scholarly journals Preparation of Methacrylate-based Polymers Modified with Chiral Resorcinarenes and Their Evaluation as Sorbents in Norepinephrine Microextraction

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1428 ◽  
Author(s):  
Castillo-Aguirre ◽  
Maldonado
Keyword(s):  
Chemical Modification ◽  
Rotating Disk ◽  
Mannich Bases ◽  
Experimental Conditions ◽  
Microscopy Imaging ◽  
Modified Polymer ◽  
Modified Polymers ◽  
Composition And Structure ◽  
Artificial Urine ◽  
Ft Ir

Aminomethylation reactions between chiral amino compounds (S)-(-)-1-phenylethylamine and l-proline with tetranonylresorcinarene and tetra-(4-hydroxyphenyl)resorcinarene in presence of formaldehyde were studied. The reaction between l-proline and resorcinarenes generated regioselectively chiral tetra-Mannich bases, due to the molecular incorporation of the fragment of the chiral amino acid. On the other hand, tetranonylresorcinarene and (S)-(-)-1-phenylethylamine formed regio- and diasteroselectively chiral tetrabenzoxazines, both by chiral auxiliary functionalization and by the transformation of the molecular structure that confers inherent chirality. The products obtained were characterized using IR, 1H-NMR, 13C-NMR, COSY, HMQC, and HMBC techniques. The reaction of (S)-(-)-1-phenylethylamine with tetra-(4-hydroxyphenyl)resorcinarene did not proceed under the experimental conditions. Once the chiral aminomethylated tetra-(4-hydroxyphenyl)resorcinarene was obtained, the chemical modification of poly(GMA–co–EDMA) was studied, and the results showed an efficient incorporation of the aminomethylated compound. For the physical modification, chiral aminomethylated tetranonylresorcinarenes were employed, finding that the incorporation of modified resorcinarenes occurs, but with less efficiency than that observed using chemical modification. The modified polymers were characterized via FT-IR, scanning electron microscopy imaging, and elemental analysis. Finally, polymers modified with chiral resorcinarenes were used as sorbents in norepinephrine microextraction; for practical purposes, artificial urine was prepared and used. To perform the microextraction, the decision was made to use the modern rotating-disk sorptive extraction technique (RDSE), because of its analytical attributes as a green, or eco-friendly, technique. According to the results, the method preliminarily validated for the determination of norepinephrine in artificial urine shows that the modified polymer with chiral derivative of tetra-(4-hydroxyphenyl)resorcinarene worked effectively as a new sorbent phase for the quantitative microextraction of norepinephrine, exhibiting high stability and homogeneity of composition and structure within the working range.

scholarly journals Aminomethylated Calix[4]resorcinarenes as Modifying Agents for Glycidyl Methacrylate (GMA) Rigid Copolymers Surface

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1147 ◽  
Author(s):  
Betty Astrid Velásquez-Silva ◽  
Alver Castillo-Aguirre ◽  
Zuly Jenny Rivera-Monroy ◽  
Mauricio Maldonado
Keyword(s):  
Elemental Analysis ◽  
Glycidyl Methacrylate ◽  
High Performance ◽  
Epoxy Group ◽  
Hydroxyl Group ◽  
Basic Medium ◽  
Reaction Products ◽  
Experimental Conditions ◽  
Microscopy Imaging ◽  
Ft Ir

