Optimal Excitation and Readout of Resonators Used as Wireless Passive Sensors.

Resonators are passive time-invariant components that do not produce a frequency shift. However, they respond to an excitation signal close to resonance with an oscillation at their natural frequencies with exponentially decreasing amplitudes. If resonators are connected to antennas, they form purely passive sensors that can be read remotely. In this work, we model the external excitation of a resonator with different excitation signals and its subsequent decay characteristics analytically as well as numerically. The analytical modeling explains the properties of the resonator during transient response and decay behavior. The analytical modeling clarifies how natural oscillations are generated in a linear time-invariant system, even if their spectrum was not included in the stimulation spectrum. In addition, it enables the readout signals to be optimized in terms of duration and bandwidth.

Multi-network approach for image segmentation in non-contrast enhanced cardiac 3D MRI of arrhythmic patients.

Left atrial appendage (LAA) is the source of thrombi formation in more than 90% of strokes in patients with nonvalvular atrial fibrillation. Catheter-based LAA occlusion is being increasingly applied as a treatment strategy to prevent stroke. Anatomical complexity of LAA makes percutaneous occlusion commonly performed under transesophageal echocardiography (TEE) and X-ray (XR) guidance especially challenging. Image fusion techniques integrating 3D anatomical models derived from pre-procedural imaging into the live XR fluoroscopy can be applied to guide each step of the LAA closure. Cardiac magnetic resonance (CMR) imaging gains in importance for radiation-free evaluation of cardiac morphology as alternative to gold-standard TEE or computed tomography angiography (CTA). Manual delineation of cardiac structures from non-contrast enhanced CMR is, however, labor-intensive, tedious, and challenging due to the rather low contrast. Additionally, arrhythmia often impairs the image quality in ECG synchronized acquisitions causing blurring and motion artifacts. Thus, for cardiac segmentation in arrhythmic patients, there is a strong need for an automated image segmentation method. Deep learning-based methods have shown great promise in medical image analysis achieving superior performance in various imaging modalities and different clinical applications. Fully-convolutional neural networks (CNNs), especially U-Net, have become the method of choice for cardiac segmentation. In this paper, we propose an approach for automatic segmentation of cardiac structures from non-contrast enhanced CMR images of arrhythmic patients based on CNNs implemented in a multi-stage pipeline. Two-stage implementation allows subdividing the task into localization of the relevant cardiac structures and segmentation of these structures from the cropped sub-regions obtained from previous step leading to efficient and effective way of automated cardiac segmentation.

In vivo assembly of epitope-coated biopolymer particles that induce anti-tumor responses.

There is an unmet need for antigen delivery systems that elicit efficient T cell priming to prevent infectious diseases or for treatment of cancers. Here, we explored the immunogenic potential of biologically assembled biopolymer particles (BPs) that have been bioengineered to display the antigenic MHC I and MHC II epitopes of model antigen ovalbumin (OVA). Purified dendritic cells (DCs) captured BP-OVA and presented the associated antigenic epitopes to CD4+ T cells and CD8+ T cells. Vaccination with BP-OVA in the absence of adjuvant elicited antigen presentation to OVA-specific CD8+ and CD4+ T cells and cross-primed effective cytotoxic T lymphocyte (CTL) killers. BP-OVA induction of CTL killing did not require CD4+ T cell help, with active CTLs generated in BP-OVA vaccinated I-Ab-/- and CD40-/- mice. In contrast, IL-15 and type I IFN were required, with abrogated CTL activity in vaccinated IL-15-/- and IFNAR1-/- mice. cDC1 and/or CD103+ DCs were not essential for BP-OVA specific CTL with immunization eliciting responses in Batf3-/- mice. Poly I:C, but not LPS or CpG, co-administered as an adjuvant with BP-OVA boosted CTL responses. Finally, vaccination with BP-OVA protected against B16-OVA melanoma and Eµ-myc-GFP-OVA lymphoma inoculation. In summary, we have demonstrated that epitope-displaying BPs represent an antigen delivery platform exhibiting a unique mechanism to effectively engage T cell immune responses.

Automatic Life Detection Based on Efficient Features of Ground-Penetrating Rescue Radar Signals.

