Satellite transition selective excitation/inversion of abundant spins across chemical shifts offers a robust opportunity for sensitivity enhancement of rare spins that are coupled to them. It is also well established that reconversion of rare spin double quantum coherence (DQC) to single quantum-single transitions (SQ-ST's) over a wide range of chemical shifts offers sensitivity enhancement in INADEQUATE-style experiments. The present contribution gives an overview of the latter category of experiments, including a brief summary of the literature, and the contributions from our Lab. In particular, the transition selective “composite refocusing” approach of Sørensen and his group is discussed for reconversion of DQC to SQ-ST's. A shorter transition selective DQC reconversion module introduced from our Lab is also described. A 2D rare spin correlation experiment introduced by us is then reviewed, in which we replace rare spin DQ evolution with immediate reconversion of DQC to SQ-ST's, followed by evolution of SQ-ST's, that is then terminated by a mixing period to deliver a diagonal-free COSY-like correlation map. Finally, our ‘indirect’, 1H detected version of this experiment is reviewed. Transition selective reconversion in ADEQUATE-style experiments was also introduced by us and is briefly mentioned. Interestingly, partial 1H transition selectivity is shown to result as a consequence of reconversion of rare spin DQC to SQ-ST's, followed by coherence order selective heteronuclear reverse transfer. The performance of these experiments when applied to small molecules is illustrated.

1H NMR has unique strengths, owing, for one, to 1H being the most sensitive NMR nucleus. However, the limited frequency range of 1H chemical shifts implies spectral crowding, leading to difficulties in assignment and interpretation of the spectra. Homonuclear broadband decoupling has been developed as a means of simplifying 1H NMR spectra but clearly leads to the inevitable and complete loss of precious information on homonuclear scalar couplings in solution state. A novel experiment is introduced in this work, which leads to partial 1H multiplet selectivity, thereby reducing spectral crowding, while at the same time permitting couplings to be inferred. The present one-dimensional (1D) experiment relies on two-way coherence transfer starting from 1H to coupled 13C carbons at natural abundance and ending finally with 1H detection. The experiment may be termed CArbon Single transition EDited (CASED) 1H NMR. The unusual spectral patterns that result are summarized, demonstrated, and rationalized for various molecular fragments. Artifacts in the present version of the CASED experiment are also described, and an application to the 1H NMR of a disaccharide is demonstrated as a first practical example.

The present study aims to establish a simple approach involving multi-field multinuclear longitudinal relaxation (R1) analysis of the solvents to decipher solute-solvent interactions during the solvation of model carbohydrates in aqueous trifluoroethanol (TFE) co-solvent systems (TFE:D2O). The behavior of D2O and TFE is monitored around β-CD (β-cyclodextrin) and glucose through R1D (2H) and R1F (19F), respectively. Correlation times (τc) are estimated for D2O and TFE for various % (v/v) compositions of TFE:D2O mixtures. The differential trends of the R1 or τc ratio for D2O and TFE (in the presence and absence of carbohydrates) revealed that both β-CD and glucose undergo selective solvation by TFE in comparison to D2O. Owing to its encapsulation properties, β-CD exhibited a comparatively higher tendency to undergo solvation by TFE than glucose. The maximum transfer of solute bound water to bulk solvent appears in the 20-30% (v/v) TFE range. The current approach emerges as being straightforward in contrast to traditional methods that primarily focus on solute behavior to unravel the preferential solvation dynamics.

