Maximum Signal Research Articles

Late iodine enhancement quantification by computed tomography: a comparison study against cardiac magnetic resonance imaging

Abstract Introduction Cardiac computed tomography (CT) has emerged as a promising alternative to cardiac magnetic resonance (CMR) for myocardial characterization. However, the quantification of late iodine enhancement (LIE) and its threshold values have not been previously reported. The Full Width Half Maximum (FWHM) technique established a cut-off value of 50% of the maximum intensity signal to quantify late gadolinium enhancement (LGE) in CMR. Nevertheless, the distinction between healthy and fibrotic myocardium in CT is less pronounced, prompting the need for specific threshold values for accurate quantification of LIE with this technique. Purpose Our primary aim was to validate and determine the optimal cut-off values for quantifying LIE using cardiac CT. Methods We included consecutive patients who underwent both LIE and LGE within a period of less than 2 months. Late enhancement quantification was performed using a commercially available software (figure 1). The FWHM technique was applied for LGE quantification. Various signal density cut-off values (70%, 75%, 80%, 85%, and 90%) were explored for LIE quantification. The total myocardial mass, total scar mass and scar proportion were calculated. The Intraclass Correlation Coefficient (ICC) was computed for each of the specified cut-off values. Results From November 2022 to February 2024, 58 patients underwent cardiac CT with LIE. Among them, 17 patients (48 (33;59) years; 13 (68,4%) male) had concomitant LGE and were included in the final analysis. The most common indication for CT was myocardial infarction with non-obstructive coronary arteries (52,9%). The total myocardial mass by CT was 108.83 ± 21.69 g, while the total myocardial mass by CMR was 100.33 ± 25.19 g. The ICC between both techniques was good (0.78, p=0.001). A cut-off value of 75% for the CT showed the strongest correlation with the CMR, both for total scar mass and scar proportion. Total scar mass was 9.43 ± 8.29 g for CT and 10.7 ± 8.46 g for CMR, with an ICC of 0.68 (p=0.01). Scar proportion was 9.97 ± 8.26% for CT and 11.09 ± 9% for CMR, showing a good correlation (ICC 0.73, p=0.006). Conclusion Late iodine enhancement quantification by cardiac computed tomography is feasible. A signal density threshold of 75% showed the strongest correlation with the cardiac magnetic resonance.Example of late iodine enhancement

Characterization of Luciferase from Photorhabdus kayaii and its Application for In vivo Imaging Studies in Mice.

Bioluminescence, or the production of light by luciferases, is the basis of a well-known reporter technology. A quick way to study the efficacy of antimicrobial drugs and vaccines is in vivo bioluminescence imaging (BLI). Photorhabdus spp. represent the only terrestrial group of bioluminescent bacteria. The luciferase obtained from Photorhabdus luminescence has been widely used in BLI studies. However, little information is available about the functions of luciferases obtained from other members of this genera. This study aimed to evaluate the applicability of the luciferase obtained from Photorhabdus kayaii for BLI studies. P. kayaii starE, an Iranian isolate of P. kayaii, was cultivated on NBTA agar plates. The resulting colonies were cultured on McConkey agar to determine the bacterial phase. Bioluminescence emission was measured using a multimode reader. The luciferase genes of this bacterium were sequenced following the PCR amplification, and the corresponding amino acid sequences were determined. The luciferase tertiary structure was then obtained from the TACOS web server and compared to that of P. luminescence in CE software. The lux operon encoding the luciferase (luxA and luxB genes) and substrate synthesis complex was cloned and expressed in Escherichia coli BL21 (DE3) using the pBBR1MCS2_START vector. The luminescence emission during the growth was examined. Moreover, the effects of pH and sodium deoxycholate (bile salt) on bioluminescence emission were investigated. Appropriate conditions for the use of bioluminescent E. coli for BLI studies in mice were demonstrated in terms of cell numbers and injection routes. The bacterium was luminescent and in phase I. Its luciferase monomers (α and β) shared 100% amino acid homology with P. kayaii M-HU2 and more than 92% with P. luminescence. Tertiary structures of the luciferase monomers were 93%- 95% identical to those of P. luminescence. The lux operon was expressed in E. coli, and the maximum bioluminescence signal was observed during the decelerating phase of growth. The bioluminescence at different pH values correlated with the cell survival. The luminescence was emitted by cells exposed to the bile salt. A strong bioluminescent signal was emitted from mice after subcutaneous injection of bioluminescent E. coli at 107 CFU. However, no signals were emitted from mice that were administered the same cell number via intraperitoneal injection. A 2.5-fold increase in the cell number resulted in bioluminescence detection in the abdomen of mice after intraperitoneal injection and a 3.22-fold increase in signal intensity after subcutaneous injection. These results demonstrated the usefulness of P. kayaii luciferase for BLI studies.