Good feature engineering is a prerequisite for accurate classification, especially in challenging scenarios such as detecting the breathing of living persons trapped under building rubble using bioradar. Unlike monitoring patients' breathing through the air, the measuring conditions of a rescue bioradar are very complex. The ultimate goal of search and rescue is to determine the presence of a living person, which requires extracting representative features that can distinguish measurements with the presence of a person and without. To address this challenge, we conducted a bioradar test scenario under laboratory conditions and decomposed the radar signal into different range intervals to derive multiple virtual scenes from the real one. We then extracted physical and statistical quantitative features that represent a measurement, aiming to find those features that are robust to the complexity of rescue-radar measuring conditions, including different rubble sites, breathing rates, signal strengths, and short-duration disturbances. To this end, we utilized two methods, Analysis of Variance (ANOVA), and Minimum Redundancy Maximum Relevance (MRMR), to analyze the significance of the extracted features. We then trained the classification model using a linear kernel support vector machine (SVM). As the main result of this work, we identified an optimal feature set of four features based on the feature ranking and the improvement in the classification accuracy of the SVM model. These four features are related to four different physical quantities and independent from different rubble sites.

Cardiac magnetic resonance imaging for preprocedural planning of percutaneous left atrial appendage closure.

Introduction: Percutaneous closure of the left atrial appendage (LAA) facilitates stroke prevention in patients with atrial fibrillation. Optimal device selection and positioning are often challenging due to highly variable LAA shape and dimension and thus require accurate assessment of the respective anatomy. Transesophageal echocardiography (TEE) and x-ray fluoroscopy (XR) represent the gold standard imaging techniques. However, device underestimation has frequently been observed. Assessment based on 3-dimensional computer tomography (CTA) has been reported as more accurate but increases radiation and contrast agent burden. In this study, the use of non-contrast-enhanced cardiac magnetic resonance imaging (CMR) to support preprocedural planning for LAA closure (LAAc) was investigated. Methods: CMR was performed in thirteen patients prior to LAAc. Based on the 3-dimensional CMR image data, the dimensions of the LAA were quantified and optimal C-arm angulations were determined and compared to periprocedural data. Quantitative figures used for evaluation of the technique comprised the maximum diameter, the diameter derived from perimeter and the area of the landing zone of the LAA. Results: Perimeter- and area-based diameters derived from preprocedural CMR showed excellent congruency compared to those measured periprocedurally by XR, whereas the respective maximum diameter resulted in significant overestimation (p < 0.05). Compared to TEE assessment, CMR-derived diameters resulted in significantly larger dimensions (p < 0.05). The deviation of the maximum diameter to the diameters measured by XR and TEE correlated well with the ovality of the LAA. C-arm angulations used during the procedures were in agreement with those determined by CMR in case of circular LAA. Discussion: This small pilot study demonstrates the potential of non-contrast-enhanced CMR to support preprocedural planning of LAAc. Diameter measurements based on LAA area and perimeter correlated well with the actual device selection parameters. CMR-derived determination of landing zones facilitated accurate C-arm angulation for optimal device positioning.

Impact of concomitant tricuspid regurgitation on outcome after edge-to-edge mitral valve repair.

AIMS: To evaluate the impact of tricuspid regurgitation (TR) on echocardiographic and functional outcome after mitral valve transcatheter edge-to-edge-repair (M-TEER). METHODS AND RESULTS: A total of 740 patients underwent M-TEER at our center from 2010 to 2021. Patients were analyzed according to severity of concomitant TR at the time of M-TEER procedure: low-grade TR (grade ≤I [trace-mild], 279 patients [37.7%]), moderate TR (grade II, 170 patients [23.0%]) and high-grade TR (grade III-V [severe-torrential], 291 patients [39.3%]). Patients with moderate to high-grade TR had higher morbidity. Procedural success of M-TEER was achieved similarly in all groups (98.2% vs. 97.6% vs. 95.9%, p = 0.22). TR severity decreased rapidly and consistently after M-TEER to only 48.0% of high-grade TR patients after 3 months (p < 0.001) and to 46.8% after 12 months (p = 0.99). High-grade TR patients had significantly higher mortality (21.5% vs. 18.2% vs. 11.1%, p = 0.003) up to 12 months after M-TEER. However, high-grade TR did not independently predict mortality (HR 1.302, 95% CI 0.937-1.810; p = 0.116). Echocardiographic and functional outcome was similar in both secondary and primary MR patients. CONCLUSIONS: High-grade concomitant TR did not independently predict adverse outcome following M-TEER. A wait-and-observe approach for these patients is reasonable.

