Underwater dynamic polarization imaging without dependence on the background region.

Active-polarization imaging holds significant promise for achieving clear underwater vision. However, only static targets were considered in previous studies, and a background region was required for image restoration. To address these issues, this study proposes an underwater dynamic polarization imaging method based on image pyramid decomposition and reconstruction. During the decomposition process, the polarized image is downsampled to generate an image pyramid. Subsequently, the spatial distribution of the polarization characteristics of the backscattered light is reconstructed by upsampling, which recovered the clear scene. The proposed method avoids dependence on the background region and is suitable for moving targets with varying polarization properties. The experimental results demonstrate effective elimination of backscattered light while sufficiently preserving the target details. In particular, for dynamic targets, processing times that fulfill practical requirements and yield superior recovery effects are simultaneously obtained.

Improved-quality graphene films via the synergism of large nanosheet aligning and nanotube bridging for flexible supercapacitors.

Scalable production of reduced graphene oxide (rGO) films with high mechanical-electrical properties are desirable candidates for wearable electronics devices and energy storage applications. Removing structural incompleteness such as wrinkles or voids in the graphene films generated from the assemble process would greatly optimize their mechanical properties. However, the densely stacked graphene sheets in the films degrades their ionic kinetics and thus limits their development. Here, a horizontal-longitudinal-structure modulating strategy is demonstrated to produce enhanced mechanical, conductive and capacitive graphene films. Typically, two-dimensional (2D) large graphene sheets (LGS) induce regular stacking of GO during assembling process to reduce wrinkles, while one-dimensional (1D) single-walled carbon nanotubes (SWCNT) bridge with graphene sheets to strengthen the multidirectional intercalation and reduce GO layer restacking. The simultaneous incorporation of LGS and SWCNT synergistically makes fine microstructure with improving the alignment of graphene sheets, increasing continuous conductive pathways to facilitate electron transport, and enlarging interlayer spacing to promote the electrolyte ion diffusion. As a result, the obtained graphene films are flat and exhibit signally reinforced mechanical properties, electrical conductivity (38727 S m-1), as well as specific capacitance (232 F g-1) as supercapacitor electrodes than those of original rGO films. Moreover, owing to the comprehensive improved properties, the flexible gel supercapacitor assembled by the graphene film-based electrodes shows high energy density, good flexibility and excellent cycling stability (93.8% capacitance retention after 10000 cycles). This work provides a general strategy to manufacture robust graphene structural materials for energy storage applications in flexible and wearable electronics.

Artificial intelligence for neuro MRI acquisition: a review.

OBJECT: To review recent advances of artificial intelligence (AI) in enhancing the efficiency and throughput of the MRI acquisition workflow in neuroimaging, including planning, sequence design, and correction of acquisition artifacts. MATERIALS AND METHODS: A comprehensive analysis was conducted on recent AI-based methods in neuro MRI acquisition. The study focused on key technological advances, their impact on clinical practice, and potential risks associated with these methods. RESULTS: The findings indicate that AI-based algorithms have a substantial positive impact on the MRI acquisition process, improving both efficiency and throughput. Specific algorithms were identified as particularly effective in optimizing acquisition steps, with reported improvements in workflow efficiency. DISCUSSION: The review highlights the transformative potential of AI in neuro MRI acquisition, emphasizing the technological advances and clinical benefits. However, it also discusses potential risks and challenges, suggesting areas for future research to mitigate these concerns and further enhance AI integration in MRI acquisition.

Influence mechanism of the particle size on underwater active polarization imaging of reflective targets.

Underwater active polarization imaging is a promising imaging method, however, it is ineffective in some scenarios. In this work, the influence of the particle size from isotropic (Rayleigh regime) to forward-scattering on polarization imaging is investigated by both Monte Carlo simulation and quantitative experiments. The results show the non-monotonic law of imaging contrast with the particle size of scatterers. Furthermore, through polarization-tracking program, the polarization evolution of backscattered light and target diffuse light are detailed quantitatively with Poincaré sphere. The findings indicate that the noise light's polarization and intensity scattering field change significantly with the particle size. Based on this, the influence mechanism of the particle size on underwater active polarization imaging of reflective targets is revealed for the first time. Moreover, the adapted principle of scatterer particle scale is also provided for different polarization imaging methods.

