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In order to meet the demand for infrared stealth materials in the military field, conjugated polymers containing Schiff base moieties were designed and prepared. Various dialdehyde monomers were introduced and their effect on the comprehensive properties were systematically characterized. The resulted polymers could be cast in solution to prepare polymer coatings. The coatings exhibited high thermal stability up to 400 °C at 5% weight loss, and excellent mechanical performance with high Young's modulus and hardness. The infrared emissivity values varied from 0.587 to 0.627 at wavelength of 8–14 µm and ranged from 0.595 to 0.609 at wavelength of 2–22 µm. Specifically, it was found that the ATTPAL structure with carbazole moieties had a lower band gap and better electrical conductivity by photoelectric test and DFT theoretical analysis. Meanwhile, the infrared emissivity value of ATTPAL coating was the lowest compared with p-phenyl and pyridyl containing analogues, suggesting it was potential material for the future development of infrared stealth technology. The combined results showed that reducing the band gap and improving the electrical conductivity of the structure were both beneficial to the reduction of infrared emissivity. It would positively provide new ideas for the design of infrared stealth materials. [ABSTRACT FROM AUTHOR]

Selenium (Se) is a vital trace element in the regulation of inflammation and antioxidant reactions in both animals and humans. Se deficiency is rapidly affecting lung function. The present study investigated the molecular mechanism of Se deficiency aggravates reactive oxygen species (ROS)-induced inflammation, leading to fibrosis in lung. Mice fed with different concentrations of Se to establish the model. In the Se-deficient group, the ROS and malondialdehyde (MDA) was increased, and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), and catalase (CAT) reduced. The histopathological observation showed that Se deficiency lead to lung texture damage with varying degrees of degeneration, necrosis, shedding of some alveolar epithelial cells, and inflammatory cell infiltration. Immunohistochemistry showed that the expression of α-smooth muscle actin (α-SMA) increased. The fibrosis index was verified with Sirius red staining. The ELISA and qPCR results showed that the inflammatory cytokines (TNF-α and IL-1β) and ECM (collagen I, collagen IV, fibronectin, and laminin) were increased with ROS increasing, which was induced by Se deficiency. The results displayed that oxidative stress with Se deficiency led to an increase in tissue inhibitors of metalloproteinase (TIMPs), but a decrease in matrix metalloproteinases (MMPs). All the results indicated that Se deficiency induced excessive ROS accumulation to generate inflammation, which disrupted ECM homeostasis and aggravated fibrosis in the lung. [ABSTRACT FROM AUTHOR]

The mechanism of electron density and temperature being influenced by a magnetic field and a grid is studied through inductively coupled Ar plasma discharge simulations and experiments. The electron density, electron temperature, ion density, plasma potential and electron energy distribution function are measured by an Impendans Langmuir probe. The conditions for all experiments are an argon gas pressure of 0.5 Pa and an RF power supply of 3.0 kW to discharge. Simulations and experiments reveal that the magnetic field constrains the mass of electrons, thus reducing the mean-free path and increasing the chance of collisions with gas. Therefore, the ionization rate will increase in the source region, which causes a low electron temperature. Coupled with plasma expansion, the magnetic field could cool the electron temperature and reduce the electron density in the diffusion region. When applying a magnetic field to the plasma, the electron density is controlled from 9.50 × 1010 to 7.30 × 1010 cm−3, while the electron temperature decreases from 4.04 to 3.80 eV. For the grid (ground bias) influence, the electron density sharply decreases to 1.98 × 1010 cm−3, and the electron temperature decreases to 3.30 eV. A mass of electrons is absorbed by the grid. Changes in other plasma parameters, such as the plasma potential and ion density, are also shown in the results. Compared with the magnetic field effect, the influence of the ground bias grid is more obvious. [ABSTRACT FROM AUTHOR]

