There has been considerable interest over the past decade in the utilization of direct and long-range 1H-15N heteronuclear shift correlation methods at natural abundance to facilitate the elucidation of small molecule structures. Recently, there has also been a high level of interest in the exploration of indirect covariance NMR methods. Our initial explorations in this area led to the development of unsymmetrical indirect covariance methods, which allow the calculation of hyphenated 2D NMR spectra such as 2D GHSQC-COSY and GHSQC-NOESY from the discrete component 2D NMR experiments. We now wish to report the utilization of unsymmetrical indirect covariance NMR methods for the combination of 1H-13C GHSQC and 1H-15N long-range (GHMBC, IMPEACH-MBC, CIGAR-HMBC, etc.) heteronuclear chemical shift correlation spectra to determine 15N-13C correlation pathways.
Utilization of long-range 1H-15N heteronuclear chemical shift correlation has continually grown in importance since the first applications were reported in 1995. More recently, indirect covariance NMR methods have been introduced followed by the development of unsymmetrical indirect covariance processing methods. The latter technique has been shown to allow the calculation of hyphenated 2D NMR data matrices from more readily acquired non-hyphenated 2D NMR spectra. We recently reported the use of unsymmetrical indirect covariance processing to combine 1H-13C GHSQC and 1H-15N GHMBC long-range spectra to yield a 13C-15N HSQC-HMBC chemical shift correlation spectrum that could not be acquired in a reasonable period of time without resorting to 15N-labeled molecules. We now report the unsymmetrical indirect covariance processing of 1H-13C GHMBC and 1H-15N IMPEACH spectra to afford a 13C-15N HMBC-IMPEACH spectrum that has the potential to span as many as 6 to 8 bonds. Correlations for carbon resonances long-range coupled to a protonated carbon in the 1H-13C HMBC spectrum are transferred via the long-range 1H-15N coupling pathway in the 1H-15N IMPEACH spectrum to afford a much broader range of correlation possibilities in the 13C-15N HMBC-IMPEACH correlation spectrum. The indole alkaloid vincamine is used as a model compound to illustrate the application of the method.
Utilization of long-range 1H-15N heteronuclear chemical shift correlation has continually grown in importance since the first applications were reported in 1995. More recently, indirect covariance NMR methods have been introduced followed by the development of unsymmetrical indirect covariance processing methods. The latter technique has been shown to allow the calculation of hyphenated 2D NMR data matrices from more readily acquired non-hyphenated 2D NMR spectra. We recently reported the use of unsymmetrical indirect covariance processing to combine 1H-13C GHSQC and 1H-15N GHMBC long-range spectra to yield a 13C-15N HSQC-HMBC chemical shift correlation spectrum that could not be acquired in a reasonable period of time without resorting to 15N-labeled molecules. We now report the unsymmetrical indirect covariance processing of 1H-13C GHMBC and 1H-15N IMPEACH spectra to afford a 13C-15N HMBC-IMPEACH spectrum that has the potential to span as many as six to eight bonds. Correlations for carbon resonances long-range coupled to a protonated carbon in the 1H-13C HMBC spectrum are transferred via the long-range 1H-15N coupling pathway in the 1H-15N IMPEACH spectrum to afford a much broader range of correlation possibilities in the 13C-15N HMBC-IMPEACH correlation spectrum. The indole alkaloid vincamine is used as a model compound to illustrate the application of the method.
Long-range 1H-15N heteronuclear shift correlation methods at natural abundance to facilitate the elucidation of small molecule structures have assumed a role of growing importance over the past decade. Recently, there has also been a high level of interest in the exploration of indirect covariance NMR methods. From two coherence transfer experiments, A→B and A→C, it is possible to indirectly determine B⟷C. We have shown that unsymmetrical indirect covariance methods can be employed to indirectly determine several types of hyphenated 2D NMR data from higher sensitivity experiments. Examples include the calculation of hyphenated 2D NMR spectra such as 2D GHSQC-COSY and GHSQC-NOESY from the discrete component 2D NMR experiments. We now wish to report the further extension of unsymmetrical indirect covariance NMR methods for the combination of 1H-13C GHSQC and 1H-15N longrange (GHMBC, IMPEACH-MBC, CIGAR-HMBC, etc.) heteronuclear chemical shift correlation spectra to establish 13C-15N correlation pathways.
We demonstrate the application of unsymmetrical indirect covariance processing methods to the mathematical combination of the 1H-13C GHSQC and long-range 1H-15N GHMBC spectra of vinblastine.
Unsymmetrical indirect covariance processing methods allow the derivation of hyphenated 2D NMR data from the component 2D spectra, potentially circumventing the acquisition of the much lower sensitivity hyphenated 2D NMR experimental data. Calculation of HSQC-COSY and HSQC-NOESY spectra from GHSQC, COSY, and NOESY spectra, respectively, has been reported . The use of unsymmetrical indirect covariance processing has also been applied to the combination of 1H-13C GHSQC and 1H-15N long-range correlation data (GHMBC, IMPEACH, or CIGAR-HMBC). The application of unsymmetrical indirect covariance processing to spectra of vinblastine is now reported, specifically the algorithmic extraction of 13C-15N correlations via the unsymmetrical indirect covariance processing of the combination of 1H-13C GHSQC and long-range 1H-15N GHMBC to produce the equivalent of a 13C-15N HSQC-HMBC correlation spectrum. The elimination of artifact responses with Aromatic Solvent-Induced Shifts (ASIS) is shown in addition to a method of forecasting potential artifact responses through the indirect covariance processing of the GHSQC spectrum used in the unsymmetrical indirect covariance processing.
