421 research outputs found
Impact of gadolinium-based contrast agent in the assessment of Crohn's disease activity: Is contrast agent injection necessary?
No full textPurpose: To determine whether magnetic resonance enterography (MRE) performed without intravenous contrast injection is diagnostically noninferior to conventional contrast-enhanced MRE (CE-MRE) in patients with Crohn’s disease (CD).
Materials and Methods: This was an Institutional Review Board (IRB)-approved retrospective study. Ninety-six patients (52 male and 44 female; 47.18 years 6 13.6) with a diagnosis of CD underwent MRE at 1.5T including T2-weighted single-shot turbo-spin-echo, T2-weighted spectral fat presaturation with inversion recovery (SPAIR), T1-weighted balanced fast-field-echo MR sequences, and CE-MRE consisting in T1-weighted breath-hold THRIVE 3D MRI sequences
after administration of gadobenate dimeglumine (0.2 mL/kg of body weight). Unenhanced MRE, CE-MRE, and unenhanced MRE plus CE-MRE were reviewed in separate sessions with blinding by two readers in consensus, and subsequently by two other readers independently considering a subgroup of 20 patients. Crohn’s Disease Endoscopic Index of Severity (CDEIS) and/or histologic analysis of the surgical specimen were considered as reference standards for the
assessment of inflammatory activity.
Results: Patients revealed prevalently active (n 5 55 patients) or quiescent CD (n 5 41 patients). The agreement between unenhanced MRE vs. CE-MRE in interpreting active bowel inflammation was 96% (123/128 bowel segments; one-sided 95% confidence interval [CI], >94.4%). Unenhanced MRE vs. CE-MRE vs. unenhanced MRE plus CE-MRE revealed a diagnostic accuracy of 93% [90/96] vs. 92% [88/96] vs. 97% [93/96] (P > 0.05) in the diagnosis of active CD.
Interreader agreement was very good for all variables (j value 5 0.8–0.9) except for the measurement of the length of disease (j value 5 0.45).
Conclusion: Unenhanced MRE was noninferior to CE-MRE in diagnosing active inflammation in patients with CD
Performance of Thin Film PV Mini-Modules in a Superstrate Configuration (CdTe) on Glass with Novel Fibre Laser Processing
No full textA new pulsed laser technique based on Photonic Crystal Fibres (PCF) has been developed and tested within the European funded Alpine project for the improvement, in terms of precision and speed, of the existing scribing technology in PV modules through the usage of high quality beam fiber lasers. In this work we report about the first evaluation of the quality of the scribing process performed by innovative PCF lasers according to the particular patterning steps (P1, P2 and P3) which are applied on CdTe thin film devices realized in superstrate configuration on glass. A comparison with devices prepared with standard scribing technology is presented. The P1, P2, P3 scribing patterning steps have been evaluated separately in this work and devices scribed with the novel laser technology reported clearly either improved characteristics in two cases (P1 and P2 scribing) or worsen characteristics in the case of P3 scribing. In detail devices with P1 and P2 patterning scribed with PCF laser reported an evident improvement in Pmax of slightly above 5% while devices with P3 scribed with the novel laser technology showed a Pmax value about 3% lower than the reference one
Picosecond and nanosecond pulsed laser ablation of aluminium, polypropylene, polyethylene and their thin-film combinations
No full textThe pico- and nano-second ablation thresholds and subsequent pulse-energy cut-depth and width relationships of aluminium, polypropylene (PP), polyethylene (PE) and their various thin-film combinations have been determined at 515 nm and 1064 nm. High quality incisions were obtained for all structures within certain parameter ranges. All ablation thresholds were found to be functions of the temporal pulse-width. Numerical simulations revealed the underlying mechanisms as phase explosion and thermal conduction. The presented results provide necessary parameters for the efficient cut and scribe of such materials, allowing the laser to prevail in lieu of more costly and energy intensive methods. © 2013 SPIE
Biochemical Markers and MR Imaging Findings as Predictors of Crohn Disease Activity in Patients Scanned by Contrast-enhanced MR Enterography
No full textRationale and Objectives: To define the best independent predictors for active inflammation in patients with Crohn disease (CD) examined
by contrast-enhanced magnetic resonance (MR) enterography.