2,2,2- Trifluoroethanol (TFE) is one of the fluoroalcohols that have been known to induce and stabilize an open helical structure in many proteins and peptides. The current study has benchmarked low-field F-19 NMR relaxation and F-19 Overhauser dynamic nuclear polarization (ODNP) by providing a brief account of TFE solvent dynamics in a model melittin (MLT, an antimicrobial peptide) solution with a TFE-D2O cosolvent mixture at pH 7.4. Further, this approach has been employed to reveal the solvation of MLT by TFE in a nonbuffered solution with pH 2.8 for the first time. The structural transition of MLT has been elucidated via solvent dynamics by measuring the F-19 TFE relaxation rates at 0.34 T for various TFE-D2O compositions in the absence (bulk TFE) and in the presence of MLT at both the pH values. A complementary initial record of circular dichroism experiments on these aqueous MLT solutions with TFE as the cosolvent at two different pH conditions demonstrated the structural transition from a random coil to a helical or from a folded helical to an open helical structure. The molecular correlation time derived from the corresponding relaxation rates shows that TFE resides on the MLT surface in both pH conditions. However, the trends in the variation of molecular correlation time ratio as a function of TFE concentration represent that the mechanism and the extent to which TFE affects the MLT structural integrity are different at different pH values. The extraction of the DNP coupling parameter from steady-state 19F ODNP experiments performed in the presence of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl at 0.34 T revealed changes in the solvation dynamics of TFE concomitant with the MLT structural transition. In summary, F-19 relaxation and ODNP measurements made at a low field have allowed direct monitoring of TFE dynamics during the MLT structural transition in terms of preferential solvation. The choice of experiments performed at a moderately low field (0.34 T) enabled us to exploit on the one hand almost 1200-fold mitigation of the strong contribution of F-19 chemical shift anisotropy at 11.76 T, whereas on the other hand, the ODNP experiment offered a window for probing molecular dynamics on timescales of the order of 10-1000 ps.

Halogen bonding is a subject of considerable interest owing to wide-ranging chemical, materials and biological applications. The motional dynamics of halogen-bonded complexes play a pivotal role in comprehending the nature of the halogen-bonding interaction. However, not many attempts appear to have been made to shed light on the dynamical characteristics of halogen-bonded species. For the first time, we demonstrate here that the combination of low-field NMR relaxometry and Overhauser dynamic nuclear polarization (ODNP) makes it possible to obtain a cogent picture of the motional dynamics of halogen-bonded species. We discuss here the advantages of this combined approach. Low-field relaxometry allows us to infer the hydrodynamic radius and rotational correlation time, whereas ODNP probes the molecular translational correlation times (involving the substrate as well as the organic radical) with high sensitivity at low field.

Electrolytic dissociation of lithium hexafluorophosphate (LiPF6) in the nonaqueous cyclic propylene carbonate (PC) has been investigated in the wide range of concentration (0.05-3.5 M) by Li-7 solution-state nuclear magnetic resonance (NMR) spectroscopy. Two-dimensional heteronuclear Overhauser enhancement spectroscopy NMR experiments have not only enabled the cation solvation and ion-pairing to be directly monitored but additionally evidence anion solvent interaction at higher concentrations (>1.2 M) of the PC electrolyte. Preliminary analysis of kinetic nOe data has been made to determine site-dependent cross-relaxation rates for the spatial interaction of the solvent with the Li+ cation and the PF6- anion. The concentration dependence of the Li-7 NMR self-diffusion coefficient (D-self), determined using very strong pulsed magnetic field gradients (similar to 1700 Gauss/cm), depicts two breaks to mark the solvation and ion-pairing events in a distinct manner. This in turn has aided the determination of solvent coordination number and average sizes of solvated and ion-paired clusters. Our results indicate that in the contact ion pair (CIP)-dominated electrolyte (>2 M), lithium-ion mobility across the solvated and ion-paired environments appears to be inhibited which makes the spectral distinction of solvated and ion-paired environments possible. The concentration dependence of the Li-7 NMR spectral and diffusometry data is in striking correspondence with that of bulk conductivity measurements and point to the detrimental effect of CIP aggregates in impeding the ionic conductivity at high salt concentrations. These results have significance in understanding the structure and dynamics of lithium-ion solvates that are ubiquitous in the working environment of a lithium-ion battery.

In the present experimental work, it is shown for the first time that liquid filled multi-walled carbon nanotubes (MWCNTs) exhibit remarkably enhanced characteristics for sensor applications, the detection threshold being lowered by as much as an order of magnitude, while detection sensitivity is doubled for a number of molecules including ascorbic acid, dopamine, and uric acid. The sensitivity obtained for DA is 84 mu A mM(-1) (linear range 3 to 30 mu M) detection limit is 1.6 mu M. NMR relaxometry at a moderately low field confirms that the improved sensor characteristics are correlated with the filling of MWCNTs with solvents such as acetonitrile, dimethyl sulfoxide, etc., such confinement resulting in increased solvent relaxation rates. The filling of MWCNTs appears to relate to solvent-CNT interactions that are in line with the principle of hard and soft acids and bases, and also correlates with solvent dipole moments. (C) 2019 The Electrochemical Society.

