Endothelial and Hemodynamic Function in a Large Animal Model in Relation to Different Extracorporeal Membrane Oxygenation Cannulation Strategies and Intra-Aortic Balloon Pumping

BACKGROUND

The use of simultaneous veno-arterial extracorporeal membrane oxygenation (ECMO) with or without an Intra-Aortic Balloon Pump (IABP) is a widely used tool for mechanical hemodynamic support. Endothelial function, especially in relation to different cannulation techniques, is rarely investigated in the setting of extracorporeal life support (ECLS). In this study, we analyzed endothelial function in relation to hemodynamic and laboratory parameters for central and peripheral ECMO, with or without concomitant IABP support in a large animal model to gain a better understanding of the underlying basic mechanisms.

METHODS

In this large animal model, healthy female pigs with preserved ejection fraction were divided into the following groups related to cannulation strategy for ECMO and simultaneous IBAP support: control (no ECMO, no IABP), peripheral ECMO (pECMO), central ECMO (cECMO), pECMO and IABP or cECMO and IABP. During the experimental setting, the blood flow in the ascending aorta, left coronary artery and arteria carotis was measured. Afterwards, endothelial function was investigated after harvesting the right coronary artery, arteria carotis and renal artery. In addition, laboratory markers, such as creatine kinase (CK), creatine kinase muscle-brain (CK-MB), troponin, creatinine and endothelin were analyzed.

RESULTS

The blood flow in the ascending aorta and the left coronary artery was significantly lower in all discussed experimental settings compared to the control group. Of note, the cECMO cannulation strategy generated favorable hemodynamic circumstances with higher blood flow in the coronary arteries than pECMO regardless of flow circumstances in the ascending aorta. The concomitant usage of IABP did not result in an improvement of the coronary blood flow, but partially showed a negative impact on the endothelial function of coronary arteries in comparison to the control. These findings correlate to higher CK/CK-MB levels in the setting of cECMO + IABP and pECMO + IABP.

CONCLUSIONS

The usage of mechanical circulatory support with concomitant ECMO and IABP in a large animal model might have an influence on the endothelial function of coronary arteries while not improving the coronary artery perfusion in healthy hearts with preserved ejection.

Investigation of the Damage Phenomenology with Dependence on the Macroporosity and Microporosity of Porous Freeze Foams

Freeze Foams are cellular, ceramic structures with hierarchical pore structures that are manufactured using the direct foaming process. By tailoring their morphology and strength, these foam structures are able to cover a wide range of application. Earlier works identified that pore-forming influencing factors (water and air content, suspension temperature, as well as pressure reduction rate) dictate the constitution on a macroscopic and microscopic scale. Therefore, the ability to manufacture foams whose properties align with the component requirements would be an important step in advancing towards a widespread application of these promising materials. With this goal in mind, the correlation between the pore-forming influencing factors and the resulting mechanical properties was quantified. Foams with independently adjustable porosities were produced at the micro and macro scales and evaluated according to their material failure behavior under compressive loads. As a result, foams with determined macroporosities between 38 and 62%, microporosities between 25 and 42%, and compression strengths between 1 and 7 MPa with different material failure characteristics were manufactured and systematically investigated.

Tailoring of Hierarchical Porous Freeze Foam Structures

Freeze foaming is a method to manufacture cellular ceramic scaffolds with a hierarchical porous structure. These so-called freeze foams are predestined for the use as bone replacement material because of their internal bone-like structure and biocompatibility. On the one hand, they consist of macrostructural foam cells which are formed by the expansion of gas inside the starting suspension. On the other hand, a porous microstructure inside the foam struts is formed during freezing and subsequent freeze drying of the foamed suspension. The aim of this work is to investigate for the first time the formation of macrostructure and microstructure separately depending on the composition of the suspension and the pressure reduction rate, by means of appropriate characterization methods for the different pore size ranges. Moreover, the foaming behavior itself was characterized by in-situ radiographical and computed tomography (CT) evaluation. As a result, it could be shown that it is possible to tune the macro- and microstructure separately with porosities of 49–74% related to the foam cells and 10–37% inside the struts.

Threshold-dependent iodine imaging and spectral separation in a whole-body photon-counting CT system

OBJECTIVE

To evaluate the dual-energy (DE) performance and spectral separation with respect to iodine imaging in a photon-counting CT (PCCT) and compare it to dual-source CT (DSCT) DE imaging.

