scholarly journals Extraction of Keratin from Rabbit Hair by a Deep Eutectic Solvent and Its Characterization

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 993 ◽  
Author(s):  
Dongyue Wang ◽  
Xu-Hong Yang ◽  
Ren-Cheng Tang ◽  
Fan Yao
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Freeze Drying ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Dissolution Temperature ◽  
Α Helix

Keratin from a variety of sources is one of the most abundant biopolymers. In livestock and textile industries, a large amount of rabbit hair waste is produced every year, and therefore it is of great significance to extract keratin from waste rabbit hair in terms of the treatment and utilization of wastes. In this study, a novel, eco-friendly and benign choline chloride/oxalic acid deep eutectic solvent at a molar ratio of 1:2 was applied to dissolve waste rabbit hair, and after dissolution keratin was separated by dialysis, filtration, and freeze-drying. The dissolution temperature effect was discussed, and the resulting keratin powder was characterized by X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, protein electrophoresis, thermogravimetry and differential scanning calorimetry, and amino acid analysis. During the dissolution process, the α-helix structure of rabbit hair was deconstructed, and the disulfide bond linkages were broken. The solubility of rabbit hair was significantly enhanced by increasing dissolution temperature, and reached 88% at 120 °C. The keratin produced by dissolving at 120 °C displayed flaky powders after freeze-drying, and had a molecular weight ranging from 3.8 to 5.8 kDa with a high proportion of serine, glutamic acid, cysteine, leucine, and arginine. Such features of molecular weight and amino acid distribution provide more choices for the diverse applications of keratin materials.

The effect of silica modified by deep eutectic solvents on the properties of nature rubber/silica composites

2021 ◽  
pp. 009524432110200
Author(s):  
Hao Yang ◽  
Liu Yang ◽  
Huaiqing Guo ◽  
Wenbo Hu ◽  
Aihua Du
Keyword(s):  
Dynamic Properties ◽  
Low Cost ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Rolling Resistance ◽  
Molar Ratio ◽  
Skid Resistance ◽  
Modified Silica ◽  
Scanning Calorimetry ◽  
Wet Skid Resistance

The effect of deep eutectic solvent (DES) modified silica on the properties of nature rubber (NR) composites were investigated. The DES is an environment-friendly and low-cost solvent, which was prepared by mixing choline chloride and urea in a 1:2 molar ratio. The NR composites filled with DES modified silica were prepared and the properties were tested. The interaction between the DES and silica were characterized by Fourier transform infrared spectroscopy (FTIR), the interaction between silica and silica were tested by differential scanning calorimetry (DSC). The dynamic properties, such as rolling resistance and wet skid resistance, and were tested by dynamic mechanical analysis (DMA). Morphologies of the composites were characterized by scanning electron microscopy (SEM). The results indicate that the DES can interact with silica by hydrogen bond to improve the compatibility between the rubber and silica. When the content of DES was 3 phr, the tensile strength, modulus at 300%, tear strength, and the crosslinking density of the composites was increased. At the same time, the proper content of DES can reduce the rolling resistance of the vulcanized rubber while maintaining good wet skid resistance.

scholarly journals Clozapine-carboxylic acid plasticized co-amorphous dispersions: Preparation, characterization and solution stability evaluation

2015 ◽  
Vol 65 (2) ◽  
pp. 133-146 ◽  
Author(s):  
Ahmed Mahmoud Abdelhaleem Ali ◽  
Adel Ahmed Ali ◽  
Ibrahim Abdullah Maghrabi
Keyword(s):  
Carboxylic Acid ◽  
Tartaric Acid ◽  
Molar Ratio ◽  
Sublingual Administration ◽  
Solution Stability ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Great Chance ◽  
Amorphous Dispersions ◽  
Pass Metabolism

Abstract This study addressed the possibility of forming of co-amorphous systems between clozapine (CZ) and various carboxylic acid plasticizers (CAPs). The aim was to improve the solubility and oral bioavailability of clozapine. Co-amorphous dispersions were prepared using modified solvent evaporation methodology at drug/plasticizer stoichiometric ratios of 1:1, 1:1.5 and 1:2. Solid state characterization was performed using differential scanning calorimetry, X-ray diffraction and infra red spectroscopy. Highly soluble homogeneous co-amorphous dispersions were formed between clozapine and CAPs via hydrogen bonding. The co-amorphous dispersions formed with tartaric acid (1:2) showed the highest dissolution percentage (> 95 % in 20 minutes) compared to pure crystalline CZ (56 %). Highly stable solutions were obtained from co-amorphous CZ-citric and CZ-tartaric acid at 1:1.5 molar ratio. The prepared dispersions suggest the possibility of peroral or sublingual administration of highly soluble clozapine at a reduced dose with the great chance to bypass the first pass metabolism.

