Standard Setup Research Articles

A Framework for Algae Modeling in Regulatory Risk Assessment.

The use of toxicokinetic-toxicodynamic (TKTD) modeling in regulatory risk assessment of plant protection products is increasingly popular, especially since the 2018 European Food Safety Authority (EFSA) opinion on TKTD modeling announced that several established models are ready for use in risk assessment. With careful adherence to the guidelines laid out by EFSA, we present a stepwise approach to validation and use of the Simple Algae Model Extended (SAM-X) for regulatory submission in Tier 2C. We demonstrate how the use of moving time windows across time-variable exposure profiles can generate thousands of virtual laboratory mimic simulations that seamlessly predict the effects of time-variable exposures across a full exposure profile while maintaining the laboratory conditions of the standard Organisation for Economic Co-operation and Development (OECD) growth inhibition test. Thus, every virtual laboratory test has a duration of 72 h, with OECD medium and constant light and temperature conditions. The only deviation from the standard test setup is the replacement of constant exposure conditions for time-variable concentrations. The present study demonstrates that for simulation of 72-h toxicity tests, the nutrient dynamics in the SAM-X model are not required, and we propose the alternative use of a simplified model version. For risk assessment, in accordance with the EFSA guidelines we use a median exposure profile of 10 as a threshold, meaning that if a time window within the exposure profile causes 50% growth inhibition when magnified by a factor of 10, the threshold will have been exceeded. We present a simplified example for chlorotoluron and isoproturon. The present case study brings to life our proposed framework for TKTD modeling of algae to establish whether a given exposure can be considered to be of low risk. Environ Toxicol Chem 2023;42:1823-1838. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Sensitive riboflavin sensing using silver nanoparticles deposited onto screen-printed electrodes via controlled-energy spark discharges

In this work, we elaborated the graphite screen-printed electrodes (SPEs) modification with metal nanoparticles formed as a result of spark discharges produced between a metal wire electrode and SPE that are connected to an Arduino board-based DC high voltage power supply. This sparking device allows, on the one hand, the toposelective formation of NPs of controlled dimensions through a direct and liquid-free approach, and on the other hand, controls the number and energy of the discharges delivered to the electrode surface during a single spark event. This way, the potential damage to the SPE surface by the action of heat evolved during the sparking process is considerably minimized compared with the standard setup in which each spark event consists of multiple electrical discharges. Data demonstrated that the sensing properties of the resulting electrodes are significantly improved compared with those achieved when conventional spark generators are employed, as demonstrated for silver-sparked SPEs that exhibit enhanced sensitivity to riboflavin. Sparked AgNp-SPEs were characterized using scanning electron microscopy and voltammetric measurements in alkaline conditions. The analytical performance of sparked AgNP-SPEs was evaluated by various electrochemical techniques. Under optimum conditions, the detection range for DPV was from 1.9 (LOQ) to 100nM riboflavin (R2=0.997), while a limit of detection (LOD, S/N 3) of 0.56nM was achieved. The analytical utility is demonstrated for the determination of riboflavin in the real matrices of B-complex pharmaceutical preparation and an energy drink.

Augmented Reality Visualization and Interaction for COVID-19 CT-Scan NN Automated Segmentation: A Validation Study

Although medical imaging technology has persisted in evolving over the last decades, the techniques and technologies used for analytical and visualisation purposes have remained constant. Manual or semi-automatic segmentation is, in many cases, complicated. It requires the intervention of a specialist and is time-consuming, especially during the Coronavirus disease (COVID-19) pandemic, which has had devastating medical and economic consequences. Processing and visualising medical images with advanced techniques represent medical professionals’ breakthroughs. This paper studies how augmented reality (AR) and artificial intelligence (AI) can transform medical practice during COVID-19 and post-COVID-19 pandemic. Here we report an augmented reality visualisation and interaction platform; it covers the whole process from uploading chest Ct-scan images to automatic segmentation-based deep learning, 3D reconstruction, 3D visualisation, and manipulation. AR provides a more realistic 3D visualisation system, allowing doctors to effectively interact with the generated 3D model of segmented lungs and COVID-19 lesions. We use the U-Net Neural Network (NN) for automated segmentation. The statistical measures obtained using the Dice score, pixel accuracy, sensitivity, G-mean, and specificity are 0.749, 0.949, 0.956, 0.955, and 0.954, respectively. The user-friendliness and usability are objectified by a formal user study that compared our augmented reality-assisted design to the standard diagnosis setup. One hundred and six doctors and medical students, including eight senior medical lecturers, volunteered to assess our platform. The platform could be used as an aid diagnosis tool to identify and analyse the COVID-19 infectious or as a training tool for residents and medical students. The prototype can be extended to other pulmonary pathologies.