Several groups of authors have reported studies in the areas of indirect and unsymmetrical indirect covariance NMR processing methods. Efforts have recently focused on the use of unsymmetrical indirect covariance processing methods to combine various discrete two-dimensional NMR spectra to afford the equivalent of the much less sensitive hyphenated 2D NMR experiments, for example icv-HSQC-COSY and icv-HSQC–NOESY. Alternatively, unsymmetrical indirect covariance processing methods can be used to combine multiple heteronuclear 2D spectra to afford icv-13C-15N HSQC-HMBC correlation spectra. We now report the use of responses contained in indirect covariance processed HSQC spectra as a means for the identification of artifacts in both indirect covariance and unsymmetrical indirect covariance processed 2D NMR spectra.
Презентація нової Муніципальної інспекції в місті Івано-Франківську, яка покликана боротись із самовільним виконанням земляних робіт, самовільним встановленням МАФ, стихійною торгівлею, незадовільним санітарним станом території, порушенням вимог до розміщення вивісок і реклами тощо.
Utilization of long-range 1H-15N heteronuclear chemical shift correlation has continually grown in importance since the first applications were reported in 1995. More recently, indirect covariance NMR methods have been introduced followed by the development of unsymmetrical indirect covariance processing methods. The latter technique has been shown to allow the calculation of hyphenated 2D NMR data matrices from more readily acquired non-hyphenated 2D NMR spectra. We recently reported the use of unsymmetrical indirect covariance processing to combine 1H-13C GHSQC and 1H-15N GHMBC long-range spectra to yield a 13C-15N HSQC-HMBC chemical shift correlation spectrum that could not be acquired in a reasonable period of time without resorting to 15N-labeled molecules. We now report the unsymmetrical indirect covariance processing of 1H-13C GHMBC and 1H-15N IMPEACH spectra to afford a 13C-15N HMBC-IMPEACH spectrum that has the potential to span as many as 6 to 8 bonds. Correlations for carbon resonances long-range coupled to a protonated carbon in the 1H-13C HMBC spectrum are transferred via the long-range 1H-15N coupling pathway in the 1H-15N IMPEACH spectrum to afford a much broader range of correlation possibilities in the 13C-15N HMBC-IMPEACH correlation spectrum. The indole alkaloid vincamine is used as a model compound to illustrate the application of the method.
Utilization of long-range 1H-15N heteronuclear chemical shift correlation has continually grown in importance since the first applications were reported in 1995. More recently, indirect covariance NMR methods have been introduced followed by the development of unsymmetrical indirect covariance processing methods. The latter technique has been shown to allow the calculation of hyphenated 2D NMR data matrices from more readily acquired non-hyphenated 2D NMR spectra. We recently reported the use of unsymmetrical indirect covariance processing to combine 1H-13C GHSQC and 1H-15N GHMBC long-range spectra to yield a 13C-15N HSQC-HMBC chemical shift correlation spectrum that could not be acquired in a reasonable period of time without resorting to 15N-labeled molecules. We now report the unsymmetrical indirect covariance processing of 1H-13C GHMBC and 1H-15N IMPEACH spectra to afford a 13C-15N HMBC-IMPEACH spectrum that has the potential to span as many as six to eight bonds. Correlations for carbon resonances long-range coupled to a protonated carbon in the 1H-13C HMBC spectrum are transferred via the long-range 1H-15N coupling pathway in the 1H-15N IMPEACH spectrum to afford a much broader range of correlation possibilities in the 13C-15N HMBC-IMPEACH correlation spectrum. The indole alkaloid vincamine is used as a model compound to illustrate the application of the method.
Long-range 1H-15N heteronuclear shift correlation methods at natural abundance to facilitate the elucidation of small molecule structures have assumed a role of growing importance over the past decade. Recently, there has also been a high level of interest in the exploration of indirect covariance NMR methods. From two coherence transfer experiments, A→B and A→C, it is possible to indirectly determine B⟷C. We have shown that unsymmetrical indirect covariance methods can be employed to indirectly determine several types of hyphenated 2D NMR data from higher sensitivity experiments. Examples include the calculation of hyphenated 2D NMR spectra such as 2D GHSQC-COSY and GHSQC-NOESY from the discrete component 2D NMR experiments. We now wish to report the further extension of unsymmetrical indirect covariance NMR methods for the combination of 1H-13C GHSQC and 1H-15N longrange (GHMBC, IMPEACH-MBC, CIGAR-HMBC, etc.) heteronuclear chemical shift correlation spectra to establish 13C-15N correlation pathways.
We demonstrate the application of unsymmetrical indirect covariance processing methods to the mathematical combination of the 1H-13C GHSQC and long-range 1H-15N GHMBC spectra of vinblastine.
Unsymmetrical indirect covariance processing methods allow the derivation of hyphenated 2D NMR data from the component 2D spectra, potentially circumventing the acquisition of the much lower sensitivity hyphenated 2D NMR experimental data. Calculation of HSQC-COSY and HSQC-NOESY spectra from GHSQC, COSY, and NOESY spectra, respectively, has been reported . The use of unsymmetrical indirect covariance processing has also been applied to the combination of 1H-13C GHSQC and 1H-15N long-range correlation data (GHMBC, IMPEACH, or CIGAR-HMBC). The application of unsymmetrical indirect covariance processing to spectra of vinblastine is now reported, specifically the algorithmic extraction of 13C-15N correlations via the unsymmetrical indirect covariance processing of the combination of 1H-13C GHSQC and long-range 1H-15N GHMBC to produce the equivalent of a 13C-15N HSQC-HMBC correlation spectrum. The elimination of artifact responses with Aromatic Solvent-Induced Shifts (ASIS) is shown in addition to a method of forecasting potential artifact responses through the indirect covariance processing of the GHSQC spectrum used in the unsymmetrical indirect covariance processing.
