Polarization Changes Research Articles

Isomerization, Protonation, and Hydrolysis Properties of Naphthalimide-Containing Spiropyran in Aqueous Media.

Synthesis of spiropyrans exhibiting ring-opening/closing isomerization driven by external stimuli is a challenging subject for the development of molecular sensors. A napthalimide-containing spiropyran (1) promotes rapid isomerization between the spirocyclic (SP) form and ring-opened merocyanine (MC) form by the change in solvent polarity even under the dark condition at room temperature. In this work, the effect of water on the isomerization behavior of 1 was studied. The addition of water caused an MC-water H-bonding interaction and shifted the resonance MC structure to the zwitterionic form with a lower ground-state energy. The stabilized MC form promoted spontaneous SP → MC isomerization and increased the equilibrium MC concentration. The effect of pH on the behavior of 1 was also studied. In acidic-neutral media, protonation/deprotonation of the naphthalimide moiety led to rapid and reversible changes in the absorption spectra. In contrast, strongly basic media (pH > 12) promoted irreversible base-catalyzed hydrolysis of the alkene moiety.

Simulation study of multi-layer titanium nitride nanodisk broadband solar absorber and thermal emitter

Solar energy has always been a kind of energy with large reserves and wide application. It is well utilized through solar absorbers. In our study, the finite difference time domain method (FDTD) is used to simulate the absorber composed of refractory metal materials, and its absorption performance and thermal emission performance are obtained. The ultra-wide band of 200 nm–3000 nm reaches 95.93% absorption efficiency, of which the bandwidth absorption efficiency of 2533 nm (200 nm–2733 nm) is greater than 90%. The absorption efficiency in the whole spectrum range (200 nm–2733 nm) is 97.17% on average. The multilayer nanodisk structure of the absorber allows it to undergo strong surface plasmon resonance and near-field coupling when irradiated by incident light. The thermal emission performance of the absorber enables it to also be applied to the thermal emitter. The thermal emission efficiency of 95.37% can be achieved at a high temperature of up to 1500 K. Moreover, the changes of polarization and incident angle do not cause significant changes in absorption. Under the gradual change of polarization angle (0°–90°), the absorption spectrum maintains a high degree of consistency. As the incident angle increases from 0° to 60°, there is still 85% absorption efficiency. The high absorption efficiency and excellent thermal radiation intensity of ultra-wideband enable it to be deeply used in energy absorption and conversion applications.

Enhancing phase modulation and group delay in reflective Huygens metasurfaces via a Fabry-Perot cavity

Huygens metasurfaces exhibit excellent optical properties such as 2π phase modulation and slow light effects. However, they face challenges including wide bandwidth and low group delay due to their high radiation losses. Here, we propose a reflective Huygens metasurface coupled with an F-P cavity. We demonstrate that F-P resonance modes can couple with magnetic-quasi-bound-state (M-QBIC) and electric-quasi-bound-state (E-QBIC) in the Huygens metasurface through constructive interference, significantly enhancing the quality factors of both QBICs. Through structural parameter optimization, our reflective Huygens metasurface achieves 4π phase modulation and a high group delay of up to 166 ps. Compared to the non-coupled Huygens metasurface with the same structural asymmetry, the group delay of the F-P coupled reflective Huygens metasurface is enhanced by up to 30 times. Our design reduces the fabrication precision requirements for Huygens metasurfaces, enabling similar group delays to be achieved in low-symmetry coupling structures as in highly symmetric non-coupling structures. Additionally, the performance of this metasurface shows robustness to changes in incident light polarization. This design highlights the potential for achieving high-quality factors, large phase modulation, and large group delay, offering new avenues for the design of highly sensitive tunable devices, efficient nonlinear optical devices, and narrowband slow light devices.

