Glucose exchange parameters in a subset of physiological conditions.

The chemical exchange of labile protons of the hydroxyl groups can be exploited in a variety of magnetic resonance experiments to gain information about the groups and their physicochemical environment. The exchangeable -OH protons provide important contributions to the of water signals thus contributing to the -weighted contrast of MRI images. This exchange can be exploited more specifically and sensitively in chemical exchange saturation transfer (CEST) or longitudinal rotating frame relaxation () experiments.

Relaxometry models compared with Bayesian techniques: ganglioside micelle example.

In this work a methodology to perform Bayesian model-comparison is developed and exemplified in the analysis of nuclear magnetic relaxation dispersion (NMRD) experiments of water in a ganglioside micelle system. NMRD is a powerful tool to probe slow dynamics in complex liquids. There are many interesting systems that can be studied with NMRD, such as ionic and lyotropic liquids or electrolytes.

NMR relaxation and modelling study of the dynamics of SF and Xe in porous organic cages.

The porous solid formed from organic CC3 cage molecules has exceptional performance for rare gas separation. NMR spectroscopy provides a way to reveal the dynamical details by using experimental relaxation and diffusion measurements. Here, we investigated T and T relaxation as well as diffusion of Xe and SF gases in the CC3-R molecular crystal at various temperatures and magnetic field strengths.

Forces applied at the footrest during ergometer kayaking among female athletes at different competing levels - a pilot study.

Background: Power output and force development during exercise are thought to be important indices of performance in elite athletes. The aim of this preliminary study was to determine the forces applied at the footrest during ergometric kayaking in individual kayakers at different competitive levels.

Methods: Three elite female kayakers participated voluntarily in the study.

Brownian Translational Dynamics on a Flexible Surface: Nuclear Spin Relaxation of Fluid Membrane Phases.

A general model for nuclear magnetic resonance (NMR) relaxation studies of fluid bilayer systems is introduced, combining a mesoscopic Brownian dynamics description of the bilayer with atomistic molecular dynamics (MD) simulations. An example is given for dipalmitoylphosphatidylcholine in HO solvent and compared with the experiment. Experimental agreement is within a factor of 2 in the water relaxation rates, based on a postulated model with fixed parameters, which are largely available from the MD simulation.

Structure and dynamics elucidation of ionic liquids using multidimensional Laplace NMR.

We demonstrate the ability of multidimensional Laplace NMR (LNMR), comprising relaxation and diffusion experiments, to reveal essential information about microscopic phase structures and dynamics of ionic liquids that is not observable using conventional NMR spectroscopy or other techniques.

Prediction of low-field nuclear singlet lifetimes with molecular dynamics and quantum-chemical property surface.

Molecular dynamics and quantum chemistry methods are implemented to quantify nuclear spin-1/2 pair singlet-state relaxation rates for three molecular systems at low magnetic field and room temperature. Computational methodology is developed for weak interactions, particularly important for singlet states at low field. These include spin-rotation and spin-internal-motion effects, which describe the coupling of the spin-carrying nuclei to fluctuating local magnetic fields induced by the overall and internal molecular fluctuations, respectively.

Synthesis of an isotopically labeled naphthalene derivative that supports a long-lived nuclear singlet state.

The synthesis of an octa-alkoxy substituted isotopically labeled naphthalene derivative, shown to have excellent properties in singlet NMR experiments, is described. This highly substituted naphthalene system, which incorporates an adjacent (13)C spin pair, is readily accessed from a commercially available (13)C2-labeled building block via sequential thermal alkynyl- and arylcyclobutenone rearrangements. The synthetic route incorporates a simple desymmetrization approach leading to a small difference in the chemical shifts of the (13)C spin pair, a design constraint crucial for accessing nuclear singlet order.

A Nuclear Singlet Lifetime of More than One Hour in Room-Temperature Solution.

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are supremely important techniques with numerous applications in almost all branches of science. However, until recently, NMR methodology was limited by the time constant for the decay of nuclear spin magnetization through contact with the thermal molecular environment. Long-lived states, which are correlated quantum states of multiple nuclei, have decay time constants that may exceed by large factors.

Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation.

Long-lived nuclear spin states have a relaxation time much longer than the longitudinal relaxation time T1. Long-lived states extend significantly the time scales that may be probed with magnetic resonance, with possible applications to transport and binding studies, and to hyperpolarised imaging. Rapidly rotating methyl groups in solution may support a long-lived state, consisting of a population imbalance between states of different spin exchange symmetries.

A nuclear singlet lifetime of more than one hour in room-temperature solution.

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) are supremely important techniques with numerous applications in almost all branches of science. However, until recently, NMR methodology was limited by the time constant T1 for the decay of nuclear spin magnetization through contact with the thermal molecular environment. Long-lived states, which are correlated quantum states of multiple nuclei, have decay time constants that may exceed T1 by large factors.

NMR resonance splitting of urea in stretched hydrogels: proton exchange and (1)H/(2)H isotopologues.

Urea at ∼12 M in concentrated gelatin gel, that was stretched, gave (1)H and (2)H NMR spectral splitting patterns that varied in a predictable way with changes in the relative proportions of (1)H2O and (2)H2O in the medium. This required consideration of the combinatorics of the two amide groups in urea that have a total of four protonation/deuteration sites giving rise to 16 different isotopologues, if all the atoms were separately identifiable. The rate constant that characterized the exchange of the protons with water was estimated by back-transformation analysis of 2D-EXSY spectra.