Application of Deep Eutectic Solvent (DES) as a Reaction Media for the Esterification of Acrylic Acid with n-Butanol

2015 ◽  
Vol 13 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Emine Sert
Keyword(s):  
Catalytic Activity ◽  
Acrylic Acid ◽  
Batch Reactor ◽  
Choline Chloride ◽  
Deep Eutectic Solvent ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Toluene Sulfonic Acid ◽  
Effects Of Temperature ◽  
Reaction Media

Abstract Within the framework of green chemistry, catalysts should be met different criteria such as biodegradability, recyclability, flammability, non-toxicity and low price. Acidic deep eutectic solvent (DES) have been synthesized for this purpose, by mixing para-toluene sulfonic acid and choline chloride. The catalytic activity of DES was studied in the esterification of acrylic acid with n-butanol. The usage of DES as catalyst is simple, safe and cheap. The effects of temperature, catalyst loading, n-butanol/acrylic acid molar ratio on the conversion of acrylic acid were performed. The batch reactor experiments were carried out at temperatures of 338, 348, 358 and 368 K, molar ratio of butanol to acrylic acid of 1, 2,3 and catalyst loading of 10, 15, 20 and 90 g/L. 90.2% of acrylic acid conversion was achieved at a temperature of 358 K and catalyst loading of 20 g/L. Reusability of DES was investigated. Reusability and catalytic activity makes DES efficient as catalyst.

scholarly journals Preparation of Co-Amorphous Systems by Freeze-Drying

Pharmaceutics ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 941
Author(s):  
Melvin Wostry ◽  
Hanna Plappert ◽  
Holger Grohganz
Keyword(s):  
Amino Acid ◽  
Freeze Drying ◽  
Sodium Dodecyl ◽  
Solid Content ◽  
Water Soluble ◽  
Tween 20 ◽  
Scanning Calorimetry ◽  
Total Solid Content ◽  
Amorphous Systems ◽  
Freeze Dried

Freeze-drying was evaluated as a production technique for co-amorphous systems of a poorly water-soluble drug. Naproxen was freeze-dried together with arginine and lysine as co-former. To increase the solubility of naproxen in the starting solution, the applicability of five surfactants was investigated, namely sodium dodecyl sulfate, pluronic F-127, polyoxyethylene (40) stearate, tween 20 and TPGS 1000. The influence of the surfactant type, surfactant concentration and total solid content to be freeze-dried on the solid state of the sample was investigated. X-ray powder diffraction and differential scanning calorimetry showed that the majority of systems formed co-amorphous one-phase systems. However, at higher surfactant concentrations, and depending on the surfactant type, surfactant reflections were observed in the XRPD analysis upon production. Crystallization of both naproxen and amino acid occurred from some combinations under storage. In conclusion, freeze-drying was shown to be a feasible technique for the production of a selection of co-amorphous drug–amino acid formulations.

scholarly journals Microstructure Evolution and Performance Improvement of Hypereutectic Al–Mg2Si Metallic Composite with Ca or Sb

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2714
Author(s):  
Min Zuo ◽  
Boda Ren ◽  
Zihan Xia ◽  
Wenwen Ma ◽  
Yidan Lv ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Nucleation Behavior ◽  
X Ray ◽  
Primary Mg2si ◽  
Before And After ◽  
And Performance ◽  
Hardness Values

In this article, the modification effects on Al–Mg2Si before and after heat treatment were investigated with Ca, Sb, and (Ca + Sb). In comparison with single Ca or Sb, the samples with composition modifiers (Ca + Sb) had the optimal microstructure. The sample with a molar ratio for Ca-to-Sb of 1:1 obtained relatively higher properties, for which the Brinell hardness values before and after heat treatment were remarkably increased by 31.74% and 28.93% in comparison with bare alloy. According to differential scanning calorimetry analysis (DSC), it was found that the nucleation behavior of the primary Mg2Si phase could be significantly improved by using chemical modifiers. Some white particles were found to be embedded in the center of Mg2Si phases, which were deduced to be Ca5Sb3 through X-ray diffraction (XRD) and field-emission scanning electron microscope (FESEM) analyses. Furthermore, Ca5Sb3 articles possess a rather low mismatch degree with Mg2Si particles based on Phase Transformation Crystallography Lab software (PTCLab) calculation, meaning that the efficient nucleation capability of Ca5Sb3 for Mg2Si particles could be estimated.