Design terahertz polarizers and vector polarized vortex terahertz wave generators based on the effective dielectric constant of metal gratings

Polarization and phase devices for terahertz waves have important applications in terahertz detection, imaging, communication, etc. Spatially variable metal gratings can be used for broad-spectrum, miniaturized, and low-cost terahertz polarization and phase modulation devices. Based on the effective dielectric constant and the theory of light propagation in multilayer media, we obtain the relationship between the transmittance and extinction ratio and the parameters such as the duty cycle of the metal grating, the frequency of the incident terahertz wave, the angle of incidence, the thickness of the metal grating, the refractive index of the substrate, and the thickness of the substrate. We propose a method of designing a spatially variable metal grating located on a transparent substrate. The designed spatially variable metal grating is also used to modulate the terahertz spatial polarization and phase to generate terahertz optical fields whose polarization and phase change simultaneously in space, such as azimuthally vector vortex terahertz optical fields, radially vector vortex terahertz optical fields, and so on. This will have important applications in terahertz time-domain spectroscopic detection, terahertz time-domain spectroscopic imaging, terahertz time-domain near-field microscopic imaging, terahertz communication, and so on.

Load characteristics of magnetization-dependent transverse thermoelectric generation in GdFeCo ferrimagnetic alloy thin films

We evaluated the thermoelectric voltage and electric power induced by the transverse and longitudinal thermoelectric generation, along with their load resistance characteristics, by measuring the load voltage in remanent magnetization states of a perpendicularly magnetized GdFeCo ferrimagnetic alloy thin film. Various load resistances were connected transversely and longitudinally to the temperature gradient. Our results showed that the load voltage induced by thermoelectric generation varied with load resistance. Additionally, the sign of the transverse load voltage reversed with the reversal of magnetization. The electric power generated thermoelectrically exhibited load dependency, reaching a local maximum. These behaviors can be qualitatively explained by the load characteristics of the power supply circuit, where polarity changes with the direction of remanent magnetization. In conclusion, we demonstrated the extraction of electric power via thermoelectric generation in a GdFeCo ferrimagnetic thin film. These observations suggest that using magnetic materials can provide new functionality for thermoelectric generators.

Numerical study on the polarity change process during internal wave shoaling

Polarity change is an important mechanism for internal waves shoaling. In this study, a numerical model for simulating the real-scale internal wave passing over slope-shelf topography is established based on the Fourier pseudo-spectral method and weakly nonlinear theory. By numerical simulation, the effects of shelf height, initial wave amplitude, and inclination angle on the waveform characteristics and energy properties of the internal wave during its shoaling are investigated. In the polarity change process, the initial internal wave converts into a depression wave and a generated elevation wave behind it. The distance between the peak of the elevation wave and the trough of the depression wave is a key feature to describe the polarity change. In terms of energy properties, the energy ratio of depression and generated elevation waves compared with the initial wave as well as their relative magnitude is mainly determined by the shelf height. In addition, the initial wave amplitude also affects the generation of the elevation wave and the attenuation of the depression wave to a certain extent. The increase in the inclination angle hinders the formation of the elevation wave but has little effect on the depression wave energy.

An in-depth comparison of dielectric, ferroelectric, piezoelectric, energy storage, electrocaloric, and piezocatalytic properties of Ba0.92Ca0.08Zr0.09Ti0.91O3 and Ba0.92Ca0.08Sn0.09Ti0.91O3 piezoceramics

The futuristic technology demands materials exhibiting multifunctional properties. Keeping this in mind, an in-depth investigation and comparison of the dielectric, ferroelectric, piezoelectric, energy storage, electrocaloric, and piezocatalytic properties have been carried out on Ba0.92Ca0.08Zr0.09Ti0.91O3 (BCZT) and Ba0.92Ca0.08Sn0.09Ti0.91O3 (BCST) lead-free compounds synthesized through the conventional solid state reaction method. Further, the Rietveld refinement against the XRD patterns affirmed the coexistence of orthorhombic (Amm2) and tetragonal (P4mm) phases at room temperature for both compounds. While BCZT compound demonstrated remarkable dielectric, piezoelectric, and piezocatalytic characteristics with maximum dielectric constant () ≈ 13304 near the Curie temperature ( ≈ 105 °C), converse piezoelectric coefficient ≈ 609 pm V-1 , power density () ≈ 89.71 KW cm-3 at room temperature, and 82.7 % Rhodamine B (RhB) dye degradation capability; on the other hand, BCST compound exceled in superior energy storage density () ≈ 191.8 mJ cm-3 with efficiency η ≈ 73.26% near room temperature and enhanced electrocaloric properties with adiabatic temperature change ≈ 0.980 K, isothermal entropy change ≈ 1.15 J Kg-1K-1 and a higher electrocaloric responsivity ) ≈ 0.49 K mm kV-1. These distinctions arise from the difference in ionic radii, lattice distortion, and the electronic configurations of the dopant ions, leading to a greater polarization change and a lower coercive electric field in the BCST ceramic. The outcome of the present study provides valuable insights for selecting a dopant tailored compound for specific application and underscores the potential of such ceramics in energy storage, piezocatalysis, and the development of advanced solid-state cooling devices for future applications.

