Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity

2014-10-06Methods & Applications, Our Publications, Our Researchalkaloids, ecology, phytochemistry, toxicityMiriam

“Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity” by Eva Castells, Patrick P.J. Mulder and Miriam Perez-Trujillo. Phytochemistry (2014) 108:137-146. DOI: 10.1016/j.phytochem.2014.09.006

Changes in plant chemical defenses after invasion could have consequences on the invaded ecosystems by modifying the interactions between plants and herbivores and facilitating invasion success. However, no comprehensive biogeographical studies have yet determined the phenotypic levels of plant chemical defenses, as consumed by local herbivores, covering large distributional areas of a species. Continue reading Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity →

Perfect-HSQC experiments: pure in-phase spectra

2014-10-04Methods & Applications, Our Publications, Our Researchheteronulear coupling constants, HSQC, one-bond proton-carbon coupling constants, perfect HSQC, proton-proton coupling constants, pure in-phase signalsLaura

“Suppresión of phase and amplitude J_HH modulations in HSQC experiments” by Laura Castañar, Eduard Sistaré, Albert Virgili, Robert Thomas Williamson and Teodor Parella. Magnetic Resonance in Chemistry, 2014 , 53:115-119. DOI: 10.1002/mrc.4149

The amplitude and the phase of cross peaks in conventional 2D HSQC experiments are modulated by both proton–proton, J_HH, and proton–carbon, ¹J_CH, coupling constants. It is shown by spectral simulation and experimentally that J_HH interferences are suppressed in a novel perfect-HSQC pulse scheme that incorporates perfect-echo INEPT periods. Continue reading Perfect-HSQC experiments: pure in-phase spectra →

SeRMN presentations at the 2014 Ibero-American NMR & GERMN Bienal & Iberian NMR meeting

2014-09-15Methods & Applications, NMR Events & Courses, Our Researchchirality, enantiodifferentiation, enhanced resolution, full sensitivity, HOBS, HOBS-TOCSY, homodecoupling, homonuclear decoupling, multipl, pure-shift NMRLaura

Some of our last research work will be presented next week at the VI Ibero-American NMR – VII GERMN Bienal – IV Iberian NMR joint meeting that will take place in Alcalá de Henares, Madrid (Spain) from 22^nd to 25^th September. Find below a summary of our contributions.

Laura Castañar presents an oral communication and a poster entitled “Enantiodifferentiation throgh frequency-selective pure shift ¹H NMR”. NMR-aided discrimination of enantiomers using chiral solvating agents (CSAs) is a well established method to carry out enantiodifferentiation studies. Continue reading SeRMN presentations at the 2014 Ibero-American NMR & GERMN Bienal & Iberian NMR meeting →

SeRMN presentations at the SMASH NMR 2014 Conference

2014-08-13News from the SeRMN, NMR Events & Courses, Our Publications, Our ResearchTeo

Some of our last research works will be presented at the annual meeting of the Small Molecule NMR Conference (SMASH) that will take place in Atlanta (USA) from 7^th to 10^th September 2014.

- Dr. Teodor Parella is a program Co-Chair.

Dr. Josep Saurí will give the talk New Methods for the Sign-Sensitive Determination of Homo- and Heteronuclear Coupling Constants in the “Analysis of Chiral Molecules and Related NMR Methods” session.

Continue reading SeRMN presentations at the SMASH NMR 2014 Conference →

Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra

2014-07-17Methods & Applications, Our Publications, Our Researchchirality, enantiodifferentiation, enhanced resolution, homodecoupling, homonuclear decoupling, HSQC, pure-shift NMR, spectral aliasingMiriam

“Simultaneous ¹H and ¹³C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra” by Miriam Pérez-Trujillo, Laura Castañar, Eva Monteagudo, Lars T. Kuhn, Pau Nolis, Albert Virgili, R. Thomas Williamson and Teodor Parella. Chemical Communications 50:10214-10217 (2014). DOI: 10.1039/C4CC04077E

NMR-aided discrimination of enantiomers using chiral solvating agents (CSAs) is a well established method of enantiodifferentiation and measurement of enantiomeric ratios (er). The analysis is traditionally performed by observing chemical shift differences (ΔΔδ) in ¹H signals by conventional 1D ¹H NMR spectra. However, low ΔΔδ values and signal overlap caused by complex multiplets lead to the lack of spectral signal dispersion that preclude a straightforward analysis. Continue reading Simultaneous 1H and 13C NMR enantiodifferentiation from highly-resolved pure shift HSQC spectra →

