Small-angle X-ray scattering intensity of multiscale models of spheroids.

The microstructure of heterogeneous catalysts often consists of multiscale aggregates of nanoparticles, some of which are highly anisotropic. Therefore, small-angle X-ray scattering, in classical or anomalous mode, is a valuable tool to characterize this kind of material. Yet, the classical exploitation of the scattered intensities through form and structure factors or by means of Boolean models of spheres is questionable. Here, it is proposed to interpret the scattered intensities through the use of multiscale Boolean models of spheroids. The numerical procedure to compute scattered intensities of such models is given and then validated on asymptotic diluted Boolean models, and its applicability is demonstrated for the characterization of alumina catalyst supports.

Ultra-high performance supercritical fluid chromatography hyphenated to atmospheric pressure chemical ionization high resolution mass spectrometry for the characterization of fast pyrolysis bio-oils.

Extensive characterization of complex mixtures requires the combination of powerful analytical techniques. A Supercritical Fluid Chromatography (SFC) method was previously developed, for the specific case of fast pyrolysis bio oils, as an alternative to gas chromatography (GC and GC × GC) or liquid chromatography (LC and LC × LC), both separation methods being generally used prior to mass spectrometry (MS) for the characterization of such complex matrices. In this study we investigated the potential of SFC hyphenated to high resolution mass spectrometry (SFC-HRMS) for this characterization using Negative ion Atmospheric Pressure Chemical ionization ((-)APCI) for the ionization source. The interface between SFC and (-)APCI/HRMS was optimized from a mix of model compounds with the objective of maximizing the signal to noise ratio. The main studied parameters included both make-up flow-rate and make-up composition. A methodology for the treatment of APCI/HRMS data is proposed. This latter allowed for the identification of molecular formulae. Both SFC-APCI/HRMS method and data processing method were applied to a mixture of 36 model compounds, first analyzed alone and then spiked in a bio-oil. In both cases, 19 compounds could be detected. Among them 9 could be detected in a fast pyrolysis bio-oil by targeted analysis. The whole procedure was applied to the characterization of a bio-oil using helpful representations such as mass-plots, van Krevelen diagrams and heteroatom class distributions. Finally the results were compared with those obtained with a Fourier Transform ion-cyclotron resonance mass spectrometer (FT-ICR/MS).

Persistent neuropathic pain after inguinal herniorrhaphy depending on the procedure (open mesh v. laparoscopy): a propensity-matched analysis.

BACKGROUND: A greater incidence of persistent pain after inguinal herniorrhaphy is suspected with the open mesh procedure than with laparoscopy (transabdominal preperitoneal), but the involvement of neuropathy needs to be clarified. METHODS: We examined the cumulative incidence of neuropathic persistent pain, defined as self-report of pain at the surgical site with neuropathic aspects, within 6 months after surgery in 2 prospective subcohorts of a multicentre study. We compared open mesh with laparoscopy using different analysis, including a propensity-matched analysis with the propensity score built from a multivariable analysis using a generalized linear model. RESULTS: Considering the full patient sample (242 open mesh v. 126 laparoscopy), the raw odds ratio for neuropathic persistent pain after inguinal herniorrhaphy was 4.3. It reached 6.8 with the propensity-matched analysis conducted on pooled subgroups of 194 patients undergoing open mesh and 125 undergoing laparoscopy (95% confidence interval 1.5-30.4, p = 0.012). A risk factor analysis of these pooled subgroups revealed that history of peripheral neuropathy was an independent risk factor for persistent neuropathic pain, while older age was protective. CONCLUSION: We found a greater risk of persistent pain with open mesh than with laparoscopy that may be explained by direct or indirect lesion of nerve terminations. Strategies to identify and preserve nerve terminations with the open mesh procedure are needed.

CONTEXTE: On soupçonne que l'incidence de la douleur persistante à la suite d'une hernioplastie inguinale est plus élevée avec la mise en place d'un filet par voie ouverte qu'avec la laparoscopie (transabdominale prépéritonéale), mais encore faut-il clarifier le rôle de la neuropathie. MÉTHODES: Nous avons mesuré l'incidence cumulative de la douleur neuropathique persistante, décrite comme une douleur au site opératoire accompagnée d'éléments neuropathiques déclarés par le patient dans les 6 mois suivant la chirurgie, auprès de 2 sous-cohortes prospectives d'une étude multicentrique. Nous avons comparé la mise en place d'un filet par voie ouverte et la laparoscopie à l'aide de différentes analyses, dont une analyse avec appariement des scores de propension, les scores de propension découlant d'une analyse multivariée générée à partir d'un modèle linéaire généralisé. RÉSULTANTS: En tenant compte de tout l'échantillon de patients (242 soumis à la mise en place d'un filet par voie ouverte c. 126 soumis à la laparoscopie), le rapport des cotes brut pour la douleur neuropathique persistante après l'hernioplastie inguinale était de 4,3. Il a atteint 6,8 à l'analyse par appariement des scores de propension réalisée auprès de sous-groupes réunis de 194 patients soumis à la technique ouverte avec treillis et 125 soumis à la laparoscopie (intervalle de confiance à 95 % 1,5­30,4, p = 0,012). Une analyse des facteurs de risque pour ces sous-groupes réunis a révélé que des antécédents de neuropathie périphérique constituaient un facteur de risque indépendant à l'égard de la douleur neuropathique persistante, tandis que l'avancée en âge a conféré un effet protecteur. CONCLUSION: Nous avons observé un risque plus élevé de douleur persistante associée à la mise en place d'un filet par voie ouverte qu'avec la laparoscopie, ce qui pourrait s'expliquer par des lésions directes ou indirectes aux terminaisons nerveuses. Des stratégies s'imposent pour identifier et préserver les terminaisons nerveuses lors de la mise en place d'un filet par voie ouverte.