Search Results (37,544)

In this paper, two parameters of the applied magnetic field—magnetic field strength and pulse length—are modified, the spatial properties of electron trajectories and radiation are studied, and conclusions are drawn. Under the premise that the radius of the laser pulse waist ${\mathrm{b}}_0=4{\lambda }_0$, and that the peak amplitude ${\mathrm{a}}_0=5$ corresponds to the peak laser intensity ${\mathrm{I}}_{\mathrm{L}}=3.45\times {10}^{19} \mathrm{W}/{\mathrm{c}\mathrm{m}}^2$ of the electrons, obtaining high-energy and highly collimated X-rays can be realized by increasing the pulse length up to 6${\lambda }_0$ and increasing the magnitude of the applied magnetic field, or by continuously increasing the pulse length and applying a smaller magnetic field. Full article

The present study investigated the effect of different polymers and manufacturing methods (hot melt extrusion, HME, and spray drying, SD) on the solid state, stability and pharmaceutical performance of amorphous solid dispersions. In the present manuscript, a combination of different binary amorphous solid dispersions containing 20% and 30% of drug loadings were prepared using SD and HME. The developed solid-state properties of the dispersions were evaluated using small- and wide-angle X-ray scattering (WAXS) and modulated differential scanning calorimetry (mDSC). The molecular interaction between the active pharmaceutical ingredients (APIs) and polymers were investigated via infrared (IR) and Raman spectroscopy. The in vitro release profile of the solid dispersions was also evaluated to compare the rate and extend of drug dissolution as a function of method of preparation. Thereafter, the effect of accelerated stability conditions on the physicochemical properties of the solid dispersions were also evaluated. The results demonstrated higher stability of Soluplus^® (SOL) polymer-based solid dispersions as compared to hydroxypropyl methylcellulose (HPMC)-based solid dispersions. Moreover, the stability of the solid dispersions was found to be higher in the case of API having high glass transition temperature (Tg) and demonstrated higher interaction with the polymeric groups. Interestingly, the stability of the melt-extruded dispersions was found to be slightly higher as compared to the SD formulations. However, the down-processing of melt-extruded strands plays critical role in inducing the API crystal nuclei formation. In summary, the findings strongly indicate that the particulate properties significantly influence the performance of the product. Full article

Collichthys lucidus is an important small-scale economic fish species in the Yangtze River Estuary. To improve the accuracy of acoustic stock assessments for C. lucidus, it is necessary to accurately measure its target strength (TS). This study obtained precise morphological parameters of C. lucidus through X-ray scanning and established a Kirchhoff ray mode (KRM) model to simulate the changes in TS of the fish body and swimbladder at different acoustic frequencies and pitch angles. At the same time, the TS was measured using the tethered method to analyze and compare the broadband scattering characteristics obtained from both methods. An empirical formula of C. lucidus relating TS to body length at two conventional frequencies was established using the least squares method. The results show that the C. lucidus TS changes, with body length ranging from 10.91 to 16.61 cm, are significantly influenced by the pitch angle at 70 kHz and 200 kHz frequencies, and the fluctuation of TS for both the fish body and swimbladder increases with the rise in frequency. The broadband TS values estimated by the KRM model and measured by the tethered method fluctuate within in the ranges from −45 dB to −55 dB and −40 dB to −55 dB, respectively. The TS of C. lucidus tends to increase with the increase in swimbladder length. When the probability density function of the pitch angle is N(−5°, 15°), the $b_{20}$ measured by the KRM and the tethered method at 70 kHz are −71.94 dB and −69.21 dB, respectively, while at 200 kHz they are −72.58 dB and −70.55 dB. This study provides a scientific basis for future acoustic target discrimination and stock assessment of C. lucidus in the Yangtze River Estuary. Full article