Underwater active polarization descattering based on a single polarized image.

Active polarization imaging techniques have tremendous potential for a variety of underwater applications. However, multiple polarization images as input are necessary for almost all methods, thereby limiting the range of applicable scenarios. In this paper, via taking full advantage of the polarization feature of target reflective light, the cross-polarized backscatter image is reconstructed via introducing an exponential function for the first time, only based on mapping relations of co-polarized image. Compared with rotating the polarizer, the result performs a more uniform and continuous distribution of grayscale. Furthermore, the relationship of degree of polarization (DOP) between the whole scene and backscattered light is established. This leads to an accurate estimation of backscattered noise and high-contrast restored images. Besides, single-input greatly simplifies the experimental process and upgrades efficiency. Experimental results demonstrate the advancement of the proposed method for objects with high polarization under various turbidities.

Manipulating the Thermal Conductivity of the Graphene/Poly(vinyl alcohol) Composite via Surface Functionalization: A Multiscale Simulation.

The reverse non-equilibrium molecular dynamics simulation is used to investigate the influence of functional groups (FGs) on the thermal conductivity of a graphene/poly(vinyl alcohol) (PVA) composite, which considers non-polar (methyl) and polar (hydroxyl, amino, and carboxyl) groups. First, the polar groups can be more effective to improve the interfacial thermal conductivity than the non-polar group. This can be explained well by characterizing the interfacial Coulombic energy, number and lifetime of hydrogen bonds, vibrational density of states, and integrated autocorrelation of the interfacial heat power. Moreover, the hydroxyl group can improve the interfacial thermal conductivity more than the other groups, which can be rationalized by analyzing the surface roughness of graphene and the radial distribution function of FGs and the PVA chains. However, the introduction of FGs destroys the graphene structure, which consequently reduces the intrinsic thermal conductivity. Furthermore, by adopting the effective medium approximation model and finite element method, there exists a critical graphene length where the overall thermal conductivities are equal for the functionalized and pristine graphene. Finally, the distribution state of graphene is emphasized to be more vital in determining the overall thermal conductivity than the generally accepted interfacial thermal conductivity.

Dual-Polarized Multi-Beam Fixed-Frequency Beam Scanning Leaky-Wave Antenna.

A fixed-frequency beam-scanning leaky-wave antenna (LWA) array with three switchable dual-polarized beams is proposed and experimentally demonstrated. The proposed LWA array consists of three groups of spoof surface plasmon polaritons (SPPs) LWAs with different modulation period lengths and a control circuit. Each group of SPPs LWAs can independently control the beam steering at a fixed frequency by loading varactor diodes. The proposed antenna can be configured in both multi-beam mode and single-beam mode, where the multi-beam mode with optional two or three dual-polarized beams. The beam width can be flexibly adjusted from narrow to wide by switching between multi-beam and single-beam states. The prototype of the proposed LWA array is fabricated and measured, and both simulation and experimental results show that the antenna can accomplish a fixed frequency beam scanning at an operating frequency of 3.3 to 3.8 GHz with a maximum scanning range of about 35° in multi-beam mode and about 55° in single-beam mode. It could be a promising candidate for application in the space-air-ground integrated network scenario in satellite communication and future 6G communication systems.

A Method for Detecting the Vacuum Degree of Vacuum Glass Based on Digital Holography.

The vacuum degree is the key parameter reflecting the quality and performance of vacuum glass. This investigation proposed a novel method, based on digital holography, to detect the vacuum degree of vacuum glass. The detection system was composed of an optical pressure sensor, a Mach-Zehnder interferometer and software. The results showed that the deformation of monocrystalline silicon film in an optical pressure sensor could respond to the attenuation of the vacuum degree of vacuum glass. Using 239 groups of experimental data, pressure differences were shown to have a good linear relationship with the optical pressure sensor's deformations; pressure differences were linearly fitted to obtain the numerical relationship between pressure difference and deformation and to calculate the vacuum degree of the vacuum glass. Measuring the vacuum degree of vacuum glass under three different conditions proved that the digital holographic detection system could measure the vacuum degree of vacuum glass quickly and accurately. The optical pressure sensor's deformation measuring range was less than 4.5 µm, the measuring range of the corresponding pressure difference was less than 2600 pa, and the measuring accuracy's order of magnitude was 10 pa. This method has potential market applications.

