Cross Polarization for Dissolution Dynamic Nuclear Polarization Experiments at Readily Accessible Temperatures 1.2< T <4.2K

Cross polarization can provide significant enhancements with respect to direct polarization of low-γ nuclei such as 13C. Substantial gains in sample throughput (shorter polarization times) can be achieved by exploiting shorter build-up times τDNP(1H)<τDNP(13C). To polarize protons rather than low-γ nuclei, nitroxide radicals with broad ESR resonances such as TEMPO are more appropriate than Trityl and similar carbon-based radicals that have narrow lines. With TEMPO as polarizing agent, the main Dynamic Nuclear Polarization (DNP) mechanism is thermal mixing (TM). Cross polarization makes it possible to attain higher polarization levels at 2.2K than one can obtain with direct DNP of low-γ nuclei with TEMPO at 1.2K, thus avoiding complex cryogenic technolog

Financiamiento de la educación en el Perú

Durante los últimos 25 años el gasto educativo público real en el Perú se ha mantenido relativamente constante, aunque con fluctuaciones relacionadas con el ciclo económico. Sin embargo, en un contexto de marcado crecimiento de la matrícula, esto ha implicado una caída significativa en el gasto por alumno, en particular, en la educación básica. Como parte de este proceso se observó un aumento del número de docentes y de personal administrativo - en particular a partir de 1985 - con una caída en los ingresos reales de los mismos. El gasto por alumno así como la variabilidad del gasto educativo en el Perú es similar al promedio latinoamericano. Sin embargo, el gasto es menos de un sexto del observado en países de la OECD. El gasto público en educación alcanzó el 2.8% del PBI en 1994. Estimaciones realizadas en base a encuestas de hogares muestran que las familias que matricularon a sus hijos en instituciones educativas públicas aportaron un 0.8%. Si además, se contabiliza el gasto de las familias en instituciones privadas, el gasto total de las familias llega a 1.9%. Así, si bien la educación pública, que en el caso de la educación básica constituye el 85% de la matrícula, es gratuita, las familias peruanas en conjunto gastan en educación -a través de aportaciones extraordinarias, cuotas de padres de familia, y gastos en materiales- 2/3 de lo que gasta el Estado. La sociedad peruana en conjunto gasta al menos 4.7% del PBI en educación. Finalmente, se encuentra que, la distribución del gasto educativo por alumno no es equitativa, siendo éste mayor en aquellos departamentos donde los indicadores de pobreza son menores.Financiamiento de la educacion, Gastos publicos, Educational financing, Public expenditure, Peru

Cross Polarization for Dissolution Dynamic Nuclear Polarization Experiments at Readily Accessible Temperatures 1.2 < T < 4.2 K

Cross polarization can provide significant enhancements with respect to direct polarization of low-gamma nuclei such as C-13. Substantial gains in sample throughput (shorter polarization times) can be achieved by exploiting shorter build-up times tau(DNP)(H-1) < tau(DNP)(C-13). To polarize protons rather than low-gamma nuclei, nitroxide radicals with broad ESR resonances such as TEMPO are more appropriate than Trityl and similar carbon-based radicals that have narrow lines. With TEMPO as polarizing agent, the main Dynamic Nuclear Polarization (DNP) mechanism is thermal mixing (TM). Cross polarization makes it possible to attain higher polarization levels at 2.2 K than one can obtain with direct DNP of low-gamma nuclei with TEMPO at 1.2 K, thus avoiding complex cryogenic technology

SHREC'20: Shape correspondence with non-isometric deformations

Estimating correspondence between two shapes continues to be a challenging problem in geometry processing. Most current methods assume deformation to be near-isometric, however this is often not the case. For this paper, a collection of shapes of different animals has been curated, where parts of the animals (e.g., mouths, tails & ears) correspond yet are naturally non-isometric. Ground-truth correspondences were established by asking three specialists to independently label corresponding points on each of the models with respect to a previously labelled reference model. We employ an algorithmic strategy to select a single point for each correspondence that is representative of the proposed labels. A novel technique that characterises the sparsity and distribution of correspondences is employed to measure the performance of ten shape correspondence methods

Cardiac indexes, cardiac damage biomarkers and energy expenditure in professional cyclists during the Giro d’Italia 3-weeks stage race

Introduction: The study of cardiac response to strenuous and continuous exercise is crucial to un-derstanding the physiology of endurance. N-terminal proB-type natriuretic peptide (NT-proBNP) is a potential marker for monitoring myocardial wall stress, and troponins (TnT and TnI) are widely used in the diagnosis of cardiac ischemia and infarction. Strenuous exercise may generate transitory ische-mia, myocardial stress, and diastolic left ventricular dysfunction, inducing the increased production of both these biomarkers. We measured changes in NT-proBNP and TnT in elite cyclists during a 3-week stage race, a model of strenuous exercise. Materials and methods: The study population was 9 professional cyclists participating in the 2011 Giro d’Italia. Pre-analytical and analytical phases scrupulously followed official recommendations. Anthropometric data, net energy expenditure and cardiac indexes (rate, diastolic and systolic blood pressure) were recorded. Blood samples were drawn pre-race (day -1) and at days 12 and 22; NT-proBNP and highly sensitive-troponin (Hs-TnT) concentrations were assayed and corrected for plas-ma volume changes. Results: Body-mass index decreased and energy expenditure increased by 52% during the race. NT-proBNP concentrations increased [day -1: 23.52 ng/L (9.67-34.33); day 12: 63.46 ng/L (22.15-93.31); P = 0.039; day 22: 89.26 ng/L (34.66-129.78) vs. day -1; P < 0.001] and correlated with heart rate (r = -0.51; P = 0.006), systolic pressure (r = 0.39; P = 0.046) and energy expenditure (r = 0.70; P < 0.001). TnT concentrations did not vary, but a widened TnT amplitude distribution was observed. Conclusions: Increases in NT-proBNP correlated with higher energy expenditure over a 3-week cy-cling stage race, possibly indicating myocardial stress