Long-lived nuclear spin states in methyl groups and quantum-rotor-induced polarization.

Substances containing rapidly rotating methyl groups may exhibit long-lived states (LLSs) in solution, with relaxation times substantially longer than the conventional spin-lattice relaxation time T1. The states become long-lived through rapid internal rotation of the CH3 group, which imposes an approximate symmetry on the fluctuating nuclear spin interactions. In the case of very low CH3 rotational barriers, a hyperpolarized LLS is populated by thermal equilibration at liquid helium temperature.

A modeling approach for compounds affecting body composition.

Body composition and body mass are pivotal clinical endpoints in studies of welfare diseases. We present a combined effort of established and new mathematical models based on rigorous monitoring of energy intake (EI) and body mass in mice. Specifically, we parameterize a mechanistic turnover model based on the law of energy conservation coupled to a drug mechanism model.

Lineshape-based polarimetry of dynamically-polarized (15)N2O in solid-state mixtures.

Dynamic nuclear polarization (DNP) of (15)N2O, known for its long-lived singlet-state order at low magnetic field, is demonstrated in organic solvent/trityl mixtures at ∼1.5 K and 5 T. Both (15)N polarization and intermolecular dipolar broadening are strongly affected by the sample's thermal history, indicating spontaneous formation of N2O clusters.

Cu(II)-porphyrin molecular dynamics as seen in a novel EPR/Stochastic Liouville equation study.

Copper porphyrin dissolved in CH2Cl2:toluene as fluid and frozen solution was studied as a function of temperature using X-band electron paramagnetic resonance (EPR). Quantitative interpretation was obtained using a recently developed Stochastic Liouville simulation method. For the first time we address the large spin system that translates into a 400,000 dimensional Liouville equation solved under slow-motion conditions.

Two distinct modes of ATR activation orchestrated by Rad17 and Nbs1.

The ATM- and Rad3-related (ATR) kinase is a master regulator of the DNA damage response, yet how ATR is activated toward different substrates is still poorly understood. Here, we show that ATR phosphorylates Chk1 and RPA32 through distinct mechanisms at replication-associated DNA double-stranded breaks (DSBs). In contrast to the rapid phosphorylation of Chk1, RPA32 is progressively phosphorylated by ATR at Ser33 during DSB resection prior to the phosphorylation of Ser4/Ser8 by DNA-PKcs.

Mobile health in emerging countries: a survey of research initiatives in Brazil.

Objective: To conduct a comprehensive survey of mobile health (mHealth) research initiatives in Brazil, discussing current challenges, gaps, opportunities and tendencies.

Methods: Systematic review of publicly available electronic documents related to mHealth, including scientific publications, technical reports and descriptions of commercial products. Specifically, 42 projects are analyzed and classified according to their goals.

A Method to Measure the Reduction of CO2 Emissions in E-Health Applications.

Climate change is perhaps the topmost challenge of our time. To prevent climate change from severely impacting almost every facet of life on the planet, scientific consensus points to a need to reduce the emissions of greenhouse gases (GHG), measured in terms of CO2 equivalents (CO2e), by as much as 80 percent by 2050. So far the focus has centered on incremental reductions of CO2 e emissions in areas in which they are highest, without negatively impacting the economy.

Implicit numerical schemes for the stochastic Liouville equation in Langevin form.

We present and numerically test implicit as well as explicit numerical schemes for solving the Stochastic Liouville Equation in Langevin form. It is found that implicit schemes provide significant gain in robustness, for example, when nonsecular Hamiltonian terms cannot be ignored in electron and nuclear spin resonance. Implicit schemes open up several spectroscopic relaxation problems for direct interpretation using the Stochastic Liouville Equation.

Efficient and robust quantum Monte Carlo estimate of the total and spin electron densities at nuclei.

The computational performance of two different variational quantum Monte Carlo estimators for both the electron and spin densities on top of nuclei are tested on a set of atomic systems containing also third-row species. Complications due to an unbounded variance present for both estimators are circumvented using appropriate sampling strategies. Our extension of a recently proposed estimator [Phys.

Extended Förster theory for determining intraprotein distances. Part III. Partial donor-donor energy migration among reorienting fluorophores.

An extended Förster theory (EFT) is derived and outlined for electronic energy migration between two fluorescent molecules which are chemically identical, but photophysically non-identical. These molecules exhibit identical absorption and fluorescence spectra, while their fluorescence lifetimes differ. The latter means that the excitation probability becomes irreversible.

Intestinal, adipose, and liver inflammation in diet-induced obese mice.

Chronic inflammation and increased visceral adipose tissue (VAT) are key elements of the metabolic syndrome. Both are considered to play a pathogenic role in the development of liver steatosis and insulin resistance. The aim of the present study was to investigate the hypothesis that an inflamed intestine, induced both by diet and chemical irritation, could induce persistent inflammation in VAT.

Gene expression analysis of BCR/ABL1-dependent transcriptional response reveals enrichment for genes involved in negative feedback regulation.

Philadelphia (Ph) chromosome-positive leukemia is characterized by the BCR/ABL1 fusion protein that affects a wide range of signal transduction pathways. The knowledge about its downstream target genes is, however, still quite limited. To identify novel BCR/ABL1-regulated genes we used global gene expression profiling of several Ph-positive and Ph-negative cell lines treated with imatinib.