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Investigation of algorithms for qualitative brachial artery diameter cycle segmentation from ultrasound b-mode videos
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Lasers, flowers, bees: modeling the number of flowers and bee forage on cherry trees using 3D point clouds
No full textCurrently, there is little quantitative data available on the number of flowers per tree, especially in relation to tree size. In our study, we modeled the number of flowers of wild cherry trees (Prunus avium L.) using a novel approach that combines manually collected count data with 3D information on tree structures. Using this data, we were able to estimate the amount of nectar and pollen, as well as the number of potentially supported bee larvae. We found that trees with larger diameters carry a disproportionately higher number of flowers compared to smaller trees
GreenHyperSpectra: a multi-source hyperspectral dataset for global vegetation trait prediction
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Evaluation of combined treatment with picosecond laser and acoustic shock wave therapy for tattoo removal: a prospective randomized controlled trial
No full textBackgroundLaser tattoo removal traditionally employs q-switched and picosecond lasers, which require multiple sessions. Besides the selective photothermolysis that laser devices offer, the photoacoustic effect by acoustic pulse devices may provide further benefits.ObjectivesTo assess the efficacy of combined use of a radial shock acoustic wave (SAW) device and a picosecond laser in quicker clearance of tattoos.MethodsA split-lesion study was performed in 32 adult patients with Fitzpatrick skin type I–III. Overall, 26 tattoos were evaluated until the end of the study. One side of each tattoo received only the picosecond laser treatment, and the other side, a sequential combination of picosecond and SAW. The sessions were repeated at 4–6 weeks intervals for a total of four sittings. Outcome assessment was carried out by two blinded assessors using standardized photography. An assessment of physician improvement score, side-effects score and patient satisfaction score (Visual Analogue Scale of Pain [VAS] and 5-point Likert scale) was taken during and at the end of the study.ResultsThe blinded assessment showed a statistically significant improvement on the SAW+picosecond laser treatment side (p = 0.14; OR: 5.44; 95% CI: 1.41–21.05). Scores in VAS for pain decreased through the sessions, with the combination side exhibiting a more pain-tolerant profile. Regarding the outcome of patient satisfaction, at Visit 4, the mean value for the SAW-treated side was 3.9 (more clear difference), whereas only 3/26 participants stated that the only laser-treated side was marginally better. No serious side effects were reported.ConclusionsThe addition of a radial shock acoustic wave device to the state-of-the-art picosecond laser treatment seems to offer a more effective and well-tolerated approach for tattoo removal
Serum metabolites characterize hepatic phenotypes and reveal shared pathways: results from population-based imaging
No full textBackgroundSteatotic liver disease is a major public health issue, with hepatic iron overload exacerbating fibrotic conditions. This study aimed to identify metabolites associated with hepatic fat and/or iron overload using targeted metabolomics in a population-based cohort.MethodsWe used the cross-sectional KORA-MRI study (N = 376 individuals). Hepatic fat and iron content were derived by magnetic resonance imaging, and serum metabolite concentrations were quantified through targeted metabolomics. Associations between 146 metabolites and 40 indicators with hepatic phenotypes were analyzed, adjusted for confounders, and corrected for multiple testing. Formal pathway analyses and mediation analyses including genetic data were conducted. Performance of metabolomics to diagnose steatosis or hepatic iron overload was evaluated using ROC curves, and compared to the fatty liver index (FLI).ResultsOverall, 50.8% of participants (mean age 56.4 years) had hepatic steatosis, and 43.6% iron overload. Twelve unique metabolites/indicators (amino acids, lysophosphatidylcholine, acyl-alkyl-phosphatidylcholine), and sums of branched chain and aromatic amino acids, and five lipids, and ratio of acyl-alkyl-phosphatidylcholines to diacyl-phosphatidylcholines were associated with hepatic fat content. 27 metabolites/indicators, including 25 lipids, were associated with hepatic iron content. Addition of these metabolites to the FLI improved diagnosis of steatosis and iron overload nominally. Glycerophospholipid metabolism, phenylalanine, tyrosine and tryptophan biosynthesis and glycerophospholipid metabolism were shared pathway between steatosis and iron overload. Alanine, isoleucine, glutamine and pimeloylcarnitine (C7-DC) mediated effects between genetic variants and hepatic phenotypes.ConclusionMetabolites were associated with hepatic fat and iron content, shared common pathways, and improved diagnosis of steatosis and iron overload, highlighting the role of iron in hepatic disorders
