scholarly journals The Role of the pH in the Impregnation of Spherical Mesoporous Silica Particles with L-Arginine Aqueous Solutions

2021 ◽  
Vol 22 (24) ◽  
pp. 13403
Author(s):  
Sara Saber Younes Mohamed ◽  
Sonia Martinez ◽  
Mauro Banchero ◽  
Luigi Manna ◽  
Silvia Ronchetti ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Basic Amino Acid ◽  
Silica Particles ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Physiological Processes ◽  
Before And After ◽  
Ft Ir

In the context of the development of carriers for amino acids delivery, Spherical Mesoporous Silica Particles (SMSP), characterized by particles size ranging from 0.15 µm to 0.80 µm and average pore diameter of 2.4 nm, were synthesised and loaded with L-arginine (ARG), a basic amino acid involved in several physiological processes. The loading was performed using water as a solvent through the wet impregnation method (with a final arginine content of 9.1% w/w). The material was characterized before and after impregnation by means of X-Ray Diffraction (XRD), nitrogen sorption analysis, Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared (FT-IR) spectroscopy. SMSP are shown to suffer degradation upon impregnation, which dramatically affects their porosity. To elucidate the role of the pH of the ARG impregnating solution (originally set at pH ≈ 11) on SMSP degradation, the loading was performed under different pH conditions (5 and 9) keeping constant the ARG concentration. The impregnation performed with acidic solution did not modify the carrier. All samples displayed ARG in amorphous form: zwitterionic species were present in SMSP impregnated at basic pH whereas positive protonated species in that impregnated at acidic pH.

Synthesis and Characterization of CuS/CdS Photocatalyst with Enhanced Visible Light-Photocatalytic Activity

2017 ◽  
Vol 48 ◽  
pp. 49-61 ◽  
Author(s):  
A. Malathi ◽  
J. Madhavan
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Diffuse Reflectance Spectroscopy ◽  
Photogenerated Electron ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Charge Generation ◽  
Visible Light Active ◽  
Ft Ir ◽  
Cds Nanocomposites

In the present study, visible light active CuS/CdS nanocomposites of various compositions (1%, 2% and 3%) were synthesized via wet impregnation method and these photocatalysts were characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and UV-visible diffuse reflectance spectroscopy (DRS). The photocatalytic degradation efficiency of the synthesized photocatalysts was evaluated from the degradation of methylene blue (MB) under the visible light irradiation. Among all compositions, a 1% CuS/CdS nanocomposite showed about 89.5% degradation in 90 min than the pure CuS, CdS and other composites. Photoluminescence and photoelectrochemical measurements indicated that the 1% CuS/CdS nanocomposite greatly enhanced the charge generation and restrained the recombination of photogenerated electron-hole pairs. A possible mechanism of photocatalytic degradation has been proposed.

scholarly journals Synthesis of ZnO Nanostructures by Microwave Irradiation Using Albumen as a Template

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
T. Prakash ◽  
R. Jayaprakash ◽  
G. Neri ◽  
Sanjay Kumar
Keyword(s):  
Electron Microscopy ◽  
Microwave Irradiation ◽  
Fast Method ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ft Ir ◽  
Size And Morphology ◽  
Microwave Assisted Method

ZnO nanostructures have been successfully prepared by a microwave irradiation method. The role of albumen as a template in addressing the size and morphology of ZnO has been investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG-DTA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. A heterogeneous mixture of Zn(OH)2 and ZnO was obtained in absence of albumen. Pure ZnO nanostructures, consisting of rod- and whisker-like nanoparticles embedded in a sheet matrix, were obtained in the presence of albumen. Optical and photoluminescence (PL) properties of the synthesized samples were also compared. Results obtained indicate that the microwave-assisted method is a promising low temperature, cheap, and fast method for the production of ZnO nanostructures.

scholarly journals Role of Zingiber Officinale Essential Oil- Chitosan Based Biopolymer Film For Bioactive Packaging

2021 ◽  
Author(s):  
Sawsan A. Al-Hilifi ◽  
Rawdah M. Al-Ali
Keyword(s):  
Essential Oil ◽  
Food Packaging ◽  
Fourier Transforms ◽  
Zingiber Officinale ◽  
Differential Scanning Calorimetric ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Biopolymer Film

Abstract The recent interest in bio-packing at field of food become trending in the development of antimicrobial coatings. The focus of this study was to assess the potential application of zingiber officinale essential oil (GEO) in chitosan films (CHf). The data indicated that there were significant differences(p < 0.05) in the chemical composition of the samples.Forty-seven active compounds of the essential oil were identified from the rhizomes of ginger, which were identified byGC-MS. Fourier transforms infrared spectra (FT-IR) confirmed that an interaction between the hydroxyl groups of the phenolic compounds of the essential oil and the amide groups of polymer matrix. As shown the appearance of peaks at wavenumbers 1639cm-1 and 1558cm-1 Furthermore, X-ray diffraction results suggested a lower crystallintiyin CHf due to GEO effect. Differential Scanning Calorimetric (DSC) analysis revealed that CHf possessed high thermal stability, especially when different concentrations of GEO added. The bioactive CHf showed distinct activity against both positive and negative gram bacteria. They are Staphylococcus aurous, Bacillus subtillis, Streptococcus Sp. Escherichia coli, Salmonella Sp. Pseudomonas erugiosa. This results provides a comprehensive insight on the importance of films incorporated with EOs of interest in food packaging.

