scholarly journals A Fast and Robust Approach for the Green Synthesis of Spherical Magnetite (Fe3O4) Nanoparticles by Tilia tomentosa (Ihlamur) Leaves and its Antibacterial Studies

2020 ◽  
Vol 26 (2) ◽  
pp. 175-183
Author(s):  
Shashanka Rajendrachari ◽  
Abdullah Cahit Karaoglanli ◽  
Yusuf Ceylan ◽  
Orhan Uzun
Keyword(s):  
Magnetite Nanoparticles ◽  
Assay Method ◽  
Bandgap Energy ◽  
Excellent Thermal Stability ◽  
Sem Image ◽  
Wide Range ◽  
Significant Research ◽  
Average Size ◽  
Dta Curve ◽  
Tilia Tomentosa

Background: In the past few years, Magnetite (Fe3O4) nanoparticles have gained a significant research interest in the field of biology, chemistry, metallurgy due to their wide range of applications. Some of their important applications include drug delivery, chemotherapy, low-friction seals, magnetic fluid, adsorbent, recovery of hazardous wastes, etc. Methods: In the present paper, we reported an eco-friendly route of preparing magnetite nanoparticles by using leaves of Tilia Tomentosa (Ihlamur) followed by calcination at 400 ˚C for 15 minutes. Results: The bandgap energy of the prepared Fe3O4 nanoparticles was studied by UV–Visible spectroscopy and the value was found to be 3.31 eV. The scanning electron microscopy (SEM) image showed the spherical magnetite nanoparticles with an average size of 25 nm. The phases and thermal properties of Fe3O4 nanoparticles were studied by using X-ray diffraction, thermogravimetric (TG) and differential thermal analysis (DTA). The enthalpy change of Fe3O4 nanoparticles was calculated by using the DTA curve and the value was found to be 4.97 kJ/mol at 8˚C/min heating rate. The antimicrobial activity of Fe3O4 nanoparticles was carried out by the minimum inhibition concentration (MIC) assay method. Except for B. subtilis, Fe3O4 nanoparticles demonstrated significant antibacterial property. Conclusion: The prepared magnetite nanoparticles showed excellent thermal stability and less weight loss over a 30–1000 ˚C temperature range. The size of the prepared magnetite nanoparticles is very less therefore they interacted effectively with the organelle, enzymes, and cells of bacteria and inhibited bacterial growth by killing them.

Wide range color tunability and efficient energy transfer of novel NaCaGd(WO4)3: Tb3+, Eu3+ phosphors with excellent thermal stability for pc-WLEDs

2021 ◽  
Author(s):  
Jihuan Xie ◽  
Liqun Cheng ◽  
he tang ◽  
Zhongxue Wang ◽  
Haiying Sun ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Solid State Reaction Method ◽  
Efficient Energy Transfer ◽  
Excellent Thermal Stability ◽  
Reaction Method ◽  
Efficient Energy ◽  
Sem Image ◽  
Wide Range ◽  
Color Tunability ◽  
Xrd Patterns

A sequence of NaCaGd(WO4)3: Tb3+, Eu3+ phosphors were prepared via the high temperature solid state reaction method. The XRD patterns, Rietveld refinement as well as SEM image were carried out...

scholarly journals The activation energy and antibacterial investigation of spherical Fe3O4 nanoparticles prepared by Crocus sativus (Saffron) flowers

2020 ◽  
Vol 10 (4) ◽  
pp. 5951-5959 ◽  
Keyword(s):  
Activation Energy ◽  
Antibacterial Activity ◽  
Magnetite Nanoparticles ◽  
Fe3o4 Nanoparticles ◽  
Crocus Sativus ◽  
Assay Method ◽  
Bandgap Energy ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Percentage Weight