Overhauser dynamic nuclear polarization (ODNP) is investigated at a moderately low field (1.2 T) for natural abundance 13C NMR of small molecules in solution state at room temperature. It is shown that ODNP transferred from 1H to 13C by NMR coherence transfer is in general significantly more efficient than direct ODNP of 13C. Compared to direct 13C ODNP, we demonstrate over 4-fold higher 13C sensitivity (signal-to-noise ratio, SNR), achieved in one-eighth of the measurement time by transferred ODNP (t-ODNP). Compared to the 13C signal arising from Boltzmann equilibrium in a fixed measurement time, this is equivalent to about 1500-fold enhancement of 13C signal by t-ODNP, as against a direct 13C ODNP signal enhancement of about 45-fold, both at a moderate ESR saturation factor of about 0.25. This owes in part to the short polarization times characteristic of 1H. Typically, t-ODNP reflects the essentially uniform ODNP enhancements of all protons in a molecule. Although the purpose of this work is to establish the superiority of t-ODNP vis-à-vis direct 13C ODNP, a comparison is also made of the SNR in t-ODNP experiments with standard high resolution NMR as well. Finally, the potential of t-ODNP experiments for 2D heteronuclear correlation spectroscopy of small molecules is demonstrated in 2D 1H-13C HETCOR experiments at natural abundance, with decoupling in both dimensions.

The purpose of the study was to find out the influence of core functional training on leg strength and flexibility among high school soccer players. In order to achieve the purpose of the study 24 high school male football players were randomly selected from Oddanchatram Town and they were equally divided in to two groups of 12 each as experimental and control group. The experimental group and control group undergone normal routine football practices and in addition the experimental group undergone core functional training for one hour in the morning before starting the football practices. The control group was not given any special training. The period of training was 8 weeks in a schedule of weekly 5 days. The data were collected on the selected variables before and after the training period. Analysis of Covariance (ANCOVA) was used to analyze the data. To test the significance 0.05 level of confidence was fixed. Based on the results the study it was concluded that the core functional training was significantly improved the leg strength and flexibility among high school soccer players.

Solution-state Overhauser dynamic nuclear polarization (ODNP) at moderate fields, performed by saturating the electron spin resonance (ESR) of a free radical added to the sample of interest, is well known to lead to significant NMR signal enhancements in the steady state, owing to electron-nuclear cross-relaxation. Here it is shown that under conditions which limit radical access to the molecules of interest, the time course of establishment of ODNP can provide a unique window into internuclear cross-relaxation, and reflects relatively slow molecular motions. This behavior, modeled mathematically by a three-spin version of the Solomon equations (one unpaired electron and two nuclear spins), is demonstrated experimentally on the 19 F/1 H system in ionic liquids. Bulky radicals in these viscous environments turn out to be just the right setting to exploit these effects. Compared to standard nuclear Overhauser effect (NOE) work, the present experiment offers significant improvement in dynamic range and sensitivity, retains usable chemical shift information, and reports on molecular motions in the sub-megahertz (MHz) to tens of MHz range-motions which are not accessed at high fields.

Quantitative aspects of hyperpolarized NMR are analyzed in the present work, and it is shown theoretically and experimentally that measured "apparent" signal enhancements could deviate significantly from real enhancements of polarization. Expressions are given as a function of spin count to deduce real enhancements from measured "apparent" enhancements, and vice versa. While the findings are of particular relevance to high-field work employing high-Q probes, and to analytical applications of hyperpolarized NMR whose objective is the measurement of spin count, our experiments demonstrate their significance even for low- and moderate-field work with probes of moderate Q-factor.

