Long-term results after fluoroscopy-guided closure of patent foramen ovale for secondary prevention of paradoxical embolism

OBJECTIVES: To carry out long-term follow-up after percutaneous closure of patent foramen ovale (PFO) in patients with cryptogenic stroke. DESIGN: Prospective cohort study. SETTING: Single tertiary care centre. PARTICIPANTS: 525 consecutive patients (mean (SD) age 51 (12) years; 56% male). INTERVENTIONS: Percutaneous PFO closure without intraprocedural echocardiography. MAIN OUTCOME MEASURES: Freedom from recurrent embolic events. RESULTS: A mean (SD) of 1.7 (1.0) clinically apparent embolic events occurred for each patient, and 186 patients (35%) had >1 event. An atrial septal aneurysm was associated with the PFO in 161 patients (31%). All patients were followed up prospectively for up to 11 years. The implantation procedure failed in two patients (0.4%). There were 13 procedural complications (2.5%) without any long-term sequelae. Contrast transoesophageal echocardiography at 6 months showed complete closure in 86% of patients, and a minimal, moderate or large residual shunt in 9%, 3% and 2%, respectively. Patients with small occluders (<30 mm; n = 429) had fewer residual shunts (small 11% vs large 27%; p<0.001). During a mean (SD) follow-up of 2.9 (2.2) years (median 2.3 years; total 1534 patient-years), six ischaemic strokes, nine transient ischaemic attacks (TIAs) and two peripheral emboli occurred. Freedom from recurrent stroke, TIA, or peripheral embolism was 98% at 1 year, 97% at 2 years and 96% at 5 and 10 years, respectively. A residual shunt (hazard ratio = 3.4; 95% CI 1.3 to 9.2) was a risk factor for recurrence. CONCLUSIONS: This study attests to the long-term safety and efficacy of percutaneous PFO closure guided by fluoroscopy only for secondary prevention of paradoxical embolism in a large cohort of consecutive patients.

Precise pose recovery of distal locking holes from single calibrated fluoroscopic image via a novel variable decomposition approach

This paper presents a novel variable decomposition approach for pose recovery of the distal locking holes using single calibrated fluoroscopic image. The problem is formulated as a model-based optimal fitting process, where the control variables are decomposed into two sets: (a) the angle between the nail axis and its projection on the imaging plane, and (b) the translation and rotation of the geometrical model of the distal locking hole around the nail axis. By using an iterative algorithm to find the optimal values of the latter set of variables for any given value of the former variable, we reduce the multiple-dimensional model-based optimal fitting problem to a one-dimensional search along a finite interval. We report the results of our in vitro experiments, which demonstrate that the accuracy of our approach is adequate for successful distal locking of intramedullary nails.

Recovery of visual field and acuity after removal of epiretinal and inner limiting membranes

BACKGROUND: Visual acuity serves as only a rough gauge of macular function. The aim therefore was to ascertain whether central an assessment of the central visual field afforded a closer insight into visual function after removal of epiretinal membranes and Infracyanine-Green- or Trypan-Blue-assisted peeling of the inner limiting membrane. Patients and methods: Fourty-three patients undergoing pars-plana vitrectomy for the removal of epimacular membranes and dye-assisted peeling of the inner limiting membrane using either Infracyanine Green (n = 29; group 1) or Trypan Blue (n = 14; group 2) were monitored prospectively for 12 months. Preoperatively, and 1, 6 and 12 months postoperatively, distance and reading visual acuities were evaluated; the central visual field was assessed by automated static perimetry. RESULTS: Twelve months after surgery, distance and reading visual acuities had improved in both groups, but to a significant degree only in Trypan-Blue-treated eyes. The difference between the two groups was not significant. Likewise at this juncture, the mean size of the visual-field defect remained unchanged in Trypan-Blue-treated eyes (preoperative: 4.3 (SD 2.1) dB; 12 months: 4.0 (2.1) dB (p = 0.15)), but had increased in Infracyanine-Green-treated ones (from 5.3 (3.7) dB to 8.0 (5.2) dB (p = 0.027)). CONCLUSION: Unlike visual acuity, the central visual field had deteriorated in Infracyanine-Green-treated eyes but not in Trypan-Blue-treated eyes 12 months after surgery. Hence, as a predictor of functional outcome, testing of the central visual field may be a more sensitive gauge than visual acuity. Furthermore, Infracyanine Green may have a chronic and potentially clinically relevant effect on the macula which is not reflected in the visual acuity.

The Recovery of Copper in Sulphide Ores by Roasting, Leaching, and Electrolysis

Sulphide ores of copper are insoluble in dilute sulphuric acid leaching solutions, but a very high extraction can be obtained if the copper ore is in the oxidized condition. The problem is to convert the sulphide into the oxide form. This can be done by giving the sulphide ore an oxidizing-sulphatizing roast. Copper sulphate is soluble in water, so acid will be saved in the leaching process if copper sulphate is present. The iron in the copper sulphide ores is present as pyrite, or in combinations as bornite, or chalcopyrite.

Ammoniacal Sulphate Leach of Ananconda Zinc Calcine Recovery of the Zinc by Electrolysis.

Zinc is produced from ores by two general methods, distillation and electrolysis. The general principles involved in the electrolytic zinc process of today were known as far back as 1880. Difficulties encountered in purifying the solution for electrolysis and lack of suitable mechanical apparatus were the main reasons that such a long time elapsed before the process was used to produce zinc in commercial quantities.

Roasting and Leaching Bulk Copper-Zinc Sulfide Concentrates with the Subsequent Recovery of the Metals by Electrolysis

The aim of this research was to investigate the possibilities of roasting and leaching a bulk copper-zinc sulfide concentrate, and the subsequent separation of the metals from the leach solution by electro­lytic deposition.

Electrolytic Recovery of Copper and Zinc from Brass

The purpose of this research was to continue the work of Thomas Parker, who worked on the recovery of copper and zinc from brass during the school year l934 - 1935. Since there is such a wide variety of brasses made with usually a third alloying constituent, remelt­ed scrap is suitable only for castings of wide tolerance in specifications.

Alkali Leaching of Antimony Sulphide and Electrolytic Recovery of Antimony from the Resulting Leach Solution

It is the purpose of this investigation to obtain some insight into optimum conditions for leaching Stib­nite with sodium hydroxide solution and also to steady the factors affecting the electrolysis of the resulting solution.

Secondary Enrichment of Copper at the Madison Gold Skarn Deposit, Silver Star District, Montana

Secondary Enrichment of Copper at the Madison Gold Skarn Deposit, Silver Star District, Montana. This paper focuses on the chemical reactions responsible for secondary enrichment of copper...we argue that most of the secondary Cu enrichment occurred during a late hydrothermal event that replaced the high temperature skarn mineral assemblage with hematitic jasperoid. Evidence favoring this "hypogene" Cu enrichment hypothesis is presented.

Electrolytic Recovery of Copper and Zinc from Brass.

The reclamation of metals from scrap is becoming increasingly important in the metallurgical industry. Copper, because it does not corrode readily and is electronegative to most common metals, is peculiarly adapted to reclamation.

The Electrolytic Recovery of Copper and Zinc from Scrap Brass with Special Reference to Lead-Bearing Brass.

Several methods have been investigated, with some success, for treating scrap brass to recover copper and zinc, either as pure metals or as salts of the metals. One of the more promising of these methods is electrolysis in sulfate solution for the recovery of pure copper and zinc.