Miniatur-Laserscanner für mobile Anwendungen

Kurzfassung Laserscanner-Systeme zur hochaufgelösten Umfelderfassung nutzen momentan hauptsächlich makroskopische Aktoren zur Strahlablenkung und unterliegen damit Einschränkungen hinsichtlich minimaler Baugröße und Unempfindlichkeit gegenüber Erschütterungen. Hauptgrund ist die Aktoreinheit, die meist große Spiegel- und Stellelemente und damit große bewegte Massen enthält. Eine deutliche Verbesserung verspricht der Einsatz von Mikroaktoren. Bisherige Entwicklungen ermöglichen meist jedoch nur kleine Scanwinkel um 10°. Große Winkel über 50° erfordern komplexe Aktorstrukturen, was mit aufwendiger Prozesstechnik und hohen Kosten verbunden ist. Die hier vorgestellte Arbeit versucht die Nachteile makroskopischer Aktoren, sowie bisheriger Mikroaktoren, durch die gezielte Anwendung sogenannter Smart Materials in mikroaktorischen Systemen zu beheben. Dazu wird zunächst ein neuartiger Aktormechanismus auf Basis der ferromagnetischen Formgedächtnislegierung Ni2MnGa eingesetzt. Dieser vereint die Wirkmechanismen des Ferromagnetismus und des Formgedächtniseffektes in einem Dünnfilm-Bauteil. Den erzeugten antagonistischen Kräften stehen sehr kleine Rückstellkräfte gegenüber, wodurch sich große Scanwinkel in einem breiten Frequenzbereich erzeugen lassen. Weitere Mikroaktoren auf der Grundlage von Smart Materials nutzen entweder Dünnfilm-Verbundschichten mit reinem Formgedächtniseffekt auf der Basis von NiTiCu oder mit rein ferromagnetischen Eigenschaften. In dieser Arbeit werden, ausgehend von den vorgestellten Aktormechanismen, 1D-Mikroaktoren mit einem Ablenkwinkel entwickelt und diese in einem weiteren Schritt zu 2D-Mikroaktoren mit zwei rechtwinklig zueinander stehenden Ablenkwinkeln erweitert. Abschließend erfolgt die Entwicklung eines 2D-Laserscanner-Systems bestehend aus einem 1D-Mikroaktor kombiniert mit einem FlugzeitEntfernungsmesssystem (TOF-System). Das Design der 1D-Mikroaktoren basiert auf Doppelbiegebalken, deren Strukturen auf eine möglichst gleichmäßige Temperaturverteilung ausgelegt sind. Bei der Herstellung kommt eine Spaltschweiß- Technik zur Erzeugung kleiner und zuverlässiger elektrischer Verbindungen zum Einsatz. Verglichen mit anderen Wirkprinzipien, die meist eine passive Feder-Rückstellung nutzen, werden bei dem 1D-Mikroaktor aus Ni2MnGa große, nahezu frequenzunabhängige optische Ablenkwinkel von 120° bei 60 Hz oder 60° bei 180 Hz erzielt. Die Baugröße liegt dabei im Millimeter- Bereich, der Energiebedarf bei weniger als 100mW. 1D-Mikroaktoren aus der Verbundschicht mit der Formgedächtnislegierung NiTiCu zeigen weit größere Scanwinkel bis zu 170°, jedoch nur in Resonanz bei 85 Hz. Das Design der 2D-Mikroaktoren ist monolithisch ausgeführt und benötigt nur einen Mikrospiegel zur Strahlablenkung. 2D-Mikroaktoren aus Ni2MnGa lehnen an das 1D-Design an und kombinieren Biegebewegungen mit einer zusätzlich hervorgerufenen Kippbewegung. Erste Prototypen zeigen in einem Frequenzbereich von 40 Hz bis 80 Hz bei leistungsoptimierter Ansteuerung 2D-Scanmuster mit optischen Scanwinkeln von 38° x 50°. Eine andere Variante besteht aus zwei strukturoptimierten und mechanisch gekoppelten, im 90°-Winkel zueinander angeordneten 1D-Aktoren aus der NiTiCuVerbundschicht und erreicht maximale optische Scanwinkel von 20° x 40°. Diese Winkel treten nur bei 25, beziehungsweise 85 Hz in Resonanz auf und zeigen eine große mechanische Kopplung. Im letzten Teil der Arbeit wird ein 2D-Laserscanner-System zur horizontalen Detektion von Entfernung und Winkel hergestellt. Dies gelingt durch die Integration einer Hochleistungs-Halbleiterlaserdiode, eines Ni2MnGa 1D-Mikroaktors, eines optischen Winkelsensors und eines TOFSystems. Der Winkelsensor wird durch einen Strahlteiler und einen positionsempfindlichen Photodetektor (PSD) auf einer optischen Bank realisiert. Dabei stellen die optischen Aperturen des TOF-Empfängers große Anforderungen an die Strahlkollimation des Lasers und die Fokussieroptik im Detektorstrahlengang. Berücksichtigt werden muss weiterhin die Abstimmung der komplexen Hardware- und Software-Komponenten der Sensorik. Ein erster Demonstrator zeigt eine maximale Messentfernung von 30 m, die neben der Laserleistung durch die Empfindlichkeit des optischen Empfängers begrenzt wird. Die erzielbare Ortsauflösung des Systems