Prediction model for retention volumes of the three-phase solvent system in high-speed countercurrent chromatography.

Owing to its ability to separate substances with a broad scope of polarities, exploring the three-phase solvent systems (TPSSs) with high-speed countercurrent chromatography is a topic of interest in separation science, and their retention volumes should be more concerned. This study primarily investigates the behavior of retention volumes while examining the isolation abilities of the TPSS in the technique above. We took standard compounds, including sophoricoside, Sudan red 7B, and rotenone, which have a broad range of polarity, for investigation in this study and separated them using different four-liquid TPSSs made up of water, acetonitrile, methyl acetate, and n-hexane (WAMH). Our findings show that the retention volumes gradually alter in response to changes in phase polarity within the proposed solvent systems. With TPSSs, we preliminarily studied compound isolation and the promising formula of their retention volumes. The proposed solvent systems WAMH in different ratios showed high correlations and adjusted correlation coefficients above 0.9978 and 0.9913 for the actual and calculated retention volumes. This study will be particularly beneficial for researchers focusing on countercurrent chromatography with TPSSs, as it offers valuable time-saving insights.

Observation of polarity changes in Sjogren's syndrome mice using a targeting lysosomes and ratiometric fluorescent probe

Utilizing non-invasive, real-time dynamic imaging and high-resolution detection tools to track polarity changes in Sjögren's syndrome (SS) contributes to a better understanding of the disease progression. Herein, a ratiometric polarity-sensitive fluorescent probe (DIM) was designed and synthesized, DIM consisted of dicyanoisophorone as the fluorophore and morpholine moiety as lysosome targeting. DIM showed a ratiometric response to polarity and high selectivity (unaffected by viscosity, pH, ROS, RNS, etc.), offering a more accurate analysis of intracellular polarity through a built-in internal reference calibration. The polarity abnormality of submandibular glands in non-obese diabetic (NOD) mice was revealed and verified by in vivo ratiometric fluorescence imaging of DIM, suggesting that fluorescent probe have great potential in the diagnosis of salivary gland abnormalities.

Chemokine-mediated F-actin dynamics, polarity, and migration in B lymphocytes depend on WNK1 signaling.

Ligand-engaged chemokine receptors trigger nucleotide exchange in heterotrimeric Gαi proteins, which stimulates cytoskeletal reorganization and cell polarity changes. To better understand the signaling events responsible for these cellular changes, we focused on early changes in F-actin dynamics after engagement of the chemokine receptor CXCR5 in murine splenic B cells. Within 10 seconds of exposure to the CXCR5 ligand CXCL13, three-dimensional lamellar-like pseudopods and F-actin-rich ridges appeared. The transient F-actin increase depended on Gαi2/3 signaling, the PI3K/AKT pathway, ERK activation, phospholipase C activity, and Rac1/2 activation mediated by Dock2 (dedicator of cytokinesis 2). Immunoblot analyses identified the kinase WNK1 (with no lysine kinase 1) as a potential early AKT effector. Treating B cells with specific WNK inhibitors disrupted F-actin dynamics and impaired B cell polarity, motility, and chemotaxis. These changes were mimicked in a murine B cell line by CRISPR-Cas9 gene editing of Wnk1, which also suggested that WNK1 contributed to B cell proliferation. Administration of a single dose of a WNK inhibitor transiently reduced B cell motility and polarity in the lymph nodes of live mice. These results indicate that WNK1 signaling maintains B cell responsiveness to CXCL13 and suggest that pharmacological inhibition of WNK1, which is involved in cancer progression and blood pressure regulation, may affect humoral immunity.

