scholarly journals Characterization of Lignin

2019 ◽  
Vol 2 (2) ◽  
pp. 55-56
Author(s):  
Mikayla McKenna-Pettit ◽  
Niloufar Manafi ◽  
Neda Nazemifard
Keyword(s):  
Zeta Potential ◽  
Human Error ◽  
Particle Diameter ◽  
Future Research ◽  
Average Particle ◽  
Complex Organic Compound ◽  
Multiple Measurements ◽  
Natural Fluorescence ◽  
The Stability ◽  
Imagej Software

Lignin is a complex organic compound crucial to the structural tissues of vascular plants, such as trees. The cyclic structure and aromaticity of lignin give it significant potential to be used as a renewable and safe replacement for toxic aromatic compounds in chemical and industrial processes. The purpose of this experiment was to characterize lignin, specifically the particle diameter and zeta potential, using both the Zetasizer Nano ZSP and the ImageJ image processing software, and to compare the accuracy of both measurement methods. Due to the natural fluorescence of lignin, a fluorescence microscope is used to capture images of lignin particles. By having a known distance and the scale of measurement, with ImageJ it is possible to calculate distances, such as the diameters of particles in images. The Zetasizer Nano ZSP is a device capable of measuring both particle diameter and zeta potential, which is the electrical charge existing on particles suspended in a medium. Small amounts of lignin, in powder form, are placed into scintillation vials with different amounts of distilled water to create 3 different concentrations of sample to measure using the Zetasizer. Between 10-15mL of sample are placed into specialized measurement cells and put into the Zetasizer. Multiple measurements are conducted and averaged to achieve accurate results. The measured zeta potential value is indicative of the stability of the lignin. If the value of zeta potential is higher than 30mV, negative or positive, it has a high stability and low reactivity. The average values of zeta potential measured by the Zetasizer ranged from -27mV to -21mV. The particle diameter is important in characterization, as the smaller and more distributed the particles are, there is a larger surface area for reactions to occur. Average particle diameter measured by the Zetasizer ranged from 926-976µm. The results from the Zetasizer Nano ZSP are more accurate than those from the ImageJ software, as ImageJ allows for a substantial amount of human error to impact the results. The outcomes help direct future experiments using lignin and beneficial to future research concerning lignin and its potential.

scholarly journals Evaluation of Biocompatibility and Release Profile of Ginger Extract Loaded Hyaluronic Acid Nanocapsules for Medical Applications

2020 ◽  
Author(s):  
Marjan Ashegh Moalla ◽  
Mahboobeh Mahmoodi ◽  
Masoumeh Tabatabaee
Keyword(s):  
Hyaluronic Acid ◽  
Surface Morphology ◽  
Control Sample ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Medical Applications ◽  
Average Particle ◽  
In Vitro Test ◽  
Ginger Extract ◽  
The Stability

Introduction: Ginger is a plant that is used as a drug for pain relieving and anti-inflammatory in traditional medicine, but conventional prescribing of it faces serious challenges. One way to overcome these problems is the loading of ginger extract in polymer carriers. The aim of this study was characterization and evaluation of the loading and releasing of ginger extract from hyaluronic acid nanocapsules for medical applications. Methods: In this applied study, ginger extract as a pain-relieving drug was loaded in hyaluronic acid nanocapsules. The hyaluronic acid nanocapsules containing ginger extract were fabricated by emulsion method. The surface morphology, particle size and zeta potential, surface roughness and functional groups on the sample surface were evaluated by field emission electron microscopy (FESEM), dynamic light scattering (DLS), atomic force microscopy (AFM) and fourier transform infrared spectroscopy (FTIR), respectively. The stability and ginger release from nanocapsules were also determined via DLS and HPLC, respectively. The toxicity and fibroblast cells viability of ginger extract encapsulated in hyaluronic acid were evaluated by MTT assay. Data were analyzed by SPSS 16 Software. The t-Student test was performed for statistical comparison of data and statistically significant was P < 0.05. Results: The ginger entrapment efficiency (EE %) in nanocapsules was 74%.  The average particle diameter and charge surface of the samples were calculated 413 nm and -10 mV, respectively. The negative charge of samples showed the stability of samples without agglomeration. Therefore, the surface morphology of the samples was observed as relatively spherical particles. In vitro test showed 95% fibroblast cell growth and proliferation on nanocapsules compared to the control sample (P < 0.05). Conclusion: The hyaluronic acid nanocapsules have a great potential for delivery of ginger extract in the area of pain and inflammation.