TRI-SCORE is superior to EuroSCORE II and STS-Score in mortality prediction following transcatheter edge-to-edge tricuspid valve repair.

BACKGROUND: The development of transcatheter tricuspid edge-to-edge repair for tricuspid regurgitation is a therapeutic milestone but a specific periprocedural risk assessment tool is lacking. TRI-SCORE has recently been introduced as a dedicated risk score for tricuspid valve surgery. AIMS: This study analyzes the predictive performance of TRI-SCORE following transcatheter edge-to-edge tricuspid valve repair. METHODS: 180 patients who underwent transcatheter tricuspid valve repair at Ulm University Hospital were consecutively included and stratified into three TRI-SCORE risk groups. The predictive performance of TRI-SCORE was assessed throughout a follow-up period of 30 days and up to 1 year. RESULTS: All patients had severe tricuspid regurgitation. Median EuroSCORE II was 6.4% (IQR 3.8-10.1%), median STS-Score 8.1% (IQR 4.6-13.4%) and median TRI-SCORE 6.0 (IQR 4.0-7.0). 64 patients (35.6%) were in the low TRI-SCORE group, 91 (50.6%) in the intermediate and 25 (13.9%) in the high-risk groups. The procedural success rate was 97.8%. 30-day mortality was 0% in the low-risk group, 1.3% in the intermediate-risk and 17.4% in the high-risk groups (p < 0.001). During a median follow-up of 168 days mortality was 0%, 3.8% and 52.2%, respectively (p < 0.001). The predictive performance of TRI-SCORE was excellent (AUC for 30-day mortality: 90.3%, for one-year mortality: 93.1%) and superior to EuroSCORE II (AUC 56.6% and 64.4%, respectively) and STS-Score (AUC 61.0% and 59.0%, respectively). CONCLUSION: TRI-SCORE is a valuable tool for prediction of mortality after transcatheter edge-to-edge tricuspid valve repair and its performance is superior to EuroSCORE II and STS-Score. In a monocentric cohort of 180 patients undergoing edge-to-edge tricuspid valve repair TRI-SCORE predicted 30-day and up to one-year mortality more reliably than EuroSCORE II and STS-Score. AUC area under the curve, 95% CI 95% confidence interval.

Wireless Passive Sensor Technology through Electrically Conductive Media over an Acoustic Channel.

Hydrogen-based technologies provide a potential route to more climate-friendly mobility in the automotive and aviation industries. High-pressure tanks consisting of carbon-fiber-reinforced polymers (CFRPs) are exploited for the storage of compressed hydrogen and have to be monitored for safe and long-term operation. Since neither wired sensors nor wireless radio technology can be used inside these tanks, acoustic communication through the hull of the tank has been the subject of research in recent years. In this paper, we present for the first time a passive wireless sensor technology exploiting an ultrasonic communication channel through an electrically conductive transmission medium with an analog resonant sensor featuring a high quality factor. The instrumentation system comprised a readout unit outside and a passive sensor node inside the tank, coupled with geometrically opposing electromechanical transducers. The readout unit wirelessly excited a resonant sensor, whose temperature-dependent resonance frequency was extracted from the backscattered signal. This paper provides a description of the underlying passive sensor technology and characterizes the electric impedances and acoustic transmission as an electrical 2-Port to design a functional measurement setup. We demonstrated a wireless temperature measurement through a 10 mm CFRP plate in its full operable temperature range from -40 to 110 °C with a resolution of less than 1 mK.

A new sample chamber for hybrid detection of scattering and fluorescence, using synchrotron radiation in the soft x-ray and extreme ultraviolet (EUV) spectral range.