Areca nut (seed of Areca catechu) is consumed by people from different parts of Asia, including India. The four major alkaloids present in areca nut are arecoline, arecaidine, guvacoline and guvacine. Upon cutting, the nut reveals two kinds of regions; white and brown. In our present study, we have monitored the formation of these two regions within the nut during maturation, using the non-invasive techniques of magnetic resonance imaging (MRI) and volume localized magnetic resonance spectroscopy (MRS). Electrospray ionization mass spectrometry (ESI MS) and desorption electrospray ionization mass spectrometry (DESI MS) imaging have been used to study the associated change in the alkaloid contents of these two regions during the growth of the nut. Our study reveals that white and brown regions start forming within the nut when the liquid within starts solidifying. At the final stage of maturity, arecoline, arecaidine and guvacoline get segregated in the brown region whereas guvacine gets to the white region of the nut. The transport of molecules with maturity and corresponding pattern formation are expected to be associated with a multitude of physiochemical changes.

We report the design and performance evaluation of novel pulse sequences for triple quantum filtered spectroscopy in homonuclear three spin-1/2 systems, employing isotropic mixing (IM) to excite triple quantum coherence (TQC). Our approach involves the generation of combination single quantum coherences (cSQC) from antisymmetric longitudinal or transverse magnetization components employing isotropic mixing (IM). cSQC's are then converted to TQC by a selective 180° pulse on one of the spins. As IM ideally causes magnetization to evolve under the influence of the spin coupling Hamiltonian alone, TQC is generated at a faster rate compared to sequences involving free precession. This is expected to be significant when the spins have large relaxation rates. Our approach is demonstrated experimentally by TQC filtered 1D spectroscopy on a (1)H AX2 system (propargyl bromide in the presence of a paramagnetic additive), as well as a (31)P linear AMX system (ATP in agar gel). The performance of the IM-based sequences for TQC excitation are compared against the standard three pulse sequence (Ernst et al., 1987) and an AX2 spin pattern recognition sequence (Levitt and Ernst, 1983). The latter reaches the unitary bound on TQC preparation efficiency starting from thermal equilibrium in AX2 systems, not considering relaxation. It is shown that in systems where spins relax rapidly, the new IM-based sequences indeed perform significantly better than the above two known TQC excitation sequences, the sensitivity enhancement being especially pronounced in the case of the proton system investigated. An overview of the differences in relaxation behavior is presented for the different approaches. Applications are envisaged to Overhauser DNP experiments and to in vivo NMR.

The purpose of the study was to find out the “effects of Pranayama Practices and interval training on selected health related physical fitness and cardiopulmonary variables among schools boys”. To achieve this purpose of the study sixty students from Government higher secondary school Markkampatti, were selected subjects at random. The age of subjects ranged from 13 to 17 years. They were divided into three groups. Experimental group I, Experimental group II, Control group. Experimental group I Pranayama practices, Experimental group II Interval training Experimental group III control group. Underwent no training the data was before and after twelve weeks training. The analysis of covariance (ANCOVA) were used to the test the significance. Three groups were compared, whenever obtained “F” ratio for adjusted posttest was find to be significant, the schefee’s test to find out the paired mean differences if any, The 0.05 level confidence was fixed as the level of significance to the test ‘F’ ratio obtained by the analysis of covariance, which was considered as an appropriate.

The purpose of the study was to find out the effect of ladder drill and SAQ training on speed and agility among sports club badminton players. In order to achieve the purpose of the study thirty men sports club badminton players were randomly selected from Dindugal city sports clubs and they were equally divided in to three groups of ten each as experimental group-I, experimental group-II and control group. The experimental groups and control group undergone normal routine badminton practices and in addition the experimental group-I underwent ladder drill and experimental group-II underwent SAQ training for one hour in the morning sessions. The control group was not given any special training. The period of training was eight weeks in a schedule of weekly three days for alternate days. The data were collected on the selected dependent variables before and after the training period. The collected the data were statistically analyzed by using Analysis of Covariance (ANCOVA) and Scheffe’s post hoc test. To test the significance .05 level of confidence was fixed. Based on the results the study it was concluded that the ladder drill and SAQ training were significantly improved the speed and agility among sports clubs badminton players.