In silico analysis of the effects of non-synonymous SNPs associated with human GSK3B gene on its structure and function

Single Nucleotide Polymorphisms (SNPs) are abundantly identified by next generation sequencing (NGS) technology. Glycogen synthase kinase-3 beta (GSK3B), a widely expressed protein kinase, plays pivotal roles in cellular pathways. However, study on SNPs associated with GSK3B and their functional consequences is lacking. In this study, we analysed non-synonymous SNPs of GSK3B gene and their implications using computational tools. From NCBI dbSNP, 103,087 SNPs of GSK3B were initially gathered, later narrowed down to 255 unique nsSNPs. Around one-third of the nsSNPs resulted in charge and polarity change of the amino acids of the protein. 41 nsSNPs were found to significantly alter the stability of GSK3B protein (ΔΔG ≤ -1 or ≥ 1 kcal/mol) and few of them also affected the disorderness at the mutation site. Evolutionary conservation of the nsSNPs in the protein revealed 25 nsSNP may be deleterious to GSK3B protein function. Finally, 4 critical nsSNPs (Y161C, R167G, P225L and Y234D) were identified that can significantly alter both the stability and function of GSK3B. Furthermore, this study predicted 60 post-translational modification sites in GSK3B among which 26 sites contained nsSNPs. Interestingly, 7 upstream ORFs (uORFs) with high ribosomal occupancy were also detected in GSK3B mRNA that can reduce the expression of GSK3B protein. Altogether, this study has employed various in silico methods to characterize GSK3B nsSNPs, but they have limitations. These tools often overlook the cellular context, interacting partners, PTMs and the dynamic nature of proteins, which can affect protein behaviour and function. Despite these limitations, in silico tools are valuable for initial screening and prioritizing SNPs. The prioritized SNPs obtained in this study (Y161C, R167G, P225L and Y234D) should be experimentally validated using techniques like genome editing, biochemical assays, interactome analysis in cell lines and animal models to confirm their biological relevance.Clinical trial registration: Not Applicable.

Polarity transitions of narrow bipolar events in thundercloud tops reaching the lower stratosphere

Blue corona discharges are often generated in thunderclouds penetrating into the stratosphere and are the optical manifestation of narrow bipolar events (NBEs) observed in radio signals. While their production appears to depend on convection, the cause and nature of such discharges are not well known. Here we show the observations by a lightning detection array of unusual amounts of 982 NBEs during a tropical storm on the coastline of China. NBEs of negative polarity are predominantly observed at the cloud top reaching the stratosphere, and positive NBEs are primarily at lower altitudes. We find that the dominant polarity changes with the typical time of development of thunderstorm cells, suggesting that the polarity depends on the phase of the storm cells. Furthermore, we find that the lightning jump of negative NBEs is associated with above-anvil cirrus plumes of ice crystals and water vapor in the lower stratosphere. We propose that variations in updrafts induce changes in the altitude and charge concentrations of the cloud layers, which lead to the polarity transition. Our results have implications for studies of the chemical perturbations of greenhouse gas concentrations by corona discharges at the tropopause.

Low-Power Driving Waveform Design for Improving the Display Effect of Electrophoretic Electronic Paper.

To address the high power consumption associated with image refresh operations in EPDs, this paper proposes a low-power driving waveform that reduces the refresh power of EPDs by lowering the system's peak power. Compared to traditional waveforms, this waveform first activates the particles before erasing them, thus reducing voltage polarity changes. Additionally, it introduces a specific duration of 0 V voltage during the activation phase based on the physical characteristics of the electrophoretic particles to reduce the voltage span. Finally, a particular duration of 0 V voltage is introduced during the erasure phase to minimize the voltage span while ensuring the stability and consistency of the reference gray scale. The experimental results demonstrate that, in standard power tests, the new driving waveform reduces the power fluctuation value by 1.33% and the energy fluctuation value by 37.24% compared to the traditional driving waveform. This reduction in refresh power also mitigates screen flicker and ghosting phenomena.