Several groups of authors have reported studies in the areas of indirect and unsymmetrical indirect covariance NMR processing methods. Efforts have recently focused on the use of unsymmetrical indirect covariance processing methods to combine various discrete two-dimensional NMR spectra to afford the equivalent of the much less sensitive hyphenated 2D NMR experiments, for example icv-HSQC-COSY and icv-HSQC–NOESY. Alternatively, unsymmetrical indirect covariance processing methods can be used to combine multiple heteronuclear 2D spectra to afford icv-13C-15N HSQC-HMBC correlation spectra. We now report the use of responses contained in indirect covariance processed HSQC spectra as a means for the identification of artifacts in both indirect covariance and unsymmetrical indirect covariance processed 2D NMR spectra.
Презентація нової Муніципальної інспекції в місті Івано-Франківську, яка покликана боротись із самовільним виконанням земляних робіт, самовільним встановленням МАФ, стихійною торгівлею, незадовільним санітарним станом території, порушенням вимог до розміщення вивісок і реклами тощо.
Several groups of authors have reported studies in the areas of indirect and unsymmetrical indirect covariance NMR processing methods. Efforts have recently focused on the use of unsymmetrical indirect covariance processing methods to combine various discrete two-dimensional NMR spectra to afford the equivalent of the much less sensitive hyphenated 2D NMR experiments, for example GHSQC-COSY and GHSQC–NOESY. Alternatively, unsymmetrical indirect covariance processing methods can be used to combine multiple heteronuclear 2D spectra to afford 13C-15N HSQC-HMBC correlation spectra. Now we wish to report the use of responses contained in indirect covariance processed GHSQC spectra as a means for the identification of artifacts in both indirect covariance and unsymmetrical indirect covariance processed 2D NMR spectra.
GHSQC-TOCSY experiments allow sorting of proton-proton connectivity information as a function of 13C chemical shift. GHSQC-TOCSY is a relatively insensitive 2D NMR experiment. Given two coherence transfer experiments, A→B and A→C, it is possible to indirectly determine B↔C. Unsymmetrical indirect covariance processing of a 1H-13C GHSQC and a GCOSY spectrum affords a GHSQC-COSY spectrum, with information content that is analogous to a GHSQC-TOCSY experiment. However GHSQC-TOCSY is of significantly lower sensitivity and requires considerably longer to acquire than either of the component experiments. Investigators needing access to GHSQC-TOCSY type data can, in principal, access it from more readily acquired 2D NMR data. Strychnine is used as a model compound to illustrate this capability.
Nuclear Magnetic Resonance (NMR) Analysis of D - (+) - Glucose: A Guide to Sp...IOSR Journals
NMR spectroscopy has a wide range of applications including exchange phenomena, the
identification and structural studies of complex biomolecules. 1D 1H-NMR without water suppression, 1D
Carbon, 1D 13C-DEPT135, 2D Cosy, 2D HSQC, 2D TOCSY, 2D HMQC, and 2D HMBC techniques were used
to completely elucidate the structure of glucose with spectral induced at 400MHz.. The spectral were analysed
using spinworks 3. The results obtained from the spectral data were systematically combined to elucidate the
structure of the D-glucose. Full characterisation of D-glucose was achieved by assigning 1H and 13C signals,
starting from the known to unknown signals.
Observing small, long-range homonuclear coupling pathways in COSY or GCOSY spectra generally requires the time-consuming acquisition of spectra with large numbers of increments of the evolution period, t1. Covariance processing of spectra acquired with modest numbers of t1 increments, however, allows the observation of long-range coupling correlations with considerable instrument time savings. In this work results obtained from covariance processed GCOSY spectra are fully analyzed and compared to normally processed GCOSY and 80 ms zTOCSY spectra. RCOSY-type correlations are observed when remote protons both exhibit correlations to the same coupling partner. Artifact correlations are observed when protons couple to different protons that overlap or partially overlap.
Small, long-range homonuclear coupling pathways in COSY or GCOSY spectra by the acquisition of spectra with large numbers of increments of the evolution period, t1, than would normally be used. Alternatively, covariance processing of COSY-type spectra acquired with modest numbers of t1 increments, however, allows the observation of multi-stage correlations. In this work results obtained from covariance processed GCOSY spectra are fully analyzed and compared to normally processed COSY and 80 ms TOCSY spectra. Multi-stage or “RCOSY-type” correlations are observed when remote protons both exhibit correlations to the same coupling partner e.g. A→B and B→C gives rise to an A→C correlation. Artifact correlations are observed when protons couple to other protons that overlap or partially overlap.
Performance analysis for power-splitting energy harvesting based two-way full...TELKOMNIKA JOURNAL
Energy harvesting relay network is considered as the promising solution for a wireless
communication network in our time. In this research, we present and demonstrate the system performance
of the energy harvesting based two-way full-duplex relaying network over Nakagami-m fading
environment. Firstly, we propose the analytical expressions of the achievable throughput and outage
probability of the proposed system. In the second step, the effect of various system parameters on
the system performance is presented and investigated. In the final step, the analytical results are also
demonstrated by Monte-Carlo simulation. The numerical results demonstrated and convinced
the analytical and the simulation results are agreed with each other.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
PRINCIPLES of FT-NMR & 13C NMR
Fourier Transform
FOURIER TRANSFORM NMR SPECTROSCOPY
THEORY OF FT-NMR
13C NMR SPECTROSCOPY
Principle
Why C13-NMR is required though we have H1-NMR?
