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- Cherifi-Hertel, S., et al.
(författare)
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Non-Ising and chiral ferroelectric domain walls revealed by nonlinear optical microscopy
- 2017
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The properties of ferroelectric domain walls can significantly differ from those of their parent material. Elucidating their internal structure is essential for the design of advanced devices exploiting nanoscale ferroicity and such localized functional properties. Here, we probe the internal structure of 180° ferroelectric domain walls in lead zirconate titanate (PZT) thin films and lithium tantalate bulk crystals by means of second-harmonic generation microscopy. In both systems, we detect a pronounced second-harmonic signal at the walls. Local polarimetry analysis of this signal combined with numerical modelling reveals the existence of a planar polarization within the walls, with Néel and Bloch-like configurations in PZT and lithium tantalate, respectively. Moreover, we find domain wall chirality reversal at line defects crossing lithium tantalate crystals. Our results demonstrate a clear deviation from the ideal Ising configuration that is traditionally expected in uniaxial ferroelectrics, corroborating recent theoretical predictions of a more complex, often chiral structure.
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- Derrien, M., et al.
(författare)
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Fasting breath H-2 and gut microbiota metabolic potential are associated with the response to a fermented milk product in irritable bowel syndrome
- 2019
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Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 14:4
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Aim of this study was to assess the effect of a fermented milk product containing Bifidobacterium lactis CNCM I-2494 (FMP) on gastrointestinal (GI) symptoms and exhaled H-2 and CH4 during a nutrient and lactulose challenge in patients with irritable bowel syndrome (IBS). We included 125 patients with IBS (Rome III). Fasted subjects were served a 400ml liquid test meal containing 25g lactulose. The intensity of eight GI symptoms and the amount of exhaled H-2 and CH4 were assessed before and during 4h after meal intake. The challenge was repeated after 14 days consumption of FMP or a control product in a double-blind, randomized, parallel design. The metabolic potential of fecal microbiota was profiled using 16S MiSeq analysis of samples obtained before and after the intervention. 106 patients with IBS were randomized. No difference between FMP or control groups was found on GI symptoms or breath H-2 and CH4 in the whole cohort. A post-hoc analysis in patients stratified according to their fasting H-2 levels showed that in high H-2 producers (fasting H-2 level >= 10ppm, n = 35), FMP consumption reduced fasting H-2 levels (p = 0.003) and H-2 production during the challenge (p = 0.002) and tended to decrease GI discomfort (p = 0.05) vs. control product. The Prevotella /Bacteroides metabolic potential at baseline was higher in high H-2 producers (p<0.05) vs. low H-2 producers and FMP consumption reduced this ratio (p<0.05) vs. control product. The response to a fermented milk product containing Bifidobacterium lactis CNCM I-2494 (FMP) in patients with IBS seems to be associated with the metabolic potential of the gut microbiota.
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- Le Neve, B., et al.
(författare)
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A Combined Nutrient and Lactulose Challenge Test Allows Symptom-Based Clustering of Patients With Irritable Bowel Syndrome
- 2013
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Ingår i: American Journal of Gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 0002-9270. ; 108:5, s. 786-795
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of the present pilot study was to evaluate the usefulness of a test meal containing lactulose in the non-invasive assessment of visceral sensitivity in irritable bowel syndrome (IBS), and to identify subsets of IBS patients based on gastrointestinal (GI) symptom generation. METHODS: We included 43 patients with IBS (Rome III) and 29 healthy controls. The fasted subjects were served three test meals consisting of a 400-ml liquid breakfast alone or containing lactulose (15 or 25g) in a double-blind crossover design. Seven GI symptoms, overall digestive comfort, and exhaled H2/CH4 were assessed at baseline and every 15min during 4h after meal intake. Anxiety and depression were assessed only at baseline. A mapping of the seven GI symptoms was done using a Principal Component Analysis (4h mean area under the curve, AUC). Independently, a hierarchical cluster analysis was performed on the same parameters to identify GI symptom-based IBS clusters. RESULTS: All three tests were well tolerated. The 25g lactulose challenge enabled discrimination of IBS from healthy controls according to the symptom response. This challenge also enabled clustering of IBS subjects in two subgroups based mainly on bloating, distension, and discomfort symptoms (2,457 (2,043–2,872), 2,450 (1,910–2,990), 2,602 (2,126–3,079) vs. 537 (383–691), 619 (458–780), 643 (432–854); 4h mean AUC; P<0.0001), overall digestive comfort (1807 (1318–2295) vs. 3350 (2942–3758); 4h mean AUC; P<0.0001), and anxiety at baseline (9.2 (7.0–11.5) vs. 5.5 (4.2–6.9); Hospital Anxiety and Depression scale anxiety mean scores; P=0.003). This clustering was independent of the Rome III subtype and the amount of exhaled H2/CH4. CONCLUSIONS: The lactulose challenge test seems to be a promising tool to assess visceral sensitivity in IBS, and to subgroup IBS patients based on their symptom pattern.
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- Le Nevé, B, et al.
(författare)
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Lactulose Challenge Determines Visceral Sensitivity and Severity of Symptoms in Patients With Irritable Bowel Syndrome.
- 2016
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Ingår i: Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. - : Elsevier BV. - 1542-7714 .- 1542-3565. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Patients with irritable bowel syndrome (IBS) can be assigned to groups with different gastrointestinal (GI) symptoms based on results from a combined nutrient and lactulose challenge. We aimed to identify factors that predict outcomes to this challenge and to determine whether this can be used in non-invasive assessment of visceral sensitivity in patients with IBS.
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