Medical image registration has become pivotal in recent years with the integration of various imaging modalities like X-ray, ultrasound, MRI, and CT scans, enabling comprehensive analysis and diagnosis of biological structures. This paper provides a comprehensive review of registration techniques for medical images, with an in-depth focus on 2D-2D image registration methods. While 3D registration is briefly touched upon, the primary emphasis remains on 2D techniques and their applications. This review covers registration techniques for diverse modalities, including unimodal, multimodal, interpatient, and intra-patient. The paper explores the challenges encountered in medical image registration, including geometric distortion, differences in image properties, outliers, and optimization convergence, and discusses their impact on registration accuracy and reliability. Strategies for addressing these challenges are highlighted, emphasizing the need for continual innovation and refinement of techniques to enhance the accuracy and reliability of medical image registration systems. The paper concludes by emphasizing the importance of accurate medical image registration in improving diagnosis. Full article

The Advanced X-ray Imaging Satellite (AXIS) promises revolutionary science in the X-ray and multi-messenger time domain. AXIS will leverage excellent spatial resolution (<1.5 arcsec), sensitivity ($80\times$ that of Swift), and a large collecting area (5–10× that of Chandra) across a 24-arcmin diameter field of view at soft X-ray energies (0.3–10.0 keV) to discover and characterize a wide range of X-ray transients from supernova-shock breakouts to tidal disruption events to highly variable supermassive black holes. The observatory’s ability to localize and monitor faint X-ray sources opens up new opportunities to hunt for counterparts to distant binary neutron star mergers, fast radio bursts, and exotic phenomena like fast X-ray transients. AXIS will offer a response time of <2 h to community alerts, enabling studies of gravitational wave sources, high-energy neutrino emitters, X-ray binaries, magnetars, and other targets of opportunity. This white paper highlights some of the discovery science that will be driven by AXIS in this burgeoning field of time domain and multi-messenger astrophysics. This White Paper is part of a series commissioned for the AXIS Probe Concept Mission; additional AXIS White Papers can be found at the AXIS website. Full article

To investigate the influence of Zn-alloying on the microstructure and tensile mechanical properties of Mg–6Bi alloy after hot extrusion, a new ternary Mg–6Bi–3Zn alloy was prepared by extrusion at 300 °C. The microstructures, texture, dynamic precipitates and tensile mechanical behaviors of the extruded alloy were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), electron backscattered diffraction (EBSD) and a material testing machine at room temperature. After extrusion, the Mg–6Bi–3Zn alloy possesses a bimodal microstructure with elongated large unrecrystallized (unDRXed) grains and fine dynamic recrystallized (DRXed) grains. In addition, non-basal <20$\stackrel{\_}{2}$1>//ED, <44$\stackrel{\_}{8}$3>//ED and <11$\stackrel{\_}{2}$1>//ED textures are observed within DRXed grains due to the Zn addition, leading to texture weakening in the extruded Mg–6Bi–3Zn alloy. Zn addition facilitates the dynamic precipitation behavior, leading to a 12.2% area fraction of Mg₃Bi₂ precipitates with an average size of 39.2 nm. Furthermore, incorporation of Zn atoms in Mg₃Bi₂ phases and segregation of Zn at the grain boundary are found. The extruded Mg–6Bi–3Zn alloy exhibits a tensile strength of 336 ± 7.1 MPa and a yield strength of 290 ± 5.5 MPa, as well as an elongation of 11.5%. Therefore, Zn addition is beneficial to enhance strength and keep good ductility for the extruded Mg–6Bi–3Zn alloy. Full article

