scholarly journals A p-tert-Butyldihomooxacalix[4]arene Based Soft Gel for Sustained Drug Release in Water

2020 ◽  
Vol 8 ◽  
Author(s):  
Hao Guo ◽  
Runmiao Zhang ◽  
Ying Han ◽  
Jin Wang ◽  
Chaoguo Yan
Keyword(s):  
Binding Sites ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Sustained Drug Release ◽  
Porous Network ◽  
Sem Images ◽  
Cone Conformation ◽  
H Nmr ◽  
And Diffusion ◽  
C Nmr

P-tert-butyldihomooxacalix[4]arene is a well-known calix[4]arene analog in which one CH2 bridge is replaced by one -CH2OCH2- group. Thus, dihomooxacalix[4]arene has a slightly larger cavity than that of calix[4]arene and usually possesses a more flexible cone conformation, and the bridged oxygen atom might provide additional binding sites. Here, we synthesized a new functional p-tert-butyldihomooxacalix[4]arene 1 through Ugi reaction with good yield (70%), starting from condensed p-tert-butyldihomooxacalix[4]arene O-alkoxy–substituted benzaldehydes, benzoic acid, benzylamine, and cyclohexyl isocyanide. Proton nuclear magnetic resonance spectroscopy (1H NMR), 13C NMR, IR, and diffusion-ordered 1H NMR spectroscopy (DOSY) methods were used to characterize the structure of 1. Then soft gel was prepared by adding 1 into cyclohexane directly. It shows remarkable thermoreversibility and can be demonstrated for several cycles. As is revealed by scanning electron microscopy (SEM) images, xerogel showed highly interconnected and homogeneous porous network structures, and hence, the gel is suitable for storage and controlled release.

scholarly journals Structural Characterization of Amadori Rearrangement Product of Glucosylated Nα-Acetyl-Lysine by Nuclear Magnetic Resonance Spectroscopy

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Chuanjiang Li ◽  
Hui Wang ◽  
Manuel Juárez ◽  
Eric Dongliang Ruan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Maillard Reaction ◽  
Structural Characterization ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Amadori Rearrangement ◽  
C Nmr ◽  
Nuclear Magnetic

Maillard reaction is a nonenzymatic reaction between reducing sugars and free amino acid moieties, which is known as one of the most important modifications in food science. It is essential to characterize the structure of Amadori rearrangement products (ARPs) formed in the early stage of Maillard reaction. In the present study, the Nα-acetyl-lysine-glucose model had been successfully set up to produce ARP, Nα-acetyl-lysine-glucose. After HPLC purification, ARP had been identified by ESI-MS with intense [M+H]+ ion at 351 m/z and the purity of ARP was confirmed to be over 90% by the relative intensity of [M+H]+ ion. Further structural characterization of the ARP was accomplished by using nuclear magnetic resonance (NMR) spectroscopy, including 1D 1H NMR and 13C NMR, the distortionless enhancement by polarization transfer (DEPT-135) and 2D 1H-1H and 13C-1H correlation spectroscopy (COSY) and 2D nuclear overhauser enhancement spectroscopy (NOESY). The complexity of 1D 1H NMR and 13C NMR was observed due to the presence of isomers in glucose moiety of ARP. However, DEPT-135 and 2D NMR techniques provided more structural information to assign the 1H and 13C resonances of ARP. 2D NOESY had successfully confirmed the glycosylated site between 10-N in Nα-acetyl-lysine and 7′-C in glucose.

scholarly journals 1 H-NMR metabolomic study of whole blood from hatchling loggerhead sea turtles ( Caretta caretta ) exposed to crude oil and/or Corexit

2017 ◽  
Vol 4 (11) ◽  
pp. 171433 ◽  
Author(s):  
Stasia A. Bembenek Bailey ◽  
Jennifer N. Niemuth ◽  
Patricia D. McClellan-Green ◽  
Matthew H. Godfrey ◽  
Craig A. Harms ◽  
...  
Keyword(s):  
Crude Oil ◽  
Whole Blood ◽  
Sea Turtles ◽  
Caretta Caretta ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Loggerhead Sea Turtles ◽  
Blood Samples ◽  
H Nmr ◽  
Whole Blood Samples