Pure In-Phase Heteronuclear Correlation NMR Experiments

2014-06-27Methods & Applications, Our Publications, Our Researchheteronulear coupling constants, HSQC, HSQMBC, IPAP, PIP experiments, proton-carbon coupling constants, proton-proton coupling constantsLaura

“Pure In-Phase Heteronuclear Correlation NMR Experiments ” by Laura Castañar, Josep Sauri, Robert Thomas Williamson, Albert Virgili and Teodor Parella. Angew. Chem. Int. Ed. 2014, 53, 8379-8382. DOI: 10.1002/anie.201404136

A general NMR approach to provide pure in-phase (PIP) multiplets in heteronuclear correlation experiments is described. The implementation of a z-filter efficiently suppresses any unwanted anti-phase contributions that usually distort the multiplet pattern of cross-peaks and can make their analysis difficult. Continue reading Pure In-Phase Heteronuclear Correlation NMR Experiments →

Presentations at the EUROMAR 2014 Conference

2014-06-18News from the SeRMN, NMR Events & Courses, Our Researchenantiodifferentiation, EUROMAR, heteronulear coupling constants, HOBS, homonuclear decoupling, NMR Conference, pure-shift NMRLaura

EUROMAR 2014

In a few days several SeRMN members will present our research work at the annual meeting of the European magnetic resonance community EUROMAR 2014 Conference that will take place in Zurich (Switzerland) from 29^thJune to 3^th July. Find below a summary of our contributions. Continue reading Presentations at the EUROMAR 2014 Conference →

PhD Thesis: Modern NMR Methodologies for the Measurement of Homo- and Heteronuclear Coupling Constants in Small Molecules

2014-05-29Methods & Applications, News from the SeRMN, Our ResearchE.COSY, HSQMBC, IPAP, J-resolved, PhD Thesis, proton-carbon coupling constants, spin-state selectionJosep

Last 21^st May 2014 I defended my PhD Thesis entitled: Modern NMR Methodologies for the Measurement of Homo- and Heteronuclear Coupling Constants in Small Molecules

The dissertation is focused on the development of modern NMR methodologies for the measurement of homo- and heteronuclear coupling constants in small molecules, and is presented as a compendium of eight (8) publications that have been published in several peer-reviewed journals as original research papers. Continue reading PhD Thesis: Modern NMR Methodologies for the Measurement of Homo- and Heteronuclear Coupling Constants in Small Molecules →

HOBS experiments to measure T₁/T₂ relaxation times in overlapped regions

2014-05-14Methods & Applications, Our Publications, Our Research, Uncategorizedband-selective, CPMG, enhanced resolution, full sensitivity, HOBS, homodecoupling, homonuclear decoupling, Inversion Recovery, PROJECT, pure-shift NMR, Relaxation times, T1-relaxation, T2-relaxationLaura

“Measurement of T₁/T₂ relaxation times in overlapped regions from homodecoupled ¹H singlet signals” by Laura Castañar, Pau Nolis, Albert Virgili and Teodor Parella. Journal of Magnetic Resonance 244 (2014) 30-35. DOI: 10.1016/j.jmr.2014.04.003

The implementation of the HOmodecoupled Band-Selective (HOBS) technique in the conventional Inversion-Recovery and CPMG-based PROJECT experiments is described. The achievement of fully homodecoupled signals allows the distinction of overlapped ¹H resonances with small chemical shift differences. It is shown that the corresponding T₁ and T₂ relaxation times can be individually measured from the resulting singlet lines using conventional exponential curve-fitting methods. Continue reading HOBS experiments to measure T₁/T₂ relaxation times in overlapped regions →

Presentations at the Joint Annual Meeting ISMRM-ESMRMB 2014

2014-05-08News from the SeRMN, NMR Events & Courses, Our Research13C-NMR, animal-model, cancer, hyperpolarization, in-vivo-DNP, liver, MRSSilvia

Next week several SeRMN members will present our research work at the Joint Annual meeting ISMRM-ESMRMB 2014 that will take place in Milan (Italy) from 10^th to 16^th May. Find below a summary of our contributions.

Continue reading Presentations at the Joint Annual Meeting ISMRM-ESMRMB 2014 →

SeRMN – NMR Service at UAB

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