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Purpose: We aim to identify the risk factors of PPOI in patients with CD and create a nomogram for prediction of PPOI for CD. Methods: Data on 462 patients who underwent partial intestinal resection for CD in Jin-ling Hospital between January 2019 and June 2021 were retrospectively collected. Univariate and multivariate analyses were performed to determine the risk factors for PPOI and we used the risk factors to create a nomogram. Then we used the Bootstrap-Concordance index and calibration diagrams to evaluate the performance of the Nomogram. Decision curve analysis was performed to evaluate clinical practicability of the model. Results: The incidence of PPOI was 27.7% (n of N). Course of CD ≥ 10 years, operation time ≥ 154 min, the lowest mean arterial pressure ≤ 76.2 mmHg, in–out balance per body weight ≥ 22.90 ml/kg, post-op day 1 infusion ≥ 2847 ml, post-op lowest K+ ≤ 3.75 mmol/L, and post-op day 1 procalcitonin ≥ 2.445 ng/ml were identified as the independent risk factors of PPOI in patients with CD. The nomogram we created by these risk factors presented with good discriminative ability (concordance index 0.723) and was moderately calibrated (bootstrapped concordance index 0.704). The results of decision curve analysis showed that the nomogram was clinically effective within probability thresholds in the 8 to 66% range. Conclusion: The nomogram we developed is helpful to evaluate the risk of developing PPOI after partial intestinal resection for CD. Clinicians can take more necessary measures to prevent PPOI in CD's patients or at least minimize the incidence. [ABSTRACT FROM AUTHOR]

Resonance magnetic tunneling in heterostructures formed by graphene single sheets separated by a hexagonal boron nitride barrier and bounded by two gates has been investigated in a strong magnetic field, which has allowed observing transitions between spin- and valley-split Landau levels with various indices belonging to different graphene sheets. An unexpected increase with the temperature in the interlayer tunneling conductance owing to transitions between the Landau levels in strong magnetic fields cannot be explained by existing theories. [ABSTRACT FROM AUTHOR]

Least-squares migration (LSM) is applied to image subsurface structures and lithology by minimizing the objective function of the observed seismic and reverse-time migration residual data of various underground reflectivity models. LSM reduces the migration artifacts, enhances the spatial resolution of the migrated images, and yields a more accurate subsurface reflectivity distribution than that of standard migration. The introduction of regularization constraints effectively improves the stability of the least-squares offset. The commonly used regularization terms are based on the L2-norm, which smooths the migration results, e.g., by smearing the reflectivities, while providing stability. However, in exploration geophysics, reflection structures based on velocity and density are generally observed to be discontinuous in depth, illustrating sparse reflectance. To obtain a sparse migration profile, we propose the super-resolution least-squares Kirchhoff prestack depth migration by solving the L0-norm-constrained optimization problem. Additionally, we introduce a two-stage iterative soft and hard thresholding algorithm to retrieve the super-resolution reflectivity distribution. Further, the proposed algorithm is applied to complex synthetic data. Furthermore, the sensitivity of the proposed algorithm to noise and the dominant frequency of the source wavelet was evaluated. Finally, we conclude that the proposed method improves the spatial resolution and achieves impulse-like reflectivity distribution and can be applied to structural interpretations and complex subsurface imaging. [ABSTRACT FROM AUTHOR]

Numerical studied on T-joints with three-dimensional four directional (3D4D) braided composite fillers was presented in this article. Compared with conventional unidirectional prepreg fillers, the 3D braided composite fillers have excellent ability to prevent crack from penetrating trigone fillers, which constantly occurred in the conventional fillers. Meanwhile, the 3D braided composite fillers had higher fiber volume fraction and eliminated the fiber folding problem in unidirectional prepreg fillers. The braiding technology and mechanical performance of 3D4D braided fillers were studied. The numerical model of carbon fiber T-joints with 3D4D braided composite fillers was built by finite element analysis software. The damage formation, extension and failing process of T-joints with 3D4D braided fillers under tensile load were investigated. Further investigation was extended to the effect of 3D4D braided fillers with different braiding angles on mechanical behavior of the T-joints. The study results revealed that the filling area was the weakest part of the T-joints where the damage first appeared and the crack then rapidly spread to the glue film around the filling area and the interface between over-laminate and soleplate. The 3D4D braided fillers were undamaged and the braiding angle change induced a little effect on the bearing capacity of T-joints. [ABSTRACT FROM AUTHOR]