CHARACTERISTIC FEATURES OF 13 C NMR
Chemical Shifts
NUCLEAR OVERHAUSER ENHANCEMENT
Short-Comings of 13C-NMR Spectra
Comparison of Control Strategies of DSTATACOM for Non-linear Load Compensationidescitation
For load compensation a number of control strategies have been developed by
researchers but choice of control strategy is important to cope with the operating condition
of system. In this paper five control strategies viz. instantaneous p-q theory, synchronous
reference frame Method(SRF), Modified SRF Method(MSRF), instantaneous symmetrical
component theory(ISCT) and Average unit power factor theory(AUPFT) are compared for
different two conditions. The performance of the system simulated in Matlab Platform and
evaluated considering the source current total harmonic distortion. The result shows
Modified SRF(id-iq) Method has improved system performance as compared to others.
49 First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Pr...Cristian Randieri PhD
First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Proton near Threshold - July 2014
di P. Levi Sandri, G. Mandaglio, O. Bartalini, V. Bellini, J. P. Bocquet, M. Capogni, F. Curciarello, A. D’Angelo, V. De Leo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. Lapik, A. Lleres, F. Mammoliti, M. Manganaro, D. Moricciani, A. Mushkarenkov, V. Nedorezov, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna and I. Zonta (2014)
Abstract
The Σ beam asymmetry in η' photoproduction off the proton was measured at the GRAAL polarized photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies the asymmetry as a function of the meson emission angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90°. The results are compared to the existing theories that fail to account for the data.
Occasionally we have the good fortune of enjoying a paradigm shift in how a discipline performs its research. NMR spectroscopy has had a number of such paradigm shifts over the years, 2D NMR methods being probably the most significant in the past several decades. Two-dimensional NMR began with very simple pulse sequences that delivered relatively high sensitivity. As 2D NMR pulse sequences became more sophisticated, leading eventually to hyphenated 2D NMR techniques such as GHSQC-TOCSY and GHSQC-NOESY, sensitivity losses associated with the correspondingly more complex pulse sequences led to information rich spectra but with the penalty of correspondingly lower sensitivity. Consequently, despite the interpretational advantages of some of the hyphenated 2D NMR experiments, they tend to be less frequently used because of their lower sensitivity and consequently longer acquisition times. Unsymmetrical indirect covariance processing, an extension of recent development in covariance NMR methods, offers a potential high sensitivity alternative to access what are normally low sensitivity hyphenated 2D NMR correlation data. Given two coherence transfer experiments, A → B and A → C, it is possible to indirectly determine B → C coherence transfer data. The application of unsymmetrical indirect covariance processing methods to generate GHSQC-COSY and GHSQC-NOESY spectra from the more readily acquired GCOSY, NOESY, and GHSQC 2D NMR spectra and related examples will be described.
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
More Related Content
Similar to Utilizing Unsymmetrical Indirect Covariance Processing to Define 15N-13C Connectivity Networks
Several groups of authors have reported studies in the areas of indirect and unsymmetrical indirect covariance NMR processing methods. Efforts have recently focused on the use of unsymmetrical indirect covariance processing methods to combine various discrete two-dimensional NMR spectra to afford the equivalent of the much less sensitive hyphenated 2D NMR experiments, for example GHSQC-COSY and GHSQC–NOESY. Alternatively, unsymmetrical indirect covariance processing methods can be used to combine multiple heteronuclear 2D spectra to afford 13C-15N HSQC-HMBC correlation spectra. Now we wish to report the use of responses contained in indirect covariance processed GHSQC spectra as a means for the identification of artifacts in both indirect covariance and unsymmetrical indirect covariance processed 2D NMR spectra.
GHSQC-TOCSY experiments allow sorting of proton-proton connectivity information as a function of 13C chemical shift. GHSQC-TOCSY is a relatively insensitive 2D NMR experiment. Given two coherence transfer experiments, A→B and A→C, it is possible to indirectly determine B↔C. Unsymmetrical indirect covariance processing of a 1H-13C GHSQC and a GCOSY spectrum affords a GHSQC-COSY spectrum, with information content that is analogous to a GHSQC-TOCSY experiment. However GHSQC-TOCSY is of significantly lower sensitivity and requires considerably longer to acquire than either of the component experiments. Investigators needing access to GHSQC-TOCSY type data can, in principal, access it from more readily acquired 2D NMR data. Strychnine is used as a model compound to illustrate this capability.
Nuclear Magnetic Resonance (NMR) Analysis of D - (+) - Glucose: A Guide to Sp...IOSR Journals
NMR spectroscopy has a wide range of applications including exchange phenomena, the
identification and structural studies of complex biomolecules. 1D 1H-NMR without water suppression, 1D
Carbon, 1D 13C-DEPT135, 2D Cosy, 2D HSQC, 2D TOCSY, 2D HMQC, and 2D HMBC techniques were used
to completely elucidate the structure of glucose with spectral induced at 400MHz.. The spectral were analysed
using spinworks 3. The results obtained from the spectral data were systematically combined to elucidate the
structure of the D-glucose. Full characterisation of D-glucose was achieved by assigning 1H and 13C signals,
starting from the known to unknown signals.
Observing small, long-range homonuclear coupling pathways in COSY or GCOSY spectra generally requires the time-consuming acquisition of spectra with large numbers of increments of the evolution period, t1. Covariance processing of spectra acquired with modest numbers of t1 increments, however, allows the observation of long-range coupling correlations with considerable instrument time savings. In this work results obtained from covariance processed GCOSY spectra are fully analyzed and compared to normally processed GCOSY and 80 ms zTOCSY spectra. RCOSY-type correlations are observed when remote protons both exhibit correlations to the same coupling partner. Artifact correlations are observed when protons couple to different protons that overlap or partially overlap.