High temperature superconductors (HTSs) are enablers of extensive electrification for aircraft propulsion. Indeed, if used in electrical machines, HTS materials can drastically improve their performance in terms of the power-to-weight ratio. Among the different topologies of superconducting electrical machines, a flux modulation machine based on HTS bulks is of interest for its compactness and light weight. Such a machine is proposed in the FROST (Flux-barrier Rotating Superconducting Topology) project led by Airbus to develop new technologies as part of their decarbonization goals driven by international policies. The rotor of the machine will house large ring-segment-shaped HTS bulks in order to increase the output power. However, the properties of those bulks are scarcely known and have barely been investigated in the literature. In this context, the present work aims to fill out partially this scarcity within the framework of FROST. Thus, a thorough characterisation of the performances and homogeneity of 11 large REBaCuO bulks was carried out. Ten of the bulks are to be utilized in the machine prototype, originally keeping the eleventh bulk as a spare. A first set of characterisation was conducted on the eleven bulks. For this set, the trapped field mapping and the critical current were estimated. Then, a series of in-depth characterisations on the eleventh bulk followed. It included critical current measurement, X-ray diffraction, and scanning electron microscopy on different millimetre-size samples cut out from the bulk at various locations. The X-ray diffraction and scanning electron microscopy showed weakly oxygenated regions inside the bulk explaining the local drop or loss in superconducting properties. The objective was to determine the causes of the inhomogeneities found in the trapped field measured on all the bulks, sacrificing one of them, here the spare one. To help obtain a clearer picture, a numerical model was then elaborated to reproduce the field map of the eleventh bulk using the experimental data obtained from the characterisation of its various small samples. It is concluded that further characterisations, including the statistics on various bulks, are still needed to understand the underlying reasons for inhomogeneity in the trapped field. Nonetheless, all the bulks presented enough current density to be usable in the construction of the proposed machine. Full article

Methane catalytic combustion, a method for efficient methane utilization, features high energy efficiency and low emissions. The key to this process is the development of highly active and stable catalysts. This study involved the synthesis of a range of catalysts, including NiO/CeO₂, NiO–M/CeO₂, and NiO-Ba/CeO₂. In order to modify the NiO/CeO₂ catalysts to improve their catalytic activity, various alkaline earth metal ions were introduced, and the catalysts were characterized to evaluate the impact of different alkaline earth metal ion doping. It was found that the introduction of Ba as a dopant yielded the highest catalytic activity among the dopants tested. Based on this, the influence of the impregnation sequence, the Ba loading amount, and other factors on the catalytic activity of the NiO/CeO₂ catalysts doped with Ba were investigated, and comprehensive characterization was conducted using a variety of analytical techniques, including N₂ adsorption/desorption, X-ray diffraction, Fourier transform infrared, hydrogen temperature-programmed reduction, methane temperature-programmed surface reaction, and oxygen temperature-programmed oxidation. The H₂–TPR characterization results suggest that Ba introduction partially enhances the reducing property of NiO/CeO₂ catalysts, and improves the surface oxygen activity in the catalysts. Meanwhile, the CH₄–TPSR and O₂–TPO results indicate that Ba introduction also boosts the bulk-phase oxygen liquidity in the catalysts, renders the migration of bulk-phase oxygen to surface oxygen, and increases the surface oxygen number in the catalysts. These results provide evidence of the effectiveness of this catalyst in methane catalytic combustion. Full article

Background/Objectives: There is a need to monitor physical fitness in HIV-diagnosed children and adolescents, and body mass index (BMI) could be an option for this due to its usability for assessing nutritional status and fat mass. The present study aimed to explore the relationship between BMI and physical fitness in HIV-diagnosed children and adolescents. Methods: A cross-sectional study was conducted with 86 HIV-diagnosed children and adolescents aged 5–15, with participants from two research protocols (Study I, n = 65; Study II, n = 21). Physical fitness was assessed through body composition (anthropometric measurements and dual energy X-ray absorptiometry), cardiorespiratory fitness (peak oxygen consumption [VO₂peak]), muscle strength/endurance (handgrip strength, standing broad jump, and abdominal and modified push-up endurance), and flexibility (sit-to reach test). The relationship between BMI and physical fitness components was analyzed through correlation and simple and multiple linear regression analysis. Results: Eutrophic participants (mean age 11.44 ± 2.20) presented a normal fat mass percentage and overweight participants (mean age 11.50 ± 2.54) presented adequate handgrip strength. The adjusted models could explain 71% of fat-free mass, 57% of fat mass percentage, 70% of bone mineral content, 72% of bone mineral density, and 52% of handgrip strength. Conclusions: Increases in BMI were associated with increases in fat-free mass, fat mass percentage, bone mineral content, bone mineral density, and handgrip strength. BMI was capable of distinguishing those presenting a normal fat mass percentage and those presenting adequate handgrip strength. Full article

