1,721,106 research outputs found
NMR and metabolic profile of human, animal, vegetable tissues and cells
No full textGiornata di approfondimento sulla risonanza magnetica nucleare applicata alle matrici in oggett
Macromolecular versus Micromolecular World
No full textThe origin of life is still a mystery with many unsolved puzzles. How were molecules created? How did they assemble into large structures? Among the misteries, the "chirality" phenomenon upon which amino acids and sugars form is particularly exciting. Single chiral molecules in any chemical system play a very particular role, and these are the only systems where one can be sure, that they display 100 % ee. If this kind of system is a sub-sytem of reaction mixtures where highly sensitive autocatalytic reactions may develop, as for example in the case of the Soai reaction, the presence of this initial chiral molecule can decisively influence the subsequent stereochemical developments. In the present work we can try to understand, how the phenomenon of chirality is related to single molecules, and how could this starting situation influence the outcome of reactions where the product(s) is (are) of high molecular weight, as synthetic or biological polymers
Molecular characterization and quantification using state of the art solid-state adiabatic TOBSY NMR in burn trauma
No full textWe describe a novel solid-state nuclear magnetic
resonance (NMR) method that maximizes the advantages of
high-resolution magic-angle-spinning (HRMAS), relative
conventional liquid-state NMR approaches, when applied to
intact biopsies of skeletal muscle specimens collected from
burn trauma patients. This novel method, termed optimized
adiabatic TOtal through Bond correlation SpectroscopY
(TOBSY) solid-state NMR pulse sequence for two-dimensional
(2D) 1H-1H homonuclear scalar-coupling longitudinal isotropic
mixing, was demonstrated to provide a 40-60% improvement
in signal-to-noise ratio (SNR) relative to its liquid-state
analogue TOCSY (TOtal Correlation SpectroscopY). Using 1-
and 2-dimensional HRMAS NMR experiments, we identified
several metabolites in burned tissues. Quantification of
metabolites in burned tissues showed increased levels of
lipid compounds, intracellular metabolites (e.g., taurine and
phosphocreatine) and substantially decreased water-soluble
metabolites (e.g., glutathione, carnosine, glucose, glutamine/
glutamate and alanine). These findings demonstrate that HRMAS NMR Spectroscopy using TOBSY is a feasible technique that reveals new insights into the pathophysiology of burn trauma. Moreover, this method has applications that facilitate the development of novel therapeutic strategies
Tracking of Labelled Stem Cells Using Molecular MR Imaging in a Mouse Burn Model in Vivo as an Approach to Regenerative Medicine
Full text linkTherapies based on stem cell transplants offer significant potential in the field of regenerative medicine. Monitoring the fate of the transplanted stem cells in a timely manner is considered one of the main limitations for long-standing success of stem cell transplants. Imaging methods that visualize and track stem cells in vivo non-invasively in real time are helpful towards the development of successful cell transplantation techniques. Novel molecular imaging methods which are non-invasive particularly such as MRI have been of great recent interest. Hence, mouse models which are of clinical relevance have been studied by injecting contrast agents used for labelling cells such as super-paramagnetic iron-oxide (SPIO) nanoparticles for cellular imaging. The MR techniques which can be used to generate positive contrast images have been of much relevance recently for tracking of the labelled cells. Particularly when the off-resonance region in the vicinity of the labeled cells is selectively excited while suppressing the signals from the non-labeled regions by the method of spectral dephasing. Thus, tracking of magnetically labelled cells employing positive contrast in vivo MR imaging methods in a burn mouse model in a non-invasive way has been the scope of this study. The consequences have direct implications for monitoring labeled stem cells at some stage in wound healing. We suggest that our approach can be used in clinical trials in molecular and regenerative medicine
Effects of two Lignosulfonate-Humates on Zea mays L. Metabolism
No full textTwo lignosulfonate-humates (a and b), derived by an industrial process from lignin, were chemically characterized and their effects on maize plants in terms of growth, nitrogen metabolism and photosynthesis were investigated. The biological effects of lignosulfonate humates were compared with those induced by a humic acid extracted from leonardite in order to better understand the complexity of their biological effects.
Our results displayed that both lignosulfonate-humates (a and b) had a hormone-like activity and increased root and leaf growth. Moreover, all treatments increased the content of chlorophyll, glucose and fructose and enhanced the activity of Rubisco, glutamine-synthetase and glutamate-synthase. The observed intense biological activity indicated that lignosulfonate-humates and leonardite humic acid had a positive role on photosynthetic
process of maize plants. In the light of these results, lignosulfonate-humates may be used as biostimulants to increase crop yield
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Crocus sativus Petals: Waste or Valuable Resource? The Answer of High-Resolution and High-Resolution Magic Angle Spinning Nuclear Magnetic Resonance
No full textIntact Crocus sativus petals were studied for the first time by high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy, revealing the presence of kinsenoside (2) and goodyeroside A (3), together with 3-hydroxy-γ-butyrolactone (4). These findings were confirmed by HR-NMR analysis of the ethanol extract of fresh petals and showed that, even though carried out rapidly, partial hydrolysis of glucopyranosyloxybutanolides occurs during extraction. On the other hand, kaempferol 3-O-sophoroside (1), which is "NMR-silent" in intact petals, is present in extracts. These results suggest to evaluate the utilization of saffron petals for phytopharmaceutical and nutraceutical purposes to exploit a waste product of massive production of commercial saffron and point to the application of HR-MAS NMR for monitoring bioactive compounds directly on intact petals, avoiding the extraction procedure and the consequent hydrolysis reaction
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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