Josephson parametric circulator with same-frequency signal ports, 200 MHz bandwidth, and high dynamic range

We demonstrate a 3-port Josephson parametric circulator matched to 50 Ω using second order Chebyshev networks. The device notably operates with two of its signal ports at the same frequency and uses only two out-of-phase pumps at a single frequency. As a consequence, when operated as an isolator, it does not require phase coherence between the pumps and the signal, thus simplifying the requirements for its integration into standard dispersive qubit readout setups. The device utilizes parametric couplers based on a balanced bridge of rf-superconducting quantum interference device arrays, which offer purely parametric coupling and high dynamic range. We characterize the device by measuring its full 3 × 3 S-matrix as a function of frequency and the relative phase between the two pumps. We find up to 15 dB nonreciprocity over a 200 MHz signal band, port match better than 10 dB, low insertion loss of 0.6 dB, and saturation power exceeding −80 dBm.

In-flight recoil separators RITU and MARA and the standard detector setups

In-flight recoil separators RITU and MARA at Jyväskylä Accelerator Laboratory are complementary devices to separate the fusion-evaporation residues from the primary beam and other reaction products. The nuclear-structure-research program at Jyväskylä utilizes these separators and the detector setups shared between the separators to identify weak reaction channels and extract nuclear-structure information via decay experiments and in-beam spectroscopic studies. For example the very weak N∼Z nuclei are studied in-beam by using β-decay tagging method (Tuike scintillator) enhanced with the mass selection (MARA) and charge particle-evaporation veto (JYTube).

Measurement of Electric Charge in a Charged Hydroxyapatite Dielectric Using Pendant Drop.

A simple noninvasive measurement method which allows one to determine the trapped charge in a biocompatible hydroxyapatite dielectric is developed. The hydroxyapatite samples are charged by electron beam with energy 30 keV and total irradiated charge ranging from 2 × 10-9 C to 2 × 10-7 C. The value of the trapped charge is determined by analyzing the shape change of a liquid droplet hanging from a needle in proximity of the charged sample surface. The shape change of the pendant drop in the field of gravity is commonly utilized in the measurements of the surface free tension (SFT) of liquids. The external electric field leads to a further modification of the droplet shape and to an effective change of the SFT. The change of the SFT as a function of distance between the droplet and sample and the critical distance at which the droplet detaches from the needle are measured for various values of the irradiated charge. These two quantities are also derived theoretically by considering the trapped charge as a single fitting parameter. We can thus determine the trapped charge in two independent noninvasive ways. It is noteworthy that our method is easily implementable into the standard pendant drop setups. As a practical application of the method, a long-term charge stability of the charged hydroxyapatite is demonstrated, thus paving the way toward quantitative studies of its bioactivity in dependence on the value of the trapped charge.

Methane Emissions from a State-of-the-Art LNG-Powered Vessel

To meet stringent fuel sulfur limits, together with NOx limits, ships are increasingly utilizing dual-fuel (DF) engines operating with liquified natural gas (LNG) as the primary fuel. Compared to diesel, LNG combustion produces less CO2, which is needed in targeting the reduction of the shipping impact on the climate; however, this could be significantly interfered with by the methane emission formation. In this study, the methane emissions, together with other emission components, were studied by measurements onboard a state-of-the-art RoPax ferry equipped with two different development-stage engines. The results from the current standard state-of-the-art DF engine showed methane levels that were, in general, lower than what has been reported earlier from onboard studies with similar sized DF engines. Meanwhile, the methane emission from the DF engine piloting the new combustion concept was even lower, 50–70% less than that of the standard DF engine setup. Although the CO2 was found to slightly increase with the new combustion concept, the CO2 equivalent (including both methane and CO2) was smaller than that from the standard DF engine, indicating that the recent development in engine technology is less harmful for the climate. Additionally, lower NOx and formaldehyde levels were recorded from the new combustion concept engine, while an increase in particle emissions compared to the standard DF engine setup was observed. These need to be considered when evaluating the overall impacts on the climate and health effects.

