X-ray Techniques Research Articles

Enhancement of SrTiO3 photocatalytic efficiency by Al doping: Answers from the structure, morphology and electronic properties contributions

Our study focuses on disclosing the mechanisms standing behind the improved photocatalytic performance of SrTiO3, where Al modification of the perovskite structure boosts the photocatalytic O2 evolution activity of the Al:SrTiO3 system. By adapting the synthesis method that produces well-crystallized materials with low defect density and employing surface modification techniques, we aim to enhance the photocatalytic efficiency of SrTiO3via Al2O3 nanoceramic oxide doping at concentrations ranging from 0 to 10% and further examining of the relationship between doping process and the changes in the electronic and crystalline structure of SrTiO3. The prepared Al-based SrTiO3 perovskite samples (Al3%:SrTiO3, Al7%:SrTiO3, Al10%:SrTiO3) were thoroughly characterized to understand their structural, electronic, and morphological properties. Complementary X-ray techniques were employed to assess the stoichiometry (X-ray photoelectron spectroscopy - XPS), local environment, and chemical state (X-ray absorption spectroscopy - XAS in both total electron yield (TEY) and fluorescence yield (TFY). The comprehensive characterization enables us to understand the changes in the electronic properties and morphological features of the modified samples elucidating the surface formation mechanism while providing insights into the structural modifications induced by Al doping in the SrTiO3 perovskite lattice. Our findings give new perspectives for the development of Al-modified SrTiO3 perovskite materials with enhanced photocatalytic performance providing rich insights into the optimization of photocatalytic processes for applications in environmental remediation and sustainable energy production.

Polarized X-ray diffraction anomalous near-edge structure study on the orbital physics of thin WSe2 layers

The electronic structures at band edges play an important role in the physical properties of few-layer and monolayer WSe2. In this study, polarization-dependent diffraction anomalous near-edge structure (DANES) is applied to measure and analyse the electronic orbitals of few-layer WSe2. By selecting diffraction geometries with the electric field perpendicular or parallel to the c axis of few-layer WSe2, this method can separately probe the in-plane and out-of-plane orbital components involved at the band edges. The WSe2 (00.8) surface normal was aligned and the preferred orientation of few-layer WSe2 grown on an Al2O3 (00.1) substrate was identified. DANES was then performed for Se K-edge WSe2 00.8 and 11.0 reflections to examine the W 5d orbitals hybridized with the Se 4p orbitals: these two DANES spectra exhibit fairly anisotropic valence orbital characteristics in few-layer WSe2. Coupled with first-principles calculations, these results allow the identification of the in-plane and out-of-plane orbital distribution and hybridization in WSe2. At the conduction band edge, the contributions of px and py orbitals are predominant over pz and the splitting of the p-orbital energy levels has been confirmed. Hence DANES is shown to be a useful synchrotron X-ray technique that can help identify the valence orbital structure of various 2D transition metal dichalcogenides.

Elucidating the Lithiation Process in Fe3-δO4 Nanoparticles by Correlating Magnetic and Structural Properties.

Due to their high potential energy storage, magnetite (Fe3O4) nanoparticles have become appealing as anode materials in lithium-ion batteries. However, the details of the lithiation process are still not completely understood. Here, we investigate chemical lithiation in 70 nm cubic-shaped magnetite nanoparticles with varying degrees of lithiation, x = 0, 0.5, 1, and 1.5. The induced changes in the structural and magnetic properties were investigated using X-ray techniques along with electron microscopy and magnetic measurements. The results indicate that a structural transformation from spinel to rock salt phase occurs above a critical limit for the lithium concentration (xc), which is determined to be between 0.5< xc ≤ 1 for Fe3-δO4. Diffraction and magnetization measurements clearly show the formation of the antiferromagnetic LiFeO2 phase. Upon lithiation, magnetization measurements reveal an exchange bias in the hysteresis loops with an asymmetry, which can be attributed to the formation of mosaic-like LiFeO2 subdomains. The combined characterization techniques enabled us to unambiguously identify the phases and their distributions involved in the lithiation process. Correlating magnetic and structural properties opens the path to increasing the understanding of the processes involved in a variety of nonmagnetic applications of magnetic materials.