Entwicklung eines piezoelektrischen MEMS-Lautsprechers mit gefalteter Membran
No full textDie zunehmende Integration portabler Audioprodukte, wie z.B. In-Ohr-Kopfhörer, in den Alltag hat in den vergangenen Jahren zu einer gestiegenen Nachfrage an entsprechenden Systemen geführt. Dabei werden insbesondere Anforderungen an eine kontinuierliche Ver-besserung der Tonqualität, an komfortablere Entwürfe, längere Batterielaufzeit und niedri-gere Preise gestellt. In Bezug auf diese Eigenschaften nimmt der integrierte Mikrolautspre-cher eine entscheidende Rolle ein. In den gegenwärtigen Systemen kommen konventionelle elektrodynamische Lautsprecher zum Einsatz, die allerdings aufgrund der verwendeten Materialien und der aufwendigen Herstellung in ihrer Miniaturisierung limitiert sind. Dies hat einen negativen Einfluss auf vor allem die akustischen Eigenschaften des Systems. Die Realisierung von Lautsprechern als mikroelektromechanisches System (MEMS) zielt darauf ab, die Vorteile des hohen Miniaturisierungsgrads und der effizienten Herstellungs-möglichkeiten zu nutzen, um konventionelle Lautsprecher in In-Ohr-Systemen zu ersetzen. Trotz der kleinen Dimensionen wird ein adäquater Schalldruckpegel erreicht, indem inno-vative Membrankonzepte entwickelt werden, die entweder zu größeren Auslenkungen oder zu größeren abstrahlenden Flächen aus einem minimalen Chipvolumen führen. In dieser Arbeit wird entsprechend des zuletzt genannten Ansatzes ein neuartiger, dreidi-mensional gefalteter MEMS-Lautsprecher konzipiert und realisiert. Die Membran besteht dabei aus einer Vielzahl vertikaler Aktoren, die piezoelektrisch in lateraler Richtung aktu-iert werden. In diesem Fall wird die aktiv abstrahlende Fläche proportional zur Anzahl und zur Dimension der Aktoren vergrößert, ohne die Chipfläche zu verändern. Zur Simulation des Lautsprecherverhaltens wird ein physikalisch basiertes Systemmodell entwickelt. Die-ses umfasst die elektrische, die mechanische und die akustische Domäne sowie den Ein-fluss eines standardisierten Ohrsimulators, in dem der Lautsprecher charakterisiert wird. Bei der technologischen Realisierung der gefalteten Membran werden kritische Einzelpro-zesse identifiziert, die in der vorliegenden Arbeit untersucht werden. Für die Integration der piezoelektrischen Schicht wird mittels Atomic Layer Deposition (ALD) abgeschiede-nes Aluminiumnitrid (AlN) ausgewählt, da es aufgrund seiner Material- und Prozesseigen-schaften für diesen Zweck besonders geeignet ist. Die Lithographieschritte erfolgen mittels Trockenfilm-Technologie, wodurch das Bearbeiten der Strukturoberflächen auf dem struk-turierten Substrat ermöglicht wird. Zur Freistellung der gefalteten Struktur wird eine Kom-bination von anisotropen und isotropen Ätzverfahren entwickelt und anhand von Teststruk-turen evaluiert. Der in dieser Arbeit entwickelte Lautsprecherchip wird elektrisch, mecha-nisch und akustisch charakterisiert. Anhand der akustischen Messergebnisse im Ohrsimu-lator kann schließlich das entworfene Systemmodell mit einer guten Übereinstimmung va-lidiert werden. Der Vergleich der gemessenen Eigenschaften mit den für die Anwendung in In-Ohr-Sys-temen erforderlichen Kennwerten zeigt, dass davon bereits einige mit dem vorliegenden Lautsprecher erfüllt werden können. Um auch die Lücke zu den noch nicht erfüllten An-forderungen zu schließen, nutzt diese Arbeit das validierte Systemmodell, um ausblickend weitere Entwicklungsschritte für den gefalteten Lautsprecher zu beschreiben
Ultrafast complex-valued 4D fMRI reveals sleep-induced brain respiratory pulsation changes in both magnitude and phase signals
No full textPhysiological brain pulsations play a critical role in sleep physiology, but their underlying mechanisms remain poorly understood. To study these pulsations more deeply, we employed ultrafast magnetic resonance encephalography (MREG) to capture complex-valued 4D fMRI brain data at a critical 10 Hz sampling rate in healthy volunteers during wakefulness and sleep. We compared the phase and magnitude components of the MREG signal, as the phase component is known to be particularly sensitive to subtle flow and susceptibility changes, offering insights beyond magnitude-only analysis. This approach enabled whole-brain mapping of the amplitudes of all three physiological pulsations - very low frequency (VLF), cardiac, and respiratory - using an extended amplitude of low frequency fluctuation (ALFF) method. We identified significant increases in respiratory amplitudes during sleep compared to wakefulness in both phase and magnitude signals, while the VLF and cardiac phase amplitudes did not show significant differences. Phase respiration map showed increase especially in default mode network regions, while additional patterns were observed in the cerebellum, ventricles, cerebral aqueduct, and subarachnoid cisterns. In contrast, the magnitude maps showed increased amplitudes more widespread across the cerebrum. These findings highlight the complementary nature of phase and magnitude data in fMRI and suggest that combining these signals provides a more comprehensive understanding of brain physiological dynamics during sleep than conventional magnitude-only analyses