ist einerseits durch die Auflösung des Winkelsensors von 0.5° vorgegeben und wird weiterhin durch die zeitliche Auflösung des TOF-Systems von etwa 1 ns bestimmt. Miniature-Laserscanner for Mobile Applications Abstract Laserscanning systems for highly resolved sensing of the environment are currently using macroscopic actuators for beam deflection and, thus, are restricted with respect to their size and insensitivity to shock. Main reason is the actuation unit, comprising large mirrors and actuators and, thus, large moving masses. It is expected that the use of microactuators will lead to a considerable improvement. In most cases, however, previous developments enable only small scanning angles in the order of 10 deg. Large angles above 50 deg require complex actuator structures resulting in extensive processing technology and higher costs. This work is an effort to resolve the disadvantages of macroscopic as well as current microactuators by the systematic implementation of so called smart materials in microactuators. For this purpose, first a novel actuation mechanism on the basis of the ferromagnetic shape memory alloy Ni2MnGa is introduced, combining the ferromagnetic and shape memory effect in one thin film component. The resulting antagonistic forces are opposed by small reset forces, thus, allowing large scanning angles in a wide frequency range. Further microactuators on the basis of smart materials make use of thin film composites with either pure shape memory effect on the basis of NiTiCu or pure ferromagnetic properties. Based on these actuation mechanisms this work pursuits the development of 1D microactuators with one deflection angle and, in a further step, their extension to 2D microactuators with two scanning directions being at right angles with respect to each other. Finally, a 2D laserscanner system is developed consisting of a 1D microactuator combined with a time-of-flight (TOF) system. The designs of the 1D microactuators are based on double-beam cantilever structures, which are constructed for a temperature distribution as homogeneous as possible. Fabrication technology comprises a gap welding technology to generate small size and reliable electrical contacts. Compared to other actuation mechanisms, which mostly utilize a passive reset spring, the 1D microactuators of Ni2MnGa achieve large, nearly frequency-independent optical scanning angles of 120 deg at 60 Hz or 60 deg at 180 Hz. The size of the actuator is in the millimeter-range, while energy consumption is less than 100 mW. 1D microactuators of the NiTiCu composite show even larger scanning angles up to 170 deg but only at their resonance frequency of 85 Hz. The 2D microactuators are designed monolithically using one micromirror for beam deflection. The 2D microactuators of Ni2MnGa are based on the 1D design and combine the bending motion with an additionally excited tilting motion. First prototypes show in the frequency range of 40 to 80 Hz at optimized driving power 2D scanning patterns with optical scanning angles of 38 x 50 deg. An other variant comprising of two mechanically coupled, at right angles oriented 1D actuators of the NiTiCu composite achieves optical scanning angles of 20 x 40 deg. These scanning angles only occur at the resonance frequencies of 25 and 85 Hz, respectively, and show a stronger mechanical coupling. In the final part of this work, a 2D laserscanner system for horizontal detection of distance and angle is built up. This is achieved by integration of a high-power semiconducting laser diode, a Ni2MnGa 1D microactuator, an angle sensor and a TOF system. The angle sensor is realized on an optical bench by a beam splitter and a position sensitive detector (PSD). Thereby, the optical apertures of the TOF detector are making high demands on the beam collimation and focussing optics in the detector beam path. Furthermore, the adjustment of the complex software and hardware components of the sensor system has to be taken into account. A first demonstrator shows a maximum range detection of 30 m which is limited, besides the laser power, by the receiver sensitivity. The achievable spatial resolution of the system is on the one hand given by the resolution of the angle sensor of 0.5 deg and in addition by the time resolution of the TOF system of about 1 ns