Validation of a Model Predictive Control Strategy on a High Fidelity Building Emulator

In recent years, advanced controllers, including Model Predictive Control (MPC), have emerged as promising solutions to improve the efficiency of building energy systems. This paper explores the capabilities of MPC in handling multiple control objectives and constraints. A first MPC controller focuses on the task of ensuring thermal comfort in a residential house served by a heat pump while minimizing the operating costs when subject to different pricing schedules. A second MPC controller working on the same system tests the ability of MPC to deal with demand response events by enforcing a time-varying maximum power usage limitation signal from the electric grid. Furthermore, multiple combinations of the control parameters are tested in order to assess their influence on the controller performance. The controllers are tested on the BOPTEST framework, which offers standardized test cases in high-fidelity emulation models, and pre-defined baseline control strategies to allow fair comparisons also across different studies. Results show that MPC is able to handle multi-objective optimal control problems, reducing thermal comfort violations by between 66.9% and 82% and operational costs between 15.8% up to 20.1%, depending on the specific scenario analyzed. Moreover, MPC proves its capability to exploit the building thermal mass to shift heating power consumption, allowing the latter to adapt its time profile to time-varying constraints. The proposed methodology is based on technologically feasible steps that are intended to be easily transferred to large scale, in-field applications.

Wideband Transmissive Programmable Metasurface for Adaptive Millimeter‐Wave Beamforming

AbstractProgrammable metasurfaces provide a promising paradigm for the beamforming of electromagnetic waves in the fifth‐generation (5G) and sixth‐generation (6G) wireless communications with low cost and low complexity. However, most of the existing researches are focused on the sub‐6 GHz spectrum, which limited the gigabits per second (Gb s−1) high‐speed data transmission on future wireless network. Additionally, as a step forward in the development of intelligent metasurfaces, extra peripheral devices are often required to sense environmental variations for self‐adaptive modulations. Here, a wideband millimeter‐wave programmable metasurface is presented for peripheral‐free self‐adaptive signal enhancement in 5G/6G wireless communication. The proposed transmissive programmable metasurface consists of meta‐atoms, exhibiting efficient transmission (1 dB loss) and a stable 1‐bit phase difference from 23.7 to 32.1 GHz, effectively covering the desired 5G millimeter‐wave frequency bands: N257, N258, and N261. By integrating the self‐adaptive algorithm based on received signal intensity into the controller, the programmable metasurface can self‐adaptively establish an optimal or acceptable channel according to the predefined threshold values. To evaluate the performance of the prototype, an experiment on wavefront modulation was first conducted in a microwave chamber, verifying the wideband beamforming performance of the programmable metasurface. Moreover, self‐adaptive signal enhancement and millimeter‐wave wireless communication experiments were conducted in indoor environments, showing a maximum signal enhancement of 21.4 dB and a significant improvement in constellation. The proposed self‐adaptive wideband programmable metasurface demonstrates high potential for application in 5G/6G millimeter‐wave wireless networks.

Acetone Sensors Based on Al-Coated and Ni-Doped Copper Oxide Nanocrystalline Thin Films.