METHODS

A semi-anthropomorphic phantom extendable with fat rings equipped with iodine vials is measured in an experimental PCCT. The system comprises a PC detector with two energy bins (20 keV, T) and (T, eU) with threshold T and tube voltage U. Measurements using the PCCT are performed at all available tube voltages (80 to 140 kV) and threshold settings (50-90 keV). Further measurements are performed using a conventional energy-integrating DSCT. Spectral separation is quantified as the relative contrast media ratio R between the energy bins and low/high images. Image noise and dose-normalized contrast-to-noise ratio (CNRD) are evaluated in resulting iodine images. All results are validated in a post-mortem angiography study.

RESULTS

R of the PC detector varies between 1.2 and 2.6 and increases with higher thresholds and higher tube voltage. Reference R of the EI DSCT is found as 2.20 on average overall phantoms. Maximum CNRD in iodine images is found for T = 60/65/70/70 keV for 80/100/120/140 kV. The highest CNRD of the PCCT is obtained using 140 kV and is decreasing with decreasing tube voltage. All results could be confirmed in the post-mortem angiography study.

CONCLUSION

Intrinsically acquired DE data are able to provide iodine images similar to conventional DSCT. However, PCCT thresholds should be chosen with respect to tube voltage to maximize image quality in retrospectively derived image sets.

KEY POINTS

• Photon-counting CT allows for the computation of iodine images with similar quality compared to conventional dual-source dual-energy CT. • Thresholds should be chosen as a function of the tube voltage to maximize iodine contrast-to-noise ratio in derived image sets. • Image quality of retrospectively computed image sets can be maximized using optimized threshold settings.

First-principles comparative study of perfect and defective CsPbX3 (X = Br, I) crystals

This paper presents first principles Density Functional Theory hybrid functional calculations of the atomic and electronic structure of perfect CsPbI₃, CsPbBr₃ and CsPbCl₃ crystals, as well as defective CsPbI₃ and CsPbBr₃ crystals.

Levosimendan Reduces Mortality and Low Cardiac Output Syndrome in Cardiac Surgery

BACKGROUND

There has been conflicting evidence concerning the effect of levosimendan on clinical outcomes in patients undergoing cardiac surgery. Therefore, we performed a systematic review and conducted this meta-analysis to provide evidence for/against the administration of levosimendan in cardiac surgery patients.

METHODS

We performed a meta-analysis from literature search in PubMed, EMBASE, and Cochrane Library. Only randomized controlled trials comparing the administration of levosimendan in cardiac surgery patients with a control group (other inotrope, standard therapy/placebo, or an intra-aortic balloon pump) were included. In addition, at least one clinical outcome had to be mentioned: mortality, myocardial infarction, low cardiac output syndrome (LCOS), acute kidney injury, renal replacement therapy, atrial fibrillation, prolonged inotropic support, length of intensive care unit, and hospital stay. The pooled treatment effects (odds ratio [OR], 95% confidence intervals [CI]) were assessed using a fixed or random effects model.

RESULTS

The literature search retrieved 27 randomized, controlled trials involving a total of 3,198 patients. Levosimendan led to a significant reduction in mortality (OR: 0.67; 95% CI: 0.49-0.91; p = 0.0087). Furthermore, the incidence of LCOS (OR: 0.56, 95% CI: 0.42-0.75; p < 0.0001), acute kidney injury (OR: 0.63; 95% CI: 0.46-0.86; p = 0.0039), and renal replacement therapy (OR: 0.70; 95% CI: 0.50-0.98; p = 0.0332) was significantly decreased in the levosimendan group.

CONCLUSION

Our meta-analysis suggests beneficial effects for the prophylactic use of levosimendan in patients with severely impaired left ventricular function undergoing cardiac surgery. The administration of levosimendan was associated with a reduced mortality, less LCOS, and restored adequate organ perfusion reflected in less acute kidney injury.

Characteristics and outcomes of patients with right-sided endocarditis undergoing cardiac surgery

Background

There has been an increasing incidence of right-sided infective endocarditis (RSIE) due to the global rise of intravenous drug use (IVDU) and an increasing number of implantable cardiac electronic devices and central venous catheters. Our aim was to investigate differences in the clinical presentation, microbiological findings and prognosis of patients undergoing surgery for RSIE compared to left-sided infective endocarditis (LSIE).

Methods

Relevant clinical data of all 432 consecutive patients undergoing valve surgery for infective endocarditis (IE) at our institution between January 2009 and December 2018 were retrospectively analyzed. Acquired data included patients' demographic and preoperative comorbidities, manifestation of IE according to the recently modified Duke Criteria, perioperative data and relevant clinical outcomes.