Effect of Ionic Strength on the Stability of Colloids Released from Injection Grout Silica Sol

2010 ◽  
Vol 1265 ◽  
Author(s):  
Pirkko L Holtta ◽  
Mari Lahtinen ◽  
Martti Hakanen ◽  
Jukka Lehto ◽  
Piia Juhola
Keyword(s):  
Particle Size ◽  
Ionic Strength ◽  
Zeta Potential ◽  
Silica Gel ◽  
Colloidal Silica ◽  
Particle Diameter ◽  
Silica Sol ◽  
Deionized Water ◽  
Silica Colloids ◽  
The Stability

AbstractIn Olkiluoto Finland colloidal silica called silica sol (EKA Chemicals) will be used as a non-cementitious grout for the sealing of fractures of the hydraulic apertures of 0.05 mm or less. The use of colloidal material has to be considered in the long-term safety assessment of a spent nuclear fuel repository. The potential relevance of colloid-mediated radionuclide transport is highly dependent on their stability in different geochemical environments. Objective of this work was to study the effect of ionic strength on stability of silica colloids released from silica gel. Silica gel samples were stored in contact with NaCl and CaCl2 electrolyte solutions and in deionized water. Colloid release and stability were followed for two years by taking the samples after one month and then twice in a year. The release and stability of colloids were followed by measuring particle size, colloidal silica concentrations and zeta potential. The particle size distributions were determined applying the dynamic light scattering (DLS) method and zeta potential based on dynamic electrophoretic mobility.In dilute NaCl (10-7–10-2 M) and CaCl2 (3 10-7– 3 10-3 M) solutions, a mean colloid diameter was less than 100 nm and high negative zeta potential values suggests the existence of stable silica colloids. After two years, the mean particle diameter was increased but it was still less than 500 nm and absolute value of zeta potential was decreased. In 0.1–1 M NaCl and 0.03–3 M CaCl2 solutions, wide particle size distribution and zeta potential values around zero suggested particle aggregation and instable colloids. In deionized water, particle size remained rather stable and zeta potential remained high negative suggests stable silica colloids. The threshold value of ionic strength was 0.03–0.1 M when salinity had an effect on the stability of colloids. In Olkiluoto, the ionic strength of saline groundwater is order of magnitude higher than the range of effect value obtained in this study. Under the prevailing conditions in Olkiluoto, silica colloids are instable, but the possible influence of glacial melt waters has to be considered.

scholarly journals PREPARATION AND CHARACTERIZATION OF LIPOSOMAL DELIVERY SYSTEM OF NATURAL HEME PROTEIN

2019 ◽  
pp. 418-425
Author(s):  
Oleksii Katsai ◽  
Olena Ruban
Keyword(s):  
Zeta Potential ◽  
Delivery System ◽  
Specific Activity ◽  
Particle Diameter ◽  
Heme Protein ◽  
Average Particle ◽  
Cyt C ◽  
Liposomal Delivery

Objective: The objective of the present study was to develop and optimize the methods for preparation and characterization of the liposomal delivery system of natural heme protein. Methods: Cytochrome C containing liposomes (Cyt-LS) were prepared by high-pressure homogenization technique using phosphatidylcholine (PC) and dipalmitoyl phosphatidylglycerol (DPPG). Nanoparticles were characterized by using: dynamic light scattering, zeta potential measurements, scanning electron microscopy and HPLC. The specific activity was studied in vitro. Results: The study of homogenization regimes for obtaining unilamellar Cyt-LS was carried out. The selected temperature regime of homogenization was kept within 38–44 °С with optimal homogenization pressure of 800 bar. The obtained Cyt-LS were characterized by the main physicochemical parameters showed: Encapsulation efficiency 95.8±2.0%, Zeta potential-57±1.0 mV, pH-6.95±0.05. Phospholipid impurities had the following content: lysophosphatidylcholine-0.60±0.05% and free fatty acids-0.4±0.05%. The average particle diameter was 156±2 nm. Also, the size of Cyt-LS particles was confirmed by the ability of emulsion subjected to the sterilizing filtration with the preservation of its main physicochemical properties. Cyt-LS exhibit specific activity, similar to non-liposomal Cyt-C solution. Conclusion: The formulation of the liposomal delivery system of heme protein was successfully prepared using natural components and evaluated for different parameters.