Acetone detection is of significant importance in various industries, from cosmetics to pharmaceuticals, bioengineering, and paints. Sensor manufacturing involves the use of different semiconductor materials as well as different metals for doping and functionalization, allowing them to achieve advanced or unique properties in different sensor applications. In the healthcare field, these sensors play a crucial role in the non-invasive diagnosis of various diseases, offering a potential way to monitor metabolic conditions by analyzing respiration. This article presents the synthesis method, using chemical solutions and rapid thermal annealing technology, to obtain Al-functionalized and Ni-doped copper oxide (Al/CuO:Ni) nanostructured thin films for biosensors. The nanocrystalline thin films are subjected to a thorough characterization, with examination of the morphological properties by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analysis. The results reveal notable changes in the surface morphology and structure following different treatments, providing insight into the mechanism of function and selectivity of these nanostructures for gases and volatile compounds. The study highlights the high selectivity of developed Al/CuO:Ni nanostructures towards acetone vapors at different concentrations from 1 ppm to 1000 ppm. Gas sensitivity is evaluated over a range of operating temperatures, indicating optimum performance at 300 °C and 350 °C with the maximum sensor signal (S) response obtained being 45% and 50%, respectively, to 50 ppm gas concentration. This work shows the high potential of developed technology for obtaining Al/CuO:Ni nanostructured thin films as next-generation materials for improving the sensitivity and selectivity of acetone sensors for practical applications as breath detectors in biomedical diagnostics, in particular for diabetes monitoring. It also emphasizes the importance of these sensors in ensuring industrial safety by preventing adverse health and environmental effects of exposure to acetone.

Viral epitope profiling of hematopoietic cell transplant recipients with respiratory syncytial virus upper respiratory tract and lower respiratory tract infections

Abstract Background The pre-fusion conformation of the F glycoprotein of respiratory syncytial virus (RSVpreF) has been the target of recent respiratory syncytial virus (RSV) therapies, including monoclonal antibodies for immunocompetent children and vaccines for the elderly. However, the utility of targeted therapies against RSVpreF is unknown in pediatric or adult hematopoietic cell transplant (HCT) recipients, and there are limited natural history studies characterizing humoral immune responses after RSV infection in HCT recipients. We utilized VirScan, a novel high-throughput profiling of antiviral antibody epitopes, to identify differences in global RSV-related epitope hits after an RSV infection. Methods We evaluated adult and pediatric allogeneic HCT recipients who acquired RSV from 12/2011 to 12/2019. Patients were categorized into 3 groups: upper respiratory tract infections (URTI) only, those who progressed from URTI to lower respiratory tract infections (progressors) and lower respiratory tract infections (LRTI) at diagnosis, and tested at baseline prior to infection (pre-RSV), at RSV URTI or LRTI diagnosis (RSV diagnosis), at LRTI progression (LRTI), 4-6 weeks after infection (Response 1) and >8 weeks after infection (Response 2), depending on sample availability. We interrogated the viral antibody repertoire using a serosurvey (VirScan) that detects immunoglobulin G responses to 206 viruses. VirScan metrics evaluated included: (1) number of RSV epitope hits, (2) log10 of the maximum RSV epitope binding signal (EBS), analogous to an antibody titer for each epitope, and (3) geometric mean of all RSV EBS. Kruskal-Wallis tests were used to compare groups for each VirScan metric at the different time points. Results A total of 129 samples from 39 patients were analyzed; 24 with URTI only, 8 progressors, and 7 with LRTI at diagnosis. At each time point, VirScan metrics were similar among the 3 patient groups (Table 1). Though patterns of VirScan metrics following RSV diagnosis varied by patient, most showed a modest increase in values (Figure 1). Conclusion In this preliminary study, we utilized the power of VirScan, a comprehensive serologic profiling tool of the entire human virome, to characterize RSV specific antibody changes after RSV infection in allogeneic HCT recipients. There were no differences in global RSV VirScan metrics between the 3 groups, suggesting that antibodies may not be the primary driver of viral infection attenuation in this population. Future analyses will focus on differences in individual epitope acquisition, including RSVpreF, between the 3 groups, and investigate possible interactions with humoral responses to other viruses. Figure 1. Longitudinal RSV VirScan metrics for each patient separated by 3 groups (top row: RSV URTI only; middle row: progressors from URTI to LRTI; bottom row: LRTI at diagnosis). Each line is an individual patient. The different panels show the changes in RSV related epitope hits (A), the log10 maximum epitope binding signal (EBS) among RSV epitopes (B), and the geometric mean of all the RSV related EBS (C). Open circles represent time points prior to RSV diagnosis, filled circles represent time points just prior to, on or after URTI, and asterisks represent time points just prior to, on, or after LRTI.

