Solvent suppression techniques for coupling of size exclusion chromatography and 1H NMR using benchtop spectrometers at 43 and 62 MHz.

The characterisation of polymeric materials in their full complexity of chain length, monomeric composition, branching and functionalization is a tremendous challenge and is best tackled by tailored multi-dimensional coupled analytical and detection techniques. Herein, we focus on the improvement of an affordable but information rich 2D-method for polymer analysis: the online hyphenation of benchtop 1H NMR spectroscopy with size exclusion chromatography (SEC). The main benefit of this approach is correlated information of chain length (SEC) to chemical composition (1H NMR). Our setup combines SEC onflow with a benchtop NMR spectrometer at 43 or 62 MHz with chemical shift resolution as a robust detector. A detailed comparison of the two instruments is included considering, that only the 43 MHz instrument is equipped with a dedicated z-gradient enabling pulse sequences such as WET. The main challenge of this method is the very low concentration of species of interest after chromatographic separation. At typical SEC conditions, the analyte dilution is typically more than a factor of 1000:1 in a protonated solvent. Therefore, an efficient solvent signal suppression is needed. In this article, several suppression pulse sequences are explored like WET, WEFT, JNR and a simple one-pulse approach - some for the first time on this hardware. By choosing an optimal method, signal strength ratios of solvent to analyte of 1:1 or better are achievable on flow. To illustrate the broad range of possible applications, three typical cases of analyte to solvent signal proximity (no overlap, partial and full overlap) are discussed using typical polymers (PS, PMMA, PEMA) and solvents (chloroform and THF). For each case, several suppression methods are compared and evaluated using a set of numerical criteria (analyte signal suppression and broadening, solvent signal suppression, remaining solvent signal width).

High-throughput authentication of edible oils with benchtop Ultrafast 2D NMR.

We report the use of an Ultrafast 2D NMR approach applied on a benchtop NMR system (43 MHz) for the authentication of edible oils. Our results demonstrate that a profiling strategy based on fast 2D NMR spectra recorded in 2.4 min is more efficient than the standard 1D experiments to classify oils from different botanical origins, since 1D spectra on the same samples suffer from strong peak overlaps. Six edible oils with different botanical origins (olive, hazelnut, sesame, rapeseed, corn and sunflower) have been clearly discriminated by PCA analysis. Furthermore, we show how this approach combined with a PLS model can detect adulteration processes such as the addition of hazelnut oil into olive oil, a common fraud in food industry.

2D 7Li Ultrafast CT-COSY: a new tool for the rapid measurement of tiny homonuclear lithium scalar couplings.

The measurement of small homonuclear 2J7Li-7Li scalar couplings relying on constant time (CT) COSY NMR suffers from strong time limitations. We describe the first Ultrafast CT COSY experiment on lithium 7, which provides a considerable acceleration in the study of the aggregation state and dynamics of n-BuLi/MeLi complexes.

3D localized 2D ultrafast J-resolved magnetic resonance spectroscopy: in vitro study on a 7 T imaging system.

2D Magnetic Resonance Spectroscopy (MRS) is a well known tool for the analysis of complicated and overlapped MR spectra and was therefore originally used for structural analysis. It also presents a potential for biomedical applications as shown by an increasing number of works related to localized in vivo experiments. However, 2D MRS suffers from long acquisition times due to the necessary collection of numerous increments in the indirect dimension (t(1)). This paper presents the first 3D localized 2D ultrafast J-resolved MRS sequence, developed on a small animal imaging system, allowing the acquisition of a 3D localized 2D J-resolved MRS spectrum in a single scan. Sequence parameters were optimized regarding Signal-to-Noise ratio and spectral resolution. Sensitivity and spatial localization properties were characterized and discussed. An automatic post-processing method allowing the reduction of artifacts inherent to ultrafast excitation is also presented. This sequence offers an efficient signal localization and shows a great potential for in vivo dynamic spectroscopy.

[Surgery of leprous neuritis (a 16 mm colour-sound film--35 minutes (author's transl)]. / Chirurgie directe de la névrite lépreuse (film 16 mm en couleur de 35 minutes commentaire sonore en français titrage bilingue français--anglais.

When medical treatment is not sufficient, surgery may still improve leprous neuritis by:--opening of osteo-fibrous tunnels where is an external compression fixing the level of physiological blockade: the elbow for the cubital nerve, the wrist for the median nerve, the peroneal neck for the peroneal nerve, the instep for the tibial nerve;--opening the thickened and consequently inextensible epineurium, inducing a release of the compression acting upon the nervous bundles and permitting their recovery if they are not yet destroyed. The film describes the various techniques immediately effective in hyperalgic neuritis and giving valuable recoveries in forms showing already a functional impairment.

[Place and importance of specific surgery in a national program for control of leprosy (author's transl)]. / Place et importance de la chirurgie "spécialisée" dans un programme national de lutte contre la lèpre.

In order to get a representative sample of the population, a survey was conducted in an rural district of the Republic of Mali. The data collected give evidence that the number of specific surgical indications can be correctly evaluated not from the number of leprosy patients numbered, but by applying a ratio of 5,5 per cent to the whole population. This easy evaluation is important for the management of any public health programme.

[Present evaluation of hansenian treatment by association of chemotherapy and immunostimulation (author's transl)]. / Bilan actuel du traitement de la lépre par chimiothérapie et immunostimulation associées

I.--Treatment with BCG and DDS in lepromatous or borderline patients. II.--Value of BCG added to a prior and long-continued treatment with DDS or rifamipicine. III.--Value of various immunostimulants given previously to a treatment with BCG and chemotherapy. IV.--Value of lysate of Neisseria perflava as an immunostimulant associated with DDS in an initial treatment of lepromatous and borderline patients. V.--Results of a seventeen months treatment of lepromatous and borderline patients with a lysate of Neisseria perflava associated with DDS. The various therapeutic trials reported in these 5 papers demonstrate that hansenian nevritis conventionnally treated may show improvement when an immunostimulant (BCG or bacterial lysate or levamisole) is given either previously or in association with DDS or rifampicine or after such a treatment. It has still been observed that two immunostimulants given simultaneously have no good effect and that this association must be discarded.

La neurolyse fasciculaire dans la lepre 20 ans apres (1957-1977) / ?

A better knowledge of the pathological and physiopathological nervous involvement in leprosy and a more extended experience of fascicular neurolysis have proved the value of this procedure proposed by Carayon in 1957. The opposed opinions are discussed and the authors give the strict rules required for a good indication and a good surgical technic according to the kind of damage and to the nerve concerned

[Tarsal tunnel syndrome. Apropos of 15 "pure" cases and 100 cases "combined" with leprosy or diabetes mellitus]. / Syndrome du canal tarsien. A propos de 15 cas "purs" et de 100 cas "associés" à la lèpre ou au diabète

The authors have observed 15 cases of the tarsal canal syndrome: the 14 cases operated on showed compression of the nerve by bone fragments resulting from trauma by local varices, by a muscular anomaly, or as a result of enclosure by post-trauma fibrosis. Surgery resulted in 10 cures and considerable improvement in 2 other cases. In addition to these 15 "pure" cases the authors report their experience of neurolysis of the posterior tibial nerve and of the plantar nerves of the tarsal canal in the treatment of perforating plantar lesions in leprosy (88 cases) and diabetes (12 cases). The good results in these cases indicate the value of extending this therapy to the treatment of perforating plantar lesions in cases of large nerve neuritis.