scholarly journals NMR Characterization of Angiogenin Variants and tRNAAla Products Impacting Aberrant Protein Oligomerization

2021 ◽  
Author(s):  
Andrea Fagagnini ◽  
Sabrina Fasoli ◽  
Miguel Garavís ◽  
Irene Gómez-Pinto ◽  
Giovanni Gotte ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Protein Oligomerization ◽  
Active Site Residues ◽  
X Ray Diffraction ◽  
Physiological Processes ◽  
Nmr Characterization ◽  
G Quadruplex ◽  
Before And After ◽  
Rna Fragments ◽  
Aberrant Protein

Protein oligomerzation is key to countless physiological processes, but also to abnormal amyloid conformations implicated in over 25 mortal human diseases. Angiogenin (h-ANG), a ribonuclease A family member, produces RNA fragments that regulate ribosome formation, the creation of new blood vessels and stress granule function. Too little h-ANG activity leads abnormal protein oligomerization resulting in Amyotrophic Lateral Sclerosis (ALS) or Parkinson&rsquo;s disease. While a score of disease linked h-ANG mutants has been studied by X-ray diffraction, some elude crystallization. There is also debate regarding the structure that RNA fragments adopt after cleavage by h-ANG. Here, to better understand the beginning of the process that leads to aberrant protein oligomerization, the solution secondary structure and residue-level dynamics of WT h-ANG and two mutants: H13A and R121C, are characterized by multidimensional heteronuclear NMR spectroscopy under near physiological conditions. All three variants are found to adopt well folded and highly rigid structures in solution, although the elements of secondary structure are somewhat shorter than those observed in cystallography studies. R121C alters the environment of nearby residues only. By constrast, the mutation H13A affects local residues as well as nearby active site residues residues K41 and H119. The conformation characterization by CD and 1D 1H NMR spectroscopies of tRNAAla before and after h-ANG cleavage reveals a retention of most duplex structure and little or no G-quadruplex formation.

scholarly journals Tuning Optical and Granulometric Properties of Gold Nanostructures Synthesized with the Aid of Different Types of Honeys for Microwave-Induced Hyperthermia

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 898
Author(s):  
Anna Dzimitrowicz ◽  
Piotr Cyganowski ◽  
Piotr Jamroz ◽  
Dorota Jermakowicz-Bartkowiak ◽  
Malgorzata Rzegocka ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
Hyperthermia Treatment ◽  
X Ray ◽  
Induced Hyperthermia ◽  
Transmission Electron ◽  
Fourier Transformation Infrared Spectroscopy ◽  
Ft Ir ◽  
Honey Solution ◽  
Size Controlled

Size-controlled gold nanoparticles (AuNPs) were synthesised with solutions of three types of Polish honeys (lime, multiflower, honeydew) and used in microwave-induced hyperthermia cancer treatment. Optical and structural properties of nanostructures were optimized in reference to measurements made by using UV/Vis absorption spectrophotometry (UV/Vis), transmission electron microscopy (TEM) supported by energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and attenuated total reflectance Fourier transformation infrared spectroscopy (ATR FT-IR). In addition, concentrations of reducing sugars and polyphenols of honeys applied were determined to reveal the role of these chemical compounds in green synthesis of AuNPs. It was found that the smallest AuNPs (20.6 ± 23.3 nm) were produced using a 20% (w/v) multiflower aqueous honey solution and 25 mg·L−1 of Au(III) ions. These AuNPs were then employed in microwave-induced hyperthermia in a system simulating metastatic tissues. This research illustrated that AuNPs, as produced with the aid of a multiflower honey solution, could be suitably used for microwave-induced heating of cancer. A fluid containing resultant Au nanostructures, as compared to water, revealed facilitated heating and the ability to maintain a temperature of 45 °C required for hyperthermia treatment.

Synthesis of Anatase/Brookite Mixtured TiO2 Nanoparticles by a Chimie Douce Technique

2013 ◽  
Vol 734-737 ◽  
pp. 2528-2531
Author(s):  
Yu Mei Gong ◽  
Qing Liang ◽  
Jing Guo ◽  
Hong Zhang ◽  
Fu Cheng Guan
Keyword(s):  
Electron Microscope ◽  
Anatase Phase ◽  
Spherical Shape ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Specific Pore Volume ◽  
Transmission Electron ◽  
Bet Method ◽  
Ft Ir

Anatase/brookite mixtured TiO2nanoparticles have been synthesized by using a two-step process through a chimie douce technique. The as-prepared powders were characterized by Fourier transform infrared (FT-IR) spectra, X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), and a nitrogen adsorption apparatus in multipoint Brunauer-Emmett-Teller (BET) method. The results indicated that the TiO2nanoparticles were composed of biphasial anatase/brookite mixtures, 38% anatase phase formed in quasi-spherical shape and 62% brookite phase formed in nanorod shape. The specific surface area, the average pore diameter, and the specific pore volume were 100.06 m2/g, 14.0 nm, and 0.561 cm3/g, respectively.