Coumarin-aurone based fluorescence probes for cysteine sensitive in-situ identification in living cells

The quantification of cysteine (Cys) levels in the organisms holds paramount significance in biological research and disease diagnosis, which can give the correlation between abnormal Cys levels and diseases. In this study, two fluorescent probes, designated as DEA-OH and DEA-AC, featuring a coumarin-aurone backbone specifically engineered for Cys detection, were meticulously designed and synthesized. The diethylamino coumarin-aurone probe DEA-OH and the acrylate-substituted probe DEA-AC demonstrated remarkable sensitivity in detecting cysteine by means of copper displacement (DEA-OH) and acrylate hydrolysis mechanisms (DEA-AC) with fluorescence detection limits of 7.25 μM and 1.65 μM, respectively. Moreover, the fluorescence peak wavelength of the two probes displayed a linear relationship with solvent polarity in the ET (30) range of 30–65 kcal•mol−1, indicating the potential for monitoring changes in environmental polarity within this ET (30) range. The outstanding attributes exhibited by DEA-AC including superior photostability, remarkable selectivity, and swift response (kinetic rate constant: 0.00747 s−1), coupled with the exceptional anti-interference ability, have significantly broadened its scope of applications, for example detecting alterations in Cys within biological systems.

Fully Optical Control of Polarization Current Direction in a Cyanide-Bridged Trinuclear Complex.

As a remote and non-contact stimulus, light offers the potential for manipulating the polarization of ferroelectric materials without physical contact. However, in current research, the non-contact write-read (erase) process lacks direct observation through the stable current as output signal. To address this limitation, we investigated the photoinduced polarization switching capabilities of the cyanide-bridged compound [Fe2Co] using visible light, leading to the achievement of rewritable polarization. By subjecting [Fe2Co] crystals to alternating irradiation with 785 nm and 532 nm light, the polarization changes exhibited a distinct square wave pattern, confirming the reliability of the writing and erasing processes. Initialization involved exposing specific crystal units to 532 nm light for storing "1" or "0" information, while reading was accomplished by scanning the units with 785 nm light, resulting in brief current pulses for "1" states and no current signal for "0" states. This research unveils new possibilities for optical storage systems, paving the way for efficient and rewritable data storage and retrieval technologies, such as the next-generation memories.

Quantitation of the physicochemical properties of myelin using Nile Red fluorescence spectroscopy.

Myelin is a vital structure that is key to rapid saltatory conduction in the central and peripheral nervous systems. Much work has been done over the decades examining the biochemical composition and morphology of myelin at the light and electron microscopic levels. Here we report a method to study myelin based on the fluorescent probe Nile Red. This lipophilic dye readily partitions into live and chemicallyfixed myelin producing bright, well-resolved images of the sheath. Using spectral confocal microscopy, a complete emission spectrum of Nile Red fluorescence can be acquired for each pixel in an image. The solvatochromic properties of Nile Red cause its emission spectrum to change depending on the polarity of its local environment. Therefore, measuring spectral shifts can report subtle changes in the physicochemical properties of myelin. We show differences in myelin polarity in central versus peripheral nervous system and in different regions of central nervous system white matter of the mouse brain, together with developmental and sex variations. This technique is also well suited for measuring subtle changes in myelin properties in live exvivo white matter specimens. We also demonstrate how light deprivation induces a myelin polarity change in adult mouse optic nerve underscoring a continuing myelin plasticity in response to axonal activity well into adulthood. The Nile Red spectroscopic method allows measurement of subtle physicochemical changes in myelin that can importantly influence its electrical properties and by extension, conduction velocities in axons.

Stereoscopic spatial graphical method of Mueller matrix: Global-Polarization Stokes Ellipsoid

A Mueller matrix covers all the polarization information of the measured sample, however the combination of its 16 elements is sometimes not intuitive enough to describe and identify the key characteristics of polarization changes. Within the Poincaré sphere system, this study achieves a spatial representation of the Mueller matrix: the Global-Polarization Stokes Ellipsoid (GPSE). With the help of Monte Carlo simulations combined with anisotropic tissue models, three basic characteristic parameters of GPSE are proposed and explained, where the V parameter represents polarization maintenance ability, and the E and D† parameters represent the degree of anisotropy. Furthermore, based on GPSE system, a dynamic analysis of skeletal muscle dehydration process demonstrates the monitoring effect of GPSE from an application perspective, while confirming its robustness and accuracy.