Spotlighting the boosted energy storage capacity of CoFe2O4/Graphene nanoribbons: A promising positive electrode material for high-energy-density asymmetric supercapacitor

CoFe2O4/Graphene Nanoribbons (GNRs) nanocomposite was successfully fabricated and utilised as an electrode active material for high-energy supercapacitor cells. Thanks to the outstanding physicochemical features of a graphene nanoribbon with excellent electrical conductivity and the synergistic effect with cobalt ferrite, as well as the pseudocapacitive effect. The CoFe2O4/GNRs nanohybrid offered an exceptional specific capacitance of 922 F g−1 (415 C g−1) at 1.0 A g−1 in 3.0 M KOH electrolyte in a standard 3-electrode set-up. Additionally, the impressive supercapacitive performance metrics showed that the suggested electrode had a distinctive morphology and could be a candidate for capacitive energy storage systems. These metrics included good cycle stability and 87% capacitance retention at the end of the 10,000th CV cycle. Moreover, the asymmetric supercapacitor cell (ASC) was designed by assembling CoFe2O4/GNRs and activated carbon (AC). The resultant ASC provided an improved specific capacitance of 487.85 F g−1 (683 C g−1) at 1.0 A g−1. At this current density value, the energy density and the power density values were computed as to be 132.8 Wh.kg−1 and 632.39 W kg−1. The highest power density was discovered to be 6730.76 W kg−1 at 10.0 A g−1, whereas the energy density was determined as 8.75 Wh.kg−1 at this current density. The results of the work proved that CoFe2O4/GNRs nanohybrids are up-and-coming electrode active materials for advanced electrochemical energy storage and conversion technologies.

A compact and versatile cryogenic probe station for quantum device testing.

Fast feedback from cryogenic electrical characterization measurements is key for the development of scalable quantum computing technology. At room temperature, high-throughput device testing is accomplished with a probe-based solution, where electrical probes are repeatedly positioned onto devices for acquiring statistical data. In this work, we present a probe station that can be operated from room temperature down to below 2K. Its small size makes it compatible with standard cryogenic measurement setups with a magnet. A large variety of electronic devices can be tested. Here, we demonstrate the performance of the prober by characterizing silicon fin field-effect transistors as a host for quantum dot spin qubits. Such a tool can massively accelerate the design-fabrication-measurement cycle and provide important feedback for process optimization toward building scalable quantum circuits.

Automated staging of zebrafish embryos using machine learning.

The zebrafish ( Danio rerio), is an important biomedical model organism used in many disciplines, including development, disease modeling and toxicology, to better understand vertebrate biology. The phenomenon of developmental delay in zebrafish embryos has been widely reported as part of a mutant or treatment-induced phenotype, and accurate characterization of such delays is imperative. Despite this, the only way at present to identify and quantify these delays is through manual observation, which is both time-consuming and subjective. Machine learning approaches in biology are rapidly becoming part of the toolkit used by researchers to address complex questions. In this work, we introduce a machine learning-based classifier that has been trained to detect temporal developmental differences across groups of zebrafish embryos. Our classifier is capable of rapidly analyzing thousands of images, allowing comparisons of developmental temporal rates to be assessed across and between experimental groups of embryos. Finally, as our classifier uses images obtained from a standard live-imaging widefield microscope and camera set-up, we envisage it will be readily accessible to the zebrafish community, and prove to be a valuable resource.