Results

A total of 403 patients (93.3%) underwent surgery for LSIE and twenty-nine patients (6.7%) for RSIE. Eleven patients with RSIE (37.9%) showed a concomitant left-sided infection. Compared to LSIE, RSIE patients were significantly younger [47.5 (40.4-69.3) vs. 65.1 (53.7-74.6); P=0.008] and presented with less comorbidities such as hypertension (41.4% vs. 65.3%; P=0.010) and coronary artery disease (6.9% vs. 29.0%; P=0.010). Rates of IVDU (34.5% vs. 4.5%; P<0.001), human immunodeficiency virus (HIV) (10.3% vs. 1.7%; P=0.023) and hepatitis C virus (HCV) infection (24.1% vs. 5.2%; P=0.001) were greater in RSIE. The proportion of Staphylococcus aureus IE was significantly higher in RSIE compared to LSIE (37.9% vs. 21.1%; P=0.035). 30-day mortality was 6.9% after surgery for RSIE compared to 14.6% after operation for LSIE (P=0.372).

Conclusions

Patients undergoing surgery for RSIE compared to LSIE presented with a higher rate of pulmonary septic emboli, more Staphylococcus aureus infections and larger vegetations. Larger multicenter prospective trials are needed to provide more reliable data on the clinical profile of these patients, in order to determine optimal surgical management.

P3724Impact of chronic kidney disease on efficacy and safety of interventional left atrial appendage closure – results from the prospective multicenter LAARGE registry

Background

The interventional left atrial appendage closure (LAAC) is an effective and safe alternative to standard oral anticoagulation (OAC) for stroke prevention in atrial fibrillation (AF) patients with contraindications for long-term OAC. Chronic kidney disease (CKD) has a high prevalence among AF patients, and was shown to increase the number of peri-procedural complications in cardiac interventions.

Purpose

This subanalysis of the LAARGE registry aimed to investigate CKD's impact on outcomes after LAAC.

Methods

This prospective, real-world LAAC registry included 625 patients with documented renal function from 37 German centers between April 2014 and January 2016. CKD was defined by an eGFR <60 mL/min/1.73 m2. Procedure was conducted with different LAAC devices considering the relevant recommendations. Baseline characteristics, procedural data, intra-hospital and one-year follow-up outcome were registered for CKD and non-CKD patients stratified by the different CKD stages.

Results

CKD patients (n=300; 48.0%) had a more pronounced cardiovascular risk profile, a higher stroke (CHA2DS2-VASc score 4.9±1.5 vs. 4.2±1.5; p<0.001) and bleeding risk (HAS-BLED score 4.3±1.0 vs. 3.5±1.0; p<0.001), and had experienced more prior bleedings (83.7 vs. 76.3%; p=0.022). Implantation success was similarly high between both groups (97.9%; p=n.s.). In CKD patients, MACCE during one-year follow-up was more frequent (18.1 vs. 6.8%; p<0.001) mainly being triggered by all-cause deaths, but in-hospital MACCE was not (0.3 vs. 0.3%; p=n.s.). Kaplan-Meier estimation showed a lower one-year survival among CKD patients (82.4 vs. 94.4%; p<0.001) without significant accentuation in patients with advanced CKD (i.e., <30 mL/min/1.73 m2; p=n.s. to other CKD patients). While annual rate of device associated complications (2.6 vs. 2.8%; p=n.s.) and strokes (0 vs. 1.0%; p=n.s.) was comparable during follow-up, annual severe bleeding rate was higher in CKD patients (2.6 vs. 0.3%; p=0.027) which was 71.4 and 94.4% less than expected from the HAS-BLED score (p<0.01 for the comparison to the estimated risks, but no significant interaction between groups).

Conclusions

Despite an increased cardiovascular risk profile of CKD patients, device implantation was safe, and annual stroke rate was statistically indifferent to non-CKD patients across all CKD stages after LAAC. Moreover, a substantial reduction of annual stroke and major bleeding risk was observed, as compared to the estimated annual risk.

Acknowledgement/Funding

Stiftung Institut für Herzinfarktforschung, Ludwigshafen, Germany

The role of extracorporeal life support in the management with severe idiopathic pulmonary artery hypertension undergoing lung transplantation: are those patients referred too late?

Background

Idiopathic pulmonary artery hypertension (iPAH) is a relatively minor indication for lung transplantation (LTx) with comparatively poorer outcomes. Extracorporeal life support (ECLS) in various forms is increasingly being used in the management of this entity. However, the data and experience with this therapy remains limited. We evaluated the role of ECLS in the management of severe iPAH patients as a bridge to LTx as well as post LTx support.