We proposed a simple and environmental-friendly method to prepare magnetite nanoparticles and their application as antibacterial material. We successfully prepared Fe3O4 nanoparticles using Crocus Sativus (Saffron) flowers followed by calcination at 400 ˚C for 15 minutes. The UV–Visible spectroscopy was used to study the bandgap energy of the prepared Fe3O4 nanoparticles and the value was found to be 3.23 eV. The scanning electron microscopy (SEM) was used to study the structure and morphology and X-ray diffraction was used to study the phase and crystallite size of the magnetite nanoparticles. The percentage weight loss, the enthalpy change and activation energy of Fe3O4 nanoparticles were calculated by using the thermogravimetric (TG) and differential thermal analysis (DTA) respectively. The DTA curve at a heating rate of 6, 8 and 10˚C/min shows endothermic peaks at 586, 594 and 600˚C respectively. The activation energy of Fe3O4 nanoparticles was calculated by the Kissinger method and was found to be 8.09 kJ/moles. The antibacterial activity of Fe3O4 nanoparticles was carried out against 3 gram-positive and 3 gram-negative bacteria by using a minimum inhibition concentration (MIC) assay method and they showed excellent antibacterial activity against gram-negative bacterial strains only.

A Color Coded STEM/SEM Image Storage System

1981 ◽  
Vol 39 ◽  
pp. 272-273
Author(s):  
Y. Kokubo ◽  
W. H. Hardy ◽  
J. Dance ◽  
K. Jones
Keyword(s):  
Image Processing ◽  
Electron Beam ◽  
Storage System ◽  
Particle Analysis ◽  
Specific Information ◽  
X Rays ◽  
Sem Image ◽  
Backscattered Electrons ◽  
Wide Range ◽  
Scanning Electron

A color coded digital image processing is accomplished by using JEM100CX TEM SCAN and ORTEC’s LSI-11 computer based multi-channel analyzer (EEDS-II-System III) for image analysis and display. Color coding of the recorded image enables enhanced visualization of the image using mathematical techniques such as compression, gray scale expansion, gamma-processing, filtering, etc., without subjecting the sample to further electron beam irradiation once images have been stored in the memory.The powerful combination between a scanning electron microscope and computer is starting to be widely used 1) - 4) for the purpose of image processing and particle analysis. Especially, in scanning electron microscopy it is possible to get all information resulting from the interactions between the electron beam and specimen materials, by using different detectors for signals such as secondary electron, backscattered electrons, elastic scattered electrons, inelastic scattered electrons, un-scattered electrons, X-rays, etc., each of which contains specific information arising from their physical origin, study of a wide range of effects becomes possible.

scholarly journals In vitro activities of Acacia nilotica (L.) Delile bark fractions against Oral Bacteria, Glucosyltransferase and as antioxidant

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ali Mahmoud Muddathir ◽  
Ebtihal Abdalla M. Mohieldin ◽  
Tohru Mitsunaga
Keyword(s):  
Antioxidant Activity ◽  
Antibacterial Activity ◽  
Gallic Acid ◽  
Crude Extract ◽  
Inhibitory Activity ◽  
Oral Bacteria ◽  
Acacia Nilotica ◽  
Assay Method ◽  
Medicinal Uses ◽  
Wide Range

Abstract Background Dental caries and periodontal disease are the most common chronic infectious oral diseases in the world. Acacia nilotica was commonly known in Sudan as Garad or Sunt has a wide range of medicinal uses. In the present study, antibacterial activity of oral bacteria (Streptococcus sobrinus and Porphyromonas gingivalis), inhibitory activity against glucosyltransferase (GTF) enzyme and antioxidant activity were assayed for methanolic crude extract of A. nilotica bark and its fractions. Methods Methanoilc crude extract of A. nilotica bark was applied to a Sephadex LH-20 column and eluted with methanol, aqueous methanol, and finally aqueous acetone to obtain four fractions (Fr1- Fr4). Furthermore, the crude extract and fractions were subjected to analytical high performance liquid chromatography (HPLC). The crude extract and its fractions were assayed for antibacterial activity against S. sobrinus and P. gingivalis using a microplate dilution assay method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), as well as GTF inhibition and antioxidant activity using ABTS radical scavenging method. Results Fractions (Fr1 and Fr2) exhibited MIC values of 0.3 mg/ml against the P. gingivalis. Additionally, Fr2 displayed MBC value of 1 mg/ml against two types of bacteria. Fr4 showed an especially potent GTF inhibitory activity with IC50 value of 3.9 μg/ml. Fr1 displayed the best antioxidant activity with IC50 value of 1.8 μg/ml. The main compound in Fr1 was identified as gallic acid, and Fr2 was mostly a mixture of gallic acid and methyl gallate. Conclusions The results obtained in this study provide some scientific rationale and justify the use of this plant for the treatment of dental diseases in traditional medicine. A. nilotica bark, besides their antibacterial potentiality and GTF inhibitory activity, it may be used as adjuvant antioxidants in mouthwashes. Further studies in the future are required to identify the rest of the active compounds.