Einfluss von gemälztem Weizen auf die zootechnische Leistung von Öko-Mastgeflügel

Durch gezielte Keimung kann die Phosphorverfügbarkeit von Getreiden verbessert werden. Aus diesem Grund wird in vorliegender Studie der Einfluss von gemälztem Weizen auf die Mast- und Schlachtleistung von Mastbroilern untersucht. Hierfür wurde ein Fütterungsversuch mit vier Varianten durchgeführt (A: Malz + P niedrig; B: Malz + P hoch; C: Weizen + P niedrig; D: Weizen + P hoch). Den 2.000 Eintagsküken (Ranger Classic) stand von Tag 1 bis Tag 16 Öko-Kükenstarter zur Verfügung. Lebendgewicht, Futter- und Wasseraufnahme wurden wöchentlich erhoben. An Tag 57 wurden die Tiere geschlachtet. Anschließend wurden der Schlachtkörper, die inneren Organe und die Teilstücke gewogen. Es konnte festgestellt werden, dass Tiere, die unbehandelten Weizen erhielten, eine durchgängig höhere Mast- und Schlachtleistung aufwiesen, als jene, die mit Weizenmalz gefüttert wurden. Der P-Gehalt hatte keinerlei Einfluss. Es ist davon auszugehen, dass Keimung von Weizen keinen positiven Effekt auf die Leistung langsam wachsender Broiler hat

Imaging of Bioprosthetic Valve Dysfunction after Transcatheter Aortic Valve Implantation.

Transcatheter aortic valve implantation (TAVI) has become the standard of care in elderly high-risk patients with symptomatic severe aortic stenosis. Recently, TAVI has been increasingly performed in younger-, intermediate- and lower-risk populations, which underlines the need to investigate the long-term durability of bioprosthetic aortic valves. However, diagnosing bioprosthetic valve dysfunction after TAVI is challenging and only limited evidence-based criteria exist to guide therapy. Bioprosthetic valve dysfunction encompasses structural valve deterioration (SVD) resulting from degenerative changes in the valve structure and function, non-SVD resulting from intrinsic paravalvular regurgitation or patient-prosthesis mismatch, valve thrombosis, and infective endocarditis. Overlapping phenotypes, confluent pathologies, and their shared end-stage bioprosthetic valve failure complicate the differentiation of these entities. In this review, we focus on the contemporary and future roles, advantages, and limitations of imaging modalities such as echocardiography, cardiac computed tomography angiography, cardiac magnetic resonance imaging, and positron emission tomography to monitor the integrity of transcatheter heart valves

Effects of hypothermia, hypoxia, and hypercapnia on brain oxygenation and hemodynamic parameters during simulated avalanche burial: a porcine study.

Avalanche patients who are completely buried but still able to breathe are exposed to hypothermia, hypoxia, and hypercapnia (triple H syndrome). In a porcine model, there was no clinically relevant reduction in cerebral oxygenation during hypothermia and initial reduction of fraction of inspiratory oxygen ([Formula: see text]), as observed during hypercapnia. Hypercapnia may be the main cause of cardiovascular instability, which seems to be the major trigger for a decrease in cerebral oxygenation in triple H syndrome despite severe hypothermia

Long-Term Persisting SARS-CoV-2 RNA and Pathological Findings: Lessons Learnt From a Series of 35 COVID-19 Autopsies

BackgroundLong-term sequelae of coronavirus disease 2019 (COVID-19), including the interaction between persisting viral-RNA and specific tissue involvement, pose a challenging issue. In this study, we addressed the chronological correlation (after first clinical diagnosis and postmortem) between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA and organ involvement.MethodsThe presence of postmortem SARS-CoV-2 RNA from 35 complete COVID-19 autopsies was correlated with the time interval between the first diagnosis of COVID-19 and death and with its relationship to morphologic findings.ResultsSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA can be evident up to 40 days after the first diagnosis and can persist to 94 hours after death. Postmortem SARS-CoV-2 RNA was mostly positive in lungs (70%) and trachea (69%), but all investigated organs were positive with variable frequency. Late-stage tissue damage was evident up to 65 days after initial diagnosis in several organs. Positivity for SARS-CoV-2 RNA in pulmonary swabs correlated with diffuse alveolar damage (p = 0.0009). No correlation between positive swabs and other morphologic findings was present. Cerebral (p = 0.0003) and systemic hemorrhages (p = 0.009), cardiac thrombi (p = 0.04), and ischemic events (p = 0.03) were more frequent in the first wave, whereas bacterial pneumonia (p = 0.03) was more prevalent in the second wave. No differences in biometric data, clinical comorbidities, and other autopsy findings were found.ConclusionsOur data provide evidence not only of long-term postmortem persisting SARS-CoV-2 RNA but also of tissue damage several weeks after the first diagnosis of SARS-CoV-2 infection. Additional conditions, such as concomitant bacterial pulmonary superinfection, lung aspergillosis, thromboembolic phenomena, and hemorrhages can further worsen tissue damage