Robust treatment planning for small animal radio-neuromodulation using focused kV x-ray beams.

In preclinical radio-neuromodulation research, small animal experiments are pivotal for unraveling radiobiological mechanism, investigating prescription and planning techniques, and assessing treatment effects and toxicities. However, the target size inside a rat brain is typically in the order of sub-millimeters. The small target inside the visual cortex neural region in rat brain with a diameter of around 1mm was focused in this work to observe the physiological change of this region. Delivering uniform doses to the small target while sparing health tissues is challenging. Focused kV x-ray technique based on modern x-ray polycapillary focusing lens is a promising modality for small animal radio-neuromodulation. The current manual planning method could lead to sub-optimal plans, and the positioning uncertainties due to mechanical accuracy limitations, animal immobilization, and robotic arm motion are not considered. This work aims to design a robust inverse planning method to optimize the intensities of focused kV x-ray beams located in beam trajectories to irradiate small mm-sized targets in rat brains for radio-neuromodulation. Focused kV x-ray beams were generated through polycapillary x-ray focusing lenses on achieving small (≤0.3mm) focus perpendicular to the beam. The beam trajectories were manually designed in 3D space in scanning-while-rotating mode. Geant4 Monte Carlo (MC) simulation generated a dose calculation matrix for each focused kV x-ray beam located in beam trajectories. In the proposed robust inverse planning method, an objective function combining a voxel-wise stochastic programming approach and L1 norm regularization was established to overcome the positioning uncertainties and obtain a high-quality plan. The fast iterative shrinkage thresholding algorithm (FISTA) was utilized to solve the objective function and obtain the optimal intensities. Four cases were employed to validate the feasibility and effectiveness of the proposed method. The manual and non-robust inverse planning methods were also implemented for comparison. The proposed robust inverse planning method achieved superior dose homogeneity and higher robustness against positioning uncertainties. On average, the clinical target volume (CTV) homogeneity index (HI) of robust inverse plan improved to 13.3 from 22.9 in non-robust inverse plan and 53.8 in manual plan if positioning uncertainties were also present. The average bandwidth at D90 was reduced by 6.5Gy in the robust inverse plan, compared to 9.6Gy in non-robust inverse plan and 12.5Gy in manual plan. The average bandwidth at D80 was reduced by 3.4Gy in robust inverse plan, compared to 5.5Gy in non-robust inverse plan and 8.5Gy in manual plan. Moreover, the dose delivery time of manual plan was reduced by an average reduction of 54.7% with robust inverse plan and 29.0% with non-robust inverse plan. Compared to manual and non-robust inverse planning methods, the robust inverse planning method improved the dose homogeneity and delivery efficiency and was resistant to the uncertainties, which are crucial for radio-neuromodulation utilizing focused kV x-rays.

Corrosion Inhibition of Expired Cefazolin Drug on Copper Metal in Dilute Hydrochloric Acid Solution: Practical and Theoretical Approaches.

In this work, we studied the corrosion of Cu metal in 0.5 mol L-1 HCl and the inhibition effect of the expired Cefazolin drug. The inhibition efficiency (IE) of Cefazolin varied according to its concentration in solution. As the Cefazolin concentration increased to 300 ppm, the IE increased to 87% at 298 K and decreased to 78% as the temperature increased to 318 K. The expired drug functioned as a mixed-type inhibitor. The adsorption of the drug on the copper surface followed Temkin's adsorption model. The magnitudes of the standard free energy change (ΔGoads) and adsorption equilibrium constant (Kads) indicated the spontaneous nature and exothermicity of the adsorption process. Energy dispersive X-ray (EDX) and scanning electron microscopy (SEM) techniques showed that the drug molecules were strongly attached to the Cu surface. The electrochemical frequency modulation (EFM), potentiodynamic polarization (PP), and electrochemical impedance spectroscopy (EIS) results were in good agreement with the results of the weight loss (WL) method. The density functional tight-binding (DFTB) and Monte Carlo (MC) simulation results indicated that the expired drug bound to the copper surface through the lone pair of electrons of the heteroatoms as well as the π-electrons of the tetrazole ring. The adsorption energy between the drug and copper metal was -459.38 kJ mol-1.

