localized d-electrons of the substituted Ba ion. Although, the Urbache energy undergoes an increase which implies the creation of energy levels below the conduction band and decreases the band gap width. The photocatalytic activity of ZnO doped 9% Ba was evaluated by the photodegradation of methylene blue under UV irradiation.Keywords: barium, doping, photodegradation, spray pyrolysis, ZnO.
Procedia PDF Downloads 111392 Effect of Clerodendrum Species on Oxidative Stress with Possible Implication in Alleviating Carcinogenesis
Authors: Somit Dutta, Pallab Kar, Arnab Kumar Chakraborty, Arnab Sen, Tapas Kumar Chaudhuri
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In the present study three species of Clerodendrum; Clerodendrum indicum, Volkameria inermis and Clerodendrum colebrookianum were used to investigate the possible activity against oxidative stress. A detailed in-vivo and in-vitro antioxidant profiling, directly associated with inflammation-related carcinogenesis, has been executed with a motive to evaluate the free radical scavenging activity of Clerodendrum extract. Measurement of cell viability and ROS generation in HEK-293 (Human Embryonic Kidney Cell Line) cells was also estimated. The immune cell proliferative properties (MTT) and in-vitro assay for evaluation of their antioxidant activities including hydroxyl radical, nitric oxide, singlet oxygen, peroxinitrate and hydrogen peroxide, etc. were investigated. GC-MS and FTIR analyses have been performed to identify the active biological compounds. These active biological compounds were further studied to assess their potential medicinal properties, aided by molecular docking and interaction analysis between the active compounds and different proteins related to oxidative stress leading to progression of carcinogenesis. The research article clearly demonstrates the role of ROS in various phases of carcinogenesis. Therefore, the antioxidant and free radical scavenging capacity of all the Clerodendrum species might prove beneficial for the immune system. It might be concluded that this plant species offers great promise for cancer prevention and therapy due to the presence of several bioactive compounds and potent antioxidant capacity of C. colebrookianum.Keywords: antioxidant, cancer, oxidative stress, reactive oxygen species (ROS)
Procedia PDF Downloads 270391 Novel Point of Care Test for Rapid Diagnosis of COVID-19 Using Recombinant Nanobodies against SARS-CoV-2 Spike1 (S1) Protein
Authors: Manal Kamel, Sara Maher, Hanan El Baz, Faten Salah, Omar Sayyouh, Zeinab Demerdash
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In the recent COVID 19 pandemic, experts of public health have emphasized testing, tracking infected people, and tracing their contacts as an effective strategy to reduce the spread of the virus. Development of rapid and sensitive diagnostic assays to replace reverse transcription polymerase chain reaction (RT-PCR) is mandatory..Our innovative test strip relying on the application of nanoparticles conjugated to recombinant nanobodies for SARS-COV-2 spike protein (S1) & angiotensin-converting enzyme 2 (that is responsible for the virus entry into host cells) for rapid detection of SARS-COV-2 spike protein (S1) in saliva or sputum specimens. Comparative tests with RT-PCR will be held to estimate the significant effect of using COVID 19 nanobodies for the first time in the development of lateral flow test strip. The SARS-CoV-2 S1 (3 ng of recombinant proteins) was detected by our developed LFIA in saliva specimen of COVID-19 Patients No cross-reaction was detected with Middle East respiratory syndrome coronavirus (MERS-CoV) or SARS- CoV antigens..Our developed system revealed 96 % sensitivity and 100% specificity for saliva samples compared to 89 % and 100% sensitivity and specificity for nasopharyngeal swabs. providing a reliable alternative for the painful and uncomfortable nasopharyngeal swab process and the complexes, time consuming PCR test. An increase in testing compliances to be expected.Keywords: COVID 19, diagnosis, LFIA, nanobodies, ACE2
Procedia PDF Downloads 130390 Electrochemical Synthesis of ZnTe and Cu-ZnTe Thin Films for Low Resistive Ohmic Back Contact for CdS/CdTe Solar Cells
Authors: Shivaji M. Sonawane, N. B. Chaure
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ZnTe is direct band gap, the P-type semiconductor with the high absorption coefficient of the order of 104cm-1 is suitable for solar cell development. It can be used as a low resistive ohmic contact to CdS/CdTe or tandem solar cell application. ZnTe and Cu-ZnTe thin film have been electrochemically synthesized on to fluorine-doped tin oxide coated glass substrates using three electrode systems containing Ag/AgCl, graphite and FTO as reference, counter and working electrode respectively were used to deposit the thin films. The aqueous electrolytic solution consist of 0.5M TeO2, 0.2M ZnSO4, and 0.1M Na3C6H5O7:2H2O, 0.1MC6H8O7:H2O and 0.1mMCuSO4 with PH 2.5 at room temperature was used. The reaction mechanism is studied in the cyclic voltammetry to identify the deposition potentials of ZnTe and Cu-ZnTe.The potential was optimized in the range -0,9 to -1,1 V. Vs Ag/AgCl reference electrode. The effect of deposition potential on the structural properties was studied by using X-ray diffraction. The X-ray diffraction result reveled cubic crystal structure of ZnTe with preferential (111) orientation with cubic structure. The surface morphology and film composition were analyzed by means of Scanning electron microscopy (SEM) and Energy Dispersive Analysis of X- Rays (EDAX). The optical absorption measurement has been analyzed for the band gap determination of deposited layers about 2.26 eV by UV-Visible spectroscopy. The drastic change in resistivity has been observed due to incorporation of copper probably due to the diffusion of Cu into grain boundaries.Keywords: ohmic back contact, zinc telluride, electrodeposition, photovoltaic devices
