75 research outputs found
Absorption profile modulation by means of 1D digital plasmonic gratings
No full textOptical simulations of 1D digital plasmonic gratings on a Silicon substrate are performed by means of the Finite Elements Method and a modal analysis. The different mechanisms of transmission of the light are elucidated. The absorption profile in Silicon can be modulated and controlled changing the geometry. Configuration maps allow to determine the different optical regimes. Surface Plasmon Polaritons and cavity-mode resonances are shown to be effectively exploitable to enhance NIR-light absorption in different shallower regions of the underlying Silicon
Functional heartburn has more in common with functional dyspepsia than with non-erosive reflux disease
No full textINTRODUCTION: Functional dyspepsia and non-erosive reflux disease (NERD) are prevalent gastrointestinal conditions with accumulating evidence regarding an overlap between the two. Still, patients with NERD represent a very heterogeneous group and limited data on dyspeptic symptoms in various subgroups of NERD are available. AIM: To evaluate the prevalence of dyspeptic symptoms in patients with NERD subclassified by using 24 h impedance-pH monitoring (MII-pH). METHODS: Patients with typical reflux symptoms and normal endoscopy underwent impedance-pH monitoring off proton pump inhibitor treatment. Oesophageal acid exposure time (AET), type of acid and non-acid reflux episodes, and symptom association probability (SAP) were calculated. A validated dyspepsia questionnaire was used to quantify dyspeptic symptoms prior to reflux monitoring. RESULTS: Of 200 patients with NERD (105 female; median age, 48 years), 81 (41%) had an abnormal oesophageal AET (NERD pH-POS), 65 (32%) had normal oesophageal AET and positive SAP for acid and/or non-acid reflux (hypersensitive oesophagus), and 54 (27%) had normal oesophageal AET and negative SAP (functional heartburn). Patients with functional heartburn had more frequent (p<0.01) postprandial fullness, bloating, early satiety and nausea compared to patients with NERD pH-POS and hypersensitive oesophagus. CONCLUSION: The increased prevalence of dyspeptic symptoms in patients with functional heartburn reinforces the concept that functional gastrointestinal disorders extend beyond the boundaries suggested by the anatomical location of symptoms. This should be regarded as a further argument to test patients with symptoms of gastro-oesophageal reflux disease in order to separate patients with functional heartburn from patients with NERD in whom symptoms are associated with gastro-oesophageal reflux
Light absorption enhancement in heterostructure organic solar cells through the integration of 1-D plasmonic gratings
No full textThe integration of a plasmonic lamellar grating in a heterostructure organic solar cell as a light trapping mechanism is investigated with numerical Finite Elements simulations. A global optimization of all the geometric parameters has been performed. The obtained wide-band enhancement in optical absorption is correlated with both the propagating and the localized plasmonic modes of the structure, which have been identified and characterized in detail
Characteristics of reflux episodes and symptom association in patients with erosive esophagitis and nonerosive reflux disease: study using combined impedance-pH off therapy
No full textOBJECTIVES: We sought to compare reflux and symptom association patterns in patients with nonerosive reflux disease (NERD), erosive esophagitis (EE), and in healthy volunteers (HVs).
METHODS: Patients with EE and NERD underwent combined impedance-pH monitoring. Normal values were defined on the basis of previously collected data from 48 HVs. We evaluated distal esophageal acid exposure time (AET), number and type of reflux episodes (acid, nonacid), acid and bolus clearance times, proximal extension of reflux episodes, and symptom association probability (SAP).
RESULTS: Distal AET (percentage time, pH<4) was higher (P<0.01) in 58 EE patients (median 7.4%, 25-75th percentile 4.2-9.9%) compared with 168 NERD patients (4.2% (1.2-6.4%)) and 48 HVs (0.7% (0.2-1.4%)). Patients with EE and NERD had a higher (P<0.01) number of acid reflux episodes compared with HVs (51 (37-66) vs. 34 (22-51) vs. 17 (8-31); P<0.05), but a similar number of nonacid reflux episodes (22 (15-39) vs. 23 (15-38) vs. 18 (14-26); P=NS). The percentage of reflux episodes reaching the proximal esophagus was higher (P<0.01) in EE patients (57% (45-73%)) than in NERD patients (45% (36-60%)) and HVs (33% (19-46%)). A positive SAP for heartburn or regurgitation was found in 161 of 168 (96%) NERD and 54 of 58 (93%) EE patients (P=NS).
CONCLUSIONS: Acid reflux episodes, volume, and acid clearance are important factors in the pathogenesis of reflux-induced lesions. Nonacid reflux contributes less to esophageal mucosa damage, but is involved in the development of reflux symptoms in both NERD and EE patients
Symptom association probability for acid and non-Acid reflux in patients with erosive esophagitis (EE) and non-Erosive reflux disease (NERD).
No full textEfficacia di Programmi Ipermediali Intelligenti per l’Apprendimento in Rete della Logica nella Scuola Elementare
No full textPeg-Interferon Alpha-2a and low-dose ribavirin for treatment of hepatitis C virus infection in patients with sickle cell anemia in Saudi Arabia.
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