Electrochemical immunosensor based on gold nanoparticles for the detection of creatine kinase as a cardiac marker

This study presents the development of an electrochemical immunosensor utilizing gold nanoparticles for the detection of creatine kinase (CK), a crucial cardiac marker. Gold nanoparticles with an average diameter of 18.3 ± 2.1 nm were synthesized and characterized, exhibiting a characteristic surface plasmon resonance peak at 520 nm. The construction of the immunosensor was observed through cyclic voltammetry and electrochemical impedance spectroscopy, showing notable alterations in electron transfer rates during each step of the assembly process. Optimal performance was achieved at pH 7.4, with an antibody concentration of 100 μg/mL and an incubation time of 45 minutes. The sensor demonstrated a sensitivity of 152.6 Ω/(ng/mL) and maintained its response in the presence of common interfering substances, with maximum signal deviation of 7.2 %. Testing with spiked human serum samples yielded recovery rates between 96.5 % and 103.8 %. Comparison with ELISA using clinical samples further validated the sensor's accuracy. This AuNP-based immunosensor offers a promising platform for rapid and sensitive CK detection in cardiac health assessment.

The differential effects of dyslipidemia status and triglyceride-glucose index on left ventricular global function and myocardial microcirculation in diabetic individuals: a cardiac magnetic resonance study

BackgroundIt remains unclear whether the association between dyslipidemia status and triglyceride-glucose (TyG) index with myocardial damage varies in the context of type 2 diabetes mellitus (T2DM). This study aimed to determine the differential effects of dyslipidemia status and TyG index on left ventricular (LV) global function and myocardial microcirculation in patients with T2DM using cardiac magnetic resonance (CMR) imaging.MethodsA total of 226 T2DM patients and 72 controls who underwent CMR examination were included. The T2DM group was further categorized into subgroups based on the presence or absence of dyslipidemia (referred to as T2DM (DysL+) and T2DM (DysL-)) or whether the TyG index exceeded 9.06. CMR-derived LV perfusion parameters, remodeling index, and global function index (GFI) were assessed and compared among groups. A multivariable linear regression model was employed to evaluate the effects of various variables on LV myocardial microcirculation, remodeling index, and GFI.ResultsThe LV GFI sequentially decreased in controls, T2DM (DysL-), and T2DM (DysL+) groups (p < 0.001), and was lower (p = 0.003) in T2DM with higher TyG index group than in lower TyG index group. The LV remodeling index was higher in higher TyG index group than in lower TyG index group (p = 0.002), but there was no significant difference in whether the subgroup was accompanied by dyslipidemia. Multivariable analysis revealed that the TyG index, but not dyslipidemia status, was independently associated with LV remodeling index (β coefficient[95% confidence interval], 0.152[0.025, 0.268], p = 0.007) and LV GFI (− 0.159[− 0.281, − 0.032], p = 0.014). For LV myocardial microcirculation, perfusion index, upslope, and max signal intensity sequentially decreased in controls, T2DM (DysL-), and T2DM (DysL+) groups (all p < 0.001). Dyslipidemia status independently correlated with perfusion index (− 0.147[− 0.272, − 0.024], p = 0.02) and upslope (− 0.200[− 0.320, 0.083], p = 0.001), while TyG index was independently correlated with time to maximum signal intensity (0.141[0.019, 0.257], p = 0.023).ConclusionsBoth dyslipidemia status and higher TyG index were associated with further deterioration of LV global function and myocardial microvascular function in the context of T2DM. The effects of dyslipidemia and a higher TyG index appear to be differential, which indicates that not only the amount of blood lipids and glucose but also the quality of blood lipids are therapeutic targets for preventing further myocardial damage.

Temperature Dependence of the Sensitivity of PVDF Pyroelectric Sensors to THz Radiation: Towards Cryogenic Applications.

The application of terahertz (THz) science in industrial technology and scientific research requires efficient THz detectors. Such detectors should be able to operate under various external conditions and conform to existing geometric constraints in the required application. Pyroelectric THz detectors are among the best candidates. This is due to their versatility, outstanding performance, ease of fabrication, and robustness. In this paper, we propose a compact pyroelectric detector based on a bioriented poled polyvinylidene difluoride film coated with sputtered metal electrodes for in situ absorption measurement at cryogenic temperature. The detector design was optimized for the registration system of the electron paramagnetic resonance (EPR) endstation of the Novosibirsk Free Electron Laser facility. Measurements of the detector response to pulsed THz radiation at different temperatures and electrode materials showed that the response varies with both the temperature and the type of electrode material used. The maximum signal level corresponds to the temperature range of 10-40 K, in which the pyroelectric coefficient of the PVDF film also has a maximum value. Among the three coatings studied, namely indium tin oxide (ITO), Au, and Cu/Ni, the latter has the highest increase in sensitivity at low temperature. The possibility of using the detectors for in situ absorption measurement was exemplified using two typical molecular spin systems, which exhibited a transparency of 20-30% at 76.9 cm-1 and 5 K. Such measurements, carried out directly in the cryostat with the main recording system and sample fully configured, allow precise control of the THz radiation parameters at the EPR endstation.