Procedia PDF Downloads 219389 Preparation and Flame-Retardant Properties of Epoxy Resins Containing Organophosphorus Compounds
Authors: Tachita Vlad-Bubulac, Ionela-Daniela Carja, Diana Serbezeanu, Corneliu Hamciuc, Vicente Javier Forrat Perez
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The present work describes the preparation of new organophosphorus compounds with high content of phosphorus followed by the incorporation of these compounds into epoxy resin systems in order to investigate the phosphorus effect in terms of thermal stability, flame-retardant and mechanical properties of modified epoxy resins. Thus, two new organophosphorus compounds have been synthesized and fully characterized. 6-Oxido-6H-dibenz[c,e][1,2]oxaphosphorinyl-phenylcarbinol has been prepared by the addition reaction of P–H group of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to carbonyl group of benzaldehyde. By treating the phenylcarbinol derivative with POCl3 a new phosphorus compound was obtained, having a content of 12.227% P. The organophosphorus compounds have been purified by recrystallization while their chemical structures have been confirmed by melting point measurements, FTIR and HNMR spectroscopies. In the next step various flame-retardant epoxy resins with different content of phosphorus have been prepared starting from a commercial epoxy resin and using dicyandiamide (DICY) as a latent curing agent in the presence of an accelerator. Differential scanning calorimetry (DSC) has been applied to investigate the behavior and kinetics of curing process of thermosetting systems. The results showed that the best curing characteristic and glass transition temperature are obtained at a ratio of epoxy resin: DICY: accelerator equal to 94:5:1. The thermal stability of the phosphorus-containing epoxy resins was investigated by thermogravimetric analysis in nitrogen and air, DSC, SEM and LOI test measurements.Keywords: epoxy resins, flame retardant properties, phosphorus-containing compounds, thermal stability
Procedia PDF Downloads 303388 Sustainable Radiation Curable Palm Oil-Based Products for Advanced Materials Applications
Authors: R. Tajau, R. Rohani, M. S. Alias, N. H. Mudri, K. A. Abdul Halim, M. H. Harun, N. Mat Isa, R. Che Ismail, S. Muhammad Faisal, M. Talib, M. R. Mohamed Zin
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Bio-based polymeric materials are increasingly used for a variety of applications, including surface coating, drug delivery systems, and tissue engineering. These polymeric materials are ideal for the aforementioned applications because they are derived from natural resources, non-toxic, low-cost, biocompatible, and biodegradable, and have promising thermal and mechanical properties. The nature of hydrocarbon chains, carbon double bonds, and ester bonds allows various sources of oil (edible), such as soy, sunflower, olive, and oil palm, to fine-tune their particular structures in the development of innovative materials. Palm oil can be the most eminent raw material used for manufacturing new and advanced natural polymeric materials involving radiation techniques, such as coating resins, nanoparticles, scaffold, nanotubes, nanocomposites, and lithography for different branches of the industry in countries where oil palm is abundant. The radiation technique is among the most versatile, cost-effective, simple, and effective methods. Crosslinking, reversible addition-fragmentation chain transfer (RAFT), polymerisation, grafting, and degradation are among the radiation mechanisms. Exposure to gamma, EB, UV, or laser irradiation, which are commonly used in the development of polymeric materials, is used in these mechanisms. Therefore, this review focuses on current radiation processing technologies for the development of various radiation-curable bio-based polymeric materials with a promising future in biomedical and industrial applications. The key focus of this review is on radiation curable palm oil-based products, which have been published frequently in recent studies.Keywords: palm oil, radiation processing, surface coatings, VOC
Procedia PDF Downloads 180387 Structural Insights into the Bypass of the Major Deaminated Purines by Translesion Synthesis DNA Polymerase
Authors: Hunmin Jung, Michael Hawkins, Seongmin Lee