We used proton nuclear magnetic resonance spectroscopy ( 1 H-NMR) to evaluate metabolic impacts of environmentally relevant crude oil and Corexit exposures on the physiology of hatchling loggerhead sea turtles ( Caretta caretta ). Sample extraction and data acquisition methods for very small volume whole blood samples and sources of variation between individual hatchlings were assessed. Sixteen unclotted, whole blood samples were obtained from 7-day-old hatchlings after a 4-day cutaneous exposure to either control seawater, crude oil, Corexit 9500A or a combination of crude oil and Corexit 9500A. After extraction, one- and two-dimensional 1 H-NMR spectra of the samples were obtained, and 17 metabolites were identified and confirmed in the whole blood spectra. Variation among samples due to the concentrations of metabolites 3-hydroxybutyrate, lactate, trimethylamine oxide and propylene glycol did not statistically correlate with treatment group. However, the characterization of the hatchling loggerhead whole blood metabolome provides a foundation for future metabolomic research with sea turtles and a basis for the study of tissues from exposed hatchling sea turtles.

scholarly journals Structural characteristics and electrochemical properties of sulfonated polyimide clay-based composite fabricated by a solution casting method

2019 ◽  
Vol 30 (21) ◽  
pp. 19164-19172 ◽  
Author(s):  
Nisar Ali ◽  
Farman Ali ◽  
Shaukat Saeed ◽  
Syed Sakhawat Shah ◽  
Muhammad Bilal
Keyword(s):  
Thin Films ◽  
Impedance Spectroscopy ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Solution Casting ◽  
Casting Method ◽  
Energy Devices ◽  
H Nmr ◽  
Sulfonated Polyimide ◽  
Solution Casting Method

Abstract Herein, the electrochemical and structural properties of sulfonated polyimide (SPI) clay-based composite films have been investigated. SPI reinforced with grafted sonicated clay (GSC) was fabricated via a solution casting method in the form of thin films. The as-synthesized thin films were light brown, tough, flexible and transparent. The thickness of the films were 0.109 mm and 0.056 for pristine SPI and GSC-SPI, respectively. The fabricated composite was fully investigated via Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), carbon (13C) NMR and impedance spectroscopy. The completion of the proton exchange reaction was confirmed by 1H NMR. The electrical properties of the SPI-clay based composite film were investigated by impedance spectroscopy. The conductivity was measured in a wide frequency range from room temperature to 363 K by applying an ac signal of 0.5 V. The appearance of two semicircular arcs at low and high frequency shows two conduction mechanisms with different relaxation times at the exterior and interior of the system. Bode plot also confirms the presence of two electro-active regions. The shift in the position of tanδ peaks to lower frequency region with increasing temperature shows that these relaxations are thermally deactivated. The ac conductivity of the system increased from 6.02E−10 for neat SPI to 6.61E−6 Ω−1 cm−1 for SPI-GSC composite. In conclusion, these layered silicates based conductive films have the potential to act as a polyelectrolyte membrane for fuel cell energy devices.

On the chemistry and high field nuclear magnetic resonance spectroscopy of rapamycin

1980 ◽  
Vol 58 (6) ◽  
pp. 579-590 ◽  
Author(s):  
John A. Findlay ◽  
Lajos Radics
Keyword(s):  
High Field ◽  
Nmr Spectra ◽  
Resonance Spectroscopy ◽  
X Ray ◽  
Conformational Isomers ◽  
H Nmr ◽  
Neutral Compounds ◽  
Complete Assignment ◽  
Hydrolysis Of ◽  
C Nmr

Base catalysed hydrolysis of rapamycin (C51H79NO13) affords six neutral compounds identified by chemical and spectroscopic means as 2a, 3b, 3d, 5, 2,4-dimethylphenol, and L(−)-piperidine-2-carboxylic acid 6, and whose generation has been plausibly rationalized. These findings as well as detailed analyses of 13C nmr and 1H nmr spectra provide independent corroboration of the X-ray derived rapamycin crystal structure 1. Structurally homogeneous in the solid state, rapamycin is found to occur in solutions as a mixture of two conformational isomers (approximately 4:1). Through nearly complete assignment of the high field 1H (400 MHz) and 13C (100.6 MHz) nmr spectra, the isomerism is shown to be associated with trans–cis rotation of an amidic bond within the 31-membered macrolide ring. The predominant form corresponds to the conformer portrayed by X-ray analysis.