Three copper(I) complexes, [Cu(PimP)(POP)]PF ( 1), [Cu(NimP)(POP)]PF ( 2), and [Cu(AimP)(POP)]PF ( 3) (PimP = 2-phenyl-1 H-imidazo[4,5-f][1,10]phenanthroline, NimP = 2-(2-naphthyl-1 H-imidazo[4,5-f]phenanthroline, AimP = 2-(9-anthryl)-1 H-imidazo[4,5-f]phenanthroline, POP = bis[2-diphenylphosphino]-phenyl)ether) have been synthesized and characterized. Investigations into the effects of the varying substituents on the structural, absorption, and emission characteristics of the corresponding complexes are presented. Complexes 1 and 2 exhibit similar photophysical properties with the weaker lowest lying MLCT absorption at λ > 400 nm and the phosphorescence MLCT/LLCT emission in the range of 570-590 nm, whereas complex 3 shows different absorption and emission properties, in which the LLCT absorption band is overlapped with the structured absorption bands belonging to the characteristic peaks of the anthracene moiety, and the emitting excited state is described as the LLCT character. Density functional theory and time-dependent density functional theory calculations were employed to rationalize the photophysical properties of the complexes. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystal/zinc oxide (CNC/ZnO) nanohybrids were prepared through citric acid/hydrochloric acid hydrolysis of commercial microcrystalline cellulose (MCC), and simple precipitation with zinc nitrate aqueous solution [Zn(NO)·6HO] via one-pot green synthesis, in which preparation and modification of CNCs were performed simultaneously and the obtained CNCs with carboxyl groups could act as a stabilizing and supporting agent to anchor ZnO nanoparticles. The influence of the Zn ion concentration on the morphology, microstructure, and properties of the CNC/ZnO nanohybrids was investigated by using Fourier-transform infrared and ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy, and thermogravimetric analysis. According to the UV-Vis and XRD results, well-dispersed ZnO nanoparticles with hexagonal wurtzite structure and smallest average diameter of 42.6 nm were successfully anchored onto the surface of the CNCs. The CNC/ZnO nanohybrid CNC/ZnO-0.5 showed improved thermal stability, high antibacterial activity, and photocatalytic activity for methylene blue (MB) due to strong interaction between the CNCs and ZnO nanoparticles. Compared to CNCs, the thermal degradation onset temperature ( T) of the nanohybrids was increased by 23.9 °C, while antibacterial ratios of 100.0 and 100.0 % against viable Escherichia coli and Staphylococcus aureus were achieved. Moreover, 93 % of MB dye was decomposed after UV light irradiation for 100 min. [ABSTRACT FROM AUTHOR]

Recently, inhaled immunosuppressive agents have attracted increasing attention for maintenance therapy following lung transplantation. The rationale for this delivery approach includes a more targeted and localized delivery to the diseased site with reduced systemic exposure, potentially leading to decreased adverse side effects. In this study, the in vitro and in vivo performance of an amorphous formulation prepared by thin film freezing (TFF) and a crystalline micronized formulation produced by milling was compared for tacrolimus (TAC). Despite the relatively large geometric size, the TFF-processed formulation was capable of achieving deep lung delivery due to its low-density, highly porous, and brittle characteristics. When emitted from a Miat® monodose inhaler, TFF-processed TAC formulations exhibited a fine particle fraction (FPF) of 83.3% and a mass median aerodynamic diameter (MMAD) of 2.26 μm. Single-dose 24-h pharmacokinetic studies in rats demonstrated that the TAC formulation prepared by TFF exhibited higher pulmonary bioavailability with a prolonged retention time in the lung, possibly due to decreased clearance ( e.g., macrophage phagocytosis), compared to the micronized TAC formulation. Additionally, TFF formulation generated a lower systemic TAC concentration with smaller variability than the micronized formulation following inhalation, potentially leading to reduced side effects related to the drug in systemic circulation. [ABSTRACT FROM AUTHOR]

Seasonal snow is one of the most important influences on the development and distribution of permafrost and the hydrothermal regime in surface soil. Alpine meadow, which constitutes the main land type in permafrost regions of the Qinghai-Tibet Plateau, was selected to study the influence of seasonal snow on the temperature and moisture in active soil layers under different vegetation coverage. Monitoring sites for soil moisture and temperature were constructed to observe the hydrothermal processes in active soil layers under different vegetation cover with seasonal snow cover variation for three years from 2010 to 2012. Differences in soil temperature and moisture in areas of diverse vegetation coverage with varying levels of snow cover were analyzed using active soil layer water and temperature indices. The results indicated that snow cover greatly influenced the hydrothermal dynamics of the active soil layer in alpine meadows. In the snow manipulation experiment with a snow depth greater than 15 cm, the snow cover postponed both the freeze-fall and thawrise onset times of soil temperature and moisture in alpine LC (lower vegetation coverage) meadows and of soil moisture in alpine HC (higher vegetation coverage) meadows; however, the opposite response occurred for soil temperatures of alpine HC meadows, where the entire melting period was extended by advancing the thaw-rise and delaying the freeze-fall onset time of the soil temperature. Snow cover resulted in a decreased amplitude and rate of variation in soil temperature, for both alpine HC meadows and alpine LC meadows, whereas the distinct influence of snow cover on the amplitude and rate of soil moisture variation occurred at different soil layers with different vegetation coverages. Snow cover increased the soil moisture of alpine grasslands during thawing periods. The results confirmed that the annual hydrothermal dynamics of active layers in permafrost were subject to the synergistic actions of both snow cover and vegetation coverage. [ABSTRACT FROM AUTHOR]