Visibility enhancement of underwater images based on polarization common-mode rejection of a highly polarized target signal.

Underwater active polarization imaging is promising due to its effect of significantly descattering. Polarization-difference is commonly used to filter out backscattered noise. However, the polarization common-mode rejection of target signal has rarely been utilized. In this paper, via taking full advantage of this feature of Stokes vectors S2 which ably avoids interference from target light, the spatial variation of the degree of polarization of backscattered light is accurately estimated, and the whole scene intensity distribution of background is reconstructed by Gaussian surface fitting based on least square. Meanwhile, the underwater image quality measure is applied as optimization feedback, through iterative computations, not only sufficiently suppresses backscattered noise but also better highlights the details of the target. Experimental results demonstrate the effectiveness of the proposed method for highly polarized target in strongly scattering water.

Effect of the content and strength of hard segment on the viscoelasticity of the polyurethane elastomer: insights from molecular dynamics simulation.

Due to the wide application, it is very crucial to understand the viscoelasticity of the polyurethane elastomer (PU, denoted by soft-hard block copolymer), which contains the soft segments (SS) and hard segments (HS). Thus, in this work, the effect of the content and strength of HS on the viscoelasticity of PU is explored in detail by adopting a coarse-grained model. First, the phase morphology of PU is characterized where both the single continuous phase and the bicontinuous phase are observed by varying the content of HS. Then, the viscoelasticity of PU is calculated by analyzing the storage modulus, the loss modulus, and the loss factor, which depends on the content and strength of HS. To further elucidate the mechanism for the storage modulus, the normalized interaction energy, the order parameter, and the formation probability of the HS or SS phase are characterized with the shear strain amplitude, which reflects the deformation of the phase structure. Then, the energy dissipation is quantified, which can rationalize the loss modulus well. A parameter is introduced, which considers the relative slippage and the content of HS or SS. It can explain the change in the loss factor with the content and strength of HS. In summary, this work can help to further understand how the content and strength of hard segments affect the viscoelasticity of the soft-hard block PU and structure evolution at the molecular level.

Correction: Effect of the content and strength of hard segment on the viscoelasticity of the polyurethane elastomer: insights from molecular dynamics simulation.

Correction for 'Effect of the content and strength of hard segment on the viscoelasticity of the polyurethane elastomer: insights from molecular dynamics simulation' by Yimin Wang et al., Soft Matter, 2022, 18, 4090-4101, https://doi.org/10.1039/D2SM00463A.

Nitroreductase Increases Menadione-Mediated Oxidative Stress in Aspergillus nidulans.

Nitroreductases (NTRs) catalyze the reduction of a wide range of nitro-compounds and quinones using NAD(P)H. Although the physiological functions of these enzymes remain obscure, a tentative function of resistance to reactive oxygen species (ROS) via the detoxification of menadione has been proposed. This suggestion is based primarily on the transcriptional or translational induction of an NTR response to menadione rather than on convincing experimental evidence. We investigated the performance of a fungal NTR from Aspergillus nidulans (AnNTR) exposed to menadione to address the question of whether NTR is really an ROS defense enzyme. We confirmed that AnNTR was transcriptionally induced by external menadione. We observed that menadione treatment generated cytotoxic levels of O2•-, which requires well-known antioxidant enzymes such as superoxide dismutase, catalase, and peroxiredoxin to protect A. nidulans against menadione-derived ROS stress. However, AnNTR was counterproductive for ROS defense, since knocking out AnNTR decreased the intracellular O2•- levels, resulting in fungal viability higher than that of the wild type. This observation implies that AnNTR may accelerate the generation of O2•- from menadione. Our in vitro experiments indicated that AnNTR uses NADPH to reduce menadione in a single-electron reaction, and the subsequent semiquinone-quinone redox cycling resulted in O2•- generation. We demonstrated that A. nidulans nitroreductase should be an ROS generator, but not an ROS scavenger, in the presence of menadione. Our results clarified the relationship between nitroreductase and menadione-derived ROS stress, which has long been ambiguous. IMPORTANCE Menadione is commonly used as an O2•- generator in studies of oxidative stress responses. However, the precise mechanism through which menadione mediates cellular O2•- generation, as well as the way in which cells respond, remains unclear. Elucidating these events will have important implications for the use of menadione in biological and medical studies. Our results show that the production of Aspergillus nidulans nitroreductase (AnNTR) was induced by menadione. However, the accumulated AnNTR did not protect cells but instead increased the cytotoxic effect of menadione through a single-electron reduction reaction. Our finding that nitroreductase is involved in the menadione-mediated O2•- generation pathway has clarified the relationship between nitroreductase and menadione-derived ROS stress, which has long been ambiguous.