Small, long-range homonuclear coupling pathways in COSY or GCOSY spectra by the acquisition of spectra with large numbers of increments of the evolution period, t1, than would normally be used. Alternatively, covariance processing of COSY-type spectra acquired with modest numbers of t1 increments, however, allows the observation of multi-stage correlations. In this work results obtained from covariance processed GCOSY spectra are fully analyzed and compared to normally processed COSY and 80 ms TOCSY spectra. Multi-stage or “RCOSY-type” correlations are observed when remote protons both exhibit correlations to the same coupling partner e.g. A→B and B→C gives rise to an A→C correlation. Artifact correlations are observed when protons couple to other protons that overlap or partially overlap.
Performance analysis for power-splitting energy harvesting based two-way full...TELKOMNIKA JOURNAL
Energy harvesting relay network is considered as the promising solution for a wireless
communication network in our time. In this research, we present and demonstrate the system performance
of the energy harvesting based two-way full-duplex relaying network over Nakagami-m fading
environment. Firstly, we propose the analytical expressions of the achievable throughput and outage
probability of the proposed system. In the second step, the effect of various system parameters on
the system performance is presented and investigated. In the final step, the analytical results are also
demonstrated by Monte-Carlo simulation. The numerical results demonstrated and convinced
the analytical and the simulation results are agreed with each other.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
PRINCIPLES of FT-NMR & 13C NMR
Fourier Transform
FOURIER TRANSFORM NMR SPECTROSCOPY
THEORY OF FT-NMR
13C NMR SPECTROSCOPY
Principle
Why C13-NMR is required though we have H1-NMR?
CHARACTERISTIC FEATURES OF 13 C NMR
Chemical Shifts
NUCLEAR OVERHAUSER ENHANCEMENT
Short-Comings of 13C-NMR Spectra
Comparison of Control Strategies of DSTATACOM for Non-linear Load Compensationidescitation
For load compensation a number of control strategies have been developed by
researchers but choice of control strategy is important to cope with the operating condition
of system. In this paper five control strategies viz. instantaneous p-q theory, synchronous
reference frame Method(SRF), Modified SRF Method(MSRF), instantaneous symmetrical
component theory(ISCT) and Average unit power factor theory(AUPFT) are compared for
different two conditions. The performance of the system simulated in Matlab Platform and
evaluated considering the source current total harmonic distortion. The result shows
Modified SRF(id-iq) Method has improved system performance as compared to others.
49 First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Pr...Cristian Randieri PhD
First Measurement of the Σ Beam Asymmetry in η' Photoproduction off the Proton near Threshold - July 2014
di P. Levi Sandri, G. Mandaglio, O. Bartalini, V. Bellini, J. P. Bocquet, M. Capogni, F. Curciarello, A. D’Angelo, V. De Leo, J. P. Didelez, R. Di Salvo, A. Fantini, D. Franco, C. Gaulard, G. Gervino, F. Ghio, G. Giardina, B. Girolami, A. Giusa, A. Lapik, A. Lleres, F. Mammoliti, M. Manganaro, D. Moricciani, A. Mushkarenkov, V. Nedorezov, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, C. Schaerf, M. L. Sperduto, M. C. Sutera, A. Turinge, V. Vegna and I. Zonta (2014)
Abstract
The Σ beam asymmetry in η' photoproduction off the proton was measured at the GRAAL polarized photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies the asymmetry as a function of the meson emission angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90°. The results are compared to the existing theories that fail to account for the data.
Occasionally we have the good fortune of enjoying a paradigm shift in how a discipline performs its research. NMR spectroscopy has had a number of such paradigm shifts over the years, 2D NMR methods being probably the most significant in the past several decades. Two-dimensional NMR began with very simple pulse sequences that delivered relatively high sensitivity. As 2D NMR pulse sequences became more sophisticated, leading eventually to hyphenated 2D NMR techniques such as GHSQC-TOCSY and GHSQC-NOESY, sensitivity losses associated with the correspondingly more complex pulse sequences led to information rich spectra but with the penalty of correspondingly lower sensitivity. Consequently, despite the interpretational advantages of some of the hyphenated 2D NMR experiments, they tend to be less frequently used because of their lower sensitivity and consequently longer acquisition times. Unsymmetrical indirect covariance processing, an extension of recent development in covariance NMR methods, offers a potential high sensitivity alternative to access what are normally low sensitivity hyphenated 2D NMR correlation data. Given two coherence transfer experiments, A → B and A → C, it is possible to indirectly determine B → C coherence transfer data. The application of unsymmetrical indirect covariance processing methods to generate GHSQC-COSY and GHSQC-NOESY spectra from the more readily acquired GCOSY, NOESY, and GHSQC 2D NMR spectra and related examples will be described.
Similar to Utilizing Unsymmetrical Indirect Covariance Processing to Define 15N-13C Connectivity Networks (20)
Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Enhancing Performance with Globus and the Science DMZGlobus
ESnet has led the way in helping national facilities—and many other institutions in the research community—configure Science DMZs and troubleshoot network issues to maximize data transfer performance. In this talk we will present a summary of approaches and tips for getting the most out of your network infrastructure using Globus Connect Server.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
Welcome to the first live UiPath Community Day Dubai! Join us for this unique occasion to meet our local and global UiPath Community and leaders. You will get a full view of the MEA region's automation landscape and the AI Powered automation technology capabilities of UiPath. Also, hosted by our local partners Marc Ellis, you will enjoy a half-day packed with industry insights and automation peers networking.
