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  1. Li NYD, Moore DJ, Thompson MA, Welfare E, Rappolt M
    Chem Phys Lipids, 2021 Dec 28;243:105165.
    PMID: 34971600 DOI: 10.1016/j.chemphyslip.2021.105165
    Humectants are used widely in topical formulations as they provide cosmetic and health benefits to skin. Of particular interest to our laboratories is the interaction of humectants in phospholipid based topical skin care formulations. This study probed the effects of three exemplary humectants on a fully hydrated lecithin system (DPPC) by use of X-ray scattering and differential scanning calorimetry. While the three humectants affected the nanostructure of 1, 2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC, bilayers in a similar manner, leading to an increased membrane order, differences in the effect on the thermal behaviour of DPPC suggest that betaine and sarcosine interacted via a different mechanism compared to acetic monoethanolamide, AMEA. At concentrations above 0.4 M, betaine and sarcosine stabilised the gel phase by depletion of the interfacial water via the preferential exclusion mechanism. At the same time, a slight increase in the rigidity of the membrane was observed with an increase in the membrane thickness. Overall, the addition of betaine or sarcosine resulted in an increase in the pre- and main transition temperatures of DPPC. AMEA, on the other hand, decreases both transition temperatures, and although the interlamellar water layer was also decreased, there was evidence from the altered lipid chain packing, that AMEA molecules are present also at the bilayer interface, at least at high concentrations. Above the melting point in the fluid lamellar phase, none of the humectants induced significant structural changes, neither concerning the bilayer stacking order nor its overall membrane fluidity. An humectant-induced increase in the Hamaker constant is the most plausible explanation for the observed reduction of the inter-bilayer distances, both in the gel and fluid phase.
  2. Klionsky DJ, Abdelmohsen K, Abe A, Abedin MJ, Abeliovich H, Acevedo Arozena A, et al.
    Autophagy, 2016;12(1):1-222.
    PMID: 26799652 DOI: 10.1080/15548627.2015.1100356
  3. Lee WS, Davidson GP, Moore DJ, Butler RN
    J Paediatr Child Health, 2000 Aug;36(4):340-2.
    PMID: 10940167
    OBJECTIVE: To assess the validity and clinical application of a hand-held breath hydrogen (H2) analyzer (BreatH2, Europa Scientific, Crewe, UK).

    METHODOLOGY: Breath samples of patients referred to the Gastroenterology Unit, Women's and Children's Hospital, North Adelaide, South Australia, for confirmation of the diagnosis of carbohydrate malabsorption were analysed with the Quintron microlyzer (Quintron Instrument Co., Milwaukee, USA) and the BreatH2 analyser, using the Quintron microlyzer as the gold standard.

    RESULTS: Twenty-nine breath H2 tests (BHT) were performed in 29 patients aged 2 months to 61 years. The sensitivity and specificity of the BreatH2 analyser in detecting a positive BHT using the Quintron microlyser as the gold standard were 0.90 and 0.95 with positive and negative predictive values of 0.90 and 0.95, respectively. There was one false positive and one false negative reading. Bland-Altman plots showed a high degree of agreement between the values obtained with two different methods.

    CONCLUSIONS: The diagnosis of carbohydrate malabsorption, using a portable breath H2 analyser (BreatH2), achieved an acceptable degree of sensitivity and specificity, enabling it to be used where no alternative is available.

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