Depth resolved imaging by digital holography via sample-shifting

Depth resolved imaging is achieved by evenly displacing the sample in the lateral direction using a standard digital holographic setup. A series of holograms are recorded in the reflection geometry while the sample is evenly moved and an algorithm is developed to selectively construct the complex amplitude of the sample at specific focal depths. The amount of information needed for reconstruction is significantly decreased by the recommended method. The suggested approach is suitable for three-dimensional imaging applications, particularly for high transmittance materials, according to experimental findings obtained using a basic holographic setup.

A High-Speed Hyperspectral Laparoscopic Imaging System.

Minimally invasive surgery (MIS) has expanded broadly in the field of abdominal and pelvic surgery. Laparoscopic and robotic surgery has improved surgeon ergonomics, instrument precision, operative time, and postoperative recovery across various abdominal procedures. The goal of this study is to establish the feasibility of implementing high-speed hyperspectral imaging into a standard laparoscopic setup and exploring its benefit to common intracorporeal procedures. A hyperspectral laparoscopic imaging system was constructed using a customized hyperspectral camera alongside a standard rigid laparoscope and was validated for both spectral and spatial accuracy. Demosaicing methods were investigated for improved full-resolution visualization. Hyperspectral cameras with different spectral ranges were considered and compared with one another alongside two different light sources to determine the most effective configuration. Finally, different porcine tissues were imaged ex-vivo to test the capabilities of the system and spectral footprints of the various tissues were extracted. The tissue was also imaged in a phantom to simulate the system's use in MIS. The results demonstrated a hyperspectral laparoscopic imaging system that could provide quantitative, diagnostic information while not disrupting normal workflow nor adding excessive weight to the laparoscopic setup. The high-speed hyperspectral laparoscopic imaging system can have immediate applications in image-guided surgery.

Simulation of the Propagation and Effects of Gravity Waves Generated by Tonga Volcano Eruption in the Thermosphere and Ionosphere Using Nested‐Grid TIEGCM

AbstractThe Hunga Tonga‐Hunga Ha'apai volcano eruption on 15 January 2022 triggered strong atmospheric gravity wave (GW) activity in the upper atmosphere, which was later detected by various observations. We perform one of the first ionosphere‐thermosphere (I‐T) model studies of the GW effects from the Tonga eruption in the ionosphere‐thermosphereI‐T system using the thermosphere‐ionosphere‐electrodynamics general circulation model (TIEGCM). We implement a high‐resolution mesh inside a regional domain (nested grid) in addition to the global low‐resolution mesh, which differs from the standard global uniform resolution setup. The nested‐grid TIEGCM (TIEGCM‐NG) successfully simulates the observed wave propagation and effects in the I‐T system by further nudging GW fields at TIEGCM lower boundaries (∼97 km) using output from the high‐resolution whole atmosphere community climate model with thermosphere and ionosphere extension simulations. The simulation results indicate that the critical parameter to simulate GW propagation is horizontal resolution. Inside the high‐resolution nested region, GWs with horizontal wavelengths of ∼400 km and periods of 10–30 min can propagate outward and upward and produce significant ionospheric disturbances close to observations. Outside the nested region, only long‐wavelength, low‐frequency waves survive. Another test indicates that GWs can be better resolved when geopotential height is nudged at TIEGCM lower boundaries. With the capability of simultaneously simulating local, small to mesoscale I‐T processes, TIEGCM‐NG is superior to global high‐resolution simulations due to its largely reduced computation cost and may find its application in the study of I‐T system regional dynamics.

On dynamic channel emulation in sector MPAC for over-the-air testing of beamformed massive MIMO devices

In this article, novel emulation strategies for the sectored multiple probe anechoic chamber (SMPAC) are proposed to enable the reliable evaluation of the massive multiple-input multiple-output (MIMO) device operating at beamforming mode, which requires a realistic non-stationary channel environment. For the dynamic propagation emulation, an efficient closed-form probe weighting strategy minimizing the power angular spectrum (PAS) emulation errors is derived, substantially reducing the associated computational complexity. On the other hand, a novel probe selection algorithm is proposed to reproduce a more accurate fading environment. Various standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed methods. The simulation results show that more competent active probes are selected with the proposed method compared to the conventional algorithms. Furthermore, the derived closed-form probe weighting strategy offers identical accuracy to that obtained with complicated numerical optimization. Moreover, a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies, and 95.6% PAS similarity can be achieved with 6 active probes. The satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.

