The Validity of the SEEV Model as a Process Measure of Situation Awareness: The Example of a Simulated Endotracheal Intubation.

OBJECTIVE: In the context of anesthesiology, we investigated whether the salience effort expectancy value (SEEV) model fit is associated with situation awareness and perception scores. BACKGROUND: The distribution of visual attention is important for situation awareness-that is, understanding what is going on-in safety-critical domains. Although the SEEV model has been suggested as a process situation awareness measure, the validity of the model as a predictor of situation awareness has not been tested. METHOD: In a medical simulation, 31 senior and 30 junior anesthesiologists wore a mobile eye tracker and induced general anesthesia into a simulated patient. When inserting a breathing tube into the mannequin's trachea (endotracheal intubation), the scenario included several clinically relevant events for situation awareness and general events in the environment. Both were assessed using direct awareness measures. RESULTS: The overall SEEV model fit was good with no difference between junior and senior anesthesiologists. Overall, the situation awareness scores were low. As expected, the SEEV model fits showed significant positive correlations with situation awareness level 1 scores. CONCLUSION: The SEEV model seems to be suitable as a process situation awareness measure to predict and investigate the perception of changes in the environment (situation awareness level 1). The situation awareness scores indicated that anesthesiologists seem not to perceive the environment well during endotracheal intubation. APPLICATION: The SEEV model fit can be used to capture and assess situation awareness level 1. During endotracheal intubation, anesthesiologists should be supported by technology or staff to notice changes in the environment.

Giant Nonlinear Circular Dichroism from Intersubband Polaritonic Metasurfaces.

Nonlinear metasurfaces are advancing into a new paradigm of "flat nonlinear optics" owing to the ability to engineer local nonlinear responses in subwavelength-thin films. Recently, attempts have been made to expand the design space of nonlinear metasurfaces through nonlinear chiral responses. However, the development of metasurfaces that display both giant nonlinear circular dichroism and significantly large nonlinear optical response is still an unresolved challenge. Herein, we propose a method that induces giant nonlinear responses with near-unity circular dichroism using polaritonic metasurfaces with optical modes in chiral plasmonic nanocavities coupled with intersubband transitions in semiconductor heterostructures designed to have giant second and third order nonlinear responses. A stark contrast between effective nonlinear susceptibility elements for the two spin states of circularly polarized pump beams was seen in the hybrid structure. Experimentally, near-unity nonlinear circular dichroism and conversion efficiencies beyond 10-4% for second- and third-harmonic generation were achieved simultaneously in a single chip.

[Ethical, Psychosocial and Legal Aspects of the Treatment of Pregnant Patients with Brain Death]. / Ethische, psychosoziale und rechtliche Aspekte der Behandlung hirntoter Schwangerer.

The therapy of brain-dead pregnant women is an extreme example not only of the possibilities in current critical care, but also of resulting ethical, social and legal controversies, an area not familiar to most clinicians. Based on the case of a patient with fatal traumatic brain injury, a previously unknown early pregnancy and stated will to donate organs, we will discuss several aspects using published case reports: therapeutic goals, especially palliative care vs. continuation; implications of brain death diagnosis; considerations on legal care; involvement of relatives, especially the child's father; dynamics within the care team; and finally the issue of putative organ donation. This complex case once more depicts that even facing such highly unfavourable framework and seemingly irreconcilable factors, pregnancy can prevail. The researched facts and considerations in this article are intended to give an overview of potential dilemmas and might serve as a starting point in similar situations.

[Pregnancy and Irreversible Loss of Brain Functions - Case Report]. / Intensivtherapie bei Schwangerer mit irreversiblem Hirnfunktionsausfall.

A 29-year-old woman suffered major traumatic brain injury caused by a car accident. As diagnostic measures had revealed an early pregnancy (9th week), treatment on the intensive care unit was continued for 5 months, after unfavourable cerebral prognosis was followed by an irreversible loss of brain function in the 10th week of pregnancy. After assisted vaginal delivery of a healthy child in the 31th week of pregnancy on the critical care unit, organ procurement took place according to the presumed will of the patient. The article presents the details of the critical care therapy and discusses the supportive medical measures. Those measures served primarily to uphold the pregnancy und support the healthy development and delivery of the fetus and only in second instance the organ preservation aiming on organ donation. Necessary measures included maintenance of vital functions, hemostasis of electrolytes, nutrition, treatment of infection, prevention of adverse effects on the fetus, substitution of hormones and vitamins as well as the preparation of a planned or an unplanned delivery.