Synthesis, Characterization, Crystal Structure, and Theoretical Calculations of Novel 1,5-Benzodiazepine Derivatives Obtained via 1,3-Dipolar Cycloaddition Reactions

A series of triazolo-benzodiazepine derivatives were synthesized by the condensation of 2,2,4-trimethyl-2,3-dihydro-1H-1,5-benzodiazepine (BZD) 1 with nitrilimine analogs (N-aryl-C-ethoxycarbonyl-nitrilimines and diarylnitrilimines). The newly synthesized cycloadducts were well-characterized by various spectroscopic techniques (1H, 13C NMR, and HRMS). The structure of single-crystal was characterized using a single-crystal X-ray technique. A theoretical study of the chemo and regioselectivity has been performed by density functional theory at the B3LYP/6-311G(d,p) level of theory. A comprehensive theoretical study of the reaction mechanism was performed. The geometry of the different reactants and products were analyzed, the transition states were located and the corresponding reaction paths were determined and characterized by the intrinsic reaction coordinate. Computational results show that the reactions were completely chemo and regioselective, the mechanism of reactions was non-concerted and explained the effect of aryl groups on the reaction yield.

Control of nano-cavitation in semi-crystalline polymer nanocomposites during uniaxial tension: In situ synchrotron X-ray study

The cavitation behavior of polypropylene-silica (PP-silica) and high density polyethylene-silica (HDPE-silica) composites with varying silica content during uniaxial tension was investigated via in situ X-ray techniques. The introduction of silica was found to significantly influence the mechanical properties of the materials. Small-angle X-ray scattering (SAXS) was employed to determine the cavitation onset strain and to observe the evolution of cavity structures. Through model fitting, the size evolution of nanoscale cavities at the onset of cavitation was quantitatively characterized. Scanning electron microscopy (SEM) was utilized to examine the morphology before and after stretching, revealing that cavity structures primarily resulted from internal defects in the polymer matrix and interfacial debonding between silica and the polymer. The long axis of the nanoscale cavities at the onset of cavitation was perpendicular to the tensile direction, and further deformation led to the coalescence into micron-sized cavities with the long axis parallel to the tensile direction. Wide-angle X-ray scattering (WAXS) was used to characterize the microscale deformation process of crystals, showing that during stretching, the lamellae reoriented with the angle between their normal direction and the tensile direction gradually decreasing. Several sets of transition strains representing the plastic deformation were used to compare the microscale and macroscale deformation, elucidating the sequence and differentiation between crystal plastic deformation, cavitation, and yield in the two polymer materials. Intriguingly, both PP-silica and HDPE-silica composites exhibited optimal silica additions and initial structural parameters for regulating cavitation behavior. These findings offer significant guidance for the control of internal structures in porous separators in industrial production.

Highly Robust Alginate-based Magnetic Nanosorbents of Pd Catalysts for the 4-Nitrophenol Reduction