Materials and Methods: Ninety-one patients (47 men and 44 women; aged 39.58 17.1 years) with a diagnosis of CD; CD activity index
(CDAI)$150 (n = 19 patients) or <150 (n = 72) underwentMR enterography including T2-weighted half-Fourier acquisition single-shot turbo
spin-echo, T2-weighted spectral fat presaturation with inversion recovery, T1-weighted balanced steady-state free precession, and
T1-weighted breath-hold resolution isotropic high volume three-dimensional MR imaging sequences before and after administration of
gadobenate dimeglumine during arterial (30 seconds), portal venous (70 seconds), and delayed phase (3 and 5 minutes from contrast injection).
Two readers analyzed the MR images in consensus. Reference standard was the Crohn’s Disease Endoscopic Index of Severity
(CDEIS) with deep mucosal biopsy or the histologic analysis of the surgical specimen in those patients (n = 30) who underwent elective
small-bowel resection. Univariate and multivariate logistic regression analyses were performed to assess CDAI, biochemical markers
(C-reactive protein and fecal calprotectin levels) and MR imaging findings as potential predictors of inflammatory CD activity.
Results: Patients revealed prevalently active (n = 47 patients) or quiescent CD with mural fibrosis (n = 44 patients). The bowel wall T2
hyperintensity (odds ratio [OR], 9.20; 95% confidence interval [CI], 2.71–31.19) and total length of disease (OR, 1.29; 95% CI,
1.11–1.49) were found as the best independent predictors of active CD. CDAI, C-reactive protein, and fecal calprotectin were not found
independent predictors of active CD.
Conclusions: The bowel wall T2 hyperintensity and the length of the involved bowel tract were predictors of active inflammation in patients
with CD examined by contrast-enhanced MR enterography
Laser processing of thin films for industrial packaging
No full textSingle layer thin-film materials such as aluminum, polyethylene, polypropylene, and their multi-layer combinations such as aluminum-paper have been exposed to different laser radiation. A wide number of samples have been processed with 10 - 12.5 ns IR and Green, and 500 - 800 ps IR laser radiation at different translating speeds ranging from 50 mm/s to 1 m/s. High quality incisions have been obtained for all tested materials within the experimental conditions. The presented results provide the necessary parameters for an efficient cut and processing of the tested materials, for the employment of pulsed laser sources in the packaging industry, allowing the laser to prevail in lieu of more costly and energy intensive methods. © 2014 SPIE
Laser scribing of CIGS based thin films solar cells
No full textLaser scribing tests on CIGS based thin films solar cells have been performed. The obtained high quality incisions show that laser scribing is a valuable tool for producing low-cost photovoltaic modules
Nanosecond and sub-nanosecond pulsed laser ablation of thin single and multi-layer packaging films
No full textTranslating single and multi-layer packaging films are exposed to 0.5-0.8 ns laser pulses of wavelength 1064 nm and 10-12.5 ns laser pulses of wavelength 515 nm. Ablation depths and threshold fluences are reported for single-layer polyethylene (PE), polypropylene (PP) and aluminium of thickness 20-50 μm. Interaction and cut widths are reported for the same single-layer films and for four multi-layer films comprising aluminium-polypropylene and aluminium-paper. Ablation of the PE and PP films is only possible in the tested parameter range with 0.5 ns, 1064 nm pulses. Though a one order of magnitude reduction in the ablation threshold of aluminium is observed with 0.5-0.8 ns, 1064 nm pulses, the efficiency of material removal for fluences >8 J cm-2 is superior with 10-12.5 ns, 515 nm pulses. Multi-layer film response is found to be heavily dictated by the thickness of metallic layers. For multi-layer films with aluminium layers of thickness 7-9 μm, adjacent layers are removed by inter-layer heat conduction from the aluminium layer, in some cases leading to very large cut widths. For multi-layer films with aluminium layers of thickness <0.1 μm, direct ablation of all layers must take place for complete film penetration. The study provides quantitative results regarding process efficiency and quality for application of pulsed laser sources within the packaging industry
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