Passive Seismology: Lightweight and Rapid Detection of Arctic Subsea and Sub‐Aquatic Permafrost

AbstractLow sea levels during the last Ice Age exposed millions of square kilometers of Arctic shelves which have been subsequently submerged, creating subsea permafrost. In onshore settings, permafrost can also exist beneath water bodies such as coastal lagoons, rivers, and thermokarst lakes. We explored passive seismology as a method for mapping unfrozen sediment thickness above subsea and sub‐aquatic permafrost. We present passive seismic data collected with the Mobile Ocean Bottom Seismic Instrument (MOBSI) from the Beaufort Sea near Tuktoyaktuk in Canada, Ivashkina Lagoon on the Bykovsky Peninsula, as well as a lake and river in the Lena Delta, Siberia, Russia. We use borehole data and frost probe measurements to identify permafrost‐related H/V measurement peaks and calibrate shear wave velocities for frequency‐to‐depth conversion. We employ the shortest path and maximum signal amplitude to connect peaks and generate geological profiles. The MOBSI detected the ice‐bonded permafrost table beneath the Beaufort Sea, as well as beneath a Siberian lake and lagoon. At Tuktoyaktuk, an ocean bottom seismometer revealed a 5% scatter about the peak frequency for three‐minute time windows and over 8 hr of recording time. With peak frequencies ranging from 4.9 ± 0.2 Hz to 27.6 ± 1.4 Hz, the depth to subsea permafrost ranged from 1.4 ± 0.1 m bsl at the shoreline to 14.0 ± 0.4 m bsl 240 m offshore. Given an accurate shear wave velocity, our findings highlight that MOBSI deployment times as short as 3 min are adequate for detecting Arctic subsea and sub‐aquatic permafrost.

Zero-Background Dual-Mode Closed Bipolar Electrode Electrochemiluminescence Biosensor Based on ZnCoN-C Potential Regulation for Ultrasensitive Detection of Ochratoxin A.

In this work, the relationship between electrochemiluminescence (ECL) signal and driving voltage was first studied by self-made reduced and oxidized closed bipolar electrodes (CBPEs). It was found that when the driving voltage was large enough, the maximum ECL signals for the two kinds of CBPEs were the same but their required drive voltages were different. Zinc cobalt nitrogen doped carbon material (ZnCoN-C) had an outstanding electric double layer (EDL) property and conductivity. Therefore, it could significantly reduce the driving voltage of two kinds of CBPE systems, reaching the maximum ECL signal of Ru(bpy)32+. Interestingly, when the ZnCoN-C modified electrode reached the maximum ECL signal, the bare electrode signal was zero. As a proof-of-concept application, a zero-background dual-mode CBPE-ECL biosensor was constructed for the ultrasensitive detection of ochratoxin A (OTA) in beer. Considering that beer samples contained a large number of reducing substances, a reduced CBPE system was selected to build the biosensor. Furthermore, a convenient ECL imaging platform using a smartphone was built for the detection of OTA. This work used a unique EDL material ZnCoN-C to regulate the driving voltage of CBPE for the first time; thus, a novel zero-background ECL sensor was constructed. Further, this work provided a deeper understanding of the CBPE-ECL system and opened a new door for zero-background detection.

