Multi-phase flow in fractured rocks plays an important role in any hydrocarbon recovery process, be it for environmental remediation or natural oil and gas extraction. Fractures may form the primary ...production conduits, and the mass transport at the fracture interfaces with the matrix determines the effectiveness of extraction processes. This paper presents specific evidence for a relationship between fracture apertures and the porosity of the adjoining perpendicular layers in Berea sandstone samples. Measurements of fracture apertures were done with high-resolution Micro-Computed Tomography (MCT) with a voxel resolution of about 0.05 mm in three dimensions. Multi-phase fluid flow experiments were done using a medical CT scanner with a voxel resolution of about 1.00
×
0.25
×
0.25 mm. MCT evidence shows a correlation between aperture and the porosity of the intersected layers. The comparison was made by generating two-dimensional maps of matrix porosity and CT values adjacent to the fracture and of the corresponding fracture apertures. High-porosity layers are lined up with large fracture apertures. Multi-phase fluid experiments provided hydraulic evidence that the high-porosity layers have high permeability. Oil injection into a water-saturated sample was tracked by a sequence of transverse scans near the downstream tip of a fracture. The hydraulic evidence from the two-phase flow experiments also confirms high permeability in fracture strips adjacent to high-porosity and high-permeability layers. The reasons for the relationship between fracture aperture and the properties of the adjacent layers are not fully understood. Some explanation for the physical and hydraulic observations rests in the method of fracturing, fracture propagation, and the lithological characteristics of the rock.
Abstract Background Examining the current practice is important for the benchmarking of quality of colonoscopy and the comparison with the standards and recommendations expected by professional ...societies. Aim To describe colonoscopy practice in Italy, on the basis of prospective analysis of a large number of examinations performed by operators with different levels of expertise in a wide range of unselected centres. Design and setting Cross-sectional, prospective and multicentre study. Methods The main features of each endoscopy centre (structure indicators) were collected through the use of a standardised questionnaire. A second questionnaire was used to prospectively record details of all the consecutive colonoscopies performed in a 2-week study period. Results Data from 278 centres and 12,835 consecutive colonoscopies were evaluated. Centres were uniformly distributed throughout Italy – north, centre and south – as was their organizational complexity and workload. Overall, adequate facilities (i.e. cleaning area for disinfection/reprocessing, equipped recovery room), and safety equipment (i.e. pulse oximetry, equipment for emergency cardiopulmonary resuscitation) were lacking in a considerable amount of centres, especially in those with a lower degree of organizational complexity. Written informed consent was routinely required in 87% of the centres, but a specific consent for colonoscopy, including detailed information on adverse events, was adopted by 66%. Regular programs for recording some quality indicators (i.e. cecal intubation, quality of bowel cleansing, patients’ satisfaction and complications) were implemented in a minority of centres. About 93% of the colonoscopies were performed for diagnostic purpose; screening and surveillance accounted for 13.7% and 25.3% of the indications, respectively. Sedation and/or analgesia was administered in about half of the patients. Overall, colonoscopies were completed to the cecum in 80.7% of cases, and only 22.1% of the centres reported a cecal intubation rate ≥90%; this figure was reported in 33.1% of centres with high-organizational complexity and in 14.4% of outpatient units. The overall incidence of immediate complications was low (2 perforations, 26 bleedings and 32 serious cardiorespiratory complications). Conclusions This study documented a wide variation in colonoscopy practice between centres and highlighted problem areas where interventions are needed to improve performance and safety of the examinations.
Background
Many benign biliary diseases (BBD) can be treated with fully covered, self-expandable metal stents (FCSEMS) but stent migration occurs in up to 35.7 %. The aim of this study was to ...prospectively assess the rate of, safety and effectiveness and stent migration of a new biliary FCSEMS with an anti-migration flap (FCSEMS-AF) in patients with BBD.
Patients and Methods
This was a prospective study from four Italian referral endoscopy centers of 32 consecutive patients (10 females and 22 males; mean age: 60.1 ± 14.8 years; range: 32–84 years) with BBD who were offered endoscopic placement of a FCSEMS-AF as first-line therapy.
Results
Were 24 strictures and 8 leaks. Stent placement was technically successful in 32/32 patients (100 %). Immediate clinical improvement was seen in all 32 patients (100 %). One late stent migration occurred (3.3 %). FCSEMS-AF were removed from 30 of the 32 patients (93.7 %) at a mean (±SD) of 124.4 ± 84.2 days (range: 10–386 days) after placement. All patients remained clinically and biochemically well at 1- and 3-month follow-up. One patient (3.3 %) with a post-laparoscopic cholecystectomy stricture developed distal stent migration at 125 days.
Conclusion
This new FCSEMS with anti-migration flap seems to be a safe and effective first-line treatment option for patients with BBD.
Continuous quality improvement (CQI) is recommended by professional societies as part of every colonoscopy program, but little is known with regard to its effectiveness for colonoscopy outcomes. We ...prospectively assessed whether the implementation of a CQI program in routine clinical practice influences the quality performance of colonoscopy.
In an open-access endoscopy unit at a secondary care center in Northern Italy, 6-monthly audit cycles were carried out over a 4-year period, to identify reasons for poor colonoscopy outcomes and institute appropriate changes to improve performance. The colonoscopy completion rate and the polyp detection rate as detected by endoscopists were considered to be key measures for improvement.
The initial crude colonoscopy completion rate was 84.6%, with a range for individual endoscopists 80.4%-94%. Four endoscopists had a completion rate lower than 90%. The overall polyp detection rate was 34%, with a wide variation among endoscopists (range 14%-42%). Poor patient tolerance and differences in colonoscopist expertise were the main determinants of lack of completion and variation in polyp detection rate. Changes to sedation practice, greater access to endoscopy sessions for the endoscopists with the lowest performance rates, and other organizational arrangements, were implemented to improve quality performance. The crude completion rates improved consistently, up to 93.1%, over the study period. This trend was confirmed even when adjusted completion rates were calculated. All endoscopists reached a crude completion rate of 90% or more and a polyp detection rate of over 20%. The introduction of CQI did not significantly change the overall incidence of procedure-related complications.
The effectiveness of colonoscopy can be improved by implementing a CQI program in routine colonoscopy practice.
Two new species of Tydeidae are described, Brachytydeus lorenzatus sp. nov. and Quasitydeus feresi sp. nov. Brachytydeus lorenzatus sp. nov. differs from B. aegyptiaca (Rasmy ampamp; El Bagoury, ...1979) by having a reticulated area on the region of f1 and f2 , dorsal setae smooth, solenidion (I shorter than or equal to the width of tarsus I, most setae on dorsal shield shorter than the length between their bases and setae d forked distally. The new species is distinguished from B. scutatus Silva, Rocha ampamp; Ferla, 2013 by having a slightly reticulate area on the aspidosoma, near setae bo , all dorsal setae slender and club-shaped. Quasitydeus feresi sp. nov. differs from the only other species of the genus, Q. ricensis (Baker, 1970), by having all dorsal setae simple and serrated, similar in shape. Eleven tydeoid species are reported also from several plants native to the state of Rio Grande do Sul, Brazil. This is the second species of Brachytydeus Thor, 1931 described from and the second species described for Quasitydeus Kaamp#378;mierski, 1996.
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