Giant nonlinear response from plasmonic metasurfaces coupled to intersubband transitions.

Intersubband transitions in n-doped multi-quantum-well semiconductor heterostructures make it possible to engineer one of the largest known nonlinear optical responses in condensed matter systems--but this nonlinear response is limited to light with electric field polarized normal to the semiconductor layers. In a different context, plasmonic metasurfaces (thin conductor-dielectric composite materials) have been proposed as a way of strongly enhancing light-matter interaction and realizing ultrathin planarized devices with exotic wave properties. Here we propose and experimentally realize metasurfaces with a record-high nonlinear response based on the coupling of electromagnetic modes in plasmonic metasurfaces with quantum-engineered electronic intersubband transitions in semiconductor heterostructures. We show that it is possible to engineer almost any element of the nonlinear susceptibility tensor of these structures, and we experimentally verify this concept by realizing a 400-nm-thick metasurface with nonlinear susceptibility of greater than 5 × 10(4) picometres per volt for second harmonic generation at a wavelength of about 8 micrometres under normal incidence. This susceptibility is many orders of magnitude larger than any second-order nonlinear response in optical metasurfaces measured so far. The proposed structures can act as ultrathin highly nonlinear optical elements that enable efficient frequency mixing with relaxed phase-matching conditions, ideal for realizing broadband frequency up- and down-conversions, phase conjugation and all-optical control and tunability over a surface.

III-V-on-Silicon Photonic Integrated Circuits for Spectroscopic Sensing in the 2-4 µm Wavelength Range.

The availability of silicon photonic integrated circuits (ICs) in the 2-4 µm wavelength range enables miniature optical sensors for trace gas and bio-molecule detection. In this paper, we review our recent work on III-V-on-silicon waveguide circuits for spectroscopic sensing in this wavelength range. We first present results on the heterogeneous integration of 2.3 µm wavelength III-V laser sources and photodetectors on silicon photonic ICs for fully integrated optical sensors. Then a compact 2 µm wavelength widely tunable external cavity laser using a silicon photonic IC for the wavelength selective feedback is shown. High-performance silicon arrayed waveguide grating spectrometers are also presented. Further we show an on-chip photothermal transducer using a suspended silicon-on-insulator microring resonator used for mid-infrared photothermal spectroscopy.

III-V-on-silicon 2-µm-wavelength-range wavelength demultiplexers with heterogeneously integrated InP-based type-II photodetectors.

2-µm-wavelength-range silicon-on-insulator (SOI) arrayed waveguide gratings (AWGs) with heterogeneously integrated InP-based type-II quantum well photodetectors are presented. Low insertion loss (2.5-3 dB) and low crosstalk (-30 to -25 dB) AWGs are realized. The InP-based type-II photodetectors are integrated with the AWGs using two different coupling approaches. Adiabatic-taper-based photodetectors show a responsivity of 1.6 A/W at 2.35 µm wavelength and dark current of 10 nA at -0.5 V, while photodetectors using grating-assisted coupling have a responsivity of 0.1 A/W and dark current of 5 nA at -0.5 V. The integration of the photodetector array does not degrade the insertion loss and crosstalk of the device. The photodetector epitaxial stack can also be used to realize the integration of a broadband light source, thereby enabling fully integrated spectroscopic systems.

2.3 µm range InP-based type-II quantum well Fabry-Perot lasers heterogeneously integrated on a silicon photonic integrated circuit.

Heterogeneously integrated InP-based type-II quantum well Fabry-Perot lasers on a silicon waveguide circuit emitting in the 2.3 µm wavelength range are demonstrated. The devices consist of a "W"-shaped InGaAs/GaAsSb multi-quantum-well gain section, III-V/silicon spot size converters and two silicon Bragg grating reflectors to form the laser cavity. In continuous-wave (CW) operation, we obtain a threshold current density of 2.7 kA/cm2 and output power of 1.3 mW at 5 °C for 2.35 µm lasers. The lasers emit over 3.7 mW of peak power with a threshold current density of 1.6 kA/cm2 in pulsed regime at room temperature. This demonstration of heterogeneously integrated lasers indicates that the material system and heterogeneous integration method are promising to realize fully integrated III-V/silicon photonics spectroscopic sensors in the 2 µm wavelength range.

MADS domain transcription factors mediate short-range DNA looping that is essential for target gene expression in Arabidopsis.

