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For the determination of the safety characteristics of dusts it is necessary to disperse the dust in the oxidating atmosphere (usually air). In the standard procedures for dusts this is realized by a partially evacuated explosion vessel (20L-sphere) in which the dust gets injected from a dust chamber pressurized with air. Shortly after that injection (60 ms) the dust cloud gets ignited under turbulent conditions, that are otherwise seen as almost ambient with 20 ◦C and about 1 bar (abs). While there has been a lot of research about the influence of the ignition delay time and the level of turbulence in the recent years little attention was paid to the pre–ignition pressure rise and the allowed variations in the standards. In the following work we showed that the allowed ranges for the pressures in the different dust standards influence the safety characteristics of dust alone severely. Even though hybrid mixtures are an emerging risk problem in an interconnected industry there is no standard for the determination of their safety characteristics. In this work it is shown that especially for the preparation of hybrid mixtures of flammable dust and gas the pressures after injection of the dust and the mixing procedure have a large influence on the composition of the tested mixtures and therefore on the safety characteristics. Considering both effects, wrong concentration of gas and wrong initial pressure, the discrepancy of safety characteristics from different facilities will be too big to applicable. The methods to overcome these weaknesses are also presented.

Inacceptable capability and durability of joint sealing systems but also inadequate traffic performance (noise emission; overrolling comfort) up to traffic safety aspects reflect the still enormous demand for data-based description of concrete pavements performance under heavy loading conditions. Especially the deformation behavior of concrete pavement slabs in the joint region in consideration of new pavement construction types and improved concrete mixtures meanwhile established but also under the steeply rising traffic loads is not sufficiently explored. To create a data basis for advanced design rules, evaluation methods and product standards - and with it to improve quality, durability and finally sustainability of pavements - an innovative 3-D sensor system SENSO JOINT adapted to german roadworking requirements and suitable for heavy-duty operating conditions was developed. The contribution introduced describes the development of an extensive technical solution based on the analysis of decisive loads, interactions and boundary conditions. Based on calibration data, results of laboratory testing and finally field-testing on different concrete pavement construction types the outcome of a multi-level evaluation process shall introduce the potential of the new sensor system.

For the determination of safety characteristics of gases, vapors and dusts different types of ignition sources are used in international standards and guidelines. The paper presents test results of a comparative calorimetric and visual study between four different types of ignition sources. The ignition procedures were analyzed visually with a high-speed camera and electric recordings. In addition to that, the influence of the electrode-orientation, -distance as well as ignition energy on the reproducibility of the exploding wire igniter was tested. The exploding wire is already in use for standardized determination of safety characteristics of gases, first tests on the suitability of the exploding wire igniter for dust testing have been carried out but are not standardized yet. Using the exploding wire, the ignition energy can be varied from 2 J to 10 000 J (2 x 5000 J) and thus it could be used for gases, vapors, dusts and hybrid mixtures. Moreover it can be used at high initial pressures and it is the only ignition source with an easily measurable ignition energy release. Furthermore, it does not introduce another chemical reaction into the system. Finally, a proposal for a standard ignition source for explosion tests on hybrid mixtures is derived from the test results.

Aims Left ventricular (LV) endocardial pacing may address the limitations in the selection of an LV pacing site and provide improvements in cardiac resynchronization therapy (CRT) effectiveness. We report on the feasibility, the safety, and the short-term outcome of a leadless ultrasound-based technology for LV endocardial resynchronization in heart failure (HF) patients enroled into the Wireless Stimulation Endocardially for CRT (WiSE-CRT) study. Methods and results Seventeen HF patients were enroled and categorized as: (i) patients in whom attempted coronary sinus lead implantation for CRT had failed ( n = 7); (ii) patients with a previously implanted CRT device, not responding to CRT ( n = 2); and (iii) patients with previously implanted pacemakers or implantable cardioverter-defibrillator and meeting the standard indications for CRT ( n = 8). System implantation was achieved in 13 patients (76.5%); mean R-wave amplitude was 5.6 ± 3.2 mV and the mean pacing threshold was 1.6 ± 1.0 V, respectively. In one patient, no sufficient pacing thresholds were found; in three patients pericardial effusion occurred. Biventricular pacing was recorded in 83% and 92% of the patients at 1 month and 6 months, respectively. QRS duration was shorter during biventricular pacing compared with right ventricular pacing at 1 month (−41 ms; P = 0.0002) and 6 months (−42 ms; P = 0.0011), respectively. At the 6-month follow-up, two-thirds of the patients had at least one functional class change. Left ventricular ejection fraction significantly increased ( P < 0.01) by 6 points at the 6-month follow-up. Conclusion The feasibility of providing an endocardial stimulation for CRT with a leadless technology was successfully demonstrated. Despite the promising results for a novel technology, further study is required to definitively conclude the safety and the performance of the system. Clinical Trial Registration Information NCT01294527.

Catheter ablation is used extensively with curative intention in atrial fibrillation. Radiofrequency ablation has long been a standard of care, while cryoballoon technology has emerged as a feasible approach with promising results. Prospective multicenter registry data referring to both ablation technologies in AF ablation therapy are lacking.Between January 2007 and August 2011, a total of 3,775 consecutive patients with symptomatic paroxysmal AF who underwent PV ablation in their respective centers were enrolled. The cohort was divided into 2 groups according to the ablation energy source used: cryoballoon ablation (group 1, n = 905 [24.0%], median age 63 years, 64.3% men) and RF ablation (group 2, n = 2870 [76.0%], median age 63 years, 62.7% men). Comorbidities and baseline clinical characteristics were similar in both groups.Acute success rate was similar in both groups (97.5% in cryo vs 97.6% in RF; P = 0.81). Procedure times were similar, ablation and fluoroscopy times were higher in cryoballoon when compared to RF ablation. Overall complication rate was similar in cryo- (4.6%) and RF-ablation (4.6%; P = 1.0). Phrenic nerve palsy was more often in cryo versus RF ablation (2.1% in cryo vs 0.0% in RF; P0.001). Other complications were more common in RF compared to cryoablation (4.6% in RF vs 2.7% in cryo; P0.05).RF ablation is the most widespread ablation method in Germany, but use of cryoballoon increased significantly. Procedure times were similar, but ablation and fluoroscopy times were longer in cryoballoon ablation. No significant differences were found in terms of acute success and overall complication rate.

The surgical treatment of atrial fibrillation (AF) by Cox and other ablation methods shows a 50-90% conversion rate to sinus rhythm. However, to date no study has addressed the influence of ablation on the mortality rate.The perioperative and postoperative mortalities of 210 consecutive patients with permanent AF was investigated for up to two years after cardiac surgery with (n = 111) or without (n = 99) endocardial microwave ablation within the framework of a prospective register study. All patients were followed up.In the ablation group, one patient (0.9%) died perioperatively, seven died during the first year of follow up (6.3%), and nine in the second year of follow up (8.1%). In the control group, five patients died perioperatively (5.1%), 12 died in the first year of follow up (12.1%), and 22 in the second year of follow up (22.2%). During the two-year follow up period, significantly more patients died in the control group than in the ablation group (Log-Rank test: p = 0.0051).The results of this register study showed that among patients with permanent AF who underwent cardiac surgery with ablation, mortality was significantly lower than in those who underwent comparable surgery but without ablation. The marked difference in mortality was essentially based on the typical clinical consequences of AF (e.g. thromboembolic complications, cardiac arrhythmias and bleeding complications due to anticoagulation therapy), which occurred less often in the ablation group.