The neurochemical profile quantified by in vivo 1H NMR spectroscopy.

Proton NMR spectroscopy is emerging from translational and preclinical neuroscience research as an important tool for evidence based diagnosis and therapy monitoring. It provides biomarkers that offer fingerprints of neurological disorders even in cases where a lesion is not yet observed in MR images. The collection of molecules used as cerebral biomarkers that are detectable by (1)H NMR spectroscopy define the so-called "neurochemical profile". The non-invasive quality of this technique makes it suitable not only for diagnostic purposes but also for therapy monitoring paralleling an eventual neuroprotection. The application of (1)H NMR spectroscopy in basic and translational neuroscience research is discussed here.

Assessing the pH and DP of canvasses with NIR spectroscopy

The canvas support in easel paintings is composed mainly of cellulose. One of the maindegradation paths of cellulose is acid-catalysed hydrolysis, which means that in an acidic environment (low pH), its degradation proceeds at a faster rate (Strlič et al., 2005).The main effect of acid-catalysed hydrolysis is the breaking up of the polymer chains,measured by the “Degree of Polymerisation” (DP). The lowering of the DP value impliesa lower mechanical strength of the textile (Scicolone, 1993), and thus this parameter canbe used to monitor degradation. Knowing these two parameters can, therefore, be veryinformative regarding the condition of the canvas support.

Evaluation of Photoacoustic Spectroscopy for Quality Control of Cement, TR-409, 1998

This report discusses the feasibility of using infrared photoacoustic spectroscopy (PAS) as a viable technique that can quickly provide information on cement composition prior to use. The PAS technique is of interest because the cost is much lower than for other types of instrumentation used for mineral analysis, it requires virtually no sample preparation, and it can perform multi-component analysis in a matter of minutes. Feasibility of the technique was based on the ability of PAS to identify and quantify sulfate species and major cement matrix components. Strengths and limitations of the technique are presented.

Raman spectroscopy as a powerful analytical tool: probing the structure of matter

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/32166

Applications of Fourier transform infrared spectroscopy

This article summarizes the basic principles of Fourier Transform Infrared Spectroscopy, with examples of methodologies and applications to different field sciences.

Photoelectron spectroscopy for surface analysis: X-ray and UV excitation

This article summarizes the basic principles of photoelectron spectroscopy for surface analysis, with examples of applications in material science that illustrate the capabilities of the related techniques.

Electron energy loss spectroscopy: physical principles, state of the art and applications to the nanosciences

In the present work we review the way in which the electron-matter interaction allows us to perform electron energy loss spectroscopy (EELS), as well as the latest developments in the technique and some of the most relevant results of EELS as a characterization tool in nanoscience and nanotechnology.

In vivo 13C NMR spectroscopy and metabolic modeling in the brain: a practical perspective.

In vivo 13C NMR spectroscopy has the unique capability to measure metabolic fluxes noninvasively in the brain. Quantitative measurements of metabolic fluxes require analysis of the 13C labeling time courses obtained experimentally with a metabolic model. The present work reviews the ingredients necessary for a dynamic metabolic modeling study, with particular emphasis on practical issues.

Phosphorus analysis in soil under herbaceous perennial leguminous cover by nuclear magnetic spectroscopy

The availability and the reserves of organic phosphorus are controlled by its mineralization rate and are also influenced by changes in soil management. The objective of this study was to evaluate the influence of soil covering with different leguminous plant on soil organic P by 31P-NMR spectroscopy. Alkaline soil extracts were obtained from two depths (0-5 and 5-10 cm) of an Ultisol cultivated with herbaceous perennial leguminous plants (Arachis pintoi, Pueraria phaseoloides, Macroptilium atropurpureum). In an adjacent area, samples of the same soil cover with a secondary tropical forest and grass (Panicum maximum) were also collected. The leguminous management was divided into with removal and without removal of shoot parts after cut on soil surface. Phosphate monoesters are the dominant P species in all soil samples and P diesters accumulated on the superficial layer of secondary forest soil. The P amount of this fraction is higher for the legume covered soil when compared with the grass covered soil. The permanence of leguminous plants on the topsoil after the cut promoted an increase in P diester/P monoester ratios. These findings can be accounted for an enhancement of P availability to plants in soils cultivated with leguminous plants.

Selective resonance suppression 1H-[13C] NMR spectroscopy with asymmetric adiabatic RF pulses.

Despite obvious improvements in spectral resolution at high magnetic field, the detection of 13C labeling by 1H-[13C] NMR spectroscopy remains hampered by spectral overlap, such as in the spectral region of 1H resonances bound to C3 of glutamate (Glu) and glutamine (Gln), and C6 of N-acetylaspartate (NAA). The aim of this study was to develop, implement, and apply a novel 1H-[13C] NMR spectroscopic editing scheme, dubbed "selective Resonance suppression by Adiabatic Carbon Editing and Decoupling single-voxel STimulated Echo Acquisition Mode" (RACED-STEAM). The sequence is based on the application of two asymmetric narrow-transition-band adiabatic RF inversion pulses at the resonance frequency of the 13C coupled to the protons that need to be suppressed during the mixing time (TM) period, alternating the inversion band downfield and upfield from the 13C resonance on odd and even scans, respectively, thus suppressing the detection of 1H resonances bound to 13C within the transition band of the inversion pulse. The results demonstrate the efficient suppression of 1H resonances bound to C3 of Glu and Gln, and C4 of Glu, which allows the 1H resonances bound to C6 of NAA and C4 of Gln to be revealed. The measured time course of the resolved labeling into NAA C6 with the new scheme was consistent with the slow turnover of NAA.