MADS domain transcription factors are key regulators of eukaryotic development. In plants, the homeotic MIKC MADS factors that regulate floral organ identity have been studied in great detail. Based on genetic and protein-protein interaction studies, a floral quartet model was proposed that describes how these MADS domain proteins assemble into higher order complexes to regulate their target genes. However, despite the attractiveness of this model and its general acceptance in the literature, solid in vivo proof has never been provided. To gain deeper insight into the mechanisms of transcriptional regulation by MADS domain factors, we studied how SEEDSTICK (STK) and SEPALLATA3 (SEP3) directly regulate the expression of the reproductive meristem gene family transcription factor-encoding gene VERDANDI (VDD). Our data show that STK-SEP3 dimers can induce loop formation in the VDD promoter by binding to two nearby CC(A/T)6GG (CArG) boxes and that this is essential for promoter activity. Our in vivo data show that the size and position of this loop, determined by the choice of CArG element usage, is essential for correct expression. Our studies provide solid in vivo evidence for the floral quartet model.

GaSb-based vertical-cavity surface-emitting lasers with an emission wavelength at 3 µm.

GaSb-based electrically pumped vertical-cavity surface-emitting lasers (VCSELs) with a buried tunnel junction emitting at 3 µm are demonstrated. To achieve this, a low optical loss VCSEL concept with an undoped epitaxial distributed Bragg reflector and intracavity contact is presented. The devices operate up to 5°C continuous wave and up to 50°C in pulsed mode. Single-mode operation with a side-mode suppression ratio of 30 dB and electro-thermal tuning range of 19.7 nm is achieved.

Attosecond photoelectron streaking with enhanced energy resolution for small-bandgap materials.

Attosecond photoelectron streaking spectroscopy allows time-resolved electron dynamics with a temporal resolution approaching the atomic unit of time. Studies have been performed in numerous systems, including atoms, molecules, and surfaces, and the quest for ever higher temporal resolution called for ever wider spectral extent of the attosecond pulses. For typical experiments relying on attosecond pulses with a duration of 200 as, the time-bandwidth limitation for a Gaussian pulse implies a minimal spectral bandwidth larger than 9 eV translating to a corresponding spread of the detected photoelectron kinetic energies. Here, by utilizing a specially tailored narrowband reflective XUV multilayer mirror, we explore experimentally the minimal spectral width compatible with attosecond time-resolved photoelectron spectroscopy while obtaining the highest possible spectral resolution. The validity of the concept is proven by recording attosecond electron streaking traces from the direct semiconductor gallium arsenide (GaAs), with a nominal bandgap of 1.42 eV at room temperature, proving the potential of the approach for tracking charge dynamics also in these technologically highly relevant materials that previously have been inaccessible to attosecond science.

2 µm wavelength range InP-based type-II quantum well photodiodes heterogeneously integrated on silicon photonic integrated circuits.

The heterogeneous integration of InP-based type-II quantum well photodiodes on silicon photonic integrated circuits for the 2 µm wavelength range is presented. A responsivity of 1.2 A/W at a wavelength of 2.32 µm and 0.6 A/W at 2.4 µm wavelength is demonstrated. The photodiodes have a dark current of 12 nA at -0.5 V at room temperature. The absorbing active region of the integrated photodiodes consists of six periods of a "W"-shaped quantum well, also allowing for laser integration on the same platform.

Evaluation of a method for improving the detection of hepatocellular carcinoma.

OBJECTIVE: To improve the detection of liver lesions in patients with hepatocellular carcinoma (HCC) via an iodine contrast enhancement tool. METHODS: Thirty-two patients with clinically proven HCCs underwent imaging with a three-phase protocol on a 256-slice MDCT. The contrast enhancement in the reconstructed slices was improved via a post-processing tool. Mean image noise was measured in four different regions: liver lesion, healthy liver, subcutaneous fat and bone. For each image set the image noise and contrast-to-noise ratio (CNR) were assessed. For subjective image assessment, four experienced radiologists evaluated the diagnostic quality. RESULTS: While employing the post-processing algorithm, CNR between the liver lesion and healthy liver tissue improves significantly by a factor of 1.78 (CNRwithout vC = 2.30 ± 1.92/CNRwith vC = 4.11 ± 3.05) (P* = 0.01). All results could be achieved without a strengthening of artefacts; mean HU values of subcutaneous fat and bone did not significantly change. Subjective image analysis illustrated a significant improvement when employing post-processing for clinically relevant criteria such as diagnostic confidence. CONCLUSION: With post-processing we see a significantly improved detection of arterial uptake in hepatic lesions compared with non-processed data. The improvement in CNR was confirmed by subjective image assessment for small lesions and for lesions with limited uptake. KEY POINTS: • Enhancement with iodine-based contrast agents is an essential part of CT. • A new post-processing tool significantly improves the diagnostics of hepatocellular carcinoma. • It also improves detection of small lesions with limited iodine uptake.