📕 Curious on our agenda? Wait no more!
10:00 Welcome note - UiPath Community in Dubai
Lovely Sinha, UiPath Community Chapter Leader, UiPath MVPx3, Hyper-automation Consultant, First Abu Dhabi Bank
10:20 A UiPath cross-region MEA overview
Ashraf El Zarka, VP and Managing Director MEA, UiPath
10:35: Customer Success Journey
Deepthi Deepak, Head of Intelligent Automation CoE, First Abu Dhabi Bank
11:15 The UiPath approach to GenAI with our three principles: improve accuracy, supercharge productivity, and automate more
Boris Krumrey, Global VP, Automation Innovation, UiPath
12:15 To discover how Marc Ellis leverages tech-driven solutions in recruitment and managed services.
Brendan Lingam, Director of Sales and Business Development, Marc Ellis
A tale of scale & speed: How the US Navy is enabling software delivery from l...sonjaschweigert1
Rapid and secure feature delivery is a goal across every application team and every branch of the DoD. The Navy’s DevSecOps platform, Party Barge, has achieved:
- Reduction in onboarding time from 5 weeks to 1 day
- Improved developer experience and productivity through actionable findings and reduction of false positives
- Maintenance of superior security standards and inherent policy enforcement with Authorization to Operate (ATO)
Development teams can ship efficiently and ensure applications are cyber ready for Navy Authorizing Officials (AOs). In this webinar, Sigma Defense and Anchore will give attendees a look behind the scenes and demo secure pipeline automation and security artifacts that speed up application ATO and time to production.
We will cover:
- How to remove silos in DevSecOps
- How to build efficient development pipeline roles and component templates
- How to deliver security artifacts that matter for ATO’s (SBOMs, vulnerability reports, and policy evidence)
- How to streamline operations with automated policy checks on container images
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
Essentials of Automations: The Art of Triggers and Actions in FME
Utilizing Unsymmetrical Indirect Covariance Processing to Define 15N-13C Connectivity Networks
1. Utilizing Unsymmetrical Indirect Covariance Processing
to Define 15N-13C Connectivity Networks
Gary E. Martin,* Patrick A. Irish, and Bruce D. Hilton
Schering-Plough Research Institute
Rapid Structure Characterization Laboratory
Pharmaceutical Sciences
Summit, NJ 07901
Kirill A. Blinov
Advanced Chemistry Development
Moscow Department
Moscow 117513
Russian Federation
Antony J. Williams
Advanced Chemistry Development
Toronto, Ontario
Canada
15
Running title: N-13C Unsymmetrical Indirect Covariance NMR
Keywords: unsymmetrical indirect covariance NMR, 1H-13C GHSQC, 1H-15N
GHMBC, IMPEACH-MBC, CIGAR-HMBC, 15N-13C connectivity
2. Abstract:
There has been considerable interest over the past decade in the utilization of direct and
long-range 1H-15N heteronuclear shift correlation methods at natural abundance to
facilitate the elucidation of small molecule structures. Recently, there has also been a
high level of interest in the exploration of indirect covariance NMR methods. Our initial
explorations in this area led to the development of unsymmetrical indirect covariance
methods, which allow the calculation of hyphenated 2D NMR spectra such as 2D
GHSQC-COSY and GHSQC-NOESY from the discrete component 2D NMR
experiments. We now wish to report the utilization of unsymmetrical indirect covariance
NMR methods for the combination of 1H-13C GHSQC and 1H-15N long-range (GHMBC,
IMPEACH-MBC, CIGAR-HMBC, etc.) heteronuclear chemical shift correlation spectra
to determine 15N-13C correlation pathways.
2
3. 1
Numerous studies utilizing H-15N heteronuclear chemical shift correlation
experiments have been reported over the past decade and are the subject of several recent
reviews.1-5 Underscoring the high level of interest and growing importance of being able
to access 1H-15N long-range heteronuclear shift correlation data, there have been two
recent reports6,7 describing pulse sequences that allow the simultaneous acquisition of
long-range 1H-13C and 1H-15N HMBC data. The ability to exploit 1H-15N connectivities
is an important adjunct to small molecule structure elucidation, particularly for
pharmaceuticals and alkaloids. Considerable recent attention has also been focused on
the development of covariance NMR methods, initially by Brüschweiler and co-
workers.8-13 Insofar as potential for small molecule application, the most interesting
report described the capability of extracting carbon-carbon connectivity information from
a GHSQC-TOCSY spectrum using indirect covariance methods. Brüschweiler and
Zhang commented that proton resonance overlap could lead to artifacts in the calculated
carbon-carbon spectra but did not explore this observation. 11 We subsequently reported
the analysis of two types of artifacts observed in inverted direct response (IDR) GHSQC-
TOCSY spectra with overlapped proton resonance, which, in turn, prompted us to
explore the elimination of these artifacts via a method that we have named unsymmetrical
indirect covariance.14 Subsequent work has shown that it is also possible to
mathematically combine various discretely acquired 2D NMR spectra. The first effort in
this direction demonstrated the combination of 1H-13C GHSQC and GHMBC spectra to
afford the equivalent of an m,n-ADEQUATE spectrum.15 Subsequent studies have
demonstrated the calculation of GHSQC-COSY16 and GHSQC-NOESY17 spectra from
discretely acquired COSY, NOESY, and 1H-13C GHSQC 2D NMR spectra. Recently,
3
4. Kupče and Freeman7 have demonstrated the use of projection reconstruction techniques
15
to establish N-13C correlations at natural abundance, using vitamin B-12 as a model
compound for the study, also noting in parallel that indirect covariance methods can be
used to obtain homonuclear correlation spectra indirectly. Thus, we would now like to
demonstrate specifically, that unsymmetrical indirect covariance NMR methods can
15
indeed be used to derive N-13C connectivity information from discretely acquired 1H-
13
C GHSQC and 1H-15N HMBC spectra.