Functionalization of tetrapropylcalix[4]resorcinarene, tetrapentylcalix[4]resorcinarene, tetranonylcalix[4]resorcinarene, and tetra-(4-hydroxyphenyl)calix[4]resorcinarene by means of aminomethylation reactions with the amino acids β-alanine and l-proline in the presence of aqueous formaldehyde was carried out. When β-alanine was used, the reaction products were tetrabenzoxazines. The reaction with tetra-(4-hydroxyphenyl)calix[4]resorcinarene did not proceed under the experimental conditions; therefore, l-proline was used, and the corresponding tetra-Mannich base was regio- and diasteroselectively formed. The products were characterized via FT-IR, 1H NMR, 13C NMR, and elemental analysis. With these aminomethylated-calix[4]resorcinarenes, the chemical surface modification of the copolymers poly(GMA–co–EDMA) and poly(BMA–co–EDMA–co–MMA) in a basic medium was studied. The results were quite satisfactory, obtaining the corresponding copolymers functionalized by nucleophilic substitution reaction and ring-opening between the carboxyl group of the upper rim of aliphatic calix[4]resorcinarenes and the hydroxyl group of the lower rim in the aromatic calix[4]resorcinarene and the epoxy group of the glycidyl methacrylate residue of each copolymer. The modified copolymers were characterized via FT-IR, scanning electron microscopy imaging, and elemental analysis. Finally, the modified copolymer surfaces exhibited interaction with peptides, showing their potential application in chromatographic separation techniques such as high-performance liquid chromatography.

Fabrication and Characterization of Nife Thin Film Composition Modulated Alloys

1996 ◽  
Vol 451 ◽  
Author(s):  
S. D. Leith ◽  
D. T. Schwartz
Keyword(s):  
Rotation Rate ◽  
Stripping Voltammetry ◽  
Rotating Disk ◽  
Oscillation Period ◽  
Rotating Disk Electrode ◽  
Disk Rotation ◽  
Rate Oscillation ◽  
Composition And Structure ◽  
Spatially Periodic

ABSTRACTDescribed are results showing that an oscillating flow-field can induce spatially periodic composition variations in electrodeposited NiFe films. Flow-induced NiFe composition modulated alloys (CMA's) were deposited on the disk of a rotating disk electrode by oscillating the disk rotation rate during galvanostatic plating. Deposit composition and structure were investigated using potentiostatic stripping voltammetry and scanning probe microscopy. Results illustrate a linear relationship between the composition modulation wavelength and the flow oscillation period. CMA's with wavelengths less than 10 nm can be fabricated when plating with a disk rotation rate oscillation period less than 3 seconds.

scholarly journals Characterization of Manganese Oxide/Alumina Catalysts

1995 ◽  
Vol 12 (3) ◽  
pp. 221-229 ◽  
Author(s):  
S.A. El-Hakam
Keyword(s):  
Manganese Oxide ◽  
Calcination Temperature ◽  
Manganese Content ◽  
Textural Properties ◽  
Catalytic Decomposition ◽  
Experimental Conditions ◽  
Surface Areas ◽  
Ft Ir ◽  
Mn Content ◽  
Alumina Catalysts

The effect of heat treatment of manganese oxide/alumina catalysts of various manganese content on the structural and textural properties and the catalytic decomposition of hydrogen peroxide were investigated. The FT-IR results have shown that depending on the calcination temperature and metal loading MnO2 and MnO3 are formed on the investigated samples. No spinel structure was detected under the experimental conditions. The surface areas were found to decrease with increasing calcination temperature and metal content up to 30 wt.% Mn. The mean pore radius increased with both calcination temperature and Mn content. The rate of catalytic decomposition of H2O2 was found to depend on the pH, the calcination temperature and the state of Mn on the catalyst surface.

scholarly journals CHEMICAL MODIFICATION, CHARACTERIZATION AND EVALUATION OF MUCOADHESIVE POTENTIALITY OF ASSAM BORA RICE STARCH

2017 ◽  
Vol 9 (9) ◽  
pp. 132 ◽  
Author(s):  
Abdul Baquee Ahmed ◽  
Iman Bhaduri
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Sustained Release ◽  
Chemical Modification ◽  
Ex Vivo ◽  
Rice Starch ◽  
Modified Starch ◽  
Native Starch ◽  
Ft Ir