We report a novel diagonal suppressed two-dimensional total correlation experiment in solution state and demonstrate its performance in H-1 and H-2 NMR. In DIagonal Suppressed spin echo TOtal Correlation SpectroscopY (DISTOCSY), diagonal peaks which occur around F-1 = 0 in spin echo mode are removed by conversion to unobservable multiple quantum or longitudinal terms in each scan of a two scan procedure, on application of an appropriately phased 90 pulse at the time of the echo maximum. The limitation of this approach to short FID acquisition times is discussed, and an alternative two-scan version of DISTOCSY for high resolution situations is presented. (C) 2015 Elsevier B.V. All rights reserved.

Two-dimensional nuclear magnetic resonance (2D NMR) correlation spectra help visualize inter- or intra-molecular spin connectivity through space or through bonds. This is accomplished by magnetization transfer between interacting (connected) spins located at different sites in molecules. In homonuclear 2D experiments, cross peaks which demonstrate spin connectivity and result from magnetization transfer between sites are unfortunately invariably accompanied by other peaks that result from magnetization that has not undergone any transfer, viz., diagonal peaks. The latter can often mask close-lying cross peaks. We report here the general principles that constitute a design strategy for diagonal suppression, relying on echo formation. Next, a novel experiment that effects diagonal suppression in the high-resolution mode is demonstrated. Pure phase capability is also introduced. Examples from both 2D exchange and high-resolution 2D correlation spectroscopy are included, and the proposed method is compared with other established as well as recent attempts to accomplish diagonal suppression.

The purpose of the study was to find out the Influence of Mallakhamb practices and Silambam practices on speed and flexibility among u-19 female Kho-Kho players. In order to achieve the purpose of the study forty five female district level Kho-Kho players, were randomly selected from Dindugal city schools and they were equally divided in to three groups of fifteen each as experimental group-I, experimental group-II and control group. The experimental groups and control group undergone normal routine Kho-Kho practices and in addition the experimental group-I underwent Mallakhamb practices and experimental group-II underwent Silambam practices for one hour in the morning sessions. The control group was not given any special training. The period of training was eight weeks in a schedule of weekly three days for alternate days. The data were collected on the selected dependent variables before and after the training period. The collected the data were statistically analyzed by using Analysis of Covariance (ANCOVA) and Scheffe’s post hoc test. To test the significance .05 level of confidence was fixed. Based on the results the study it was concluded that the Mallakhamb practices and Silambam practices were significantly improved the speed and flexibility among district level Kho-Kho players.

Overhauser-DNP-enhanced homonuclear 2D (19)F correlation spectroscopy with diagonal suppression is presented for small molecules in the solution state at moderate fields. Multi-frequency, multi-radical studies demonstrate that these relatively low-field experiments may be operated with sensitivity rivalling that of standard 200-1000 MHz NMR spectroscopy. Structural information is accessible without a sensitivity penalty, and diagonal suppressed 2D NMR correlations emerge despite the general lack of multiplet resolution in the 1D ODNP spectra. This powerful general approach avoids the rather stiff excitation, detection, and other special requirements of high-field (19)F NMR spectroscopy.

We report a novel rare spin correlation experiment termed ADEQUATE with composite refocusing (CR), which is the (1)H-detected version of 2D INADEQUATE CR. ADEQUATE CR begins with a polarization transfer from protons to the attached carbon, followed by (13)C-(13)C double-quantum (DQ) preparation. Unlike the ADEQUATE class of experiments, (13)C DQ coherence is converted after evolution to single-quantum single transitions (SQ-STs) by CR. (13)C SQ-ST is then transferred back to the coupled protons by a coherence order selective reconversion. The present sequence produces partial transition selectivity in the (1)H dimension as does (1)H Indirect detected (13)C Low-Abundance Single-transition correlation Spectroscopy (HICLASS), thereby mitigating the reduction in sensitivity enhancement because of the presence of homonuclear proton couplings. However, unlike HICLASS (which is an experiment that involves SQ-TS evolution), no homonuclear zero quantum mixing is required on the (13)C channel in the present experiment. Experimental results are demonstrated on a variety of samples, establishing the efficiency of the proposed method.