Smaller and more complex nanostructures in the semiconductor industry require a constant upgrade of accompanying metrological methods and equipment. A central task for nanometrology is the precise determination of structural features of gratings in the nanometer range as well as their elemental composition. Scatterometry and x-ray fluorescence in the soft x-ray and extreme ultraviolet spectral ranges are ideally suited to this task. We here present a new, compact measurement chamber that can simultaneously detect the elastically scattered signal and the fluorescence, originating from nanoscale grating samples. Its geometry enables detecting scattered intensity over a wide angular range with a variable angle of incidence. We show first experiments on industry-relevant test structures from the commissioning process alongside the specifications of the setup, located at PTB's soft x-ray radiometry beamline at the synchrotron radiation facility BESSY II in Berlin.

Frequency Comb-Based Ground-Penetrating Bioradar: System Implementation and Signal Processing.

Radars can be used as sensors to detect the breathing of victims trapped under layers of building materials in catastrophes like earthquakes or gas explosions. In this contribution, we present the implementation of a novel frequency comb continuous wave (FCCW) bioradar module using a commercial software-defined radio (SDR). The FCCW radar transmits multiple equally spaced frequency components simultaneously. The data acquisition of the received combs is frequency domain-based. Hence, it does not require synchronization between the transmit and receive channels, as time domain-based broadband radars, such as ultra wideband (UWB) pulse radar and frequency-modulated CW (FMCW) radar, do. Since a frequency comb has an instantaneous wide bandwidth, the effective scan rate is much higher than that of a step frequency CW (SFCW) radar. This FCCW radar is particularly suitable for small motion detection. Using inverse fast Fourier transform (IFFT), we can decompose the received frequency comb into different ranges and remove ghost signals and interference of further range intervals. The frequency comb we use in this report has a bandwidth of only 60 MHz, resulting in a range resolution of up to 2.5 m, much larger than respiration-induced chest wall motions. However, we demonstrate that in the centimeter range, motions can be detected and evaluated by processing the received comb signals. We want to integrate the bioradar into an unmanned aircraft system for fast and safe search and rescue operations. As a trade-off between ground penetrability and the size and weight of the antenna and the radar module, we use 1.3 GHz as the center frequency. Field measurements show that the proposed FCCW bioradar can detect an alive person through different nonmetallic building materials.

Nanoscale grating characterization using EUV scatterometry and soft x-ray scattering with plasma and synchrotron radiation.

Modern semiconductor structures reach sizes in the nanometer regime. Optical metrology characterizes test structures for the quality assessment of semiconductor fabrication. The limits of radiation to resolve nanometer structure sizes can be overcome by shortening the wavelength. The compact source extreme ultraviolet (EUV) scatterometer presented here characterizes samples in the EUV spectral range using plasma radiation. Reference measurements with synchrotron radiation are carried out using a beamline scatterometer. A comparison including Markov chain Monte Carlo sampling shows that the compact source and beamline setups can both determine the given dimensional parameters of a nanoscale grating with uncertainties in the sub-nanometer range. Grating characterization based on soft x ray scattering has increased accuracy.

Computed tomography angiography/magnetic resonance imaging-based preprocedural planning and guidance in the interventional treatment of structural heart disease.

Preprocedural planning and periprocedural guidance based on image fusion are widely established techniques supporting the interventional treatment of structural heart disease. However, these two techniques are typically used independently. Previous works have already demonstrated the benefits of integrating planning details into image fusion but are limited to a few applications and the availability of the proprietary tools used. We propose a vendor-independent approach to integrate planning details into periprocedural image fusion facilitating guidance during interventional treatment. In this work, we demonstrate the feasibility of integrating planning details derived from computer tomography and magnetic resonance imaging into periprocedural image fusion with open-source and commercially established tools. The integration of preprocedural planning details into periprocedural image fusion has the potential to support safe and efficient interventional treatment of structural heart disease.

An Algorithm for Solving the Phase Ambiguity Problem of SAW Delay-Line Sensor Systems.

Solving the phase ambiguity problem is crucial to achieving a wide-range and high-precision measurement for the frequency-domain sampling (FDS)-based surface acoustic wave (SAW) delay-line sensor systems. This study proposes an improved phase estimation algorithm called dual-band phase estimation (DBPE) to solve the problem. By using DBPE, the SAW sensor system can obtain an extensive and alterable measuring range without further requirements for sensor design or transmitted signals. Thus, it can be widely used in various FDS-based SAW delay-line sensor systems. Monte Carlo simulations and temperature measuring experiments, based on a YZ-cut LiNbO3 SAW delay-line sensor and a switched frequency-stepped continuous wave (S-FSCW) reader, are performed to demonstrate the algorithm's validity. The Monte Carlo simulations show that DBPE can effectively solve the phase ambiguity problem and has better performance than frequency estimation in measuring precision at a low signal-to-noise ratio (SNR). The temperature-sensing experiments show that DBPE has a good performance in measuring range and precision, serving as a phase ambiguity solver in the temperature sensor system.