Paleozoic subduction of the Paleo-Asian Ocean plate: Constraints from Ordovician-Carboniferous volcano-sedimentary rocks in the northern Beishan orogenic collage, NW China

The subduction history of the Hongshishan Ocean within the Beishan orogenic collage is crucial to understand the evolutionary mechanism of the Paleo-Asian Ocean. In this study, we describe the petrography, ages and geochemistry of an Ordovician–Carboniferous volcano-sedimentary succession, which provides a record of the subduction history of the Hongshishan Ocean. We obtained early Ordovician zircon U-Pb ages (482 ± 6 Ma and 472 ± 2 Ma) from the Xianshuihu Formation. The youngest weighted mean detrital zircon age from the Yuanbaoshan Formation is 421.0 ± 8.8 Ma. Most detrital zircons have prominent age peaks at 900–840 Ma and 543–462 Ma, suggesting a main source from the southern Mongolian microcontinent. Volcanic rocks from the Baishan Formation yielded weighted mean ages of 299.3–300.3 Ma. During the Ordovician–Devonian, some volcanic arcs formed on the northern side of Hongshishan-Baiheshan-Erlegen Ula (HBEU) ophiolitic belt, indicating that the Hongshishan Ocean had a northward subduction polarity. During the Carboniferous, continental arcs were well developed on both sides of the HBEU belt, suggesting a bidirectional subduction. An archipelago of multiple arcs of the Hongshishan Ocean resembles that of the West Pacific Ocean. The change in subduction polarity can be attributed to characteristics of multi-oceanic accretion.

Lysosome-Targeted Polarity-Sensitive NIR Fluorescence Probe for Imaging Injured Lung and Liver in Diabetes.

Diabetes is a chronic disease marked by high blood glucose. With the progress of diabetes, complications gradually appear, and various organs may be affected. However, due to the lack of noninvasive in situ detection probes, the diagnosis of organ damage caused by diabetes is significantly delayed, which will cause many complications that cannot be treated in time. Here, we report a BODIPY-based fluorescent probe SNL, which can be used to detect lung and liver damage caused by diabetes. By introducing methylpiperazine and extending the conjugated system, SNL can locate lysosomes and exhibit absorption and emission both in the near-infrared (NIR) region. In addition, SNL is sensitive to polarity and can be used for sensitive detection of lysosomal polarity changes. Unexpectedly, SNL targets and images the lungs and liver of mice. Subsequently, hyperglycemia-stimulated cell models and diabetic mouse models were successfully established, and SNL was utilized to reveal that polarity can be used as a diagnostic signal of diabetic complications. Notably, SNL for the first time confirmed the lung injury and liver injury caused by diabetes using the fluorescent probes method, providing a new approach for the diagnosis of diabetes complications.

Helicity-Resolved Vibrational Coupling in Twist WS2/WSe2 Heterostructures.

Helicity-resolved Raman spectra can provide an intricate view into lattice structural details. Through the analysis of peak positions, intensities, and circular polarized Raman signals, a wealth of information about chiral structure arrangement within the moiré superlattice, interlayer interaction strength, polarizability change in chemical bond, and beyond can be unveiled. However, the relationship between the circular polarization of high-frequency Raman and twist angle is still not clear. Here, we utilize helicity-resolved Raman spectroscopy to explore the interlayer interactions and the effect of the moiré superlattice in WS2/WSe2 heterostructures. For the out-of-plane Raman mode A1g of WS2 (A1g and 1E2g of WSe2), its intensity is significantly enhanced (suppressed) in WS2/WSe2 heterostructures when θ is less than 10° or greater than 50°. This observation could be attributed to the large polarizability changes in both W-S and W-Se covalent bonds. The circular polarization of 2LA(M) in WSe2 of the WS2/WSe2 heterostructure (θ < 10° or θ > 50°) is significantly enhanced compared to that of 2LA(M) in the monolayer WSe2. We deduce that the circular polarization of the Raman mode correlates with the proportion of high-symmetry area within a supercell of the moiré lattice. Our findings improve the understanding of twist-angle-modulated Raman modes in TMD heterostructures.