This work presents the synthesis of alginate-coated magnetite nanoparticle (MNP) containing amino-enriched moieties for the immobilization of palladium (Pd), and its use as a recyclable catalyst for the reduction of 4-nitrophenol (4NP) in water. The alginate grafted onto the surface of MNP contained carboxylate anions that served as coordination sites for Pd. Additionally, the incorporation of amino-enriched components, such as poly(vinyl amine) (PVAm) and 2-(dimethyl amino)ethyl methacrylate (DMAEMA), onto the alginate-coated MNPs resulted in additional interactions, including the formation of carboxylate-ammonium salts. In this study, the influence of these amino groups on the efficiency of Pd immobilization, catalytic activity and reusability of nanosorbents for 4NP reduction was investigated. The existence of Pd in the nanosorbents was detected by inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy, and energy-dispersive X-ray techniques. The average size of MNPs was approximately 12.3 ± 2.9 nm, and for Pd, it was about 3.9 ± 0.8 nm. It was found that the incorporation of these amino-enriched moieties into the particles significantly enhanced the catalytic activity of the nanosorbents. Notably, MNP containing extended DMAEMA units exhibited excellent tolerance to 4NP reduction, with an insignificant loss of catalytic performance even after 20 consecutive reuses, maintaining a conversion of over 98 %. HIGHLIGHTS Synthesis of alginate-based magnetite nanoparticle for the immobilization of Pd and its use as a catalyst for the reduction of 4-nitrophenol in water were presented The carboxylate groups in alginate provided the coordinating sites for Pd immobilization and improved the particle dispersibility in water The incorporation of amino-enriched components to the particle reduced the degree of Pd aggregation on the particle surface The catalysts had high catalytic performance for the reduction of 4-nitrophenol in water and exhibited highly robust properties with excellent reusability for up to 20 cycles with insignificant changes in their performance GRAPHICAL ABSTRACT

Development and tuning of models for accurate simulation of CT spatial resolution using CatSim.

Objective. We sought to systematically evaluate CatSim's ability to accurately simulate the spatial resolution produced by a typical 64-detector-row clinical CT scanner in the projection and image domains, over the range of clinically used x-ray techniques.Approach.Using a 64-detector-row clinical scanner, we scanned two phantoms designed to evaluate spatial resolution in the projection and image domains. These empirical scans were performed over the standard clinically used range of x-ray techniques (kV, and mA). We extracted projection data from the scanner, and we reconstructed images. For the CatSim simulations, we developed digital phantoms to represent the phantoms used in the empirical scans. We developed a new, realistic model for the x-ray source focal spot, and we empirically tuned a published model for the x-ray detector temporal response. We applied these phantoms and models to simulate scans equivalent to the empirical scans, and we reconstructed the simulated projections using the same methods used for the empirical scans. For the empirical and simulated scans, we qualitatively and quantitatively compared the projection-domain and image-domain point-spread functions (PSFs) as well as the image-domain modulation transfer functions. We reported four quantitative metrics and the percent error between the empirical and simulated results.Main Results.Qualitatively, the PSFs matched well in both the projection and image domains. Quantitatively, all four metrics generally agreed well, with most of the average errors substantially less than 5% for all x-ray techniques. Although the errors tended to increase with decreasing kV, we found that the CatSim simulations agreed with the empirical scans within limits required for the anticipated applications of CatSim.Significance.The new focal spot model and the new detector temporal response model are significant contributions to CatSim because they enabled achieving the desired level of agreement between empirical and simulated results. With these new models and this validation, CatSim users can be confident that the spatial resolution represented by simulations faithfully represents results that would be obtained by a real scanner, within reasonable, known limits. Furthermore, users of CatSim can vary parameters including but not limited to system geometry, focal spot size/shape and detector parameters, beyond the values available in physical scanners, and be confident in the results. Therefore, CatSim can be used to explore new hardware designs as well as new scanning and reconstruction methods, thus enabling acceleration of improved CT scan capabilities.

Technical Quality and Diagnostic Impact of Chest X-rays in Tuberculosis Screening: Insights From a Saudi Teleradiology Cohort.