Structure and mechanism of the RNA dependent RNase Cas13a from Rhodobacter capsulatus.

Cas13a are single-molecule effectors of the Class II, Type VI family of CRISPR-Cas systems that are part of the bacterial and archaeal defense systems. These RNA-guided and RNA-activated RNA endonucleases are characterized by their ability to cleave target RNAs complementary to the crRNA-spacer sequence, as well as bystander RNAs in a sequence-unspecific manner. Due to cleavage of cellular transcripts they induce dormancy in the host cell and thus protect the bacterial population by aborting the infectious cycle of RNA-phages. Here we report the structural and functional characterization of a Cas13a enzyme from the photo-auxotrophic purple bacteria Rhodobacter capsulatus. The X-ray crystal structure of the RcCas13a-crRNA complex reveals its distinct crRNA recognition mode as well as the enzyme in its contracted, pre-activation conformation. Using site-directed mutagenesis in combination with mass spectrometry, we identified key residues responsible for pre-crRNA processing by RcCas13a in its distinct catalytic site, and elucidated the acid-base mediated cleavage reaction mechanism. In addition, RcCas13a cleaves target-RNA as well as bystander-RNAs in Escherichia coli which requires its catalytic active HEPN (higher eukaryotes and prokaryotes nucleotide binding) domain nuclease activity. Our data provide further insights into the molecular mechanisms and function of this intriguing family of RNA-dependent RNA endonucleases that are already employed as efficient tools for RNA detection and regulation of gene expression.

Behavioral Modeling of DC/DC Converters in Self-Powered Sensor Systems with Modelica.

DC/DC converters are the essential component of power management in applications such as self-powered systems. Their simulation plays an important role in the configuration, analysis and design. A major drawback is the lack of behavioral models for DC/DC converters for long-term simulations (days or months). Available models are cycle-to-cycle-based due to the switch-mode nature of the converters and are therefore not applicable. In this work, we present a new behavioral model of a DC/DC power converter. The model is based on a thorough discussion of the model aspects that are relevant for self-powered systems, such as electrical representation and the causal connection if input and output. The model implementation is shown in the Modelica language and is available as an open-source library. The highlights of the model are a feedback controller for operation at the maximum power point (MPP), a loss-based efficiency function, and the start/stop behavior. The model's capabilities are demonstrated in a 24h-experiment to predict voltage levels and the conversion efficiency.

A Novel Electrically Small Ground-Penetrating Radar Patch Antenna with a Parasitic Ring for Respiration Detection.

An electrically small patch antenna with a low-cost high-permittivity ceramic substrate material for use in a ground-penetrating radar is proposed in this work. The antenna is based on a commercial ceramic 915 MHz patch antenna with a size of 25 × 25 × 4 mm3 and a weight of 12.9 g. The influences of the main geometric parameters on the antenna's electromagnetic characteristics were comprehensively studied. Three bandwidth improvement techniques were sequentially applied to optimize the antenna: tuning the key geometric parameters, adding cuts on the edges, and adding parasitic radiators. The designed antenna operates at around 1.3 GHz and has more than 40 MHz continuous -3 dB bandwidth. In comparison to the original antenna, the -3 and -6 dB fractional bandwidth is improved by 1.8 times and 4 times, respectively. Two antennas of the proposed design together with a customized radar were installed on an unmanned aerial vehicle (UAV) for a quick search for survivors after earthquakes or gas explosions without exposing the rescue staff to the uncertain dangers of moving on the debris.

Ribosomal Peptides and Small Proteins on the Rise.