Synthesis of new 3H-chromeno[2,3-d]pyrimidine-4,6(5H,7H)-diones via the tandem intramolecular Pinner/Dimroth rearrangement

2018 ◽  
Vol 24 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Nasrin Karimi ◽  
Abolghasem Davoodnia ◽  
Mehdi Pordel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Proton Nuclear Magnetic Resonance ◽  
Phosphoryl Chloride ◽  
Dimroth Rearrangement ◽  
H Nmr ◽  
High Yields ◽  
Aliphatic Carboxylic Acids ◽  
C Nmr ◽  
Nuclear Magnetic

Abstract The reaction of 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitriles with excess aliphatic carboxylic acids in the presence of phosphoryl chloride (POCl3) afforded new 2-alkyl-5-aryl-8,8-dimethyl-8,9-dihydro-3H-chromeno[2,3-d]pyrimidine-4,6(5H,7H)-diones in high yields. The suggested mechanism involves a tandem intramolecular Pinner/Dimroth rearrangement. The synthesized compounds were characterized by infrared (IR), proton nuclear magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C NMR) and elemental analysis.

scholarly journals Metabolomic and metallomic profile differences between Veterans and Civilians with Pulmonary Sarcoidosis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mohammad Mehdi Banoei ◽  
Isabella Iupe ◽  
Reza Dowlatabadi Bazaz ◽  
Michael Campos ◽  
Hans J. Vogel ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Inductively Coupled Plasma ◽  
Granulomatous Inflammation ◽  
Pulmonary Sarcoidosis ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Inductively Coupled ◽  
H Nmr ◽  
Plasma Mass Spectrometry ◽  
Unclear Etiology

AbstractSarcoidosis is a disorder characterized by granulomatous inflammation of unclear etiology. In this study we evaluated whether veterans with sarcoidosis exhibited different plasma metabolomic and metallomic profiles compared with civilians with sarcoidosis. A case control study was performed on veteran and civilian patients with confirmed sarcoidosis. Proton nuclear magnetic resonance spectroscopy (1H NMR), hydrophilic interaction liquid chromatography mass spectrometry (HILIC-MS) and inductively coupled plasma mass spectrometry (ICP-MS) were applied to quantify metabolites and metal elements in plasma samples. Our results revealed that the veterans with sarcoidosis significantly differed from civilians, according to metabolic and metallomics profiles. Moreover, the results showed that veterans with sarcoidosis and veterans with COPD were similar to each other in metabolomics and metallomics profiles. This study suggests the important role of environmental risk factors in the development of different molecular phenotypic responses of sarcoidosis. In addition, this study suggests that sarcoidosis in veterans may be an occupational disease.

Serum analysis by1H Nuclear Magnetic Resonance spectroscopy: a new tool for distinguishing neuromyelitis optica from multiple sclerosis

2013 ◽  
Vol 20 (5) ◽  
pp. 558-565 ◽  
Author(s):  
F-M Moussallieh ◽  
K Elbayed ◽  
JB Chanson ◽  
G Rudolf ◽  
M Piotto ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Neuromyelitis Optica ◽  
Demyelinating Diseases ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Nuclear Magnetic

Background:Neuromyelitis optica (NMO) and multiple sclerosis (MS), two inflammatory demyelinating diseases, are characterized by different therapeutic strategies. Currently, the only biological diagnostic tool available to distinguish NMO from MS is the specific serum autoantibody that targets aquaporin 4, but its sensitivity is low.Objective:To assess the diagnostic accuracy of metabolomic biomarker profiles in these two neurological conditions, compared to control patients.Methods:We acquired serum spectra (47 MS, 44 NMO and 42 controls) using proton nuclear magnetic resonance (1H-NMR) spectroscopy. We used multivariate pattern recognition analysis to identify disease-specific metabolic profiles.Results:The1H-NMR spectroscopic analysis evidenced two metabolites, originating probably from astrocytes, scyllo-inositol and acetate, as promising serum biomarkers of MS and NMO, respectively. In 87.8% of MS patients, scyllo-inositol increased 0.15 to 3-fold, compared to controls and in 74.3% of NMO patients, acetate increased 0.4 to 7-fold, compared to controls. Using these two metabolites simultaneously, we can discriminate MS versus NMO patients (sensitivity, 94.3%; specificity, 90.2%).Conclusion:This study demonstrates the potential of1H-NMR spectroscopy of serum as a novel, promising analytical tool to discriminate populations of patients affected by NMO or MS.

scholarly journals Green anionic polymerization of vinyl acetate using Maghnite-Na+ (Algerian MMT): synthesis characterization and reactional mechanism

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Badia Imene Cherifi ◽  
Mohammed Belbachir ◽  
Abdelkader Rahmouni
Keyword(s):  
Vinyl Acetate ◽  
Polymerization Reaction ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Simple Filtration ◽  
Renewable Material ◽  
Ft Ir ◽  
C Nmr