Objectives To assess the standard of chest X-ray techniques in tuberculosis (TB) screening within Saudi Arabian healthcare facilities and evaluate the impact of technical quality on radiological interpretation. Materials and methods Analysis of 250 posteroanterior chest radiographs sourced from a network of five clinics was conducted. These images were scrutinized for technical quality by a radiologist. Results Of the radiographs analyzed, 57% exhibited technical issues, with overexposure and clothing artifacts being the most commonly encountered. Notably, only 14% of these radiographs were deemed to have compromised diagnostic ability. Conclusion The presence of technical issues in most chest X-rays for TB screening highlights a significant area for improvement. However, the relatively low percentage of radiographs impacting diagnostic quality indicates that most issues do not critically hinder the radiologist's interpretative capability. This underscores the importance of balanced quality control measures in radiographic practices for effective TB detection in the region.

Eco-friendly synthesis of clay-chitosan composite for efficient removal of alizarin red S dye from wastewater: A comprehensive experimental and theoretical investigation

Alizarin Red S (ARS) is commonly utilized for dyeing in textile industry. The dye represents a refractory pollutant in the aquatic environment unless properly treated. To tackle this pollutant, the applicability of chitosan-clay composite (3C) for the ARS removal from textile wastewater was studied. Characterization studies were conducted on the synthesized adsorbent using Fourier transformation infrared (FT-IR), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) techniques. Optimized parameters such as adsorbent's dosage, pH, reaction time, and initial concentrations were tested in a batch system. Additionally, density functional theory (DFT) was calculated to understand the adsorption mechanism and the role of benzene rings and oxygen atoms in the ARS as electron donors. At the same initial concentration of 30 mg/L and optimized conditions of 50 mg of dose, pH 2, and 10 min of reaction time, about 86% of ARS removal was achieved using the composite. The pseudo-second-order kinetic was applicable to model a reasonable fitness of the adsorption reaction, while the Temkin model was representative to simulate the reaction with a maximum adsorption capacity of 44.39 mg/g. This result was higher than magnetic chitosan (40.12 mg/g), or pure chitosan (42.48 mg/g). With ΔH = 27.22 kJ/mol and ΔG<0, the data implied the endothermic and spontaneous nature of the adsorption process. Overall, this implies that the clay-chitosan composite is promising to remove target dye from contaminated wastewater.

Characterization of PPS Piston and Packing Ring Materials for High-Pressure Hydrogen Applications.

The widespread adoption of renewable energy hinges on the efficient transportation of hydrogen. Reciprocating piston compressor technology in non-lubricated operation will play a key role, ensuring high flow rates and compression ratios. These systems rely on advanced high-strength sealing solutions for piston and rod packing rings utilizing advanced fiber-reinforced polymers. Polyphenylene sulfide (PPS) polymer matrix composites have seen use in tribological applications and promise high mechanical strength and wear resistance. The presented work describes carbon and glass fiber-reinforced PPS matrix polymers in comparison, which are characterized by complementary methods to investigate their properties and potential for application in reciprocating compressor under non-lubricated operation. Thermo-mechanical and tribological testing was supported by microstructure analysis utilizing advanced X-ray and electron imaging techniques. New insights in micromechanical deformation behavior in regard to fiber materials, interface strength and orientation in fiber-reinforced polymers are given. Conclusions on the suitability of different PPS matrix composites for high-pressure hydrogen compression applications were obtained.

Gustav Peter Bucky: An Engineer in the Service of Health.

This history page in the series "Leaders in MSK radiology" is dedicated to the memory and achievements of the German radiologist Gustav Peter Bucky who invented the Bucky diaphragm grids. He wanted to become an engineer but bowed to his parents' wishes and went to medical school. By using his technical skills, he made revolutionary contributions to the early X-ray technique.