The structure of the title compound (4d), unexpectedly obtained in the reaction between o-phenylenediamine and 2-benzoylcyclohexanone instead of the target 3H-benzo[b][1,4]diazepine derivative 3d, was determined spectroscopically in solution and by a single-crystal X-ray diffraction (XRD) study. It involves two enantiomeric rotamers, called forms D and U, of which the structure was elucidated based on NMR spectra measured and predicted in DFT-GIAO calculations. An averaging of δ_Cs for all tautomeric positions in the benzimidazole part of the 4d hydrate studied in wet (probably slightly acidic) CDCl₃ unambiguously indicates tautomeric exchange in its imidazole unit. An XRD analysis of this material confirms the existence of only one tautomer in the solid phase. The non-covalent interactions forming between molecules of water and benzimidazole derivative are shorter than the sum of van der Waals radii and create an infinite-chain hydrogen bond motif along the b-axis. A possible mechanism for the observed cyclocondensation is also proposed. Full article

This study aimed to evaluate the staining sensitivity and surface changes in recent composite resins (Herculite Ultra XRV (Kerr, Bolzano, Italy), G-ænial A’CHORD (GC Corp, Tokyo, Japan), and Omnichroma (Yamaguchi, Japan)) when exposed to common beverages such as coffee, red wine, and Coca-Cola. A total of 60 disk-shaped specimens were prepared from three different resin composites (n = 20 each). The specimens were exposed to coffee, red wine, and Coca-Cola for 10 days. Color measurements were taken using a spectrophotometer, and surface morphology and elemental composition were analyzed using SEM and EDS. The SEM and EDS analyses revealed significant changes in the surface morphology and elemental composition of the composites after immersion. Coffee and wine caused significant surface degradation, whereas Coca-Cola resulted in the greatest degree of surface and elemental variations. Color changes (ΔE = 4 ± 0.52) were most notable in Coca-Cola for Herculite Ultra XRV (Kerr, Italy), in red wine for G-ænial A’CHORD (GC Corp, Japan) (ΔE = 12.51 ± 0.38), and in coffee for Omnichroma (Yamaguchi, Japan) (ΔE = 10.85 ± 1.03). The tested beverages significantly affected both the surface condition and the chemical composition of the resin at the surface level. These findings highlight the importance of understanding the effects of common dietary beverages on dental composites. Full article

Water may easily become polluted by pharmaceutical wastes, such as phenazopyridine hydrochloride. The pollutant can be removed by electrochemical oxidation in the form of minerals. A novel electrode has been developed for this purpose. Pt nanoparticles (PtNPs) are electrodeposited onto multiwalled carbon nanotubes supported onto fluorine-doped tin oxide (FTO/Glass). The resulting PtNP@MWCNT-FTO-E electrode is characterized by X-ray diffraction, atomic force microscopy, scanning electron microscopy, electron diffraction spectroscopy and X-ray photoelectron spectroscopy. The electrode exhibits high efficiency in the electrochemical oxidation process thanks to the large specific surface area of the PtNPs and their ability to behave as charge transfer catalysts. The contaminant undergoes complete mineralization, leaving no organics after treatment. The resulting nitrate ions further confirm contaminant mineralization, but fortunately, they disappear over time, which confirms the safety of the process in water treatment. Moreover, the electrode operates under a variety of applied potentials, pH values, temperatures and contaminant concentrations. The electrode exhibits high stability upon recovery and reuse while retaining its physical characteristics before and after use. This study highlights the benefit of using Pt nanoparticles in the electro-degradation of aqueous organic contaminants, especially waste pharmaceuticals, for the first time. It also recommends scaling up the process and studying the continuous-flow reaction process to assess the economic and technical feasibility in future large-scale applications. Full article