EXPRESS: Method dependent variation in TSH and FT4 reference intervals in pregnancy: a systematic review

2021 ◽  
pp. 000456322110269
Author(s):  
O E Okosieme ◽  
Medha Agrawal ◽  
Danyal Usman ◽  
Carol Evans
Keyword(s):  
Systematic Review ◽  
Reference Interval ◽  
First Trimester ◽  
Reference Intervals ◽  
Assay Method ◽  
Specific Reference ◽  
Upper Limits ◽  
Wide Range ◽  
Assay Methods ◽  
In Pregnancy

Background: Gestational TSH and FT4 reference intervals may differ according to assay method but the extent of variation is unclear and has not been systematically evaluated. We conducted a systematic review of published studies on TSH and FT4 reference intervals in pregnancy. Our aim was to quantify method-related differences in gestation reference intervals, across four commonly used assay methods, Abbott, Beckman, Roche, and Siemens. Methods: We searched the literature for relevant studies, published between January 2000 and December 2020, in healthy pregnant women without thyroid antibodies or disease. For each study, we extracted trimester-specific reference intervals (2.5–97.5 percentiles) for TSH and FT4 as well as the manufacturer provided reference interval for the corresponding non-pregnant population. Results: TSH reference intervals showed a wide range of study-to-study differences with upper limits ranging from 2.33 to 8.30 mU/L. FT4 lower limits ranged from 4.40–13.93 pmol/L, with consistently lower reference intervals observed with the Beckman method. Differences between non-pregnant and first trimester reference intervals were highly variable, and for most studies the TSH upper limit in the first trimester could not be predicted or extrapolated from non-pregnant values. Conclusions: Our study confirms significant intra and inter-method disparities in gestational thyroid hormone reference intervals. The relationship between pregnant and non-pregnant values is inconsistent and does not support the existing practice in some laboratories of extrapolating gestation references from non-pregnant values. Laboratories should invest in deriving method-specific gestation reference intervals for their population.

scholarly journals Influence of Alumina Nanofibers Sintered by the Spark Plasma Method on Nickel Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Strength Properties ◽  
Alumina Nanoparticles ◽  
Metal Powders ◽  
Wide Range ◽  
The Matrix ◽  
Spark Plasma ◽  
Average Size

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.

Interfacial defect engineering and Photocatalysis Properties of hBN/MX2(M = Mo, W, and X = S, Se) Heterostructures

2021 ◽  
Author(s):  
Zhihai Sun ◽  
Jiaxi Liu ◽  
Ying Zhang ◽  
Ziyuan Li ◽  
Leyu Peng ◽  
...  
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Band Alignment ◽  
Type I ◽  
Defect Engineering ◽  
Wide Range ◽  
Interfacial Defects ◽  
Significant Research ◽  
P Type ◽  
The Impact

Abstract Van der Waals (VDW) heterostructures have attracted significant research interest due to their tunable interfacial properties and potential in a wide range of applications such as electronics, optoelectronic, and heterocatalysis. In this work, the impact of interfacial defects on the electronic structures and photocatalytic properties of hBN/MX2(M = Mo, W, and X = S, Se) are studied using density functional theory calculations. The results reveal that the band alignment of hBN/MX2 can be adjusted by introducing vacancies and atomic doping. The type-I band alignment of the host structure was maintained in the heterostructure with n-type doping in the hBN sublayer. Interestingly, the band alignment changed to the type-II heterostructrue as VB defect and p-type doping was introduced in the hBN sublayer. This could be profitable for the separation of photo-generated electron−hole pairs at the interfaces and is highly desired for heterostructure photocatalysis. In addition, two Z-type heterostructures including hBN(BeB)/MoS2, hBN(BeB)/MoSe2, and hBN(VN)/MoSe2 were achieved, showing reducing band gap and ideal redox potential for water splitting. Our results reveal the possibility of engineering the interfacial and photocatalysis properties of hBN/MX2 heterostructures via interfacial defects.

