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Proton Nuclear Magnetic Resonance Spectroscopy (proton + nuclear_magnetic_resonance_spectroscopy)
Selected AbstractsApplication of proton nuclear magnetic resonance spectroscopy to the study of Cryptococcus and cryptococcosisFEMS YEAST RESEARCH, Issue 4 2006Tania C. Sorrell Abstract Proton nuclear magnetic resonance spectroscopy is a nondestructive technique that identifies chemicals in solution and in living cells. It has been used in cryptococcal research to identify the primary structure of capsular glucuronoxylomannans, link cellular apoptosis susceptibility (CAS) genes to positioning of residues on the mannose backbone of glucuronoxylomannan, and verify that the cryptococcal virulence determinant, phospholipase B, is elaborated in vivo. Promising clinical applications include speciation (Cryptococcus neoformans and Cryptococcus gattii), with preliminary evidence that varieties neoformans and grubii can also be distinguished, non-invasive diagnosis of cerebral cryptococcomas, and, in cases of meningitis, monitoring therapeutic response by analysis of cerebrospinal fluid. [source] Detection of new amino acid markers of liver trauma by proton nuclear magnetic resonance spectroscopyLIVER INTERNATIONAL, Issue 6 2006Priyadarshi Ranjan Abstract: Objective: We examined serum in patients of liver injury to explore the possible clinical application of abnormal micrometabolites as a marker of liver injury and severity in cases of traumatic liver damage. Methods: Serum were screened by proton nuclear magnetic resonance spectroscopy in 96 patients with varying degree of liver injury and compared with concentrations in healthy control volunteers. Results: Large quantities of phenylalanine and tyrosine were detected by spectroscopic analysis in patients with liver injury but not in those without liver injury (P<0.001). Proton nuclear magnetic resonance spectroscopy revealed two unique amino acids, phenylalanine and tyrosine, in the sera of the subjects with liver injury, irrespective of the extent and type of injury gauged by radiology or laparotomy. Phenylalanine spectrum was obtained in all 84 patients with liver injury (100% sensitivity) whereas tyrosine spectrum was present in 83 out of 84 patients (98.8% sensitivity) suggesting that these amino acids were specifically released in the patients of liver injury. Significant correlations were observed between phenylalanine and tyrosine concentrations and total bilirubin levels and albumin levels. Serum phenylalanine and tyrosine concentrations correlated well with imaging and laparotomy findings of liver injury. Conclusion: Phenylanaline and tyrosine appear to be specific and new markers of liver injury. [source] Application of proton nuclear magnetic resonance spectroscopy to the study of Cryptococcus and cryptococcosisFEMS YEAST RESEARCH, Issue 4 2006Tania C. Sorrell Abstract Proton nuclear magnetic resonance spectroscopy is a nondestructive technique that identifies chemicals in solution and in living cells. It has been used in cryptococcal research to identify the primary structure of capsular glucuronoxylomannans, link cellular apoptosis susceptibility (CAS) genes to positioning of residues on the mannose backbone of glucuronoxylomannan, and verify that the cryptococcal virulence determinant, phospholipase B, is elaborated in vivo. Promising clinical applications include speciation (Cryptococcus neoformans and Cryptococcus gattii), with preliminary evidence that varieties neoformans and grubii can also be distinguished, non-invasive diagnosis of cerebral cryptococcomas, and, in cases of meningitis, monitoring therapeutic response by analysis of cerebrospinal fluid. [source] Methyl 3-[3,,4,-(methylenedioxy)phenyl]-2-methyl glycidate: An Ecstasy Precursor Seized in Sydney, AustraliaJOURNAL OF FORENSIC SCIENCES, Issue 4 2007Michael Collins Ph.D. Abstract:, Five 44 gallon drums labeled as glycidyl methacrylate were seized by the Australian Customs Service and the Australian Federal Police at Port Botany, Sydney, Australia, in December 2004. Each drum contained a white, semisolid substance that was initially suspected to be 3,4-methylenedioxymethylamphetamine (MDMA). Gas chromatography,mass spectroscopy (GC/MS) analysis demonstrated that the material was neither glycidyl methacrylate nor MDMA. Because intelligence sources employed by federal agents indicated that this material was in some way connected to MDMA production, suspicion fell on