Genetically encoded and ribosomally synthesised peptides and small proteins act as important regulators in fundamental cellular processes, including gene expression, development, signalling and metabolism. Moreover, they also play a crucial role in eukaryotic and prokaryotic defence against microorganisms. Extremely diverse in size and structure, they are often subject to extensive post-translational modification. Recent technological advances are now allowing the analysis of the whole cellular transcriptome and proteome, revealing the presence of hundreds of long-overlooked alternative and short open reading frames (short ORFs, or sORFs) in mRNA and supposedly noncoding RNAs. However, in many instances the biological roles of their translational products remain to be elucidated. Here we provide an overview on the intriguing structural and functional diversity of ribosomally synthesised peptides and newly discovered peptides and small proteins.

Selective Activation of Human Caseinolytic Protease†P (ClpP).

Caseinolytic protease P (ClpP) is the proteolytic component of the ClpXP protein degradation complex. Eukaryotic ClpP was recently found to act within the mitochondria-specific unfolded protein response (UPRmt ). However, its detailed function and dedicated regulation remain largely unexplored. A small molecule (D9) acts as a potent and species-selective activator of human ClpP (hClpP) by mimicking the natural chaperone ClpX. Structure-activity relationship studies highlight the importance of a halogenated benzyl motif within D9 that interacts with a unique aromatic amino acid network in hClpP. Mutational and structural studies suggest that this YYW motif tightly controls hClpP activity and regulates substrate turnover by interaction with cognate ligands. This signature motif is unique to ClpP from higher organisms and does not exist in tested bacterial homologues, allowing a species-selective analysis. Thus, D9 is a versatile tool to analyze mechanistic features of hClpP.

Evaluation of combined growth media for in vitro cultivation of oropharyngeal biofilms on prosthetic silicone.

In the upper aerodigestive tract, biofilm deposits by oropharyngeal microbes can cause failure of medical polymer devices like voice prostheses. Previous studies on testing of inhibitive strategies still lack of comparability due to varying study protocols concerning growth media, microbial species and growth conditions. Goal of the study was therefore to test cultivation of a mixed biofilm of isolated oropharyngeal microbes under in vitro growth conditions using mixtures of common growth media. Mixtures of yeast peptone dextrose medium (YPD), fetal bovine serum (FBS), RPMI 1640, Yeast nitrogen base medium (YNB) and brain heart infusion (BHI) were tested to grow mixed biofilm deposits of Candida albicans, Candida tropicalis, Staphylococcus aureus, Streptococcus epidermidis, Rothia dentocariosa and Lactobacillus gasseri on medical grade silicone. Periodic assessment of living biofilm was performed over 22 days by a digital microscope and the cultivated biofilm structures were analyzed by scanning electron microscopy after completion of the study. Mixtures of BHI, YPD and FBS improved microscopic growth of multispecies biofilm deposits over time, while addition of RPMI and YNB resulted in reduction of visible biofilm deposit sizes. A mixtures of FBS 30% + YPD 70% and BHI 30% + YPD 70% showed enhanced support of permanent surface growth on silicone. Growth kinetics of in vitro multispecies biofilms can be manipulated by using mixtures of common growth media. Using mixtures of growth media can improve growth of longterm multispecies oropharyngeal biofilm models used for in vitro testing of antibiofilm materials or coatings for voice prostheses.

Medlay: A Reconfigurable Micro-Power Management to Investigate Self-Powered Systems.

In self-powered microsystems, a power management is essential to extract, transfer and regulate power from energy harvesting sources to loads such as sensors. The challenge is to consider all of the different structures and components available and build the optimal power management on a microscale. The purpose of this paper is to streamline the design process by creating a novel reconfigurable testbed called Medlay. First, we propose a uniform interface for management functions e.g., power conversion, energy storing and power routing. This interface results in a clear layout because power and status pins are strictly separated, and inputs and outputs have fixed positions. Medlay is the ready-to-use and open-hardware platform based on the interface. It consists of a base board and small modules incorporating e.g., dc-dc converters, power switches and supercapacitors. Measurements confirm that Medlay represents a system on one circuit board, as parasitic effects of the interconnections are negligible. The versatility regarding different setups on the testbed is determined to over 250,000 combinations by layout graph grammar. Lastly, we underline the applicability by recreating three state-of-the-art systems with the testbed. In conclusion, Medlay facilitates building and testing power management in a very compact, clear and extensible fashion.