Objective: The objective of the present study was to chemical modification, characterization and evaluation of mucoadhesive potentiality of Assam bora rice starch as potential excipients in the sustained release drug delivery system. Methods: The starch was isolated from Assam bora rice and esterified using thioglycolic acid and characterized by Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC) and Nuclear magnetic resonance (NMR). The 10% w/v gel formulation based on modified bora rice starch loaded with irinotecan (0.6%) was prepared and evaluated for various rheological properties, ex-vivo mucoadhesion using goat intestine and in vitro drug release study in phosphate buffer pH 6.8.Results: The chemical modification was confirmed by FT-IR and NMR studies with the presence of the peak at 2626.74 cm-1 and a singlet at 2.51 respectively due to–SH group. Ex-vivo mucoadhesion studies showed 6.6 fold increases in mucoadhesion of the modified starch with compared to native starch (46.3±6.79g for native starch; 308.7±95.31g for modified starch). In vitro study showed 89.12±0.84 % of drug release after 6 h in phosphate buffer pH 6.8 and the release kinetics followed Non-Fickian diffusion.Conclusion: The modified Assam bora rice starch enhanced a mucoadhesive property of the native starch and thus, can be explored in future as a potential excipient for the sustained release mucoadhesive drug delivery system.

scholarly journals Customizable live-cell imaging chambers for multimodal and multiplex fluorescence microscopy

2020 ◽  
Vol 98 (5) ◽  
pp. 612-623
Author(s):  
Adam Tepperman ◽  
David Jiao Zheng ◽  
Maria Abou Taka ◽  
Angela Vrieze ◽  
Austin Le Lam ◽  
...  
Keyword(s):  
Live Cell Imaging ◽  
Cell Imaging ◽  
Super Resolution ◽  
Live Cell ◽  
Imaging Modalities ◽  
Experimental Conditions ◽  
Microscopy Imaging ◽  
Glass Coverslip ◽  
Multiple Imaging ◽  
Microscopy Techniques

Using multiple imaging modalities while performing independent experiments in parallel can greatly enhance the throughput of microscopy-based research, but requires the provision of appropriate experimental conditions in a format that meets the optical requirements of the microscope. Although customized imaging chambers can meet these challenges, the difficulty of manufacturing custom chambers and the relatively high cost and design inflexibility of commercial chambers has limited the adoption of this approach. Herein, we demonstrate the use of 3D printing to produce inexpensive, customized, live-cell imaging chambers that are compatible with a range of imaging modalities, including super-resolution microscopy. In this approach, biocompatible plastics are used to print imaging chambers designed to meet the specific needs of an experiment, followed by adhesion of the printed chamber to a glass coverslip, producing a chamber that is impermeant to liquids and that supports the growth and imaging of cells over multiple days. This approach can also be used to produce moulds for casting microfluidic devices made of polydimethylsiloxane. The utility of these chambers is demonstrated using designs for multiplex microscopy, imaging under shear, chemotaxis, and general cellular imaging. Together, this approach represents an inexpensive yet highly customizable approach for producing imaging chambers that are compatible with modern microscopy techniques.

scholarly journals Removal of Cd2+ from Water by Use of Super-Macroporous Cryogels and Comparison to Commercial Adsorbents

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2405
Author(s):  
Alzhan Baimenov ◽  
Dmitriy Berillo ◽  
Seitkhan Azat ◽  
Talgat Nurgozhin ◽  
Vassilis Inglezakis
Keyword(s):  
Zeolite Y ◽  
Tap Water ◽  
Cation Exchange Resin ◽  
Experimental Conditions ◽  
Equilibrium Studies ◽  
Maximum Sorption Capacity ◽  
Physico Chemical ◽  
Maximum Sorption ◽  
Ft Ir ◽  
The Stability