Methods

A retrospective analysis of iPAH patients that received LTx between January 2007 and May 2014 was performed. Early- and mid-term outcomes were analyzed for this patient cohort. Also, early and mid-term outcomes after LTx were compared to the control group of patients with other diagnoses using unadjusted analysis and 1:3 propensity score matching.

Results

Of 321 LTx performed during the study period in our centre 15 patients had iPAH as a cause of end-stage lung disease. Four iPAH (27%) patients were bridged to LTx utilizing ECLS in the form of veno-arterial ECMO and extra-corporeal CO₂ removal device, whereas 9 patients (60%) required ECLS support for primary graft dysfunction (PGD) after surgery. Patients with iPAH required more frequently on-pump LTx, both pre and post LTx ECLS, and had significantly lower pO₂/FiO₂ ratio at 24, 48 and 72 hours after LTx. Also iPAH patients had significantly longer ICU and hospital stay. Whereas the incidence of postoperative bronchiolitis obliterans syndrome (BOS) and rejection was comparable to the control group, overall cumulative survival with up to 6 years follow-up was significantly poorer in the iPAH group. After propensity score matching, the results in terms of postoperative outcomes remained as in the unadjusted analysis.

Conclusions

ECLS is an essential tool in the armamentarium of any lung transplant program treating iPAH with a potential of bridge patients to transplantation and to overcome graft dysfunction after LTx. Despite utilization of ECLS in the management of iPAH, the outcomes in terms of primary graft failure and survival remain poor compared to patients with other diagnoses.

Monitoring of adult patient on venoarterial extracorporeal membrane oxygenation in intensive care medicine

Nowadays high-tech medical assist device therapy is a crucial part of intensive care medicine. Especially, management of circulatory assist device systems poses an increasing challenge for intensive care medicine. So far, autonomous recommendations for monitoring of extracorporeal life support systems in the form of guidelines or position papers are lacking. The purpose of this paper was to present an orientation guide on this important topic.

Adipose-tissue-derived therapeutic cells in their natural environment as an autologous cell therapy strategy: the microtissue-stromal vascular fraction

The prerequisite for a successful clinical use of autologous adipose-tissue-derived cells is the highest possible regenerative potential of the applied cell population, the stromal vascular fraction (SVF). Current isolation methods depend on high enzyme concentration, lysis buffer, long incubation steps and mechanical stress, resulting in single cell dissociation. The aim of the study was to limit cell manipulation and obtain a derivative comprising therapeutic cells (microtissue-SVF) without dissociation from their natural extracellular matrix, by employing a gentle good manufacturing practice (GMP)-grade isolation. The microtissue-SVF yielded larger numbers of viable cells as compared to the improved standard-SVF, both with low enzyme concentration and minimal dead cell content. It comprised stromal tissue compounds (collagen, glycosaminoglycans, fibroblasts), capillaries and vessel structures (CD31+, smooth muscle actin+). A broad range of cell types was identified by surface-marker characterisation, including mesenchymal, haematopoietic, pericytic, blood and lymphatic vascular and epithelial cells. Subpopulations such as supra-adventitial adipose-derived stromal/stem cells and endothelial progenitor cells were significantly more abundant in the microtissue-SVF, corroborated by significantly higher potency for angiogenic tube-like structure formation in vitro. The microtissue-SVF showed the characteristic phenotype and tri-lineage mesenchymal differentiation potential in vitro and an immunomodulatory and pro-angiogenic secretome. In vivo implantation of the microtissue-SVF combined with fat demonstrated successful graft integration in nude mice. The present study demonstrated a fast and gentle isolation by minor manipulation of liposuction material, achieving a therapeutically relevant cell population with high vascularisation potential and immunomodulatory properties still embedded in a fraction of its original matrix.

Investigation of the Foam Development Stages by Non-Destructive Testing Technology Using the Freeze Foaming Process

With a novel Freeze Foaming method, it is possible to manufacture porous cellular components whose structure and composition also enables them for application as artificial bones, among others. To tune the foam properties to our needs, we have to understand the principles of the foaming process and how the relevant process parameters and the foam's structure are linked. Using in situ analysis methods, like X-ray microcomputed tomography (µCT), the foam structure and its development can be observed and correlated to its properties. For this purpose, a device was designed at the Institute of Lightweight Engineering and Polymer Technology (ILK). Due to varying suspension temperature and the rate of pressure decrease it was possible to analyze the foam's developmental stages for the first time. After successfully identifying the mechanism of foam creation and cell structure formation, process routes for tailored foams can be developed in future.