the various MDMA precursor chemicals. Using a number of techniques including proton nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR), GC/MS, infrared spectroscopy, and total synthesis, the unknown substance was eventually identified as methyl 3-[3,,4,(methylenedioxy)phenyl]-2-methyl glycidate. The substance was also subjected to a published hydrolysis and decarboxylation procedure and gave a high yield of the MDMA precursor chemical, 3,4-methylenedioxyphenyl-2-propanone, thereby establishing this material as a "precursor to a precursor." [source] A novel thermotropic liquid crystalline copolyester containing phosphorus and aromatic ether moity toward high flame retardancy and low mesophase temperatureJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2010Xiang-Cheng Bian Abstract A series of thermotropic liquid crystalline polyesters containing phosphorus and aromatic ether groups (TLCP-AEs) were synthesized from p -acetoxybenzoic acid (p -ABA), terephthalic acid (TPA), 4,4,-oxybis(benzoic acid) (OBBA), and acetylated 2-(6-oxid-6H-dibenz(c,e) (1,2) oxaphosphorin 6-yl) 1,4-benzenediol (DOPO-AHQ). The chemical structure and the properties of TLCP-AEs were characterized by Fourier-transform spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electronic microscopy (SEM), polarizing optical microscopy (POM), limiting oxygen index, and UL-94 tests, respectively. The results showed that TLCP-AEs had low and broad mesophase temperatures (230,400 °C). TLCP-AEs also showed excellent thermal stability; their 5%-weight-loss temperatures were above 440 °C and the char yields at 700 °C were higher than 45 wt %. All TLCP-AE polyesters exhibited high flame retardancy with a LOI value of higher than 70 and UL-94 V-0 rating. The SEM observation revealed that TLCP-AEs had good fibrillation ability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1182,1189, 2010 [source] A phosphorus-containing thermotropic liquid crystalline copolyester with low mesophase temperature and high flame retardanceJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2008Cheng-Shou Zhao Abstract A novel phosphorus-containing thermotropic liquid crystalline copolyester with flexible spacers (P-TLCP-FS) was synthesized by melt transesterification from p -acetoxybenzoic acid (p -ABA), terephthalic acid (TPA), ethylene glycol, and acetylated 2-(6-oxid-6H-dibenz(c,e) (1,2) oxaphosphorin 6-yl) 1,4-benzenediol (AODOPB). The chemical structure and properties of the obtained P-TLCP-FS were characterized by Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), inherent viscosity measurements, differential scanning calorimetry (DSC), thermogravimetry (TGA), polarizing light microscopy (PLM), and X-ray diffraction (XRD) analysis. P-TLCP-FS had inherent viscosities of 0.92,1.12 dL/g and exhibited low and wide mesophase temperatures, ranging from 185 to 330 °C, which can match with the processing temperatures of most conventional polymers and high flame retardancy with a limiting oxygen index value of 70% and UL-94 V-0 rating. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5752,5759, 2008 [source] Detection of new amino acid markers of liver trauma by proton nuclear magnetic resonance spectroscopyLIVER INTERNATIONAL, Issue 6 2006Priyadarshi Ranjan Abstract: Objective: We examined serum in patients of liver injury to explore the possible clinical application of abnormal micrometabolites as a marker of liver injury and severity in cases of traumatic liver damage. Methods: Serum were screened by proton nuclear magnetic resonance spectroscopy in 96 patients with varying degree of liver injury and compared with concentrations in healthy control volunteers. Results: Large quantities of phenylalanine and tyrosine were detected by spectroscopic analysis in patients with liver injury but not in those without liver injury (P<0.001). Proton nuclear magnetic resonance spectroscopy revealed two unique amino acids, phenylalanine and tyrosine, in the sera of the subjects with liver injury, irrespective of the extent and type of injury gauged by radiology or laparotomy. Phenylalanine spectrum was obtained in all 84 patients with liver injury (100% sensitivity) whereas tyrosine spectrum was present in 83 out of 84 patients (98.8% sensitivity) suggesting that these amino acids were specifically released in the patients of liver injury. Significant correlations were observed between phenylalanine and tyrosine concentrations and total bilirubin levels and albumin levels. Serum