1
For the present study, multiplicity-edited H-13C GHSQCAD and 1
H-15N
GHMBC spectra were acquired using an ~5 mg sample of strychnine (1) dissolved in
~180 μL CDCl3 in a 3 mm NMR tube. The spectra were recorded at 500 MHz using a
Varian two channel spectrometer equipped with a 3 mm gradient inverse triple resonance
probe. The 1H-13C GHSQCAD spectrum was recorded in 36 m while the 1H-15N
GHMBC spectrum was recorded in 3 h 6 m. The spectra were acquired with identical
proton spectral widths and the data were processed to yield data matrices that were
identically digitized with F1,F2 dimensions of 512 x 2048 points.
The unsymmetrical indirect covariance matrix can be calculated by
C = RN * RCT [1]
where RN and RC correspond to the real data matrices from the long-range 1H-15N
GHMBC and 1H-13C multiplicity-edited GHSQCAD spectra, respectively. In the present
report, the GHSQCAD data are plotted with CH and CH3 resonances with positive phase
and CH2 resonances with negative phase. The 1H-13C data matrix is transposed to RCT
4
5. during processing. The data were acquired and processed so that there were equal
numbers of columns in the data sets, i.e. RN is N * M1 and RC is N * M2 to allow the
multiplication of the data matrices. In the present example, F2 spectral widths were
identical although that is not an absolute requirement. By definition, the following
formula is used to calculate each element Cij (i and j are row indices in the initial
matrices, correspondingly, RN and RC) of data matrix C:
Cij = (RN)ij * (RC)ij = (RN)i1 * (RC)j1 + (RN)i2 * (RC)j2 + (RN)ik * (RC)jk + (RN)iN * (RC)jN [2]
Each element of matrix C is the sum of products of values (RN)ik and (RC)jk. A
necessary condition is to have non-zero elements in equivalent positions in the rows of
(RN)i and (RC)j. For two “ideal” 2D NMR spectra, assuming zero noise in the data
matrices, the sum of a matrix element will be non-zero when rows (RN)i and (RC)j have
crosspeaks in the same position.
The resulting GHSQCAD and GHMBC data sets were subjected to
15
unsymmetrical indirect covariance processing to yield the N-13C long-range correlation
spectrum shown in Figure 1. The 1H-15N HMBC spectrum is shown in the top left panel;
the 1H-13C GHSQCAD spectrum is shown in the bottom right panel and has been
13 15
transposed to reflect the orientation of the C spectrum as the F2 axis in the N-13C
15
correlation spectrum shown in the top right panel. In the N-13C correlation spectrum,
15 13
N Chemical shift information is displayed in the F1 frequency domain while C
15
chemical shift information is presented in the F2 frequency domain. N-13C correlation
responses in the spectrum shown in Figure 1 are “modulated” via the nJNH correlation
5
6. response in the 1H-15N HMBC spectrum, the 13
C chemical shift information deriving
from the chemical shift of the carbon directly bound to the proton in question in the 1H-
13
C GHSQCAD spectrum.
39.6
18 N 20
19
17 16
7 15
8 14 21
N 13 22
155.2 9
10 12 23
O 11 O
1
15
N-13C long-range heteronuclear correlations observed in Figure 1 are shown on
15
the structure above. Correlations plotted using red contours in the N-13C correlation
spectrum shown in Figure 1 arise from correlations between methylene carbons and the
nitrogen; correlations plotted in black arise from correlations from methine (or methyl,
although there are no methyl resonances in the structure of strychnine) carbons to
nitrogen. The phase of the 13C resonance from the multiplicity-editing of responses in the
15
GHSQCAD spectrum is carried forward into the N-13C unsymmetrical indirect
covariance processed spectrum shown in the top right panel in Figure 1. Presumably,
13
methine and methylene carbons with the same C chemical shift that correlate to the
same nitrogen could partially or completely cancel, hence it may useful to consider the
acquisition of both conventional and multiplicity-edited 1H-13C GHSQCAD spectra when
6
7. the data are acquired since these data can be accumulated in a very reasonable periods of
time. An interesting corollary arises in the case of overlapped protons, one of which is
15
long-range correlated to a nitrogen resonance. By calculating the N-13C correlation
spectrum, as shown in Figure 1, the specific proton (via the 1H/13C response in the
15 15
GHSQC spectrum) correlating to the N resonance can be determined by the N-13C
correlation response.
15
In conclusion, N-13C heteronuclear chemical shift correlation spectra can be
derived through the unsymmetrical indirect covariance processing of 1H-13C GHSQCAD
and 1H-15N long-range heteronuclear chemical shift correlation spectra ( 1H-15N HMBC in
the present example, but we have obtained the same results with 1H-15N IMPEACH-
MBC18 and 1
H-15N CIGAR-HMBC19 experiments). The utilization of 15
N-13C
heteronuclear chemical shift connectivity information may prove useful in the structural
characterization of pharmaceuticals (>80% contain nitrogen in their structures) and
alkaloids as well as in the characterization of other nitrogenous compounds. These data
may also allow investigators to differentiate between overlapped protons, one of which is
15
long-range coupled to N, provided that the carbons directly bound to the overlapped
protons are resolved. Generally, it is highly unlikely that both the proton and carbon
resonances for two sites in a molecule will have identical 1H and 13C chemical shifts. It
will be quite interesting to see what other applications for 15N-13C heteronuclear chemical
shift correlation data will arise. In a parallel vein, it will be equally interesting to see
what other types of data can be beneficially co-processed using unsymmetrical indirect
covariance NMR methods. These investigations are presently underway in our
laboratories and will form the basis of forthcoming reports.