Influence of Surface Defects on the Thermal Conductivity of Hexagonal Boron Nitride/Poly(dimethylsiloxane) Nanocomposites: A Molecular Dynamics Simulation.

In this simulation, the reverse nonequilibrium molecular dynamics simulation is employed to explore how the surface defects in hexagonal boron nitride (h-BN) influence the thermal conductivity of poly(dimethylsiloxane) (PDMS)-based composites. First, the interfacial thermal conductivity and the intrinsic thermal conductivity of h-BN are obtained by tuning the defect density, the inhomogeneity of the defect distribution, and the number of h-BN layers. The defects enhance the interfacial thermal conductivity, especially for h-BNs with high inhomogeneity of the defect distribution and multilayer. However, the intrinsic thermal conductivity of h-BN is declined significantly by the defects. They can be explained well by the vibrational density of states of PDMS and h-BNs and their overlap. Then, by combining the effective medium approximation model with the simulation, the overall thermal conductivity of composites is obtained. It exhibits a gradual decrease with increasing defect density or reducing the inhomogeneity of the defect distribution. Meanwhile, the enhancement extent of the overall thermal conductivity by improving the concentration and size of h-BNs depends on the defect density and the defect distribution. Finally, the comparison between the simulation and experiment is discussed. In summary, our work provides some valuable insights into how the defect density, the defect distribution, and the number of layers influence the thermal conductivity of the PDMS-based composite.

Association of Hepatic Steatosis Index and Fatty Liver Index with Carotid Atherosclerosis in Type 2 Diabetes.

Background/aim: Previous studies have suggested that the hepatic steatosis index (HSI) and fatty liver index (FLI) can be used as a predictor of non-alcoholic fatty liver disease (NAFLD). The aim of our study was to determine whether non-invasive indices of hepatic steatosis (HSI and FLI) are associated with carotid atherosclerosis in type 2 diabetes mellitus (T2DM). Methods: This was a cross-sectional study conducted in the T2DM patients (n=768). Carotid intima-media thickness (CIMT) was measured by the Color Doppler ultrasound. The HSI was calculated based on gender, body mass index (BMI), and transaminases level. The FLI was based on BMI, waist circumference (WC), triacylglycerols (TG) and g-glutamyl transferase (GGT). Results: Raised HSI and FLI levels was associated with increased CIMT levels in T2DM patients. Patients with greater CIMT had higher HSI (39.10 ± 5.70 vs 36.10 ± 4.18, P < 0.001) and FLI (46.35 (29.96, 65.54) vs 36.93 (18.7, 57.93), P < 0.001) than those with lower CIMT. Subjects with existing carotid plaque had higher HSI (38.28 ± 5.63 vs 35.69 ± 3.45 P < 0.001) and FLI (47.41 (27.77, 66.62) vs 37.19 (17.71, 51.78), P < 0.001) accordingly. HSI (r = 0.343, P < 0.001) and FLI (r = 0.184, P < 0.001) were positively related with the CIMT. In the linear regression, after full adjustment metabolic risk factors, smoking, and measures of insulin resistance, HSI and FLI were independently associated with CIMT (HSI: ß = 0.011, FLI: ß = 0.001, all P < 0.01). Further, logistic regression analyses showed that higher HSI and FLI had an impact on the risk for carotid atherosclerosis [HSI: OR (95%CI): 1.174 (1.123-1.228), FLI: OR (95%CI): 1.011(1.004-1.019), all P < 0.01]. Overall, increasing values of HSI and FLI were associated with CIMT (P < 0.05) significantly across different categories of age and hypertension. Conclusion: Current data suggest HSI and FLI are independently correlated with carotid atherosclerosis in T2DM. They may be a simple and useful marker for assessing the progression of diabetic macrovascular complications.