Effect of preoperative low serum albumin on postoperative complications and early mortality in patients undergoing transcatheter aortic valve replacement

Background

Patients undergoing transcatheter aortic valve replacement (TAVR) are mostly elderly patients with substantial comorbidities. Established risk scores are not validated for TAVR and collectives with elderly patients making periprocedural risk stratification difficult. Serum albumin is known to be an indicator for malnutrition and frailty and is simple to measure, independent of physician's bias. Using serum albumin as a preoperative marker for postoperative complications might help estimating morbidity and mortality of these patients.

Methods

A total of 457 patients with severe symptomatic aortic stenosis undergoing TAVR at our institution in a period from January 2014 to December 2015 were included in this retrospective study. Baseline characteristics as well as preoperative laboratory parameters were registered. Postoperative morbidity and 30-day mortality were analyzed as primary end points. Enrolled patients with preoperative low serum albumin (<3.5 g/dL) were compared with those revealing normal serum albumin (≥3.5 g/dL).

Results

Among 457 patients, 51 (11%) presented pre-procedural low serum albumin and 406 (89%) had normal serum albumin. Patients' mean age was 81±6 years and 50% of them were male. Postoperative complications such as requirement of blood transfusions (63% versus 33%, P<0.001), infection (53% versus 24%, P<0.001), acute kidney injury (41% versus 19%, P=0.001) and 30-day mortality (10% versus 3%, P=0.045) showed significant differences between preoperative low and normal albumin groups.

Conclusions

Preoperative low serum albumin might be an indicator for higher morbidity and mortality in patients undergoing TAVR.

Impact of ascending aortic, hemiarch and arch repair on early and long-term outcomes in patients with Stanford A acute aortic dissection

BACKGROUND:

Stanford A acute aortic dissection (AAD) is a life-threatening emergency associated with major morbidity and mortality. The aim of this study was to compare outcomes of three different surgical approaches in patients with Stanford A AAD.

METHODS:

From January 2006 to March 2015 a total of 240 consecutive patients with diagnosed Stanford A AAD underwent elective, isolated surgical aortic repair in our centre. Patients were divided into three groups according to the extent of surgical repair: isolated replacement of the ascending aorta, hemiarch replacement and total arch replacement. Patients were followed up for up to 9 years. After univariate analysis multinomial logistic regression was performed for subgroup analysis. Baseline characteristics and endpoints as well as long-term survival were analysed.

RESULTS:

There were no statistically significant differences among the three groups in terms of demographics and preoperative baseline and clinical characteristics. Incidence of in-hospital stroke ( p = 0.034), need for reopening due to bleeding ( p = 0.031) and in-hospital mortality ( p = 0.017) increased significantly with the extent of the surgical approach. There was no statistical difference in terms of long-term survival ( p = 0.166) among the three groups. Applying multinomial logistic regression for subgroup analysis significantly higher odds for stroke ( p = 0.023), reopening for bleeding ( p = 0.010) and in-hospital mortality ( p = 0.009) for the arch surgery group in comparison to the ascending aorta surgery group as well as significantly higher odds for stroke ( p = 0.029) for the total arch surgery group in comparison to the hemiarch surgery group were identified.

CONCLUSIONS:

With Stanford A AAD the incidence of perioperative complications increased significantly with the extent of the surgical approach. Subgroup analysis and long-term follow up in patients undergoing isolated ascending or hemiarch surgery showed a lower incidence of cerebrovascular events compared with surgery for total arch replacement.

High Lithium Transference Number Electrolytes Containing Tetratriflylpropene's Lithium Salt

Electrolytes with a high lithium transference number linked with high ionic conductivity are urgently needed for high power battery operation. In this work, we present newly synthesized lithium tetra(trifluoromethanesulfonyl)propene as a salt-in-glyme-based "salt-in-solvent" electrolyte. We employ impedance spectroscopy in symmetric Li/electrolyte/Li cells and pulsed field gradient nuclear magnetic resonance spectroscopy to investigate the lithium conduction mechanism. We find predominant lithium conductivity with very high lithium transference numbers (∼70% from the polarization experiments) and three times higher ionic conductivity compared to well-known lithium triflate in diglyme electrolyte. This is a consequence of the reduced mobilities of large anions linked with improved ionic dissociation.

Impact of age on early outcomes and long-term survival of patients undergoing aortic repair with Stanford A dissection

Objectives:

Stanford A acute aortic dissection (AAD) is a life-threatening emergency, typically occurring in older patients and requiring immediate surgical repair. The aim of this study was to evaluate early outcome and short- and long-term survival of patients under and above 65 years of age.