Measurement of microRNA-106b as a gastric cancer biomarker based on Zn-BTC MOF label-free genosensor

Due to the late detection of stomach cancer, this cancer usually causes high mortality. The development of an electrochemical genosensor to measure microRNA 106b (miR-106b), as a gastric cancer biomarker, is the aim of this effort. In this regard, first, 1,3,5-benzenetricarboxylate (BTC) metal-organic frameworks (Zn-BTC MOF) were self-assembled on the glassy carbon electrode and then the probe (ssDNA) was immobilized on it. The morphology Zn-BTC MOF was characterized by SEM, FT-IR, Raman and X-Ray techniques. Zn-BTC MOF as a biosensor substrate has strong interaction with ssDNA. Quantitative measurement of miR-106b was performed by electrochemical impedance spectroscopy (EIS). To perform this measurement, the difference of the charge transfer resistances (ΔRct) of Nyquist plots of the ssDNA probe modified electrode before and after hybridization with miR-106b was obtained and used as an analytical signal. Using the suggested genosensor, it is possible to measure miR-106b in the concentration range of 1.0 fM to 1.0 μM with a detection limit of 0.65 fM under optimal conditions. Moreover, at the genosensor surface, miR-106b can be detected from a non-complementary and a single base mismatch sequence. Also, the genosensor was used to assess miR-106b in a human serum sample and obtained satisfactory results.

Room temperature synthesis of β-ketonitriles catalyzed by metal–organic framework supported Pd nanoparticles

A Pd supported on a metal–organic framework catalyst has been prepared and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray techniques. The designed heterogeneous catalyst Nd-MOF/Pd can promote the addition reaction of aryl boronic acids with dinitriles to give the corresponding β-ketonitriles in high yields at room temperature. Moreover, the catalyst can be recovered and recycled, running for five times without obvious loss of its reactivity.

Eye Disease Detection Portal

Eye diseases and cancer, affecting millions of people in the developing world, can lead to vision loss. Tomography, a type of X-ray technique, is used for their detection, but symptoms like pain, blurriness, and redness may go unnoticed. Limited access to expertise in metropolitan areas poses a challenge for accurate diagnosis, despite the availability of scanning centers in many towns. By utilizing Deep Learning techniques, we have revolutionized the detection of eye diseases and cancer. This project involves extensive datasets obtained from previously scanned tomography scans, which are subjected to preprocessing steps to ensure optimal quality. The trained models learn from these datasets, enabling them to accurately classify eye conditions. To facilitate ease of use, we have developed an intuitive interface that allows ophthalmologists to input eye images from scans. Leveraging the power of Deep Learning algorithms, the system swiftly analyzes the images and generates comprehensive reports indicating the presence of various eye diseases and cancer. This approach addresses the limitations of traditional diagnostic methods, as it significantly reduces the time and effort required for disease identification. By incorporating advanced Deep Learning techniques, our system achieves the highest levels of accuracy in detecting and diagnosing eye diseases, ensuring prompt and effective treatment for patients. Overall, our project showcases the potential of Deep Learning in revolutionizing the detection and diagnosis of eye diseases and cancer, ensuring that patients receive prompt and accurate treatment regardless of their geographical location.

General Algorithm Applicability in Determining DBS Lead Orientation: Adapting 2D and 3D X-Ray Techniques for SenSightTM Leads

Introduction: With recent advancements in deep brain stimulation (DBS), directional leads featuring segmented contacts have been introduced, allowing for targeted stimulation of specific brain regions. Given that manufacturers employ diverse markers for lead orientation, our investigation focuses on the adaptability of the 2017 techniques proposed by the Cologne research group for lead orientation determination. Methods: We tailored the two separate 2D and 3D X-ray-based techniques published in 2017 and originally developed for C-shaped markers, to the dual-marker of the Medtronic SenSight™ lead. In a retrospective patient study, we evaluated their feasibility and consistency by comparing the degree of agreement between the two methods. Results: The Bland-Altman plot showed favorable concordance without any noticeable systematic errors. The mean difference was 0.79°, with limits of agreement spanning from 21.4° to −19.8°. The algorithms demonstrated high reliability, evidenced by an intraclass correlation coefficient of 0.99 (p < 0.001). Conclusion: The 2D and 3D algorithms, initially formulated for discerning the circular orientation of a C-shaped marker, were adapted to the marker of the Medtronic SenSight™ lead. Statistical analyses revealed a significant level of agreement between the two methods. Our findings highlight the adaptability of these algorithms to different markers, achievable through both low-dose intraoperative 2D X-ray imaging and standard CT imaging.

