1,721,008 research outputs found
Alternating Delays Achieve Polarization Transfer (ADAPT) to heteronuclei in PHIP experiments
No full textA new methodology for producing hyperpolarized 13C nuclei in small organic systems via parahydrogen induced polarization (PHIP) is proposed: ADAPT (Alternating Delays Achieve Polarization Transfer). The theoretical foundation of the process is investigated in some detail and experimental examples demonstrating the viability of the approach are provided as well. The number of adjustable parameters is fewer than most of other conversion schemes. The achieved theoretical heteronuclear polarization is close to unity for any examined magnetic equivalence regime. The duration of the pulse sequence, which was successfully implemented, can be shorter than other established methods reducing possible relaxation losses. The conversion scheme is robust to B1 inhomogeneities, but more sensitive to off-resonance RF irradiation
Chapter 11: Converting Spin Order from Singlet to Heteronuclear Magnetisation
No full textSome singlet to heteronuclear polarization transfer strategies are presented. The NMR sequences and relative parameters are described
Chapter 2. Symmetry and Long-lived Spin Order
No full textA permutation symmetry theory for nuclear long-lived spin states is examined. The theory predicts the number of expected long-lived states (LLS), which are described as population imbalances of states belonging to different irreducible representations
Entrapment of the sciatic nerve at the linea aspera: A case report and literature review
No full textNontraumatic, non-neoplastic sciatic nerve entrapment at the level of the thigh is extremely rare. In its course, in proximity of the linea aspera, the nerve is exposed to unexpected neuropathic syndromes associated with bone disorders
Homonuclear ADAPT: A general preparation route to long-lived nuclear singlet order
No full textWe introduce a simple strategy to access and readout nuclear singlet order based on the alternate repetition of hard pulses and delays. We demonstrate the general applicability of the method by accessing nuclear singlet order in spin systems characterized by diverse coupling regimes. We show that the method is highly efficient in the strong-coupling and chemical equivalence regimes, and can overcome some limitations of other well-established and more elaborated pulse sequences. A simulation package is provided which allows the determination of pulse sequence parameters
A rapid photometric micromethod for serum lipase determination.
No full textA new micromethod for the determination of serum lipase activity is presented. Small quantities of serum are incubated for 30 min at 40° in a substrate consisting of an olive oil suspension in the presence of deoxycholic acid. The pH is 8.5. The hydrolyzed fatty acids are determined with a photometric technique, with a slight modification of the method of Duncombe. The normal values are lower than 20 I.U. © 1972
A pulse sequence for singlet to heteronuclear magnetization transfer: S2hM
No full textWe have recently demonstrated, in the context of para-hydrogen induced polarization (PHIP), the conversion of hyperpolarized proton singlet order into heteronuclear magnetisation can be efficiently achieved via a new sequence named S2hM (Singlet to heteronuclear Magnetisation). In this paper we give a detailed theoretical description, supported by an experimental illustration, of S2hM. Theory and experiments on thermally polarized samples demonstrate the proposed method is robust to frequency offset mismatches and radiofrequency field inhomogeneities. The simple implementation, optimisation and the high conversion efficiency, under various regimes of magnetic equivalence, makes S2hM an excellent candidate for a widespread use, particularly within the PHIP arena
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
Modello digitale 3D dell’area archeologica di Montegrotto mediante integrazione di dati GPS e laser scanner in ambiente GRASS GIS
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