7
8. References:
1. G. E. Martin and C. E. Hadden, J. Nat. Prod., 65, 543 (2000).
2. R. Marek and A. Lycka, Curr. Org. Chem., 6, 35 (2002).
3. G. E. Martin and A. J. Williams, “Long-Range 1H-15N 2D NMR Methods,” in
Ann. Rep. NMR Spectrosc., vol. 55, G. A. Webb, Ed., Elsevier, Amsterdam, 200,
pp. 1-119.
4. P. Forgo, J. Homann, G. Dombi, and L. Máthé, “Advanced Multidimensional
NMR Experiments as Tools for Structure Determination of Amaryllidaceae
Alkaloids,” in Poisonous Plants and Related Toxins, T. Acamovic, S. Steward and
T. W. Pennycott, Eds., Wallingford, UK, 2004, pp. 322-328.
5. G. E. Martin, M. Solntseva, and A. J. Williams, “Applications of 15N NMR in
Alkaloid Chemistry,” in Modern Alkaloids, E. Fattorusso and O. Taglialatela-
Scafati, Eds., Wiley-VCH, 2007, in press.
6. M. Pérez-Trujillo, P. Nolis, and T. Parella, Org. Lett., 9, 29 (2007).
7. E. Kupče and R. Freeman, Magn. Reson. Chem., 45, 103 (2007).
8. R. Brüschweiler and F. Zhang, J. Chem. Phys., 120, 5253 (2004)
9. R. Brüschweiler, J. Chem. Phys., 121, 409 (2004).
10. F. Zhang and R. Brüschweiler, Chem. Phys. Chem., 5, 794 (2004).
11. F. Zhang, and R. Brüschweiler, J. Am. Chem. Soc., 126, 13180 (2004).
12. N. Trbovic, S. Smirnov, F. Zhang, and R. Brüschweiler, J. Magn Reson., 171, 177
(2004).
13. Y. Chen, F. Zhang, W. Bermel, and R. Brüschweiler, J. Am. Chem. Soc., 126,
15564 (2006).
8
9. 14. K. A. Blinov, N. I. Larin, M. P. Kvasha, A. Moser, A. J. Williams, and G. E.
Martin, Magn. Reson. Chem., 43, 999 (2005).
15. K. A. Blinov, N. I. Larin, A. J. Williams, M. Zell, and G. E. Martin, Magn. Reson.
Chem., 44, 107 (2006).
16. K. A. Blinov, N. I. Larin, A. J. Williams, K. A. Mills, and G. E. Martin, J.
Heterocyclic Chem., 43, 163 (2006).
17. K. A. Blinov, A. J. Williams, B. D. Hilton, P. A. Irish, and G. E. Martin, Magn.
Reson. Chem., 45, in press (2007).
18. C. E. Hadden, G. E. Martin, and V. V. Krishnamurthy, J. Magn. Reson., 140, 274
(1999); G. E. Martin and C. E. Hadden, Magn. Reson. Chem., 38, 251 (2000).
19. C. E. Hadden, G. E. Martin, and V. V. Krishnamurthy, Magn. Reson. Chem., 38,
143 (2000).
9
10. 15
N-13C unsymm. indirect covariance
40 N19 40
C16 C18 C20 C17 C14 C15
60 60
F1 Chemical Shift (ppm)
F1 Chemical Shift (ppm)
80 80
15
100 100
N
120 120
140 C8 C13 C11 140
N9
4.0 3.5 3.0 2.5 2.0 1.5 1.0 65 60 55 50 45 40 35 30 25 20
F2 Chemical Shif t (ppm) F2 Chemical Shif t (ppm)
1 13
H-15N GHMBC C
1.5
F2 Chemical Shift (ppm)
2.0
multiplicity-edited 2.5
1
H-13C GHSQC 3.0
3.5
4.0
65 60 55 50 45 40 35 30 25 20
F1 Chemical Shif t (ppm)
11. 15
Figure 1. N-13C (F1,F2) Heteronuclear chemical shift correlation spectrum (upper right panel) derived by the unsymmetrical
indirect covariance processing of discretely acquired, multiplicity-edited 1H-13C GHSQCAD (bottom right panel,
transposed to reflect the orientation of the 13C chemical shift axis in the final 15N-13C correlation spectrum CH/CH3
resonances are plotted in black and have positive phase, CH2 resonances are inverted and plotted in red) and the 1H-
15
N GHMBC spectrum (top left panel). The data were recorded at 500 MHz using an ~5 mg sample of strychnine in
180 μL CDCl3. Total data acquisition time for the two 2D spectra was < 4 h. The individual 2D NMR spectra were
processed to yield a pair of spectra comprised of 512 x 2048 points that were the subjected to unsymmetrical indirect
covariance processing. Processing time was approximately 4 sec. The N9 and N19 resonances of strychnine (1) are
observed at 155.2 and 39.6 ppm, respectively. Correlations are observed, as expected, between the C8, C11, and C13
resonances and the N9 amide nitrogen resonance. Correlations are observed from the C14, C15, C16, C17, C18, and
C20 resonances to the N19 aliphatic nitrogen resonance. There is no way to differentiate between the overlapped C8
and C16 resonances in the 15N-13C correlation spectrum, although the H8 and H16 resonances are resolved in the 500
MHz 1H-15N GHMBC spectrum, allowing an unequivocal assignment to be made.
11