AbstractIn this work, the green polymerization of vinyl acetate is carried out by a new method which consists in the use of clay called Maghnite-Na+ as an ecological catalyst, non-toxic, inexpensive and recyclable by simple filtration. X-ray diffraction (XRD) showed that Maghnite-Na+ is successfully obtained after cationic treatment (sodium) on raw Maghnite. It is an effective alternative to replace toxic catalysts such as benzoyl peroxide (BPO) and Azobisisobutyronitrile (AIBN) which are mostly used during the synthesis of polyvinyl acetate (PVAc) making the polymerization reaction less problematic for the environment. The synthesis reaction is less energetic by the use of recycled polyurethane as container for the reaction mixture and which is considered as a renewable material and a good thermal insulator which maintains the temperature at 0 °C for 6 h. The reaction in bulk is also preferred to avoid the use of a solvent and therefore to stay in the context of green chemistry. In these conditions, the structure of obtained polymer is established by Nuclear Magnetic Resonance Spectroscopy 1H NMR and 13C NMR. Infrared spectroscopy (FT-IR) is also used to confirm the structure of PVAc. Thermogravimetric analysis (TGA) showed that it is thermally stable and it starts to degrade from 330 °C while Differential Scanning calorimetry (DSC) shows that this polymer has a glass transition temperature (Tg  = 50 °C). The composition in PVAc/Maghnite-Na+ (7 wt% of catalyst) is the most tensile resistant with a force of 182 N and a maximum stress of 73.16 MPa, the most flexible (E  = 955 MPa) and the most ductile (εr  = 768%).

scholarly journals Metabolomics comparison of rumen fluid and milk in dairy cattle using proton nuclear magnetic resonance spectroscopy

2021 ◽  
Vol 34 (2) ◽  
pp. 213-222
Author(s):  
Jun Sik Eom ◽  
Eun Tae Kim ◽  
Hyun Sang Kim ◽  
You Young Choi ◽  
Shin Ja Lee ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Dairy Cattle ◽  
Metabolic Diseases ◽  
Rumen Fluid ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Nuclear Magnetic

Objective: The metabolites that constitute the rumen fluid and milk in dairy cattle were analyzed using proton nuclear magnetic resonance (<sup>1</sup>H-NMR) spectroscopy and compared with the results obtain for other dairy cattle herds worldwide. The aim was to provide basic dataset for facilitating research on metabolites in rumen fluid and milk.Methods: Six dairy cattle were used in this study. Rumen fluid was collected using a stomach tube, and milk was collected using a pipeline milking system. The metabolites were determined by <sup>1</sup>H-NMR spectroscopy, and the obtained data were statistically analyzed by principal component analysis, partial least squares discriminant analysis, variable importance in projection scores, and metabolic pathway data using Metaboanalyst 4.0.Results: The total numbers of metabolites in rumen fluid and milk were measured to be 186 and 184, and quantified as 72 and 109, respectively. Organic acid and carbohydrate metabolites exhibited the highest concentrations in rumen fluid and milk, respectively. Some metabolites that have been associated with metabolic diseases (acidosis and ketosis) in cows were identified in rumen fluid, and metabolites associated with ketosis, somatic cell production, and coagulation properties were identified in milk.Conclusion: The metabolites measured in rumen fluid and milk could potentially be used to detect metabolic diseases and evaluate milk quality. The results could also be useful for metabolomic research on the biofluids of ruminants in Korea, while facilitating their metabolic research.

Characterization of the Polyphenolics Related to the Colour of Western Red Cedar (Thuja plicata Donn) Heartwood

Holzforschung ◽  
2000 ◽  
Vol 54 (3) ◽  
pp. 246-254 ◽  
Author(s):  
C. Ingemar Johansson ◽  
John N. Saddler ◽  
Rodger P. Beatson
Keyword(s):  
Thuja Plicata ◽  
Resonance Spectroscopy ◽  
Initial Examination ◽  
Pyrolysis Gas ◽  
H Nmr ◽  
Red Cedar ◽  
Mild Acid ◽  
Thuja Plicata Donn ◽  
C Nmr

Summary Three quarters of the western red cedar's heartwood colour is due to a polymeric material easily isolated by methanol extraction. The nature of this polymer has not been fully investigated and published information is contradictory. Our initial examination of the coloured polymer by pyrolysis-gas chromatography, combined with mass spectrometry, indicated that the polymer was guaiacyl in nature and thus similar to softwood lignin. However, analysis by infrared spectroscopy indicated the presence of both lignin and lignan like moieties. To clarify this issue a more detailed analysis was conducted using nuclear magnetic resonance spectroscopy (1H NMR, 31P NMR, 13C NMR). Analysis of the spectra and comparison with the spectra of plicatic acid and a product from mild acid treatment of plicatic acid, indicated that the polymeric fraction was derived almost entirely from lignans. During polymer formation, the highly reactive pyrocatechol moiety in the plicatic acid is destroyed, leaving a guaiacyl-like polymer. The reaction mechanism appears to proceed via an ortho-quinone intermediate followed by polymerization.

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