Label-free and liquid state SERS detection of multi-scaled bioanalytes via light-induced pinpoint colloidal assembly

Surface-enhanced Raman scattering (SERS) has been extensively applied to detect complex analytes due to its ability to enhance the fingerprint signals of molecules around nanostructured metallic surfaces. Thus, it is essential to design SERS-active nanostructures with abundant electromagnetic hotspots in a probed volume according to the dimensions of the analytes, as the analytes must be located in their hotspots for maximum signal enhancement. Herein, we demonstrate a simple method for detecting robust SERS signals from multi-scaled bioanalytes, regardless of their dimensions in the liquid state, through a photothermally driven co-assembly with colloidal plasmonic nanoparticles as signal enhancers. Under resonant light illumination, plasmonic nanoparticles and analytes in the solution quickly assemble at the focused surface area by convective movements induced by the photothermal heating of the plasmonic nanoparticles without any surface modification. Such collective assemblies of plasmonic nanoparticles and analytes were optimized by varying the optical density and surface charge of the nanoparticles, the viscosity of the solvent, and the light illumination time to maximize the SERS signals. Using these light-induced co-assemblies, the intrinsic SERS signals of small biomolecules can be detected down to nanomolar concentrations based on their fingerprint spectra. Furthermore, large-sized biomarkers, such as viruses and exosomes, were successfully detected without labels, and the complexity of the collected spectra was statistically analyzed using t-distributed stochastic neighbor embedding combined with support vector machine (t-SNE + SVM). The proposed method is expected to provide a robust and convenient method to sensitively detect biologically and environmentally relevant analytes at multiple scales in liquid samples.

Effect of Methyl Butyrate blending on soot formation in Jet A laminar diffusion flame

To investigate the effect of methyl butyrate (MB) blending on soot formation in a Jet A laminar diffusion flame, laser-induced incandescence (LII) and laser-induced fluorescence (LIF) techniques were employed to assess the distributions of soot-LII signal and polycyclic aromatic hydrocarbons (PAH) signal in Jet A with varying MB blending ratios from 0% to 80%. The experimental results revealed that an increase in the MB blending ratio resulted in decreased flame height, reduced radially integrated natural luminosity peak signal, and lower the total spatially integrated natural luminosity, while the flame base height increased. The starting position of soot-LII signal moved downstream gradually, and the peak signal magnitude on the axis decreased. The addition of MB effectively reduced the soot-LII signal in Jet A. Compared to pure Jet A, the average soot-LII signal for MB20, MB40, MB60, and MB80 decreased by 18.9%, 79.6%, 85.3%, and 94.2%, respectively. The maximum soot-LII signal decreased by 18.2%, 68.3%, 76.0%, and 93.5%, respectively. Furthermore, the PAH-LIF signal gradually decreased as the MB blending ratio increased. Moreover, the MB-Jet A-PAH mechanism was constructed, and the formation pathways of the soot precursor based on a diffusion flame model were calculated. The kinetic results indicate that an increase in the MB blending ratio reduces the rates of different reactions involved in the generation of A1, leading to a reduction in A1. The dilution of PBZ in Jet A by MB is identified as the primary factor for the reduction in soot.

Assessing biological self-organization patterns using statistical complexity characteristics: a tool for diffusion tensor imaging analysis.

Diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) are well-known and powerful imaging techniques for MRI. Although DTI evaluation has evolved continually in recent years, there are still struggles regarding quantitative measurements that can benefit brain areas that are consistently difficult to measure via diffusion-based methods, e.g., gray matter (GM). The present study proposes a new image processing technique based on diffusion distribution evaluation of López-Ruiz, Mancini and Calbet (LMC) complexity called diffusion complexity (DC). The OASIS-3 and TractoInferno open-science databases for healthy individuals were used, and all the codes are provided as open-source materials. The DC map showed relevant signal characterization in brain tissues and structures, achieving contrast-to-noise ratio (CNR) gains of approximately 39% and 93%, respectively, compared to those of the FA and ADC maps. In the special case of GM tissue, the DC map obtains its maximum signal level, showing the possibility of studying cortical and subcortical structures challenging for classical DTI quantitative formalism. The ability to apply the DC technique, which requires the same imaging acquisition for DTI and its potential to provide complementary information to study the brain's GM structures, can be a rich source of information for further neuroscience research and clinical practice.

Integrated erbium-doped waveguide amplifier on lithium niobate on insulator

The erbium-doped lithium niobate on insulator (Er:LNOI) has garnered significant attention as it combines outstanding gain property with integration capabilities, making it a promising solution for active devices on the versatile LNOI platform. This also paves a way for the development of appealing erbium-doped waveguide amplifiers. Here, we demonstrate an efficient integrated Er:LNOI micro-waveguide amplifier directly compatible with the lens fiber. In a 5.6-cm-long Er:LNOI micro-waveguide, we demonstrate a maximum internal net gain of 18.8 dB for 1531-nm signal light with 1460-nm pumping. Moreover, the maximum output signal power surpasses 20 mW, thereby confirming the practicality of the Er:LNOI micro-waveguide amplifier.