Rapid Screening Alpha-Glucosidase Inhibitors from Polygoni Vivipari Rhizoma by Multi-Step Matrix Solid-Phase Dispersion, Ultrafiltration and HPLC.

Polygoni Vivipari Rhizoma (PVR), the dried root of Polygonum viviparum, has been used as herbal medicine in China for a long time. In the present study, a new method based on multi-step matrix solid-phase dispersion (MSPD), ultrafiltration and high performance liquid chromatography (HPLC) for screening alpha-glucosidase inhibitors (AGIs) from PVR was proposed. First, three different PVR extractions were prepared by multi-step MSPD with 15% methanol, 60% methanol and 100% methanol. Second, the alpha-glucosidase inhibition tests for the three extracts were carried out, and the 60% methanol extraction showed the best activity. Then, the AGIs screening experiment was performed with ultrafiltration and HPLC analysis using the 60% methanol extraction. Seven binding components (quercetin-3-O-vicianoside, quercetin 3-O-neohesperidoside, rutin, hyperoside, quercetin 3-O-glucuronide, luteolin-7-O-neohesperidoside, kaempferol 3-glucuronide) were found. These seven components were further validated as the AGIs by molecular docking analysis. The developed method was a rapid and efficient tool for screening AGIs from PVR, which provided scientific data for the bioactive components study of PVR.

Characterization of the promoter of the nitrate transporter-encoding gene nrtA in Aspergillus nidulans.

Aspergillus nidulans nrtA encodes a nitrate transporter that plays an important role in the [Formula: see text] assimilatory process. Many studies have focused on protein functions rather than gene regulation. The knowledge of nrtA[Formula: see text] uptake process, particularly in the regulation mechanism of transcription factors AreA and NirA on nrtA transcription, is very limited. Herein, we investigated the transcriptional regulation of nrtA in response to various N-sources in detail and characterized the promoter activity of nrtA. We confirmed that nrtA was induced by [Formula: see text] and repressed by preferred N-sources. Additionally, for the first time, we found that the transcription of nrtA increased under N-starvation conditions. AreA mediates nrtA transcription under both [Formula: see text] and N-starvation conditions, while NirA is effective only under [Formula: see text] conditions. All of the proposed AreA and NirA binding sites in the promoter region were capable of binding to their corresponding transcription factors in vitro. In vivo, all of the NirA binding sites showed regulation activities, but to AreA, only several of the initiation-codon-proximal binding sites participated in nrtA transcription. Moreover, the active binding sites contributed in different degrees of regulation strength to nrtA transcription, which is unrelated to the distance between the binding sites and initiation codon. These results provided an extensive map of nrtA promoter, defining the functional regulatory elements of A. nidulans nrtA.

Correction to: A combination of omega-3 and plant sterols regulate glucose and lipid metabolism in individuals with impaired glucose regulation: a randomized and controlled clinical trial.

Following publication of the original article [1], the Authors' Contributions statement need to be changed.

Cavitation, crazing and bond scission in chemically cross-linked polymer nanocomposites.

It is very important to understand the molecular mechanism of the fracture behavior of chemically cross-linked polymer nanocomposites (PNCs). Thus, in this work, by employing a coarse-grained molecular dynamics simulation we investigated the effect of the cross-link density and the cross-link distribution on it by calculating the void formation and the chemical bond scission. Considering the fracture energy, the optimal fracture properties of PNCs are realized at the moderate cross-link density which results from the competition between the chain slippage induced voids and the bond scission induced voids. Meanwhile, more bond scission occurs on the chain backbone while a high broken percentage of the cross-link bonds appears between chains because of the higher average stress borne by one cross-linked bead than by one other bead. In addition, the number of voids is quantified which first increases and then decreases with the strain at low cross-link density. However, the number of newly formed voids increases again at high cross-link density. Finally, it decreases because of the low rate of bond scission. Furthermore, the chemical bonds are broken at a similar strain for the uniform cross-link distribution while they are broken at any strain for the nonuniform cross-link distribution. The low number of broken bonds induces the disappearance of the second peak of the number of voids with the strain for the nonuniform cross-link distribution. In summary, this work could provide a clear understanding of the fracture mechanism of the chemically cross-linked PNCs on the molecular level.