Methods:

Two hundred and forty patients with Stanford A AAD underwent aortic surgical repair from January 2006 to April 2015 in our center. After statistical analysis and logistic regression analysis, Kaplan-Meier survival estimation was performed, with up to 9-year follow-up, comprising patients under and above 65 years of age.

Results:

The proportion of patients above 65 years of age suffering from Stanford A AAD was 50% (n=120). The group of patients above 65 years of age compared to the group under 65 years of age showed statistically significant differences in terms of higher odds ratios (OR) for hypertension (p=0.012), peripheral vascular disease (p=0.026) and tachyarrhythmia absoluta (p=0.004). Patients over 65 years of age also showed significantly poorer short- and long-term survival. Our subgroup analysis revealed that male patients (Breslow p=0.001, Log-Rank p=0.001) and patients suffering with hypertension (Breslow p=0.003, Log-Rank p=0.001) were reasonable for these results whereas younger and older female patients showed similar short- and long-term outcome (Breslow p=0.926, Log-Rank p=0.724). After stratifying all patients into 4 age groups (<45; 55-65; 65-75; >75years), short-term survival of the patients appeared to be significantly poorer with increasing age (Breslow p=0.026, Log-Rank p=0.008) whereas long-term survival of patients free from cerebrovascular events (Breslow p=0.0494, Log-Rank p=0.489) remained similar.

Conclusions:

All patients referred to our hospital for repair of Stanford A AAD with higher age had poorer short- and long-term survival, caused by male patients and patients suffering from hypertension, whereas survival of women and survival free from cerebrovascular events of the entire patient cohort was similar, irrespective of age.

Verstehen kontroverser wissenschaftlicher Themen

Zusammenfassung. Wenn Rezipient_innen sich z. B. im Internet zu einem öffentlich diskutierten wissenschaftlichen Thema informieren, lesen sie meist mehrere Texte, die widersprüchliche empirische Evidenz oder konkurrierende Annahmen enthalten können. Zugleich verfügen sie in der Regel über inhaltliche (Vor–)‌Überzeugungen, die die Verarbeitung der gelesenen Informationen beeinflussen können. Diese Bedingungen können (1) zu verzerrten Bewertungen wissenschaftlicher Argumente führen, erschweren (2) den Aufbau einer ausgewogenen und angemessenen Repräsentation wissenschaftlicher Sachverhalte und begünstigen (3) die Entstehung und Aufrechterhaltung fehlerhafter und einseitiger Vorstellungen. In unserem Beitrag illustrieren wir diese Probleme mit empirischen Beispielen und beschreiben die selektive Aktivierung von Gedächtnisinhalten und die automatische Validierung von Textinhalten als kognitive Mechanismen, die allen drei Problemen zugrunde liegen. Abschließend diskutieren wir, wie Trainings und eine entsprechende Gestaltung der Wissenschaftskommunikation Rezipient_innen dabei unterstützen können, ein adäquates und ausgewogenes Verständnis wissenschaftlicher Informationen zu erzielen.

Microsurgical sequestectomy at 36 weeks of pregnancy: A case report

About 30% of pregnant women experience lower back pain. The cause is usually increased mechanical stress combined with the ligament laxity induced by relaxin. Rarely, lower back pain is related to disc herniation. We report such a case, where microsurgical sequestectomy was performed at 36 weeks and three days of gestation because of severe extensor paresis of the left foot and big toe. The case shows that microsurgical treatment during pregnancy is safe. After treatment the patient regained full motor function and her pain regressed. She had a spontaneous vaginal delivery at 38 weeks.

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Disc prolapse in pregnancy is rare.

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We report a case of lumbar disc prolapse at 36 weeks' gestation where microsurgical sequestectomy was undertaken.

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Motor function was restored and pain regressed after the procedure.

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Spontaneous vaginal delivery occurred at 38 weeks.

High-temperature superconductivity at the lanthanum cuprate/lanthanum-strontium nickelate interface

The utilization of interface effects in epitaxial systems at the nanoscale has emerged as a very powerful approach for engineering functional properties of oxides. Here we present a novel structure fabricated by a state-of-the-art oxide molecular beam epitaxy method and consisting of lanthanum cuprate and strontium (Sr)-doped lanthanum nickelate, in which interfacial high-temperature superconductivity (Tc up to 40 K) occurs at the contact between the two phases. In such a system, we are able to tune the superconducting properties simply by changing the structural parameters. By employing electron spectroscopy and microscopy combined with dedicated conductivity measurements, we show that decoupling occurs between the electronic charge carrier and the cation (Sr) concentration profiles at the interface and that a hole accumulation layer forms, which dictates the resulting superconducting properties. Such effects are rationalized in the light of a generalized space-charge theory for oxide systems that takes account of both ionic and electronic redistribution effects.