Variations in threshold values for border zone and dense scar produce significant changes in scar parameters obtained by ADAS-3D

BackgroundADAS-3D software elaborates cardiac magnetic resonance (CMR) images to obtain a quantitative evaluation of dense scar and border zone (BZ), including BZ channels, which can be useful for ventricular tachycardia ablation and risk stratification. However, most prior reports with ADAS-3D used flexible thresholds (60% ± 5% and 40% ± 5% of maximum pixel signal intensity) to define dense scar and BZ. The impact of such variations of the threshold values on the measurements obtained with ADAS-3D is unknown. ObjectiveThis study aimed to quantify the degree of change in ADAS-3D measurements when different thresholds for dense scar and BZ are employed. MethodsA single-center retrospective observational cohort study including 87 consecutive patients with previous myocardial infarction who underwent CMR was conducted. ADAS-3D software semiautomatically processed CMR sequences. We compared the scar measurements obtained with the 9 possible combinations of thresholds (55%/60%/65% and 35%/40%/45% of maximum pixel signal intensity). ResultsThe overall comparison between thresholds showed highly significant differences (P < .001) in all scar parameters. Not a single patient maintained the same number of BZ channels with all the thresholds settings. A percentage difference of up to 200% in BZ channel numbers and channel mass was observed in all 36 comparisons. An absolute difference of up to 10 channels was also recorded. Of note, the highest median channel mass (obtained with the thresholds 35–65) was 59-fold higher compared with the lowest one (obtained with the 45-55 cutoffs). ConclusionVariations in threshold values result in statistically significant and high-magnitude changes in the quantification of scar parameters by ADAS-3D.

Myocardial perfusion impairment in children with Kawasaki disease: assessment with cardiac magnetic resonance first-pass perfusion.

Kawasaki disease (KD) potentially increases the risk of myocardial ischemia. This study aimed to semi-quantitatively evaluate myocardial perfusion impairment using cardiac magnetic resonance (CMR) first-pass perfusion in children with KD and explore the association between coronary artery (CA) dilation and myocardial perfusion. From December 2018 to July 2021, 77 patients with KD (48 male, 5.71±2.80 years) and 37 age- and sex-matched normal controls (20 male, 6.19±3.32 years) who underwent CMR in West China Second University Hospital were enrolled in this cross-sectional study with prospective data collection. A total of 30 of these patients completed the follow-up CMR, with a median interval of 13 months. Myocardial perfusion parameters including perfusion index (PI) and maximum signal intensity (Max SI) were obtained through rest first-pass perfusion. The internal diameter of the CA was assessed via coronary magnetic resonance angiography (CMRA) to calculate the coronary Z score. The global and regional myocardial parameters among the subgroups were compared. Statistical analysis included one-way analysis of variance (ANOVA), Pearson's correlation, and multivariate linear regression. The global Max SI and regional Max SI of all segments in patients with and without CA dilation decreased compared with those in controls (P=0.19 and P<0.001, respectively). The global PI of patients with CA dilation and regional PI in segments subtended by dilated CA were lower than that of controls (P=0.002 and P<0.001, respectively) and were negatively correlated with the Z score (global: r=-0.576; regional: r=-0.351, both P<0.001). Multivariate analysis revealed that the Z score was negatively associated with global PI in KD (β=-0.409, P=0.02, model R2=0.170). The global Max SI of patients with and without CA dilation during the follow-up CMR decreased compared with that of the first CMR (42.18±9.84 vs. 34.48±8.24, P=0.02; 44.82±7.13 vs. 36.61±7.67, P=0.03, respectively). CMR myocardial first-pass perfusion imaging can semi-quantitatively evaluate impaired myocardial perfusion in KD patients. Not only patients with CA dilation and segments subtended by dilated CA but also those without CA dilation and segments subtended by non-dilated CA developed myocardial perfusion impairment, the severity of myocardial perfusion impairment is associated with the degree of CA dilation.