Photocatalytic Oxidation of Hexanol over Titanium Dioxide Supported on Mesoporous Silica

2015 ◽  
Vol 1112 ◽  
pp. 176-179
Author(s):  
Nur Umisyuhada Mohd Nor ◽  
Hendrik O. Lintang ◽  
Salasiah Endud ◽  
Leny Yuliati
Keyword(s):  
Photocatalytic Activity ◽  
Mesoporous Silica ◽  
Photocatalytic Oxidation ◽  
Sol Gel ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Diffraction Peaks ◽  
Loading Amount ◽  
Xrd Patterns ◽  
Mcm 41

In order to improve the efficiency of TiO2, material with large surface area such as mesoporous silica is usually used as a support. In this study, the TiO2 was dispersed on mesoporous silica, MCM-41 by an impregnation method, meanwhile the bulk TiO2 was prepared by sol gel method. The X-ray diffraction (XRD) patterns showed that the intensities of diffraction peaks for MCM-41 decreased with the increase of the TiO2 loading, suggesting that the higher loading amount of TiO2 might lead to less ordered structure of MCM-41. The successful addition of TiO2 on MCM-41 was also confirmed from the fluorescence spectra, which the emission intensities of TiO2 and MCM-41 increased and decreased, respectively, with the increase of TiO2 loading on the MCM-41. The activities were compared between the bulk and dispersed TiO2 for photocatalytic oxidation of hexanol. Both bulk and dispersed TiO2 on MCM-41 showed good photocatalytic activity, while the MCM-41 did not show photocatalytic activity. Since the efficiency of photocatalyst can be defined by its respective turnover number (TON), the comparison between bulk and dispersed TiO2 on MCM-41 was made based on their TON values. It was revealed that the dispersed TiO2 on the MCM-41 with 5 wt% of TiO2 loading was the most efficient photocatalyst among all the samples.

Microstructural of Cr/MWCNT Composites and its Catalysis in Synthesis of Biodiesel

2012 ◽  
Vol 455-456 ◽  
pp. 1053-1059
Author(s):  
Xue Hai Fan ◽  
Guo Min Xiao
Keyword(s):  
Electron Microscopy ◽  
Potassium Dichromate ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Ft Ir ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs), potassium dichromate (K2Cr2O7) and sulphuric acid were used for the preparation of Cr/MWCNT composite by impregnation method. The composites were comprehensively characterized by transmission electron microscopy （TEM），energy dispersive X-ray analysis (EDX), infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermal gravity analysis (TGA). Due to its unique electrical and structural properties, this composite was applied to the synthesis of biodiesel (FAME) as a catalyst, showing effectively catalytic performance.

FeAs2 biomineralization on encrusted bacteria in hot springs: an ecological role of symbiotic bacteria

2003 ◽  
Vol 40 (11) ◽  
pp. 1725-1738 ◽  
Author(s):  
Kazue Tazaki ◽  
Islam ABM Rafiqul ◽  
Kaori Nagai ◽  
Takayuki Kurihara
Keyword(s):  
Metal Binding ◽  
Microbial Mats ◽  
Hot Springs ◽  
Hot Spring ◽  
Binding Potential ◽  
Resistant Bacteria ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Ir Analysis

Bacterial FeAs2 mineralization was found in the reddish-brown microbial mats that have grown on the walls of the drainage systems of Masutomi Hot Springs, Yamanashi Prefecture, Japan. The reddish-brown microbial mats, which are mainly composed of bacilliform and coccoid types of bacteria, have been analyzed and observed by microtechniques to interpret the bacterial biomineralization and search for the clues to bioremediation. These bacteria accumulate Fe and As along with other trace elements to form various biominerals. The electron diffraction (ED) pattern of the bacterial capsule identified lollingite (FeAs2) and calcite (CaCO3) on the surface of the cell. Based on Fourier-transform infrared absorbance spectroscopy (FT–IR) analysis, the presence of organic components such as C—H, C=O, CNH, –COOH, and N—H in the reddish-brown microbial mats emphasized the metal-binding potential of the bacteria. X-ray diffraction (XRD) data showed the poorly crystalline character of the precipitates, which consist mainly of hydrous iron oxides (2.7 Å (1 Å = 0.1 nm)). The FeAs2 biominerals form by adsorption onto the bacterial cell wall, as demonstrated by microscopic observations and spectroscopic analysis. These showed that bacteria in the reddish-brown microbial mats have the ability to form biominerals with heavy metals and toxic metalloids like As. Particularly significant in hot spring environments is the role of symbiotic and toxic-resistant bacteria, which have the ability to adapt to high As concentrations. Bacterial FeAs2 mineralization might also be considered a mechanism by which toxic As is removed from the aquatic ecosystem. The results provide evidence for detoxification processes and offer clues to possible methods of bioremediation.

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