<sup>13</sup>C MRS in Human Tissue

Krššák, Martin

doi:10.1002/9780470034590.emrstm1490

Cited by 8 publications

(5 citation statements)

References 105 publications

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“…(3.8)), but this does not switch-off the effect of the cosmological constant, which has a divergent contribution to the action on its own. However, preliminary results show that it is possible to modify our method to address the problem of a cosmological constant as well [21].…”

Section: Discussionmentioning

confidence: 99%

Spin connection and renormalization of teleparallel action

2015

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In general relativity, inertia and gravitation are both included in the Levi-Civita connection. As a consequence, the gravitational action, as well as the corresponding energy-momentum density, are in general contaminated by spurious contributions coming from inertial effects. In teleparallel gravity, on the other hand, because the spin connection represents inertial effects only, it is possible to separate inertia from gravitation. Relying on this property, it is shown that to each tetrad there is naturally associated a spin connection that locally removes the inertial effects from the action. The use of the appropriate spin connection can be viewed as a renormalization process in the sense that the computation of energy and momentum naturally yields the physically relevant values. A self-consistent method for solving field equations and determining the appropriate spin connection is presented.

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Section: Discussionmentioning

confidence: 99%

Spin connection and renormalization of teleparallel action

2015

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“…This crucial property makes the f (T ) teleparallel gravity different from f (R) gravity. However, it has been shown that a covariant formulation of f (T ) gravity can be obtained by including the non-trivial spin connection, see Krššák & Saridakis (2016), in addition the determination of the spin connection associated to a certain vierbein has been investigated, see Golovnev et al (2017); Krššák (2017).…”

Section: The Field Equationsmentioning

confidence: 99%

H ₀ Tension and the Phantom Regime: A Case Study in Terms of an Infrared f(T) Gravity

El-Zant

Hanafy

Elgammal

2019

ApJ

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We propose an f (T ) teleparallel gravity theory including a torsional infrared (IR) correction. We show that the governing Friedmann's equations of a spatially flat universe include a phantom-like effective dark energy term sourced by the torsion IR correction. As has been suggested, this phantom phase does indeed act as to reconcile the tension between local and global measurements of the current Hubble value H 0 . The resulting cosmological model predicts an electron scattering optical depth τ e ≈ 0.058 at reionization redshift z re ∼ 8.1, in agreement with observations. The predictions are however in contradiction with baryon acoustic oscillations (BAO) measurements, particularly the distance indicators. We argue that this is the case with any model with a phantom dark energy model that has effects significant enough at redshifts z 2 as to be currently observable. The reason being that such a scenario introduces systematic differences in terms of distance estimates in relation to the standard model; e.g., if the angular diameter distance to the recombination era is to be kept constant while H 0 is increased in the context of a phantom scenario, the distances there are systematically overestimated to all objects at redshifts smaller than recombination. But no such discrepancies exist between ΛCDM predictions and current data for z 2.

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“…Hepatic glycogen synthesis and degradation fluxes are key components of systemic glucose homeostasis and are highly sensitive to the insulin/glucagon ratio. The application of in vivo 13 C MR to measure changes in hepatic glycogen during fasting and feeding has advanced our understanding of hepatic carbohydrate metabolism in subjects with insulin resistance, as well as in patients with diabetes [65][66][67][68][69]. Among other things, it revealed that while both hepatic glycogen deposition and degradation rates are significantly reduced in Type-1 diabetic subjects undergoing standard insulin therapy, these fluxes may be restored to normal with intensive insulin therapy [70,71].…”

Section: [56]mentioning

confidence: 99%

Non-Invasive Analysis of Human Liver Metabolism by Magnetic Resonance Spectroscopy

Jones

2021

Metabolites

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The liver is a key node of whole-body nutrient and fuel metabolism and is also the principal site for detoxification of xenobiotic compounds. As such, hepatic metabolite concentrations and/or turnover rates inform on the status of both hepatic and systemic metabolic diseases as well as the disposition of medications. As a tool to better understand liver metabolism in these settings, in vivo magnetic resonance spectroscopy (MRS) offers a non-invasive means of monitoring hepatic metabolic activity in real time both by direct observation of concentrations and dynamics of specific metabolites as well as by observation of their enrichment by stable isotope tracers. This review summarizes the applications and advances in human liver metabolic studies by in vivo MRS over the past 35 years and discusses future directions and opportunities that will be opened by the development of ultra-high field MR systems and by hyperpolarized stable isotope tracers.

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¹³C MRS in Human Tissue

Cited by 8 publications

References 105 publications

Spin connection and renormalization of teleparallel action

Spin connection and renormalization of teleparallel action

H ₀ Tension and the Phantom Regime: A Case Study in Terms of an Infrared f(T) Gravity

Non-Invasive Analysis of Human Liver Metabolism by Magnetic Resonance Spectroscopy

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13C MRS in Human Tissue

Cited by 8 publications

References 105 publications

Spin connection and renormalization of teleparallel action

Spin connection and renormalization of teleparallel action

H 0 Tension and the Phantom Regime: A Case Study in Terms of an Infrared f(T) Gravity

Non-Invasive Analysis of Human Liver Metabolism by Magnetic Resonance Spectroscopy

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About

¹³C MRS in Human Tissue

H ₀ Tension and the Phantom Regime: A Case Study in Terms of an Infrared f(T) Gravity