Cross polarization from H-1 to quadrupolar Li-6 nuclei for dissolution DNP

Cross polarization from protons to quadrupolar Li-6 nuclei is combined with dynamic nuclear polarization of protons at 1.2 K and 6.7 T using TEMPOL as a polarizing agent followed by rapid dissolution. Compared to direct Li-6 DNP without cross-polarization, a higher nuclear spin polarization P(Li-6) can be obtained in a shorter time. A double resonance H-1-Li-6 probe was designed that is equipped for Longitudinally Detected Electron Spin Resonance

The quantum J_{1}-J_{1'}-J_{2} spin-1/2 Heisenberg antiferromagnet: A variational method study

The phase transition of the quantum spin-1/2 frustrated Heisenberg antiferroferromagnet on an anisotropic square lattice is studied by using a variational treatment. The model is described by the Heisenberg Hamiltonian with two antiferromagnetic interactions: nearest-neighbor (NN) with different coupling strengths J_{1} and J_{1'} along x and y directions competing with a next-nearest-neighbor coupling J_{2} (NNN). The ground state phase diagram in the ({\lambda},{\alpha}) space, where {\lambda}=J_{1'}/J_{1} and {\alpha}=J_{2}/J_{1}, is obtained. Depending on the values of {\lambda} and {\alpha}, we obtain three different states: antiferromagnetic (AF), collinear antiferromagnetic (CAF) and quantum paramagnetic (QP). For an intermediate region {\lambda}_{1}<{\lambda}<1 we observe a QP state between the ordered AF and CAF phases, which disappears for {\lambda} above some critical value {\lambda}_{1}. The boundaries between these ordered phases merge at the quantum critical endpoint (QCE). Below this QCE there is again a direct first-order transition between the AF and CAF phases, with a behavior approximately described by the classical line {\alpha}_{c}{\simeq}{\lambda}/2

Pulse sequence and sample formulation optimization for dipolar order mediated 1H-13C cross-polarization

We have recently demonstrated the use of contactless radiofrequency pulse sequences under dissolution-dynamic nuclear polarization conditions as an attractive way of transferring polarization from sensitive 1H spins to insensitive 13C spins with low peak radiofrequency pulse powers and energies via a reservoir of dipolar order. However, many factors remain to be investigated and optimized to enable the full potential of this polarization transfer process. We demonstrate herein the optimization of several key factors by: (i) implementing more efficient shaped radiofrequency pulses; (ii) adapting 13C spin labelling; and (iii) avoiding methyl group relaxation sinks. Experimental demonstrations are presented for the case of [1-13C]sodium acetate and other relevant molecular candidates. By employing the range of approaches set out above, polarization transfer using the dipolar order mediated cross-polarization radiofrequency pulse sequence is improved by factors approaching ∼1.65 compared with previous results. Dipolar order mediated 1H→13C polarization transfer efficiencies reaching ∼76% were achieved using significantly reduced peak radiofrequency pulse powers relative to the performance of highly sophisticated state-of-the-art cross-polarization methods, indicating 13C nuclear spin polarization levels on the order of ∼32.1% after 10 minutes of 1H DNP. The approach does not require extensive pulse sequence optimization procedures and can easily accommodate high concentrations of 13C-labelled molecules

Hybrid polarizing solids for pure hyperpolarized liquids through dissolution dynamic nuclear polarization

Hyperpolarization of substrates for magnetic resonance spectroscopy (MRS) and imaging (MRI) by dissolution dynamic nuclear polarization (D-DNP) usually involves saturating the ESR transitions of polarizing agents (PAs; e.g., persistent radicals embedded in frozen glassy matrices). This approach has shown enormous potential to achieve greatly enhanced nuclear spin polarization, but the presence of PAs and/or glassing agents in the sample after dissolution can raise concerns for in vivo MRI applications, such as perturbing molecular interactions, and may induce the erosion of hyperpolarization in spectroscopy and MRI. We show that D-DNP can be performed efficiently with hybrid polarizing solids (HYPSOs) with 2,2,6,6-tetramethyl-piperidine-1-oxyl radicals incorporated in a mesostructured silica material and homogeneously distributed along its pore channels. The powder is wetted with a solution containing molecules of interest (for example, metabolites for MRS or MRI) to fill the pore channels (incipient wetness impregnation), and DNP is performed at low temperatures in a very efficient manner. This approach allows high polarization without the need for glass-forming agents and is applicable to a broad range of substrates, including peptides and metabolites. During dissolution, HYPSO is physically retained by simple filtration in the cryostat of the DNP polarizer, and a pure hyperpolarized solution is collected within a few seconds. The resulting solution contains the pure substrate, is free from any paramagnetic or other pollutants, and is ready for in vivo infusion

Leber's Hereditary Optic Neuropathy: A Report on Novel mtDNA Pathogenic Variants

Leber's hereditary optic neuropathy (LHON) is due to missense point mutations affecting mitochondrial DNA (mtDNA); 90% of cases harbor the m.3460G&gt;A, m.11778G&gt;A, and m.14484T&gt;C primary mutations. Here, we report and discuss five families with patients affected by symptomatic LHON, in which we found five novel mtDNA variants. Remarkably, these mtDNA variants are located in complex I genes, though without strong deleterious effect on respiration in cellular models: this finding is likely linked to the tissue specificity of LHON. This study observes that in the case of a strong clinical suspicion of LHON, it is recommended to analyze the whole mtDNA sequence, since new rare mtDNA pathogenic variants causing LHON are increasingly identified