The region makes the difference: disparities in management of acute myocardial infaction within Switzerland

Purpose: To assess geographical differences within Switzerland regarding management and revascularization procedures for acute myocardial infarction (AMI). Methods: Swiss hospital discharge database for period 2007-2008. The main inclusion criterion was AMI as a primary discharge diagnosis. AMI revascularization procedures were identified and seven Swiss regions (Leman, Mittelland, Northwest, Zurich, Central, Eastern and Ticino) were analyzed. Results: Data from 25,674 AMI discharges were analyzed. Almost half (53.6%) of them were managed in a single hospital, the values ranging from 63.1% (Leman) to 31.4% (Ticino) see table. Relative to the total number of discharges, the highest Intensive Care Unit admission rate was in Leman (69.7%), the lowest (16.4%) in Ticino (Swiss average: 35.8%). Intracoronary revascularization rates were highest in Leman (51.6%) and lowest (30.8%) in Central Switzerland (Swiss average: 41.4%). Bare (non-drug-eluting) stents use was highest in Leman (33.1%) and lowest (7.0%) in Ticino (Swiss average: 15.8%), while drug eluting stent use was highest (32.8%) in Ticino and lowest (13.9%) in Central Switzerland (Swiss average: 24.0%). Coronary artery bypass graft rates were highest (4.6%) in Ticino and lowest (0.4%) in Eastern Switzerland (Swiss average: 2.6%). Mechanical circulatory assistance rates were highest (4.1%) in Zurich and lowest (0.4%) in Ticino (Swiss average: 1.7%). The differences in revascularization procedures remained after adjusting for age, single or multiple hospital management and gender. Conclusion: In Switzerland, significant geographical differences in management and revascularization procedures for AMI were found.

Longitudinal neurochemical modifications in the aging mouse brain measured in vivo by (1)H magnetic resonance spectroscopy.

Alterations to brain homeostasis during development are reflected in the neurochemical profile determined noninvasively by (1)H magnetic resonance spectroscopy. We determined longitudinal biochemical modifications in the cortex, hippocampus, and striatum of C57BL/6 mice aged between 3 and 24 months . The regional neurochemical profile evolution indicated that aging induces general modifications of neurotransmission processes (reduced GABA and glutamate), primary energy metabolism (altered glucose, alanine, and lactate) and turnover of lipid membranes (modification of choline-containing compounds and phosphorylethanolamine), which are all probably involved in the frequently observed age-related cognitive decline. Interestingly, the neurochemical profile was different in male and female mice, particularly in the levels of taurine that may be under the control of estrogen receptors. These neurochemical profiles constitute the basal concentrations in cortex, hippocampus, and striatum of healthy aging male and female mice.

On periodic solutions of 2-periodic Lyness difference equations

We study the existence of periodic solutions of the non--autonomous periodic Lyness' recurrence u_{n+2}=(a_n+u_{n+1})/u_n, where {a_n} is a cycle with positive values a,b and with positive initial conditions. It is known that for a=b=1 all the sequences generated by this recurrence are 5-periodic. We prove that for each pair (a,b) different from (1,1) there are infinitely many initial conditions giving rise to periodic sequences, and that the family of recurrences have almost all the even periods. If a is not equal to b, then any odd period, except 1, appears.

Sex difference in hepatic peroxisome proliferator-activated receptor alpha expression: influence of pituitary and gonadal hormones.

Peroxisome proliferator-activated receptor (PPAR) alpha is a nuclear receptor that is mainly expressed in tissues with a high degree of fatty acid oxidation such as liver, heart, and skeletal muscle. Unsaturated fatty acids, their derivatives, and fibrates activate PPARalpha. Male rats are more responsive to fibrates than female rats. We therefore wanted to investigate if there is a sex difference in PPARalpha expression. Male rats had higher levels of hepatic PPARalpha mRNA and protein than female rats. Fasting increased hepatic PPARalpha mRNA levels to a similar degree in both sexes. Gonadectomy of male rats decreased PPARalpha mRNA expression to similar levels as in intact and gonadectomized female rats. Hypophysectomy increased hepatic PPARalpha mRNA and protein levels. The increase in PPARalpha mRNA after hypophysectomy was more pronounced in females than in males. GH treatment decreased PPARalpha mRNA and protein levels, but the sex-differentiated secretory pattern of GH does not determine the sex-differentiated expression of PPARalpha. The expression of PPARalpha mRNA in heart or soleus muscle was not influenced by gender, gonadectomy, hypophysectomy, or GH treatment. In summary, pituitary-dependent hormones specifically regulate hepatic PPARalpha expression. Sex hormones regulate the sex difference in hepatic PPARalpha levels, but not via the sexually dimorphic GH secretory pattern.