Miniaturized sensor for particles in air using Fresnel ring lenses and an enhanced intensity ratio technique.

We present a miniaturized particle sensor collecting scattered light in two solid angle intervals by Fresnel ring lenses. The particle size is determined from the ratio of both scattering amplitudes (intensity ratio) in addition to a linear diversity combining technique, generating a 3D particle size matrix that reduces the ambiguity by the index of refraction on the particle size identification. A signal-to-noise ratio of 30.3 was achieved for 147 nm sized polystyrene latex particles. Measurements of polydisperse particle size distribution show good agreement with the results by a scanning mobility particle sizer.

Enhanced luminescence properties of InAs-InAsP core-shell nanowires.

Utilizing narrow band gap nanowire (NW) materials to extend nanophotonic applications to the mid-infrared spectral region (>2-3 µm) is highly attractive, however, progress has been seriously hampered due to their poor radiative efficiencies arising from nonradiative surface and Auger recombination. Here, we demonstrate up to ~ 10(2) times enhancements of the emission intensities from InAs NWs by growing an InAsP shell to produce core-shell NWs. By systematically varying the thickness and phosphorus (P)-content of the InAsP shell, we demonstrate the ability to further tune the emission energy via large strain-induced peak shifts that already exceed >100 meV at comparatively low fractional P-contents. Increasing the P-content is found to give rise to additional line width broadening due to asymmetric shell growth generated by a unique transition from {110}- to {112}-sidewall growth as confirmed by cross-sectional scanning transmission electron microscopy. The results also elucidate the detrimental effects of plastic strain relaxation on the emission characteristics, particularly in core-shell structures with very high P-content and shell thickness. Overall, our findings highlight that enhanced mid-infrared emission efficiencies with effective carrier confinement and suppression of nonradiative recombination are highly sensitive to the quality of the InAs-InAsP core-shell interface.

[Awake fiberoptic intubation - gold standard for the anticipated difficult airway]. / Fiberoptische Wachintubation - Goldstandard für den erwartet schwierigen Atemweg.

Awake fiberoptic intubation seems to continually lose importance in recent years. Alternative options of airway management are coming more and more into the focus of clinical anaesthesia and are moreover advertised specifically for the difficult airway. The concern seems justified that this intubation technique - once the indisputed standard in the management of the anticipated difficult airway - is practised less and less so that especially younger colleagues can hardly gain routine practice. This article aims at counteracting this trend and particularly demonstrates a practical approach. Against this background the equipment is described and tips and tricks are given for execution. The main focus are safety aspects and the success factor of a good topical mucosal anaesthesia, which is of greater importance than a concomitant sedation.

[Personalized treatment of pheochromocytoma]. / Personalisierte Therapie des Phäochromozytoms.

BACKGROUND: Pheochromocytoma is a rare but severe disease of the adrenal glands. The aim of this study is to present and discuss recent developments in the diagnosis and treatment of pheochromocytoma. MATERIAL AND METHODS: A narrative review article based on the most recent literature is presented. RESULTS AND DISCUSSION: The proportion of pheochromocytomas as tumors of adrenal origin is about 5% of incidentally discovered adrenal tumors. The classical symptomatic triad of headaches, sweating, and palpitations occurs in only about 20% of patients, while almost all patients show at least 1 of these symptoms. To diagnose pheochromocytoma, levels of free plasma metanephrines or alternatively, fractionated metanephrines in a 24­h urine collection is required in a first step. In the second step an imaging procedure, computed tomography (CT) or magnetic resonance imaging (MRI), is performed to localize the adrenal tumor. Functional imaging is also recommended to preoperatively detect potential metastases. Genetic testing should always be offered during the course of treatment as 30-40% of pheochromocytomas are associated with genetic mutations. The dogma of preoperative alpha blockade is increasingly being questioned and has been controversially discussed in recent years. Minimally invasive removal of the adrenal tumor is the standard surgical procedure to cure patients with pheochromocytoma. The transabdominal and retroperitoneal laparoscopic approaches are considered equivalent. The choice of the minimally invasive procedure depends on the expertise and experience of the surgeon and should be tailored accordingly. Individualized and regular follow-up care is important after surgery.