Structure and chemistry of interfaces between ceria and yttria-stabilized zirconia studied by analytical STEM

Epitaxial undoped and Gd₂O₃-doped ceria films were grown by pulsed laser deposition on (1 1 1) faced Y₂O₃-stabilized zirconia (YSZ). Highly localized cerium reduction at the film-substrate interfaces is revealed by atomically resolved valence EELS mapping using C_s aberration-corrected scanning transmission electron microscopy. The chemical profiles reveal interdiffusion of Ce, (Gd), Y, Zr, forming an intermixing zone at the interface 7-9 (1 1 1) lattice planes wide. In its vicinity, the fraction of Ce³⁺ raises gradually over 6-8 lattice planes from zero in the bulk ceria to ≈100% in one single plane at the interface. Beyond this plane the Ce³⁺ fraction drops sharply within the YSZ substrate. In the vicinity of the interface systematic scan deflections are observed during EELS line scans. The advancing electron probe experiences a retarding force at the ceria side, and an accelerating force at the YSZ side, irrespective of the scan direction. This behavior is suggestive of coulombic interactions between the electron probe and a charged interface. This is interpreted as an indication of the presence of a space-charge situation at the YSZ/ceria interface, resulting from an excess negative charge at the ceria side (due to Ce³⁺cations) and an excess positive charge at the YSZ side (due to oxygen vacancies).

Social cognitive aspects of the participation in workplace health promotion as revealed by the theory of planned behavior

Health-promoting efforts strongly depend on individual cognitions such as attitudes as well as social cognitive aspects of the work environment such as leadership and support. Using the theory of planned behavior (TPB) as a theoretical frame, participation behavior of employees in courses offered by the workplace health promotion (WHP) program of the German Armed Forces was investigated. Social cognitive aspects of the work environment, such as leadership behaviors by setting an example or optimizing organization of work, were included in the TPB components of subjective norm and perceived behavioral control, which allowed for an investigation of the specific effects of leadership on WHP participation. A survey study with N=1385 members of the German Armed Forces was conducted in 2015 in Germany. Results showed that perceived behavioral control and attitudes towards WHP were the strongest predictors for WHP participation. While subjective norm was positively related to attitudes, it had a slightly negative effect on intention to participate in WHP activities. These findings suggest that the most effective way for leadership to increase WHP participation is to enhance perceived behavioral control. Quite contrary, creating a positive subjective norm regarding WHP participation may even result in psychological reactance.

Extracorporeal shock wave therapy in situ - novel approach to obtain an activated fat graft

One of the mainstays of facial rejuvenation strategies is volume restoration, which can be achieved by autologous fat grafting. In our novel approach, we treated the adipose tissue harvest site with extracorporeal shock wave therapy (ESWT) in order to improve the quality of the regenerative cells in situ. The latter was demonstrated by characterizing the cells of the stromal vascular fraction (SVF) in the harvested liposuction material regarding cell yield, adenosine triphosphate (ATP) content, proliferative capacity, surface marker profile, differentiation potential and secretory protein profile. Although the SVF cell yield was only slightly enhanced, viability and ATP concentration of freshly isolated cells as well as proliferation doublings after 3 weeks in culture were significantly increased in the ESWT compared with the untreated group. Likewise, cells expressing mesenchymal and endothelial/pericytic markers were significantly elevated concomitant with an improved differentiation capacity towards the adipogenic lineage and enhancement in specific angiogenic proteins. Hence, in situ ESWT might be applied in the future to promote cell fitness, adipogenesis and angiogenesis within the fat graft for successful facial rejuvenation strategies with potential long-term graft survival.

[Civilian blast injuries: an underestimated problem? : Results of a retrospective analysis of the TraumaRegister DGU®]

BACKGROUND

Blast injuries are a rare cause of potentially life-threatening injuries in Germany. During the past 30 years such injuries were seldom the cause of mass casualties, therefore, knowledge and skills in dealing with this type of injury are not very extensive.

MATERIAL AND METHODS

A retrospective identification of all patients in the TraumaRegister DGU® of the German Trauma Society (TR-DGU) who sustained blast injuries between January 1993 and November 2012 was carried out. The study involved a descriptive characterization of the collective as well as three additional collectives. The arithmetic mean, standard deviation and 95 % confidence interval of the arithmetic mean for different demographic parameters and figures for prehospital and in-hospital settings were calculated. A computation of prognostic scores, such as the Revised Injury Severity Classification (RISC) and the updated version RISC II (TR-DGU-Project-ID 2012-035) was performed.