scholarly journals Rapid Synthesis of Gold Nanoparticles with Ginger Waste using Microwave Irradiation

2019 ◽  
Vol 32 (2) ◽  
pp. 471-476
Author(s):  
G. Bhagavanth Reddy ◽  
B. Rajkumar ◽  
K. Girija Mangatayaru ◽  
T.V.D. Prasad Rao
Keyword(s):  
Gold Nanoparticles ◽  
Zeta Potential ◽  
Microwave Irradiation ◽  
Pathogenic Bacteria ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
The Stability

In the present investigation, synthesis of gold nanoparticles (AuNPs) was carried out with microwave irradiation of HAuCl4 and the extract of ginger waste. Synthesized AuNPs were characterized by various techniques including UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The TEM images revealed that the nanoparticles were spherical in shape and the average particle size of the AuNPs was found to be approximately 6 ± 2 nm. The stability of gold nanoparticles was analyzed by zeta potential measurements. A negative zeta potential value of -18.4 mV indicates the stability of the AuNPs. Further, gold nanoparticles exhibited the excellent catalytic activity in reducing 4-nitrophenol to 4-aminophenol in the presence of NaBH4 (reducing agent), and it was found to depend on the amount of AuNPs and temperature. Gold nanoparticles did not show any significant antibacterial activity against the pathogenic bacteria studied.

scholarly journals STABILITY OF SYNTHESIZED SILVER NANOPARTICLES IN CITRATE AND MIXED GELATIN/CITRATE SOLUTION

2018 ◽  
Vol 58 (2) ◽  
pp. 104 ◽  
Author(s):  
Jana Kavuličová ◽  
Anna Mražíková ◽  
Oksana Velgosová ◽  
Dana Ivánová ◽  
Martina Kubovčíková
Keyword(s):  
Silver Nanoparticles ◽  
Zeta Potential ◽  
Colloidal Stability ◽  
Particle Diameter ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Term Stability ◽  
Vis Spectroscopy ◽  
Term Storage

The study focuses on an investigation of the influence of both citrate and mixed gelatin/citrate as a reductant and stabilizer on the colloidal stability of silver nanoparticles (AgNPs)synthesized by a chemical reduction of Ag<sup>+</sup> ions after a short - (7th day) - and long - (118th day) - term storage. Formed AgNPs were characterized by a UV–vis Spectroscopy, Transmission Electron Microscope (TEM), Dynamic light scattering (DLS) and Zeta-potential (ZP). The obtained results revealed that a short-term stability of the synthesized AgNPs was greatly influenced by a citrate stabilizer with the absence of gelatin. Smaller-sized AgNPs (average particle diameter of 3 nm), roughly spherical in a shape, were obtained with a narrow size distribution. The very negative value of the Zeta-potential confirmed a strong stability of the citrate capped AgNPs. However, a surface coating of the AgNPs by a gelatin/citrate stabilizer was found to be a dominant contributor in improving a long-term stability of the AgNPs (average particle diameter of 26 nm). The use of gelatin in mixed stabilizer solution provided the AgNPs with higher monodispersity and a controllable size after both the short and long-term storage.

scholarly journals SYNTHESIS AND STABILITY OF RESVERATROL-GOLD NANOPARTICLE-POLYETHYLENE GLYCOL-FOLIC ACID CONJUGATES

2020 ◽  
pp. 237-241
Author(s):  
SUTRIYO SUTRIYO ◽  
RADITYA ISWANDANA ◽  
FIRDA MARETHA IVARIANI
Keyword(s):  
Particle Size ◽  
Folic Acid ◽  
Polyethylene Glycol ◽  
Zeta Potential ◽  
High Surface ◽  
Average Particle Size ◽  
Average Particle ◽  
Nanoparticle Stability ◽  
Model Drug ◽  
The Stability