Virtual reality set-up for studying vestibular function during head impulse test.

Virtual reality (VR) offers an ecological setting and the possibility of altered visual feedback during head movements useful for vestibular research and treatment of vestibular disorders. There is however no data quantifying vestibulo-ocular reflex (VOR) during head impulse test (HIT) in VR. The main objective of this study is to assess the feasibility and performance of eye and head movement measurements of healthy subjects in a VR environment during high velocity horizontal head rotation (VR-HIT) under a normal visual feedback condition. The secondary objective is to establish the feasibility of VR-HIT recordings in the same group of normal subjects but under altered visual feedback conditions. Twelve healthy subjects underwent video HIT using both a standard setup (vHIT) and VR-HIT. In VR, eye and head positions were recorded by using, respectively, an imbedded eye tracker and an infrared motion tracker. Subjects were tested under four conditions, one reproducing normal visual feedback and three simulating an altered gain or direction of visual feedback. During these three altered conditions the movement of the visual scene relative to the head movement was decreased in amplitude by 50% (half), was nullified (freeze) or was inverted in direction (inverse). Eye and head motion recording during normal visual feedback as well as during all 3 altered conditions was successful. There was no significant difference in VOR gain in VR-HIT between normal, half, freeze and inverse conditions. In the normal condition, VOR gain was significantly but slightly (by 3%) different for VR-HIT and vHIT. Duration and amplitude of head impulses were significantly greater in VR-HIT than in vHIT. In all three altered VR-HIT conditions, covert saccades were present in approximatively one out of four trials. Our VR setup allowed high quality recording of eye and head data during head impulse test under normal and altered visual feedback conditions. This setup could be used to investigate compensation mechanisms in vestibular hypofunction, to elicit adaptation of VOR in ecological settings or to allow objective evaluation of VR-based vestibular rehabilitation.

Automated staging of zebrafish embryos using machine learning

The zebrafish (Danio rerio), is an important biomedical model organism used in many disciplines, including development, disease modeling and toxicology, to better understand vertebrate biology. The phenomenon of developmental delay in zebrafish embryos has been widely reported as part of a mutant or treatment-induced phenotype, and accurate characterization of such delays is imperative. Despite this, the only way at present to identify and quantify these delays is through manual observation, which is both time-consuming and subjective. Machine learning approaches in biology are rapidly becoming part of the toolkit used by researchers to address complex questions. In this work, we introduce a machine learning-based classifier that has been trained to detect temporal developmental differences across groups of zebrafish embryos. Our classifier is capable of rapidly analyzing thousands of images, allowing comparisons of developmental temporal rates to be assessed across and between experimental groups of embryos. Finally, as our classifier uses images obtained from a standard live-imaging widefield microscope and camera set-up, we envisage it will be readily accessible to the zebrafish community, and prove to be a valuable resource.

Minimizing the distortions in electrophysiological source imaging of cortical oscillatory activity via Spectral Structured Sparse Bayesian Learning.

