Photochemistry of pyruvic acid is governed by photo-induced intermolecular electron transfer through hydrogen bonds.

Despite more than 85 years of research, the mechanism behind the photodecarboxylation of pyruvic acid remains elusive. Most studies focused on the gas and liquid phase of diluted solutions of pyruvic acid to understand the impact of sun light on the degradation of this molecule in the atmosphere. By analyzing concentrated supercooled solutions at 77 K, we demonstrate that instead of decarboxylating, the pyruvic acid molecule plays the role of electron donor and transfers an electron to an acceptor molecule that subsequently degrades to form CO.

Labile Photo-Induced Free Radical in α-Ketoglutaric Acid: a Universal Endogenous Polarizing Agent for In Vivo Hyperpolarized C Magnetic Resonance.

Hyperpolarized (HP) C magnetic resonance enables non-invasive probing of metabolism in vivo. To date, only C-molecules hyperpolarized with persistent trityl radicals have been injected in humans. We show here that the free radical photo-induced in alpha-ketoglutaric acid (α-KG) can be used to hyperpolarize photo-inactive C-molecules such as [1-C]lactate.

Genetic algorithm-based optimization of pulse sequences.

Purpose: The performance of pulse sequences in vivo can be limited by fast relaxation rates, magnetic field inhomogeneity, and nonuniform spin excitation. We describe here a method for pulse sequence optimization that uses a stochastic numerical solver that in principle is capable of finding a global optimum. The method provides a simple framework for incorporating any constraint and implementing arbitrarily complex cost functions.

Labile Photo-Induced Free Radical in α-Ketoglutaric Acid: a Universal Endogenous Polarizing Agent for In Vivo Hyperpolarized C Magnetic Resonance.

Hyperpolarized (HP) C magnetic resonance enables non-invasive probing of metabolism in vivo. To date, only C-molecules hyperpolarized with persistent trityl radicals have been injected in humans. We show here that the free radical photo-induced in alpha-ketoglutaric acid (α-KG) can be used to hyperpolarize photo-inactive C-molecules such as [1- C]lactate.

A multisample 7 T dynamic nuclear polarization polarizer for preclinical hyperpolarized MR.

Dynamic nuclear polarization (DNP) provides the opportunity to boost liquid state magnetic resonance (MR) signals from selected nuclear spins by several orders of magnitude. A cryostat running at a temperature of ~ 1 K and a superconducting magnet set to between 3 and 10 T are required to efficiently hyperpolarize nuclear spins. Several DNP polarizers have been implemented for the purpose of hyperpolarized MR and recent systems have been designed to avoid the need for user input of liquid cryogens.

Determining the Sample Size for Future Trials of Hearing Instruments for Unilaterally Deaf Adults: An Application of Network Meta-analysis.

Objective: Previous trials have compared the efficacy of hearing instruments to no intervention in adults with single-sided deafness (SSD) or the relative efficacy of different instruments. Network meta-analysis (NMA) was used to refine estimates of effect sizes to determine required sample sizes for further trials.

Data Sources: PubMed, EMBASE, MEDLINE, Cochrane, CINAHL, and DARE databases were searched with no restrictions on language, with studies to February 2015 included.

Photogenerated Radical in Phenylglyoxylic Acid for in Vivo Hyperpolarized C MR with Photosensitive Metabolic Substrates.

Whether for C magnetic resonance studies in chemistry, biochemistry, or biomedicine, hyperpolarization methods based on dynamic nuclear polarization (DNP) have become ubiquitous. DNP requires a source of unpaired electrons, which are commonly added to the sample to be hyperpolarized in the form of stable free radicals. Once polarized, the presence of these radicals is unwanted.

Magnetic Resonance Imaging: A Tool for Pork Pie Development.

The traditional British pork pie consists of roughly chopped pork cooked in a hot water pastry crust. Due to shrinkage of the meat during cooking, the gap formed around the meat is usually sealed using a gelatin based jelly to exclude air and thus help to preserve the pie. The properties of the jelly are such that it will ingress into the pastry crust causing undesirable softening.