Akimotoite, ilmenite-type MgSiO₃ high-pressure polymorph can be stable in the lower-mantle transition zone along average mantle and subducting slab geotherms. Significant amounts of Al₂O₃ can be incorporated into the structure, having the pyrope (Mg₃Al₂Si₃O₁₂) composition. Previous studies have investigated the effect of Al₂O₃ on its crystal structure at nearly endmember compositions. In this study, we synthesized high-quality ilmenite-type Mg₃Al₂Si₃O₁₂ phase at 27 GPa and 1073 K by means of a Kawai-type multi-anvil press and refined the crystal structure at ambient conditions using a synchrotron X-ray diffraction data via the Rietveld method to examine the effect of Al₂O₃. The unit-cell lattice parameters were determined to be a = 4.7553(7) Å, c = 13.310(2) Å, and V = 260.66(6) ų, with Z = 6 (hexagonal, R$\overline{3}$). The volume of the present phase was placed on the akimotoite-corundum endmember join. However, the refined structure showed a strong nonlinear behavior of the a- and c-axes, which can be explained by Al incorporation into the MgO₆ and SiO₆ octahedral sites, which are distinctly different each other. Ilmenite-type Mg₃Al₂Si₃O₁₂ phase may be found in shocked meteorites and can be a good indicator for shock conditions at relatively low temperatures of 1027–1127 K. Full article

Exposure to ionizing radiation can result in the development of a number of diseases, including cancer, cataracts and neurodegenerative pathologies. Certain occupational groups are exposed to both natural and artificial sources of radiation as a consequence of their professional activities. The development of non-invasive biomarkers to assess the risk of exposure to ionizing radiation for these groups is of great importance. In this context, our objective was to identify epigenetic and molecular biomarkers that could be used to monitor exposure to ionizing radiation. The impact of X-ray exposure on the miRNAs profile and the level of cf mtDNA were evaluated using the RT-PCR method. The levels of pro-inflammatory cytokines in their blood were quantified using the ELISA method. A significant decrease in miR-19a-3p, miR-125b-5p and significant increase in miR-29a-3p was observed in the blood plasma of individuals exposed to X-ray. High levels of pro-inflammatory cytokines and cf mtDNA were also detected. In silico identification of potential targets of these miRNAs was conducted using MIENTURNET. VDAC1 and ALOX5 were identified as possible targets. Our study identified promising biomarkers such as miRNAs and cf mtDNA that showed a dose-dependent effect of X-ray exposure. Full article

This study investigates the cytotoxicity profile of superparamagnetic Fe₃O₄-Ag decorated nanoparticles against human fibroblasts (HFF-1) and breast cancer cells (MCF-7). The nanoparticles underwent comprehensive characterization employing scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and magnetic assays including hysteresis curves and zero-field-cooled (ZFC) plots. The nanoparticles exhibited superparamagnetic behavior as evidenced by magnetic studies. Cytotoxicity assays demonstrated that both HFF-1 and MCF-7 cells maintained nearly 100% viability upon nanoparticle exposure, underscoring the outstanding biocompatibility of Fe₃O₄/Ag decorated nanoparticles and suggesting their potential utility in biomedical applications such as drug delivery and magnetic targeting. Furthermore, the study analyzed the cytotoxic effects of Fe₃O₄ and Fe₃O₄-Ag decorated nanoparticles to evaluate their biocompatibility for further therapeutic efficacy. Results showed that neither type of nanoparticle significantly reduced cell viability in HFF-1 fibroblasts, indicating non-cytotoxicity at the tested concentrations. Similarly, MCF-7 breast cancer cells did not exhibit a significant change in viability when exposed to different nanoparticle concentrations, highlighting the compatibility of these nanoparticles with both healthy and cancerous cells. Additionally, the production of reactive oxygen species (ROS) by cells exposed to the nanoparticles was examined to guarantee their biosafety for further therapeutic potential. Higher concentrations (50–100 μg/mL) of Fe₃O₄-Ag nanoparticles decreased ROS production in both HFF-1 and MCF-7 cells, while Fe₃O₄ nanoparticles were more effective in generating ROS. This differential response suggests that Fe₃O₄-Ag nanoparticles might modulate oxidative stress more effectively, thus beneficial for future anticancer strategies due to cancer cells’ susceptibility to ROS-induced damage. These findings contribute to understanding nanoparticle interactions with cellular oxidative mechanisms, which are crucial for developing safe and effective nanoparticle-based therapies. This investigation advances our understanding of nanostructured materials in biological settings and highlights their promising prospects in biomedicine. Full article