We have investigated theoretically the gas phase reactions of dimethyl sulfoxide (DMSO) with atom Cl in the absence and presence of a single water molecule. The calculations of the potential energy surfaces in the water-free and water-assisted along the different channels are performed at the CCSD(T)/6-311++G(2df,2p)//MP2/6-31G(d) level. The calculated results show that energy barriers of the H-abstraction reaction are reduced due to one water molecule added. The computed rate constants of H-abstraction reaction indicate that the reaction with water is faster than the value of the naked reaction. However, H-abstraction reaction, path2, path3, and path4 are slower without water than hydrous channels. [ABSTRACT FROM AUTHOR]

Purpose: Inhalation of low-density porous particles enables deep lung delivery with less dependence on device design and patient inspiration. The purpose of this study was to implement Thin Film Freezing (TFF) to investigate a novel approach to dry powder inhalation. Methods: Powders produced by TFF were evaluated for aerodynamic and geometric particle size by cascade impaction and laser light scattering, respectively. Density measurements were conducted according to USP methods and calculated using data from particle size measurements. Excipient inclusion and its effect on moisture sorption was measured by Dynamic Vapor Sorption (DVS). Results: TFF-produced brittle matrix powders were sheared apart into respirable microparticles using a passive DPI device, producing fine particle fractions (FPF) up to 69% and mass median aerodynamic diameters (MMAD) as low as 2.6 μm. Particles had a mean geometric diameter ranging from 25 μm to 50 μm and mass densities of approximately 0.01 g/cm. Powders were susceptible to moisture-induced matrix collapse, capillary forces and electrostatic charging; although formulations containing mannitol or no sugar excipient proved to be more robust. Conclusions: Aerosolized brittle matrices produced by TFF may prove to be a useful platform for highly efficient pulmonary delivery of thermally labile, highly potent, and poorly soluble drugs. [ABSTRACT FROM AUTHOR]

Van der Waals heterostructures have been lately intensively studied because they offer a large variety of properties that can be controlled by selecting 2D materials and their sequence in the stack. The exact arrangement of the layers as well as the exact arrangement of the atoms within the layers, both are important for the properties of the resulting device. However, it is very difficult to control and characterize the exact position of the atoms and the layers in such heterostructures, in particular, along the vertical (z) dimension. Recently it has been demonstrated that convergent beam electron diffraction (CBED) allows quantitative three-dimensional mapping of atomic positions in three-dimensional materials from a single CBED pattern. In this study we investigate CBED in more detail by simulating and performing various CBED regimes, with convergent and divergent wavefronts, on a somewhat simplified system: a two-dimensional (2D) monolayer crystal. In CBED, each CBED spot is in fact an in-line hologram of the sample, where in-line holography is known to exhibit high intensity contrast in detection of weak phase objects that are not detectable in conventional in-focus imaging mode. Adsorbates exhibit strong intensity contrast in the zero and higher order CBED spots, whereas lattice deformation such as strain or rippling cause noticeable intensity contrast only in the first and higher order CBED spots. The individual CBED spots can thus be reconstructed as typical in-line holograms, and a resolution of 2.13 Å can in principle be achieved in the reconstructions. We provide simulated and experimental examples of CBED of a 2D monolayer crystal. The simulations show that individual CBED spots can be treated as in-line holograms and sample distributions such as adsorbates, can be reconstructed. Individual atoms can be reconstructed from a single CBED pattern provided the later exhibits high-order CBED spots. The experimental results were obtained in a transmission electron microscope (TEM) at 80 keV on free-standing monolayer hBN containing adsorbates. Examples of reconstructions obtained from experimental CBED patterns at a resolution of 2.7 Å are shown. CBED technique can be potentially useful for imaging individual biological macromolecules, because it provides a relatively high resolution and does not require additional scanning procedure or multiple image acquisitions and therefore allows minimizing the radiation damage. [ABSTRACT FROM AUTHOR]