Objective: Gold nanoparticles (AuNPs) can be used as targeted drug delivery systems, however, AuNPs have high surface energy and easily aggregate,thus negatively impacting nanoparticle stability. Therefore, it is necessary to add a stabilizing agent to AuNPs. To synthesize AuNPs stabilized bypolyethylene glycol conjugated to folic acid (FA), thus creating a model drug (resveratrol [RSV]) carrier that targets FA receptors on cancer cells.Methods: AuNPs were synthesized using the Turkevich method and stabilized by adding FA conjugated to polyethylene glycol (PEG). After RSV wasloaded, the conjugate was physically characterized and subjected to stability tests.Results: The RSV-AuNP had an average particle size of 51.97 nm (polydispersity index [PDI] 0.694, zeta potential – 24.6 mV). The RSV-AuNP-PEG-FAconjugate (RSV-AuNP-PEG-FA) had an average particle size of 195.6 nm (PDI=0.233, zeta potential=−21.1 mV). Stability tests showed that RSV-AuNPPEG-FA was more stable than RSV-AuNP. Furthermore, RSV-AuNP-PEG-FA and RSV-AuNP were more stable in buffer pH 7.4 and bovine serum albumin2% than in buffer pH 4, cysteine 1%, and NaCl 0.9% solutions.Conclusion: PEG-FA conjugates can improve the stability of RSV-loaded AuNP.

An Experimental Investigation on Thermal Conductivity and Viscosity of Graphene doped CNTs /TiO2 Nanofluid

2020 ◽  
Vol 17 (3) ◽  
Author(s):  
A.M. Zetty Akhtar ◽  
M.M. Rahman ◽  
K. Kadirgama ◽  
M.A. Maleque
Keyword(s):  
Thermal Conductivity ◽  
Zeta Potential ◽  
Base Fluid ◽  
Minimum Quantity Lubrication ◽  
Cutting Fluid ◽  
Cutting Zone ◽  
Observation Method ◽  
The Stability ◽  
The Relationship ◽  
Zeta Potential Analysis

This paper presents the findings of the stability, thermal conductivity and viscosity of CNTs (doped with 10 wt% graphene)- TiO2 hybrid nanofluids under various concentrations. While the usage of cutting fluid in machining operation is necessary for removing the heat generated at the cutting zone, the excessive use of it could lead to environmental and health issue to the operators. Therefore, the minimum quantity lubrication (MQL) to replace the conventional flooding was introduced. The MQL method minimises the usage of cutting fluid as a step to achieve a cleaner environment and sustainable machining. However, the low thermal conductivity of the base fluid in the MQL system caused the insufficient removal of heat generated in the cutting zone. Addition of nanoparticles to the base fluid was then introduced to enhance the performance of cutting fluids. The ethylene glycol used as the base fluid, titanium dioxide (TiO2) and carbon nanotubes (CNTs) nanoparticle mixed to produce nanofluids with concentrations of 0.02 to 0.1 wt.% with an interval of 0.02 wt%. The mixing ratio of TiO2: CNTs was 90:10 and ratio of SDBS (surfactant): CNTs was 10:1. The stability of nanofluid checked using observation method and zeta potential analysis. The thermal conductivity and viscosity of suspension were measured at a temperature range between 30˚C to 70˚C (with increment of 10˚C) to determine the relationship between concentration and temperature on nanofluid’s thermal physical properties. Based on the results obtained, zeta potential value for nanofluid range from -50 to -70 mV indicates a good stability of the suspension. Thermal conductivity of nanofluid increases as an increase of temperature and enhancement ratio is within the range of 1.51 to 4.53 compared to the base fluid. Meanwhile, the viscosity of nanofluid shows decrements with an increase of the temperature remarks significant advantage in pumping power. The developed nanofluid in this study found to be stable with enhanced thermal conductivity and decrease in viscosity, which at once make it possible to be use as nanolubricant in machining operation.

Adsorption of safranine T from aqueous medium by nano mesoporous MCM-41: adsorption equilibrium, kinetics, and thermodynamics

2020 ◽  
Vol 10 ◽  
Author(s):  
Xiao-Dong Li ◽  
Qing-Zhou Zhai
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Particle Diameter ◽  
Spherical Particles ◽  
Practical Significance ◽  
Average Particle ◽  
Average Pore ◽  
Kinetics And Thermodynamics ◽  
Safranine T ◽  
Mcm 41