A new method for quantifying accommodation parameters based on objective dynamic accommodometry

Purpose: to develop a technique for an objective multifactorial assessment of accommodation parameters, including accommodation stability and microfluctuations (MF), and an assessment of the diagnostic value of the technique. Material and methods. The dynamic monocular accommodative response (MAR) was measured using a WAM-5500 device (Grand Seiko, Japan) over a period of 10 to 60 seconds with a recording frequency of at least 6 Hz. The approximating cubic spline was calculated, and the temporal change of signal trend was assessed. The developed technique was used to evaluate the dynamics of MAR for 46 eyes of 23 patients aged 8–12 years with acquired myopia from -0.87 to -5.75 D (ave. -2.96 D). Results. In the examined eyes, the MF frequency varied from 0.4 Hz to 2.3 Hz (ave. 1.4 Hz), and the maximum amplitude ranged from 0.4 D to 2.47 D (ave. 1.2 D). Over the research period, the MAR trend remained constant in 10 eyes, increased from 0.17 to 0.47 (ave. 0.29 D) in 8, and decreased from 0.1 to 1.53 D (ave. 0.35 D) in 28 eyes. MAR varied from 0.79 to 2.63 (ave. 1.8 D). A correlation was found between the minimum MAR and the signal range with the trend level (r= 0.29 and r=0.4, respectively) and a weak correlation was revealed between the MF frequency and the signal range (r=0.2). A set of criteria for accommodation instability was identified: a decreasing trend of more than 0.35 D, a MF frequency of more than 1.4 per second and/or a maximum signal span of more than 1.2 D. Conclusion. The developed technique or objective multifactorial assessment of accommodation parameters, including stability and MF, in real time and space proves to be useful for the diagnosing of accommodation disorders.

Patterning of 2D second harmonic generation active arrays in ferroelectric nematic fluids

Ferroelectric nematic liquid crystals exhibit unique non-linear optical properties, with the potential to become transformative materials for photonic applications. A promising direction relies on the fabrication of tailored polar orientational patterns via photoalignment, thus shaping the non-linear optical susceptibility through thin slabs of the ferroelectric fluid. Here, we explore the fabrication of 2D periodic SHG active arrays in ferroelectric nematic fluids, for different materials, cell thicknesses and motifs. Based on polarizing optical microscopy observations in combination with optical simulations, second harmonic generation microscopy and interferometry, the 3D structure of the motifs is revealed. Two different 2D periodic patterns are explored, showing that the balance between flexoelectric and electrostatic energy can lead to different domain structures, an effect which is rooted in the difference between the flexoelectric properties of the materials. It is shown that by combining the surface-inscribed alignment with different spontaneous degrees of twist, 2D SHG active arrays can be obtained in the micrometre scale, in which adjacent areas exhibit maximum SHG signals at opposite angles.

Elicitation of fetal ECG from abdominal recordings using Blind Source Separation techniques and Robust Set Membership Affine Projection algorithm for signal quality enhancement

Background:The utilization of non-invasive techniques for fetal cardiac health surveillance is pivotal in evaluating fetal well-being throughout the gestational period. This process requires clean and interpretable fetal Electrocardiogram (fECG) signals. Method:The proposed work is the novel framework for the elicitation of fECG signals from abdominal ECG (aECG) recordings of the pregnant mother. The comprehensive approach encompasses pre-processing of the raw ECG signal, Blind Source Separation techniques (BSS), Decomposition techniques like Empirical Mode Decomposition (EMD), and its variants like Ensemble Empirical Mode Decomposition (EEMD), and Complete Ensemble Empirical Mode Decomposition with Additive Noise (CEEMDAN). The Robust Set Membership Affine Projection (RSMAP) Algorithm is deployed for the enhancement of the obtained fECG signal. Result:The results show significant improvements in the elicited fECG signal with a maximum Signal Noise Ratio (SNR) of 31.72 dB and correlation coefficient = 0.899, Maximum Heart Rate(MHR) obtained in the range of 108–142 bpm for all the records of abdominal ECG signals. The statistical test gave a p-value of 0.21 accepting the null hypothesis. The Abdominal and Direct Fetal Electrocardiogram Database (ABDFECGDB) from PhysioNet has been used for this analysis. Conclusion:The proposed framework demonstrates a robust and effective method for the elicitation and enhancement of fECG signals from the abdominal recordings.