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The exocyclic amines of nucleobases can undergo deamination by various DNA damaging agents such as reactive oxygen species, nitric oxide, and water. The deamination of guanine and adenine generates the promutagenic xanthine and hypoxanthine, respectively. The exocyclic amines of bases in DNA are hydrogen bond donors, while the carbonyl moiety generated by the base deamination acts as hydrogen bond acceptors, which can alter base pairing properties of the purines. Xanthine is known to base pair with both cytosine and thymine, while hypoxanthine predominantly pairs with cytosine to promote A to G mutations. Despite the known promutagenicity of the major deaminated purines, structures of DNA polymerase bypassing these lesions have not been reported. To gain insights into the deaminated-induced mutagenesis, we solved crystal structures of human DNA polymerase η (polη) catalyzing across xanthine and hypoxanthine. In the catalytic site of polη, the deaminated guanine (i.e., xanthine) forms three Watson-Crick-like hydrogen bonds with an incoming dCTP, indicating the O2-enol tautomer of xanthine involves in the base pairing. The formation of the enol tautomer appears to be promoted by the minor groove contact by Gln38 of polη. When hypoxanthine is at the templating position, the deaminated adenine uses its O6-keto tautomer to form two Watson-Crick hydrogen bonds with an incoming dCTP, providing the structural basis for the high promutagenicity of hypoxanthine.Keywords: DNA damage, DNA polymerase, deamination, mutagenesis, tautomerization, translesion synthesis
Procedia PDF Downloads 127386 Extraction of Dyes Using an Aqueous Two-Phase System in Stratified and Slug Flow Regimes of a Microchannel
Authors: Garima, S. Pushpavanam
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In this work, analysis of an Aqueous two-phase (polymer-salt) system for extraction of sunset yellow dye is carried out. A polymer-salt ATPS i.e.; Polyethylene glycol-600 and anhydrous sodium sulfate is used for the extraction. Conditions are chosen to ensure that the extraction results in a concentration of the dye in one of the phases. The dye has a propensity to come to the Polyethylene glycol-600 phase. This extracted sunset yellow dye is degraded photo catalytically into less harmful components. The cloud point method was used to obtain the binodal curve of ATPS. From the binodal curve, the composition of salt and Polyethylene glycol -600 was chosen such that the volume of Polyethylene glycol-600 rich phase is low. This was selected to concentrate the dye from a dilute solution in a large volume of contaminated solution into a small volume. This pre-concentration step provides a high reaction rate for photo catalytic degradation reaction. Experimentally the dye is extracted from the salt phase to Polyethylene glycol -600 phase in batch extraction. This was found to be very fast and all dye was extracted. The concentration of sunset yellow dye in salt and polymer phase is measured at 482nm by ultraviolet-visible spectrophotometry. The extraction experiment in micro channels under stratified flow is analyzed to determine factors which affect the dye extraction. Focus will be on obtaining slug flow by adding nanoparticles in micro channel. The primary aim is to exploit the fact that slug flow will help improve mass transfer rate from one phase to another through internal circulation in dispersed phase induced by shear.Keywords: aqueous two phase system, binodal curve, extraction, sunset yellow dye
Procedia PDF Downloads 354385 Stabilization of Transition Metal Chromite Nanoparticles in Silica Matrix
Authors: J. Plocek, P. Holec, S. Kubickova, B. Pacakova, I. Matulkova, A. Mantlikova, I. Němec, D. Niznansky, J. Vejpravova
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This article presents summary on preparation and characterization of zinc, copper, cadmium and cobalt chromite nano crystals, embedded in an amorphous silica matrix. The ZnCr2O4/SiO2, CuCr2O4/SiO2, CdCr2O4/SiO2 and CoCr2O4/SiO2 nano composites were prepared by a conventional sol-gel method under acid catalysis. Final heat treatment of the samples was carried out at temperatures in the range of 900–1200 °C to adjust the phase composition and the crystallite size, respectively. The resulting samples were characterized by Powder X-ray diffraction (PXRD), High Resolution Transmission Electron Microscopy (HRTEM), Raman/FTIR spectroscopy and magnetic measurements. Formation of the spinel phase was confirmed in all samples. The average size of the nano crystals was determined from the PXRD data and by direct particle size observation on HRTEM; both results were correlated. The mean particle size (reviewed by HRTEM) was in the range from ~ 4 to 46 nm. The results showed that the sol-gel method can be effectively used for preparation of the spinel chromite nano particles embedded in the silica matrix and the particle size is driven by the type of the cation A2+ in the spinel structure and the temperature of the final heat treatment. Magnetic properties of the nano crystals were found to be just moderately modified in comparison to the bulk phases.Keywords: sol-gel method, nanocomposites, Rietveld refinement, Raman spectroscopy, Fourier transform infrared spectroscopy, magnetic properties, spinel, chromite
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