Introduction: In industrial production, a small amount of saffron T emissions will cause increase of water color and increase of chemical oxygen consumption, so study of the decolorization of saffron T wastewater has an important practical significance. Methods: MCM (Mobil Composition of Matter)-41 molecular sieve was synthesized by hydrothermal method. Power Xray diffraction and scanning electron microscopy were used to characterize the sample. Safranine T dye was adsorbed from water by the MCM-41 prepared. Kinetics and thermodynamics of the adsorption were studied. Results: The MCM-41 sample presented spherical particles and regular. The BET (Brunner-Emmett-Teller) specific surface area of the sample determined by 77 K low temperature nitrogen adsorption-desorption isotherm was 932 m2 /g. Its average particle diameter was 110 nm. TEM (transmission electron microscopy) results showed that the sample structure presented a honeycomb pore structure and the average pore diameter was 3.0 nm. The results showed that when room temperature was 20 ± 1 ℃, adsorbate safranine T: adsorbent MCM-41 = 20 : 1，the optimum pH value of adsorption was 4.0 and contact time was 20 min, the adsorption rate reached 98.29% and the adsorption capacity was 19.66 mg/g. The entropy change and enthalpy change of the adsorption system are respectively ΔS0 = 157.5 J/(mol·K); ΔH0 = 21.544 kJ/mol. When temperature was 277.15, 293.15, 303.15 K，the free energy change was respectively △G1 0 = -22.107 kJ/mol, △G2 0 = -24.627 kJ/mol, △G3 0 = -26.202 kJ/mol. Conclusion: The adsorption of safranine T by MCM-41 belongs to a pseudo-second-order adsorption. This adsorption accords with the Freundlich equation and belongs to a heterogeneous adsorption. The adsorption is an endothermic reaction of entropy increase, being spontaneous.

Supplier Development at LG Electronics

2020 ◽  
Author(s):  
Hyojin Kim ◽  
Daesik Hur ◽  
Tobias Schoenherr
Keyword(s):  
Management Practice ◽  
Digital Technologies ◽  
Supply Management ◽  
Future Research ◽  
Supplier Development ◽  
Environmentally Conscious ◽  
Competitive Capabilities ◽  
The Stability ◽  
Buyer Firm

Supplier development has been a critical supply management practice since the 1990s. In many instances, it has even become imperative for buyer firms to support and prepare their supply bases for uncertain economic and market environments, socially and environmentally conscious customers, advances in digital technologies, and increasing competition. Yet, research that approaches supplier development with the objective to advance all these dimensions in an integrated fashion is scarce. This study fills this void by exploring how a buyer firm may address these emerging challenges in its supply base. Specifically, an in-depth case study of LG Electronics explores how the firm designs and operates multidimensional supplier development activities to foster the stability and sustainability of its supply base while enhancing its core suppliers’ competitive capabilities. This chapter illustrates how supplier development can be taken to the next level, presents implications for managerial practice, and outlines promising future research avenues.

scholarly journals A Comparative Evaluation of Nanohydroxyapatite-Enriched Hydrogen Peroxide Home Bleaching System on Color, Hardness and Microstructure of Dental Enamel

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3072
Author(s):  
Riccardo Monterubbianesi ◽  
Vincenzo Tosco ◽  
Tiziano Bellezze ◽  
Giampaolo Giuliani ◽  
Mutlu Özcan ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Diameter ◽  
Dental Enamel ◽  
Sem Analysis ◽  
Control Group ◽  
Average Particle ◽  
Color Analysis ◽  
Enamel Microstructure ◽  
Prismatic Structure ◽  
20 Nm

This study aimed to evaluate two hydrogen peroxide (HP)-based at-home bleaching systems in order to analyze whether nano-hydroxyapatite (nHA) addition may represent a reliable and safe solution for tooth whitening without altering dental microstructure and hardness. Human third molars (N = 15) were treated with two bleaching agents, one containing 6%HP (6HP) and the other 6% HP nHA-enriched (6HP-nHA) with average particle diameter ranging from 5–20 nm. Their effects on enamel were assessed using a spectrophotometer, Vickers microhardness (VMH) test and Scanning Electron Microscopy (SEM), comparing the treated groups with the non-treated control group (CTR). Color analysis revealed improvement in whiteness in both groups compared to CTR. VMH test results showed no differences among the groups. SEM analysis highlighted no evident changes in the enamel microstructure of tested groups compared to CTR. At high magnification, in 6HP group, a slight increase in irregularities of enamel surface morphology was observed, while 6HP-nHA group displayed removal of the aprismatic layer but preservation of the intact prismatic structure. These results suggest that the 6HP-nHA agent may be recommended to provide reliable whitening treatment, without damaging the enamel micromorphology and hardness.

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