A combination of omega-3 and plant sterols regulate glucose and lipid metabolism in individuals with impaired glucose regulation: a randomized and controlled clinical trial.

BACKGROUND: Lipid metabolism imbalance has been recognized as one of the major drivers of impaired glucose metabolism in the context of type 2 diabetes mellitus (T2DM), the rates of which are steadily increasing worldwide. Impaired glucose regulation (IGR) plays a vital role in the prevention and treatment of T2DM. The goal of this study was to further clarify whether the combination of plant sterols (PS) and omega-3 fatty acids yields any synergistic effect that enhances the prevention and treatment of IGR. METHODS: A total of 200 participants were randomized to receive PS and omega-3 fatty acids (n = 50), PS alone (n = 50), omega-3 fatty acids alone (n = 50), or placebo soy bean powder plus placebo capsules (n = 50) for 12 weeks. Patient characteristics including body composition, blood pressure, glucose metabolism (Fasting plasma glucose (FPG), fasting insulin (FINS), glycosylated hemoglobin (HbA1c), Homeostasis Model Assessment of Insulin Resistance (HOMA-IR)), lipid metabolism (TG, TC, HDL-C, LDL-C) and inflammatory factors (Hs-CRP, IL-6) were all monitored in these IGR individuals. RESULTS: Compared to the placebo group, the group receiving the combined intervention exhibited significantly decreased TG, HDL-C, FBG, HOMA-IR and HbA1c. Omega-3 fatty acids alone were associated with significant reductions in waistline, TG, FBG, HOMA-IR and Hs-CRP. PS alone was only associated with decreased TG and Hs-CRP. No interventions produced significant changes in body weight, BMI, blood pressure, FINS, body fat percentage, visceral fat rating, TC, LDL-C or IL-6. CONCLUSIONS: In summary, this study has demonstrated for the first time that PS, omega-3 fatty acids or the combination thereof significantly improved inflammation, insulin resistance, as well as glucose and lipid metabolism in IGR individuals. These findings may provide a scientific basis for the development of nutritional products incorporating PS and omega-3 fatty acids, and also for the development of nutritional supplement strategies aimed at preventing the development of disease in the IGR population.

Mental health literacy among Arab men living in high-income Western countries: A systematic review and narrative synthesis.

While interest in mental health literacy (MHL) is growing rapidly, cross-cultural research focusing on MHL is developing more slowly. This inaugural systematic review explored the recognition and beliefs about the causes of mental health disorders amongst Arab men living in high income Western countries (HIWC), their help-seeking beliefs, behaviors, and sources of help, as well as barriers and facilitators to help-seeking. Six electronic database searches were conducted using Medline, Embase, ProQuest Dissertations & Theses Global, PsycINFO, Scopus, and Web of Science. These searches yielded a total of 9,460 citations. After applying inclusion criteria through both database and manual hand searches, 46 studies were identified. The findings corresponded with four of the socioecological model's five factors: intrapersonal, interpersonal, societal, and institutional. Intrapersonal factors included attributing mental health illness to life and migration stressors, and religious reasons. Interpersonal and societal factors included men favoring informal help-seeking sources as stigma was a barrier to formal help-seeking. Institutional factors around the perceived cultural competence of healthcare professionals and access difficulties were obstacles to seeking formal help. The growth in Arab migration to HIWC highlights the need for culturally tailored care. Research is needed to understand the perspectives of healthcare providers working with Arab men in addition to how men's stigmatizing attitudes are an obstacle to formal help-seeking. Interventions should be designed to address the unique mental health needs of Arab men, recognizing that some explanatory beliefs may not align with current Western models of mental health. Moreover, efforts should be made to integrate men's informal sources of support into treatment planning.