Fruit and seed plumpness, germination and viability of rare plants in Yakutia

Background. With the increasing anthropogenic impact on nature, conservation and renewal of rare and endangered plants in natural cenoses is an urgent problem. Quality assessment, identification of full-fledged plump seeds, and determination of their viability is the way to develop reproduction technologies and provide a possibility of repatriating these species to their natural habitats. Collecting and studying natural flora species in botanical gardens helps to save biological resources of useful species and recommend them for urban landscaping.Materials and methods. X-ray techniques were used to analyze seed quality and viability of rare species in the flora of Yakutia: Adonis sibirica Patrin, Phlojodicarpus sibiricus (Steph. ex Spreng.) Koso-Pol., Iris laevigata Fisch. et C.A. Mey., Iris sanguinea Donn, and Paeonia anomala L. Methods developed for the application of microfocus radiography to fruits and seeds were used in the X-ray analysis.Results. Seed quality was assessed according to guidelines. It was shown that fruits and seeds of the studied species developed under the conditions of Yakutia were full-fledged (plump), but due to the presence of a morphophysiological type of dormancy in them, they could germinate only after a cold or multistage stratification.Conclusion. Assessment of reproductive diaspore quality and viability in rare and endangered plant species of Yakutia will make it possible to develop technologies for increasing their seed germination rates and restoring the natural populations of these species.

Use of the X-ray technique to evaluate the internal morphology of seeds of green manure species

ABSTRACT: Image analysis through X-ray technique has been receiving great attention due to its importance in identifying internal damage in seeds quickly and accurately, in addition to being a non-destructive method. The aim of this study was to assess the use of X-rays to evaluate the internal morphology of seeds of green manure species. Seeds of Lupinus albus L., Cajanus cajan (L.) Millsp., Canavalia ensiformis (L.) DC. and Stylosanthes spp. were radiographed. Two hundred seeds were studied for each species, and intact seeds, seeds with mechanical damage, damage caused by insects and deteriorated tissues were recorded, considering the severity and location of the damage. The same seeds were subjected to a germination test. It was concluded that image analysis using X-ray technique was effective in detecting internal damage in seeds of some green manure species and it has relationship with negative aspects in germination.

Structure affinity of the Langmuir monolayer and the corresponding Langmuir-Blodgett film revealed by X-ray techniques.

The possibility of reproducing the structural organization and functional abilities of a Langmuir monolayer in a film formed from it is one of the fundamental problems of ultrathin film science. This work is devoted to the comparison of monolayer and Langmuir-Blodgett (LB) film characteristics using the example of 2D systems based on the dithia-aza-crown substituted hemicyanine dye HCS. As was shown earlier, the investigated systems are promising for the preparation of selective sensors and extractors for mercury ions in aqueous solutions with a subnanomolar sensitivity threshold. Therefore, the study of the analyte binding mechanism by such a film is of great importance. The study carried out using an ultra-highly brilliant X-ray source (ESRF) allows the application of highly sensitive techniques such as X-ray reflectometry (XRR) and X-ray standing wave (XSW). Comparison of the electron density depth profile of the HCS Langmuir monolayer at the air/water interface and the HCS film transferred to a silicon substrate shows the preservation of the film structure and its functional features. The XSW measurements in turn reveal the similarities in the fine structure of preorganized Langmuir monolayers and Langmuir-Blodgett films of HCS. The integration of X-ray techniques with molecular modeling methods allowed us to show that the crown-ether groups of HCS molecules in the pre-organized monolayer and in the corresponding LB film lie on the surface of water or silicon, and the bound mercury ion is located above the crown-ether, partially binding to the nitrogen atom. The latter loses conjugation to the chromophore group, thereby altering the UV-vis spectrum and providing a response signal. The revealed mechanism of imprinting preorganization allows the proposed approach to be extended to other crown-substituted amphiphilic dyes to significantly enhance the sensory response.