scholarly journals Methylene-Bridged Tridentate Salicylaldiminato Binuclear Titanium Complexes as Copolymerization Catalysts for the Preparation of LLDPE through [Fe]/[Ti] Tandem Catalysis

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1114 ◽  
Author(s):  
Yani Luo ◽  
Jian Li ◽  
Derong Luo ◽  
Qingliang You ◽  
Zifeng Yang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Temperature ◽  
Gel Permeation Chromatography ◽  
13C Nmr Spectroscopy ◽  
Molar Ratio ◽  
Tandem Catalysis ◽  
Titanium Complexes ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Branching Degree

A novel tandem catalysis system consisted of salicylaldiminato binuclear/mononuclear titanium and 2,6-bis(imino)pyridyl iron complexes was developed to catalyze ethylene in-situ copolymerization. Linear low-density polyethylene (LLDPE) with varying molecular weight and branching degree was successfully prepared with ethylene as the sole monomer feed. The polymerization conditions, including the reaction temperature, the Fi/Ti molar ratio, and the structures of bi- or mononuclear Ti complexes were found to greatly influence the catalytic performances and the properties of obtained polymers. The polymers were characterized by differential scanning calorimetry (DSC), high temperature gel permeation chromatography (GPC) and high temperature 13C NMR spectroscopy, and found to contain ethyl, butyl, as well as some longer branches. The binuclear titanium complexes demonstrated excellent catalytic activity (up to 8.95 × 106 g/molTi·h·atm) and showed a strong positive comonomer effect when combined with the bisiminopyridyl Fe complex. The branching degree can be tuned from 2.53 to 22.89/1000C by changing the reaction conditions or using different copolymerization pre-catalysts. The melting points, crystallinity and molecular weights of the products can also be modified accordingly. The binuclear complex Ti2L1 with methylthio sidearm showed higher capability for comonomer incorporation and produced polymers with higher branching degree and much higher molecular weight compared with the mononuclear analogue.

scholarly journals Alumina Extraction from Coal Fly Ash via Low-Temperature Potassium Bisulfate Calcination

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 585 ◽  
Author(s):  
Chunbin Guo ◽  
Jingjing Zou ◽  
Shuhua Ma ◽  
Jianlin Yang ◽  
Kehan Wang
Keyword(s):  
Fly Ash ◽  
Low Temperature ◽  
Extraction Efficiency ◽  
Coal Fly Ash ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Increasing Demand ◽  
Technology Effects ◽  
Best Fit

Owing to the depletion of bauxite and increasing demand for alumina, calcination methods for extracting alumina from coal fly ash (CFA) were developed. However, these methods have disadvantages such as the need for high temperatures and the emission of toxic gases. Hence, in this study, Al2O3 was extracted from CFA via low-temperature potassium bisulfate calcination technology. Effects of the potassium bisulfate amount, calcination temperature, and calcination time on the alumina extraction efficiency were investigated using X-ray diffraction, thermal gravimetry, scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectroscopy. It was found that this technique could recover alumina efficiently, and potassium bisulfate significantly contributed to the degradation of mullite and corundum phases. Al2O3 in CFA was converted into soluble K3Al(SO4)3. With a KHSO4/Al2O3 molar ratio of 7:1, calcining temperature of 230 °C, and calcining time of 3 h, the alumina extraction efficiency reached a maximum of 92.8%. The Avrami–Erofeev equation showed the best fit with the kinetic data for the low-temperature calcination of CFA with KHSO4. The activation energy was 28.36 kJ/mol.

scholarly journals The Anodic Behaviour of Bulk Copper in Ethaline and 1-Butyl-3-Methylimidazolium Chloride

2019 ◽  
Vol 9 (20) ◽  
pp. 4401 ◽  
Author(s):  
Karim ◽  
Aziz ◽  
Brza ◽  
Abdullah ◽  
Kadir
Keyword(s):  
Electrochemical Impedance ◽  
Choline Chloride ◽  
Metallic Copper ◽  
Electrochemical Techniques ◽  
Deep Eutectic Solvent ◽  
Molar Ratio ◽  
Interfacial Region ◽  
Dissolution Mechanism ◽  
Spectroscopic Techniques ◽  
Electrochemical Dissolution