Gut microbiota and acylcarnitine metabolites connect the beneficial association between estrogen and lipid metabolism disorders in ovariectomized mice

Decreased estrogen level is one of the main causes of lipid metabolism disorders and coronary heart disease in women after menopause. Exogenous estradiol benzoate is effective to some extent in alleviating lipid metabolism disorders caused by estrogen deficiency. However, the role of gut microbes in the regulation process is not yet appreciated. The objective of this study was to investigate the effects of estradiol benzoate supplementation on lipid metabolism, gut microbiota, and metabolites in ovariectomized (OVX) mice and to reveal the importance of gut microbes and metabolites in the regulation of lipid metabolism disorders. This study found that high doses of estradiol benzoate supplementation effectively attenuated fat accumulation in OVX mice. There was a significant increase in the expression of genes enriched in hepatic cholesterol metabolism and a concomitant decrease in the expression of genes enriched in unsaturated fatty acid metabolism pathways. Further screening of the gut for characteristic metabolites associated with improved lipid metabolism revealed that estradiol benzoate supplementation influenced major subsets of acylcarnitine metabolites. Ovariectomy significantly increased the abundance of characteristic microbes that are significantly negatively associated with acylcarnitine synthesis, such as Lactobacillus and Eubacterium ruminantium group bacteria, while estradiol benzoate supplementation significantly increased the abundance of characteristic microbes that are significantly positively associated with acylcarnitine synthesis, such as Ileibacterium and Bifidobacterium spp. The use of pseudosterile mice with gut microbial deficiency greatly facilitated the synthesis of acylcarnitine due to estradiol benzoate supplementation and also alleviated lipid metabolism disorders to a greater extent in OVX mice. IMPORTANCE Our findings establish a role for gut microbes in the progression of estrogen deficiency-induced lipid metabolism disorders and reveal key target bacteria that may have the potential to regulate acylcarnitine synthesis. These findings suggest a possible route for the use of microbes or acylcarnitine to regulate disorders of lipid metabolism induced by estrogen deficiency

Critically ill COVID-19 patients with neutralizing autoantibodies against type I interferons have increased risk of herpesvirus disease

Autoantibodies neutralizing the antiviral action of type I interferons (IFNs) have been associated with predisposition to severe Coronavirus Disease 2019 (COVID-19). Here, we screened for such autoantibodies in 103 critically ill COVID-19 patients in a tertiary intensive care unit (ICU) in Switzerland. Eleven patients (10.7%), but no healthy donors, had neutralizing anti-IFNα or anti-IFNα/anti-IFNω IgG in plasma/serum, but anti-IFN IgM or IgA was rare. One patient had non-neutralizing anti-IFNα IgG. Strikingly, all patients with plasma anti-IFNα IgG also had anti-IFNα IgG in tracheobronchial secretions, identifying these autoantibodies at anatomical sites relevant for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. Longitudinal analyses revealed patient heterogeneity in terms of increasing, decreasing, or stable anti-IFN IgG levels throughout the length of hospitalization. Notably, presence of anti-IFN autoantibodies in this critically ill COVID-19 cohort appeared to predict herpesvirus disease (caused by herpes simplex viruses types 1 and 2 (HSV-1/-2) and/or cytomegalovirus (CMV)), which has been linked to worse clinical outcomes. Indeed, all 7 tested COVID-19 patients with anti-IFN IgG in our cohort (100%) suffered from one or more herpesviruses, and analysis revealed that these patients were more likely to experience CMV than COVID-19 patients without anti-IFN autoantibodies, even when adjusting for age, gender, and systemic steroid treatment (odds ratio (OR) 7.28, 95% confidence interval (CI) 1.14 to 46.31, p = 0.036). As the IFN system deficiency caused by neutralizing anti-IFN autoantibodies likely directly and indirectly exacerbates the likelihood of latent herpesvirus reactivations in critically ill patients, early diagnosis of anti-IFN IgG could be rapidly used to inform risk-group stratification and treatment options. Trial Registration: ClinicalTrials.gov Identifier: NCT04410263