Oscillatory processes at all spatial scales and on all frequencies underpin brain function. Electrophysiological Source Imaging (ESI) is the data-driven brain imaging modality that provides the inverse solutions to the source processes of the EEG, MEG, or ECoG data. This study aimed to carry out an ESI of the source cross-spectrum while controlling common distortions of the estimates. As with all ESI-related problems under realistic settings, the main obstacle we faced is a severely ill-conditioned and high-dimensional inverse problem. Therefore, we opted for Bayesian inverse solutions that posited a priori probabilities on the source process. Indeed, rigorously specifying both the likelihoods and a priori probabilities of the problem leads to the proper Bayesian inverse problem of cross-spectral matrices. These inverse solutions are our formal definition for cross-spectral ESI (cESI), which requires a priori of the source cross-spectrum to counter the severe ill-condition and high-dimensionality of matrices. However, inverse solutions for this problem were NP-hard to tackle or approximated within iterations with bad-conditioned matrices in the standard ESI setup. We introduce cESI with a joint a priori probability upon the source cross-spectrum to avoid these problems. cESI inverse solutions are low-dimensional ones for the set of random vector instances and not random matrices. We achieved cESI inverse solutions through the variational approximations via our Spectral Structured Sparse Bayesian Learning (ssSBL) algorithm https://github.com/CCC-members/Spectral-Structured-Sparse-Bayesian-Learning. We compared low-density EEG (10-20 system) ssSBL inverse solutions with reference cESIs for two experiments: (a) high-density MEG that were used to simulate EEG and (b) high-density macaque ECoG that were recorded simultaneously with EEG. The ssSBL resulted in two orders of magnitude with less distortion than the state-of-the-art ESI methods. Our cESI toolbox, including the ssSBL method, is available at https://github.com/CCC-members/BC-VARETA_Toolbox.

The following video describes our technique of Mitral Valve Repair on a fibrillating heart. We demonstrate our standard setup as well as port placement followed by several steps in preparation for a fibrillatory arrest. The video displays the access to the left atrium followed by neocords creation and ring placement as a reproducible and safe technique.

The following video describes our technique of Mitral Valve Repair on a fibrillating heart. We demonstrate our standard setup as well as port placement followed by several steps in preparation for a fibrillatory arrest. The video displays the access to the left atrium followed by neocords creation and ring placement as a reproducible and safe technique.

Thermally corrected masses and freeze-in dark matter: A case study

If coupled \emph{feebly} to the Standard Model bath, a dark matter can evade the severe constraints from the direct search experiments. At the same time, such interactions help produce dark matter via the freeze-in mechanism. The freeze-in scenario becomes more interesting if one also includes the thermal masses of the different particles involved in the dark matter phenomenology. Incorporating such thermal corrections opens up the possibility of dark matter production via forbidden channels that remain kinematically disallowed in the standard freeze-in setup. Motivated by this, we investigate such freeze-in production of the dark matter in a minimally extended $U(1)_{L_\mu-L_\tau}$ framework that remains consistent with the recent muon $(g-2)$ data. Here, the role of the dark matter is played by the scalar with a non-trivial charge under the additional symmetry $U(1)_{L_\mu-L_\tau}$. This scalar dark matter obtains a thermally corrected mass at high temperatures for a not-so-small self-coupling. We show that the thermal correction to the dark matter mass plays a significant role in the dark matter phenomenology.

Simulation of Cocrystal Formation in Planetary Atmospheres: The C6H6:C2H2 Cocrystal Produced by Gas Deposition.

The formation of molecular cocrystals in condensed aerosol particles has been recently proposed as an efficient pathway for generation of complex organics in Titan's atmosphere. It follows that cocrystal precipitation may facilitate the transport of biologically important precursors to the surface to be sequestered in an organic karstic and sand environment. Recent laboratory studies on these planetary minerals have predominantly synthesized cocrystals by the controlled freezing of binary mixtures from the liquid phase, allowing for their structural and spectroscopic characterization. However, these techniques are perhaps not best representative of aerosol nucleation and growth microphysics in planetary atmospheres. Herein, we report the first synthesis of the known 1:1 C6H6:C2H2 cocrystal using vapor deposition methods onto a cryogenically cooled substrate. Subsequent transmission FTIR spectroscopy has confirmed the formation of the empirical C6H6:C2H2 cocrystal structure via the observation of diagnostic infrared spectral features. Predicted by periodic-DFT calculations, altered vibrational profiles depict a changing site symmetry of the C6H6 and C2H2 components after transition to the cocrystal unit cell geometry. The 80 K temperature of the cocrystal phase transition overlaps with the condensation curves obtained for both species in Titan's lower stratosphere, revealing that the cocrystal may act as an important environment for photo- and radio-lytic processes leading to the formation of higher order organics in Titan's atmosphere. Such solid-state astrochemistry can now be pursued in oxygen-free laboratory settings under (ultra)high vacuum using standard surface science setups.