Perioperative Enhanced Recovery Concepts Significantly Improve Postoperative Outcome in Patients with Crohn`s Disease.

BACKGROUND AND AIMS: Despite recent advancements in medical and surgical techniques in patients suffering from Crohn`s Disease (CD), postoperative morbidity remains relevant due to a long-standing, non-curable disease burden. As demonstrated for oncological patients, perioperative enhanced recovery concepts provide great potential to improve postoperative outcome. However, robust evidence about the effect of perioperative enhanced recovery concepts in the specific cohort of CD patients is lacking. METHODS: In a prospective single-center study, all patients receiving ileocecal resection due to CD between 2020 and 2023 were included. A specific perioperative enhanced recovery concept (ERC) was implemented and patients were divided into two groups (before and after implementation). The primary outcome focused on postoperative complications as measured by the Comprehensive Complication Index (CCI), secondary endpoints were severe complications, length of hospital stay, and rates of re-admission. RESULTS: 83 patients were analyzed of which 33 patients participated in the enhanced recovery program (postERC). While patient characteristics were comparable between both groups, ERC resulted in significantly decreased rates of overall and severe postoperative complications (CCI: 21.4 versus 8.4, p=0.0036; Clavien Dindo >2: 38% versus 3.1%, p=0.0002). Additionally, postERC-patients were earlier ready for discharge (6.5 days versus 5 days, p=0.001) and rates of re-admission were significantly lower (20% versus 3.1%, p=0.03). In a multivariate analysis, the recovery concept was identified as independent factor to reduce severe postoperative complications (p=0.019). CONCLUSION: A specific perioperative enhanced recovery concept significantly improves the postoperative outcome of patients suffering from Crohn`s Disease.

Monte Carlo study of terahertz difference frequency generation in quantum cascade lasers.

We present an extended ensemble Monte Carlo approach, allowing for the self-consistent modeling of terahertz difference frequency generation in quantum cascade lasers. Our simulations are validated against available experimental data for a current room temperature design. Tera-hertz output powers in the mW range are predicted for ideal light extraction.

Cladribine treatment specifically affects peripheral blood memory B cell clones and clonal expansion in multiple sclerosis patients.

Introduction: B cells are acknowledged as crucial players in the pathogenesis of multiple sclerosis (MS). Several disease modifying drugs including cladribine have been shown to exert differential effects on peripheral blood B cell subsets. However, little is known regarding functional changes within the peripheral B cell populations. In this study, we obtained a detailed picture of B cell repertoire changes under cladribine treatment on a combined immunoglobulin (Ig) transcriptome and proteome level. Methods: We performed next-generation sequencing of Ig heavy chain (IGH) transcripts and Ig mass spectrometry in cladribine-treated patients with relapsing-remitting multiple sclerosis (n = 8) at baseline and after 6 and 12 months of treatment in order to generate Ig transcriptome and Ig peptide libraries. Ig peptides were overlapped with the corresponding IGH transcriptome in order to analyze B cell clones on a combined transcriptome and proteome level. Results: The analysis of peripheral blood B cell percentages pointed towards a significant decrease of memory B cells and an increase of naive B cells following cladribine therapy. While basic IGH repertoire parameters (e.g. variable heavy chain family usage and Ig subclasses) were only slightly affected by cladribine treatment, a significantly decreased number of clones and significantly lower diversity in the memory subset was noticeable at 6 months following treatment which was sustained at 12 months. When looking at B-cell clones comprising sequences from the different time-points, clones spanning between all three time-points were significantly more frequent than clones including sequences from two time-points. Furthermore, Ig proteome analyses showed that Ig transcriptome specific peptides could mostly be equally aligned to all three time-points pointing towards a proportion of B-cell clones that are maintained during treatment. Discussion: Our findings suggest that peripheral B cell related treatment effects of cladribine tablets might be exerted through a reduction of possibly disease relevant clones in the memory B cell subset without disrupting the overall clonal composition of B cells. Our results -at least partially- might explain the relatively mild side effects regarding infections and the sustained immune response after vaccinations during treatment. However, exact disease driving B cell subsets and their effects remain unknown and should be addressed in future studies.