Publications by authors named "M Engelhart"

38 Publications

Improving aeration systems in saline water (part II): effect of different salts and diffuser type on oxygen transfer of fine-bubble aeration systems.

Water Sci Technol 2021 Jun;83(11):2778-2792

Technical University of Darmstadt, Institut IWAR, Franziska-Braun-Str. 7, 64287 Darmstadt, Germany E-mail:

The objective of the present study is to investigate the different effects on the oxygen transfer of fine-bubble aeration systems in saline water. Compared to tap water, oxygen transfer increases due to the inhibition of bubble coalescence. In Part I of the present study, we investigated in laboratory-scale experiments the effect of design of diffuser membrane. The objective of Part II is the assessment of effects of different salts, diffuser type and diffuser density. We measured the concentration of various salts (MgCl; CaCl; NaSO; NaCl; KCl) above which coalescence is fully inhibited and oxygen transfer reaches its maximum (referred to as the critical coalescence concentration; CCC). For this purpose, we developed a new analytical approach, which enables investigation of the coalescence behaviour of any aeration system and (mixed) salt solution quickly and easily by evaluating the results of oxygen transfer tests. To investigate the transferability to large scale and the effect of diffuser type and density, we repeated lab-scale experiments in a 17,100 L pilot-scale test tank and carried out additional tests with tube and plate diffusers at different diffuser densities. The results show that despite the higher pressure drop, diffusers with dense slit density and smaller slits are to be recommended in order to improve efficiency of aeration systems in saline water.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
June 2021

[Resuscitative endovascular balloon occlusion of the aorta (REBOA) : Current aspects of material, indications and limits: an overview].

Chirurg 2020 Nov;91(11):934-942

Gefäßchirurgie und endovaskuläre Chirurgie, Medizinische Fakultät, Universitätsklinikum Augsburg, Stenglinstr. 2, 86156, Augsburg, Deutschland.

Background: Resuscitative endovascular balloon occlusion of the aorta (REBOA) describes an endovascular procedure in which a blocking balloon is introduced into the aorta to reduce bleeding situated distal to the balloon and simultaneously to improve cardiac and cerebral oxygenation.

Objective: Presentation of the REBOA technique, the possible indications, the required material and possible complications of the procedure.

Material And Methods: Non-systematic review of the currently available literature.

Results: The REBOA procedure is an adjunct to achieve hemodynamic stabilization in patients with traumatic hemorrhage and ruptured aortic aneurysms. The complication rate of the procedure is approximately 5%, whereby access complications are the most common; however, fatal complications are also possible.

Conclusion: A balloon block of the aorta is well established in the treatment of ruptured aortic aneurysms. There is growing evidence that REBOA is a minimally invasive alternative to open surgical cross-clamping of the aorta by thoracotomy for the treatment of patients with polytrauma and hemorrhagic shock due to abdominal or visceral bleeding. Due to the development of new balloon catheters, which can be placed without stiff guidewires and require smaller sheath diameters, REBOA is also discussed for treatment of postoperative abdominal or gynecological bleeding or as a possible adjunct to cardiopulmonary resuscitation for nontraumatic cardiac arrest.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
November 2020

Trends in incidence, mortality, and causes of death associated with systemic sclerosis in Denmark between 1995 and 2015: a nationwide cohort study.

BMC Rheumatol 2018 7;2:36. Epub 2018 Dec 7.

5Department of Cardiology, Herlev and Gentofte Hospital, Gentofte, Kildegårdsvej 28, 2900 Hellerup, Denmark.

Background: To investigate the incidence and the mortality-rates of systemic sclerosis (SSc), its primary causes of death, and the temporal trends in events in Denmark during the last decades.

Methods: Using the Danish National Patient Registry, we identified all persons aged ≥18 years with a first-time diagnosis of SSc (ICD-10 code M34, excluding M34.2) between 1995 and 2015.

Results: A total of 2778 incident SSc cases were identified. The mean age at time of SSc diagnosis was 56 (standard deviation 15) years and 76% were women. The overall incidence rate (per 1,000,000 person-years) of diagnosed SSc was 24.4 (95% confidence interval 23.6-25.4), with a slight increase over the study period, age- and sex-adjusted incidence rate ratio 1.02 (95% confidence interval 1.01-1.02) per 1-year increase. The 1-year all-cause mortality rate per 100 person-years decreased from 6.1 (3.1-12.2) in 1995 to 5.3 (2.5-11.1) in 2015, sex- and age-adjusted hazard ratio 0.96 (95% CI 0.94-0.98) per 1-year increase. Over the period, the average age at SSc diagnosis increased and the proportion of women decreased, whereas the burden of comorbidities increased. One fifth of all deaths were attributable to cardiovascular causes, a fourth to pulmonary diseases, and 15% were due to cancer.

Conclusions: Within the last few decades, the incidence of SSc has increased and the 1-year mortality rate has decreased slightly in Denmark. Almost half of all deaths were attributable to cardiopulmonary causes.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
December 2018

Fouling mitigation in anaerobic membrane bioreactors using fluidized resin beads.

Water Sci Technol 2017 Nov;76(9-10):2445-2454

Technische Universität Darmstadt, Institute IWAR, Franziska-Braun-Str. 7, Darmstadt 64287, Germany E-mail:

This study focuses on the use of fluidized resin beads to mitigate fouling during ultrafiltration (UF) of the effluent of an anaerobic bioreactor. Two different module configurations were tested: A fluidized bed of resin beads was generated in a tubular UF membrane, and a hollow fiber (HF) UF membrane was submerged into a fluidized bed, respectively. During filtration of anaerobically treated synthetic wastewater using the tubular module, fluidized resin beads with a diameter of 0.5-0.71 mm did not show any beneficial effect. In contrast, the presence of fluidized resin beads (diameter of 0.5-0.71 and 1.00-1.25 mm) in the HF module reduced the fouling rate significantly. Furthermore, particle diameter and the bed voidage affected the cleaning efficiency of a pre-fouled membrane in the HF module. Interestingly, short-term filtration tests (<2 h) of a dextran solution showed that fluidized resin beads are able to minimize concentration polarization of a macromolecule, even in the tubular module. Therefore, it is supposed that fouling of the anaerobically treated synthetic wastewater was mainly attributed to the deposition of colloidal and particulate matter.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
November 2017

Infection Mimicking Progression of Scleroderma.

Case Rep Rheumatol 2017 27;2017:4029271. Epub 2017 Sep 27.

Center for Rheumatology and Spine Diseases, Rigshospitalet, 2100 Copenhagen, Denmark.

This case report describes a patient with scleroderma who developed infection, which for more than a year mimicked worsening of her connective tissue disorder. The patient was diagnosed with scleroderma based on puffy fingers that developed into sclerodactyly, abnormal nail fold capillaries, interstitial lung disease, Raynaud's phenomenon, esophageal dysmotility, and positivity for rheumatoid factor and anti-SSA antibodies. She developed massive inflammatory changes of the cutis, the subcutis, and the muscle fasciae of the right leg, that after several failed attempts of immunosuppressive treatments were found to be caused by . While she was receiving high-dose prednisolone, as worsening of her connective tissue disease was suspected to be the cause of the inflammatory changes, she had meningitis and was hospitalized for several weeks, but she recovered from this without sequelae. After infection was diagnosed, she was treated with clarithromycin and rifampicin. Her skin manifestations, arthralgias, and fatigue improved considerably, and the wounds of the right leg healed, unfortunately with significant scarring. Immunodeficiency testing was unremarkable. In summary, an infection with was mistaken for an unusually severe progression of scleroderma.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
September 2017