The anodic dissolution of bulk metallic copper was conducted in ionic liquids (ILs)—a deep eutectic solvent (DES) ((CH3)3NC2H4OH) comprised of a 1:2 molar ratio mixture of choline chloride Cl (ChCl), and ethylene glycol (EG)—and imidazolium-based ILs, such as C4mimCl, using electrochemical techniques, such as cyclic voltammetry, anodic linear sweep voltammetry, and chronopotentiometry.To investigate the electrochemical dissolution mechanism, electrochemical impedance spectroscopy (EIS) was used. In addition to spectroscopic techniques, for instance, UV-visible spectroscopy, microscopic techniques, such as atomic force microscopy (AFM), were used. The significant industrial importance of metallic copper has motivated several research groups to deal with such an invaluable metal. It was confirmed that the speciation of dissolved copper from the bulk phase at the interface region is [CuCl3]− and [CuCl4]2− in such chloride-rich media, and the EG determine the structure of the interfacial region in the electrochemical dissolution process. A super-saturated solution was produced at the electrode/solution interface and CuCl2 was deposited on the metal surface.

scholarly journals Novel Deep Eutectic Solvent Based on Levulinic Acid and 1,4-Butanediol as an Extraction Media for Bioactive Alkaloid Rutaecarpine

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 171 ◽  
Author(s):  
Yue-Yue Si ◽  
Shi-Wei Sun ◽  
Kun Liu ◽  
Yang Liu ◽  
Hai-Lin Shi ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Extraction Efficiency ◽  
Choline Chloride ◽  
Extraction Procedure ◽  
Deep Eutectic Solvent ◽  
Supermolecular Structure ◽  
Molar Ratio ◽  
Resonance Spectroscopy ◽  
Extraction Temperature ◽  
Unripe Fruits

Deep eutectic solvents (DESs) are increasingly receiving interest as a new type of green and sustainable alternative to hazardous organic solvents. In this work, a novel DES based on levulinic acid (La) and 1,4-butanediol (Buta) as an extraction media was developed for extracting the bioactive alkaloid rutaecarpine from the unripe fruits of Tetradium ruticarpum. 24 different DESs consisting of choline chloride, betaine, sugar alcohols, organic acids, amides, and sugars were prepared and tailored to test their extraction efficiency. After initial screening, a hydrophilic DES composed of La and Buta with 1:0.5 molar ratio containing 25% water was tailored for the highest extraction efficiency, followed by the optimizations of molar ratio and water content. The interaction between the molecules of La-Buta DES was investigated by nuclear magnetic resonance spectroscopy in order to confirm its deep eutectic supermolecular structure feature. The extraction conditions were optimized by single-factor experiments, including extraction temperature, extraction time, and solid-liquid ratio. The developed La-Buta DES extraction procedure was successfully applied for the analysis of rutaecarpine in Chinese patent medicines containing the unripe fruits of T. ruticarpum. The excellent property of La-Buta DES indicated its potential as a promising green solvent instead of conventional organic solvent for the extraction of rutaecarpine from the unripe fruits of T. ruticarpum, and that it can used as a sustainable and safe extraction media for other applications.

Purification and studies of some physicochemical properties of glutamine synthetase of Neurospora crassa

1978 ◽  
Vol 56 (10) ◽  
pp. 927-933 ◽  
Author(s):  
W. S. Lin ◽  
M. Kapoor
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Glutamine Synthetase ◽  
Neurospora Crassa ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Sedimentation Coefficient ◽  
Affinity Column ◽  
Subunit Structure ◽  
Α Helix

Glutamine synthetase (EC 6.3.1.2) of Neurospora crassa was purified to near homogeneity by chromatography on a glutamate–Sepharose affinity column. Its properties, including molecular weight, subunit structure, amino acid composition, and approximate α-helix content, have been examined. In the native state, this enzyme has been demonstrated by gel filtration to be an octamer of molecular weight 360 000 and as having a sedimentation coefficient of 13.2 S by sedimentation velocity measurements. Circular dichroism spectra in the far ultraviolet range suggest an approximate α-helix content of 23–24%. The subunit generated by treatment with urea was found to be 45 000 daltons by gel filtration methods and a molecular weight of 46 000 was calculated for the monomer obtained by sodium dodecyl sulphate (SDS) treatment and electrophoresis in SDS-polyacrylamide gels. Interprotomeric cross-linking experiments, using diimidoesters, suggest the presence of two noncovalently linked tetramers comprising the native octameric structure. Amino acid analyses revealed the presence of six tryptophans, four half cystines, and nine methionine residues per monomer of 45 000 daltons.

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