In this study amphoteric cryogels were synthesized by the use of free-radical co-polymerization of acrylate-based precursors (methacrylic acid and 2-acrylamido-2-methyl-1-propansulfonic acid) with allylamine at different ratios. The physico-chemical characteristics of the cryogels were examined using SEM/EDX, FT-IR, XPS and zeta potential measurements. The cryogels were tested toward Cd2+ removal from aqueous solutions at various pH and initial concentrations. Equilibrium studies revealed a maximum sorption capacity in the range of 132–249 mg/g. Leaching experiments indicated the stability of Cd2+ in the cryogel structure. Based on kinetics, equilibrium and characterization results, possible removal mechanisms are proposed, indicating a combination of ion exchange and complexation of Cd2+ with the cryogels’ surface functional groups. The cryogels were compared to commercially available adsorbents (zeolite Y and cation exchange resin) for the removal of Cd2+ from various water matrices (ultrapure water, tap water and river water) and the results showed that, under the experimental conditions used, the cryogels can be more effective adsorbents.

Effects of basicity and CaF2 on the viscosity of CaF2–CaO–SiO2 slag for electroslag remelting process

2019 ◽  
Vol 116 (6) ◽  
pp. 638 ◽  
Author(s):  
Yigui Lao ◽  
Yunming Gao ◽  
Fangjie Deng ◽  
Qiang Wang ◽  
Guangqiang Li
Keyword(s):  
Rotating Cylinder ◽  
Electroslag Remelting ◽  
Experimental Conditions ◽  
Ft Ir ◽  
Cylinder Method ◽  
The Fourier Transform ◽  
The Relationship ◽  
Complex Anions ◽  
Silicate Complex ◽  
Ft Ir Spectroscopy

Effects of the basicity and the CaF2 content on viscosity of CaF2–CaO–SiO2 slag with high CaF2 content for electroslag remelting process were investigated by the rotating cylinder method in the temperature ranging from 1773 to 1533 K. The relationship between the structure and the viscosity variation of the slag was also clarified by the Fourier transform infrared (FT-IR) spectroscopy of water-quenched slags. The results show that the viscosity gradually decreases with the increase in the basicity of the slag from 1 to 3 under the present experimental conditions. It is found that the CaO does not depolymerize all silicate complex anions for the slag with the basicity of 1 at 1773 K and there are still some bridging oxygens. With the increase in the basicity to 3, the silicate complex anions are almost completely depolymerized to simple ions. As the CaF2 content increases from 40 to 80 mass%, the viscosity of the slag decreases due to the dilution of CaF2 for the concentration of the silicate complex anions in unit volume of the slag. Moreover, the effect of the temperature on the viscosity is not remarkable. The activation energy of viscous flow exhibits the decrease from 40.4 to 26.7 kJ · mol−1 with the increase in the basicity from 1 to 3, and also the decrease from 66.6 to 31.0 kJ · mol−1 with the increase in the CaF2 content from 40 to 80 mass%.

Screen-Printing-Based Fabrication of Silver Patterns on Polyimide Substrate

2012 ◽  
Vol 510 ◽  
pp. 176-181 ◽  
Author(s):  
Fang Yang ◽  
Wei Su ◽  
Li Bei Yao ◽  
Li Fang Liang ◽  
Yu Xin Liu ◽  
...  
Keyword(s):  
Screen Printing ◽  
Substrate Surface ◽  
Silver Ions ◽  
Reduction Reaction ◽  
Contact Angles ◽  
Simple Method ◽  
Ion Exchange Reaction ◽  
Composition And Structure ◽  
Dimethylamine Borane ◽  
Ft Ir

A simple method for fabricating silver circuit patterns on polyimide (PI) substrate was developed. Firstly, partially potassium hydroxide (KOH) modified pattern was produced on the surface of PI film via a screen printing process. Then the silver ions were doped into the interior of the PI substrate through an ion-exchange reaction. Finally, the silver circuit patterns with the lines of 200 µm width were formed on the PI substrate surface due to the reduction reaction of dimethylamine borane (DMAB). Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, infrared spectra (FT-IR) and contact angles analyses were conducted to study the morphology, composition and structure of the obtained silver patterns on the PI substrate. This approach is simple and versatile, and need not the expensive apparatus, which is a promising candidate for a broad range of application in high-density circuitry electronic industry.

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