RESULTS

A total of 137 patients with blast injuries could be identified in the dataset of the TR-DGU. Of the patients 90 % were male and 43 % were transported by the helicopter emergency service (HEMS) to the various trauma centres. The severely injured collective with a mean injury severity scale (ISS) of 18.0 (ISS ≥ 16 = 52 %) had stable vital signs. In none of the cases was it necessary to perform on-site emergency surgery but a very high proportion of patients (59 %) had to be surgically treated before admittance to the intensive care unit (ICU). Of the patients 27 % had severe soft tissue injuries with an Abbreviated Injury Scale (AIS) ≥ 3 and 90 % of these injuries were burns. The 24 h in-hospital fatality was very low (3 %) but the stay in the ICU tended to be longer than for other types of injury (mean 5.5 ventilation days and 10.7 days in the intensive care unit). Organ failure occurred in 36 % of the cases, multiorgan failure in 29 % and septic events in 14 %. Of the patients 16 % were transferred to another hospital during the first 48 h. The RISC and the updated RISC II tended to underestimate the severity of injuries and mortality (10.2 % vs. 6.8 % and 10.7 % vs. 7.5 %, respectively) and the trauma associated severe hemorrhage (TASH) score underestimated the probability for transfusion of more than 10 units of packed red blood cells (5.0 % vs. 12.5 %).

CONCLUSION

This article generates several hypotheses, which should be confirmed with additional investigations. Until then it has to be concluded that patients who suffer from accidental blast injuries in the civilian setting (excluding military operations and terrorist attacks) show a combination of classical severe trauma with blunt and penetrating injuries and additionally a high proportion of severe burns (combined thermomechanical injury). They stay longer in the ICU than other trauma patients and suffer more complications, such as sepsis and multiorgan failure. Established scores, such as RISC, RISC II and TASH tend to underestimate the severity of the underlying trauma.

The oxidation kinetics of thin nickel films between 250 and 500 °C

The oxidation kinetics of thin polycrystalline Ni films is of fundamental interest as well as being relevant for potential applications. It was investigated between 250 and 500 °C for 10-150 nm thick films. Even for the thinnest films, oxidation was found to be diffusion controlled. The high density of grain boundaries in the formed NiO layer leads to a tracer diffusion coefficient that is higher than reported in the literature, indicating accelerated Ni diffusion along the grain boundaries. Cr segregation to the bottom interface in doped-NiO films hindered the acceleration of the oxidation of thin films.

Use of site symmetry in supercell models of defective crystals: polarons in CeO2

Polarons and oxygen site symmetry in hybrid DFT calculations.

Fast pyrolysis char - Assessment of alternative uses within the bioliq® concept

Experiments with a process development unit for fast pyrolysis of biomass residues of 10kgh(-1) have been performed to quantify the impact of two different product recovery options. Wheat straw, miscanthus and scrap wood have been used as feedstock. A separate recovery of char increases the organic oil yield as compared to a combined recovery of char and organic condensate (OC). Furthermore, it allows for an alternative use of the byproduct char which represents an important product fraction for the high ash biomass residues under consideration. The char produced shows little advantage over its biomass precursor when considered as energy carrier due to its high ash content. Significant value can be added by demineralizing and activating the char. The potential to increase the economic feasibility of fast pyrolysis is shown by an assessment of the bioliq® process chain.

High-temperature superconductivity in space-charge regions of lanthanum cuprate induced by two-dimensional doping

The exploitation of interface effects turned out to be a powerful tool for generating exciting material properties. Such properties include magnetism, electronic and ionic transport and even superconductivity. Here, instead of using conventional homogeneous doping to enhance the hole concentration in lanthanum cuprate and achieve superconductivity, we replace single LaO planes with SrO dopant planes using atomic-layer-by-layer molecular beam epitaxy (two-dimensional doping). Electron spectroscopy and microscopy, conductivity measurements and zinc tomography reveal such negatively charged interfaces to induce layer-dependent superconductivity (T_c up to 35 K) in the space-charge zone at the side of the planes facing the substrate, where the strontium (Sr) profile is abrupt. Owing to the growth conditions, the other side exhibits instead a Sr redistribution resulting in superconductivity due to conventional doping. The present study represents a successful example of two-dimensional doping of superconducting oxide systems and demonstrates its power in this field.

Introduction of higher-dimensional structure elements into solids is used to generate unusual materials properties. Here, the authors report how replacing LaO planes with SrO dopants yields space-charge induced superconductivity, showing the potential of two-dimensional doping in this field.