scholarly journals A fine desintegration of plants suitable for composite biofuels production

2012 ◽  
Vol 49 (No. 1) ◽  
pp. 7-11 ◽  
Author(s):  
J. Souček ◽  
I. Hanzlíková ◽  
P. Hutla
Keyword(s):  
Energy Consumption ◽  
Technological Process ◽  
Material Properties ◽  
Statistical Evaluation ◽  
Raw Materials ◽  
Correct Choice ◽  
Input And Output ◽  
Input Material ◽  
Wide Range ◽  
Average Size

In case of pressed composite biofuels production the important part of the production process is the input row materials disintegration. In dependence on disintegrated material properties, disintegration device, grinding stage and technological process there is in practice necessary for disintegration of culm materials 0.5–7% and of wooden species even 0.75–10% of total energetical content of material. A wide range of these figures means that in this sphere of raw materials adaptation can be reached relative high savings through correct choice of technological process and device. The authors of the paper have measured energy consumption of fine disintegration of lignocellulose materials in dependence on particles size and moisture. By the realized measurement of different average size of both input and output particles and consequent statistical evaluation was proved the fiducial energy consumption increase at higher stage of disintegration and higher moisture of the input material. All measurements were carried-out for the grinding mill ŠK 300 and the output particles size was limited by the exchange sieves mesh dimension.

scholarly journals Effect of the polymeric coating over Fe3O4 particles used for magnetic separation

2010 ◽  
Vol 8 (5) ◽  
pp. 1041-1046 ◽  
Author(s):  
Raúl Reza ◽  
Carlos Martínez Pérez ◽  
Claudia Rodríguez González ◽  
Humberto Romero ◽  
Perla García Casillas
Keyword(s):  
Particle Size ◽  
Magnetite Nanoparticles ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Polymeric Coating ◽  
Average Particle ◽  
Synthesis Conditions ◽  
Aging Conditions ◽  
Magnetite Particles ◽  
Average Size

AbstractIn this work, the synthesis of magnetite nanoparticles by two variant chemical coprecipitation methods that involve reflux and aging conditions was investigated. The influence of the synthesis conditions on particle size, morphology, magnetic properties and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle size directly influenced by the synthesis technique. Particles of average size 27 nm and 200 nm were obtained. When the coprecipitation method was used without reflux and aging, the smallest particles were obtained. Magnetite nanoparticles obtained from both methods exhibited a superparamagnetic behavior and their saturation magnetization was particle size dependent. Values of 67 and 78 emu g−1 were obtained for the 27 nm and 200 nm magnetite particles, respectively. The nanoparticles were coated with silica, aminosilane, and silica-aminosilane shell. The influence of the coating on protein absorption was studied using Bovine Serum Albumin (BSA) protein.

Synthesis of LiCoO2 particles with tunable sizes by a urea-based-homogeneous-precipitation method

2020 ◽  
Vol 111 (4) ◽  
pp. 347-355
Author(s):  
Munekazu Motoyama ◽  
Hiroki Iwasaki ◽  
Miyuki Sakakura ◽  
Takayuki Yamamoto ◽  
Yasutoshi Iriyama
Keyword(s):  
Size Distribution ◽  
Average Diameter ◽  
Precipitation Method ◽  
Homogeneous Precipitation ◽  
Uniform Size ◽  
Homogeneous Precipitation Method ◽  
Wide Range ◽  
Size Uniformity ◽  
Average Size ◽  
Uniform Size Distribution

Abstract This paper reports the synthesis of monodisperse spherical LiCoO2 particles in a wide range of average diameter using a urea-based-uniform-precipitation method. The average diameter of LiCoO2 particles can be varied from 2 to 14 lm with a uniform size distribution. The effective approach to maintain the size uniformity while changing the average size of LiCoO2 particles is to keep the ratio of [CO(NH2)2] to [CoSO4] at 8 even when the CoSO4 and urea concentrations are changed.

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