phenylalanine and tyrosine concentrations correlated well with imaging and laparotomy findings of liver injury. Conclusion: Phenylanaline and tyrosine appear to be specific and new markers of liver injury. [source] Photopolymerization of alicyclic methacrylate hydrogels for controlled releasePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2009Jing Han Abstract Alicyclic hydroxy methacrylate monomer, o -hydroxycyclohexyl methacrylate (HCMA), was synthesized and characterized by Fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H-NMR). Photopolymerization kinetics of HCMA was investigated via real-time infrared spectroscopy (RT-IR). Polymeric network hydrogels based on hydroxyethyl methacrylate (HEMA) and HCMA were prepared by using the photopolymerization technique. Mechanical strength, swelling characteristic, and controlled release behavior of hydrogels with various feed compositions were studied. Poly(HEMA-co-HCMA) hydrogel had higher storage modulus than that of poly(HEMA) hydrogel as investigated by dynamic mechanical analysis (DMA). Acid orange 8 was used as a model drug for the investigation of drug release behavior of copolymeric hydrogels. Results indicated that increase in HCMA ratio in hydrogel composition could reduce the swelling rate and prolong the release time. Scanning electron microscopy (SEM) was also utilized to study the surface morphology of hydrogels, and the results indicated that HCMA content influenced pore diameter on the hydrogel surface. Copyright © 2008 John Wiley & Sons, Ltd. [source] Free sialic acid storage disease without sialuria,ANNALS OF NEUROLOGY, Issue 6 2009Fanny Mochel MD We performed high-resolution in vitro proton nuclear magnetic resonance spectroscopy on cerebrospinal fluid and urine samples of 44 patients with leukodystrophies of unknown cause. Free sialic acid concentration was increased in cerebrospinal fluid of two siblings with mental retardation and mild hypomyelination. By contrast, urinary excretion of free sialic acid in urine was normal on repeated testing by two independent methods. Both patients were homozygous for the K136E mutation in SLC17A5, the gene responsible for the free sialic acid storage diseases. Our findings demonstrate that mutations in the SLC17A5 gene have to be considered in patients with hypomyelination, even in the absence of sialuria. Ann Neurol 2009;65:753,757 [source] Online coupling of enantioselective capillary gas chromatography with proton nuclear magnetic resonance spectroscopyCHIRALITY, Issue 9 2010Maximilian Kühnle Abstract The hyphenation of enantioselective capillary gas chromatography and mass spectrometry is not always sufficient to distinguish between structural isomers, thus requiring peak identification by NMR spectroscopy. Here the first online coupling of enantioselective capillary gas chromatography with proton nuclear resonance spectroscopy is described for the unfunctionalized chiral alkane 2,4-dimethylhexane resolved on octakis(6- O -methyl-2,3-di- O -pentyl)-,-cyclodextrin at 60°C. NMR allows constitutional and configurational isomers (diastereomers and enantiomers) to be distinguished. Enantiomers display identical spectra at different retention times, which enable an indirect identification of these unfunctionalized alkanes. The presented method is still at an early development stage, and will require instrumental optimization in the future. Chirality 2010. © 2010 Wiley-Liss, Inc. [source] Novel anti-bacterial acid dyes derived from naphthalimide: synthesis, characterisation and evaluation of their technical properties on nylon 6COLORATION TECHNOLOGY, Issue 2 2010Zinat Mohammadkhodaei As an attempt to combine the dyeing and functional finishing steps into one process, two novel anti-bacterial monoazo acid dyes based on N -ester-1,8-naphthalimide were synthesised. To do this, 4-amino- N -ethyl glycinate-1,8-naphthalimide was prepared, diazotised and then coupled to thiosalicylic acid or salicylic acid to produce anti-bacterial dyes. The synthesised dyes were purified and then fully characterised using Fourier Transform,infrared spectrometry, proton nuclear magnetic resonance spectroscopy and melting point analysis. Dispersion of the dyes was prepared in water and applied to nylon 6 fabrics. The novel dyes offered good build-up properties on the substrate. The anti-bacterial efficacy of the synthesised dyes was assessed, with the dyes showing activity against both Gram-positive and Gram-negative bacteria. [source] | ||||||||||||||||