Х-ray Study and Computer Simulation of the Structure of Amorphous-Crystalline Titanite

The structure of amorphous-crystalline titanite obtained by mechanical activation was studied by X-ray diffraction and simulation methods. The short-range order characteristics were calculated using Finbak-Warren's method. It was found that the coordination numbers of metal atoms decreased as the result of titanite grinding. The atomic configurations of short-range order of ground titanite were constructed by translation of titanite unit cell. The theoretical X-ray patterns were calculated using Debye's method and were compared with the experimental curves. The structure of ground titanite in the mill with centrifugal factor 40 g was described satisfactorily by the model of mechanical mixture of clusters containing 2016 atoms, disordered during the molecular dynamics with clusters containing 12096 atoms. The increase of grinding intensity led to the sharp decrease of sizes of small cluster.

The Effect of Gel-Type Contributions in Lime-Sand Bricks, Alkali-Activated Slags and CEMI/CEMIII Pastes: Implications for Next Generation Concretes

Lime-sand bricks of different ages were investigated using IR-spectroscopy, thermogravimetry, and X-ray diffraction/scattering. After subtraction of the dominant quartz contribution (80%), the IR spectra show the absorption peaks of the hydrothermally formed binder phases. The spectra also show the alteration of the binder during ageing under atmospheric conditions by the influence of CO2 forming carbonate and a condensed SiO2-gel (secondary gel). The alteration could also be proven in X-ray pattern, obtaining a separation between crystalline CSH and amorphous contributions in the freshly produced lime-sand brick, too. Here, the formation of CSHamorph could be understood as a precursor state (primary gel) to the crystallization of CSH phases. X-ray patterns of aged bodies of alkali-silicate solution activated slags (AAS), CEM-I/CEM-III pastes, and CEM-I concrete indicate that in all cases a similar amorphous CSH-type phase (CSHamorph) was formed, which is responsible for the hardening properties as the glue. The main X-ray peak of CSHamorph obtained using CuKα-radiation with a usual diffractometer is observed between 24° and 35° 2 Theta with maximum at about 29° 2 Theta, whereas it appears much more broadly distributed between 15° and 35° 2 Theta with maximum between 26° and 28° 2 Theta for a geopolymer body prepared using the reaction of alkali-silicate solution and metakaolin (AAMK). This is due to the network formed by siloxo and sialate units in the case of AAMK, given that any crystallization can be ruled out. The origin of increasing mechanical strength during the ageing of AAS mortars must be due to further crosslinking of the preformed siloxo chains. Thermal treatment up to 800 °C leads to a complete loss of any mechanical strength of the CEM pastes due to the destruction of crystalline CSH-phases, whereas geopolymer bodies maintain their strength. Implications for next generation concrete include that cement clinker could be completely replaced by using a using alkali silcate solution technology for gel formation.

Processes of structure and phase formation of aerated concrete of non-autoclave hardening containing ferrosilicon as a gasifier

The paper deals with the structure and phase composition of non-autoclave aerated concrete with a density of 600–800 kg m–3 using ferrosilicon as a gasifier. The conditions of formation of porous structure of aerated concrete and preparation of calcium hydrosilicates were considered. Phase composition of the samples was investigated by means of X-ray phase analysis and differential thermal analysis. Analysis of X-ray patterns showed that the test samples contained tobermorite 11.3 Å (5CaO6SiO25.5H2O), xonotlite (6CaO6SiO2H2O) and -dicalcium silicate hydrate (2CaOSiO2H2O) as a binder. It was established that there is an increase in the content of hydrosilicate phases with an increase in the content of gasifier in the vast majority of cases. The obtained data were confirmed by the results of differential thermal analysis.

Synthesis and release behavior of layered double hydroxides–carbamazepine composites

Carbamazepine (CBZ) was incorporated into layered double hydroxides (LDH) to be used as a controlled drug system in solid tumors. CBZ has a formal charge of zero, so its incorporation in the anionic clay implies a challenge. Aiming to overcome this problem, CBZ was loaded into LDH with sodium cholate (SC), a surfactant with negative charge and, for comparison, without SC by the reconstruction method. Surprisingly, it was found that both resultant nanocomposites had similar CBZ encapsulation efficiency, around 75%, and the LDH-CBZ system without SC showed a better performance in relation to the release kinetics of CBZ in simulated body fluid (pH 7.4) and acetate buffer simulating the cellular cytoplasm (pH 4.8) than the system with SC. The CBZ dimensions were measured with Chem3D and, according to the basal spacing obtained from X-ray patterns, it can be arranged in the LDH-CBZ system as a monolayer with the long axis parallel to the LDH layers. Fourier transform infrared spectroscopy and solid state NMR measurements confirmed the presence of the drug, and thermogravimetric analyses showed an enhanced thermal stability for CBZ. These results have interesting implications since they increase the spectrum of LDH application as a controlled drug system to a large number of nonionic drugs, without the addition of other components.

Radiologic Diagnostics of Lung Lesions by Granulomatosis with Polyangiitis in the Context of the COVID-19 Pandemic

Granulomatosis with polyangiitis (GPA), formerly known as Wegener’s granulomatosis, and lung damage in coronavirus infection have many common clinical and radiological symptoms. In the context of the COVID-19 pandemic the ability of a radiologist to differentiate a viral lung lesion from a granulomatous one is relevant due to the difficulty of recognizing them. In order to develop differential radiation diagnostics, a comparative analysis of the computer tomographic picture of lung lesions in each disease was carried out and the leading X-ray patterns were determined. 61 patients with lung damage were examined, including 30 with HPA, 30 with COVID-19 and 1 patient with a combination of these diseases. A total of 74 native computer tomography examinations of the chest organs were accomplished using a Toshiba Aquilion 64 multi-slice CT scanner. It was found that the most informative radiological sign of HPA are nodes, nodules and masses in the lungs, which were detected in 22 (73.3 %) patients, including 11 (36.7 %) with a necrotic cavitation. Ground-glass opacity is often found in both diseases, but COVID-19 is more characterized by a rounded (56.7 %) or polygonal shape (20.0 %) of pathological areas and their peripheral location (70.0 %) mainly in the posterior parts of the lungs, and triangular areas (42.1 %) with a central location (42.1 %) are more often found in HPA. The rapid dynamics of changes in the lungs on control CT scans is of great diagnostic value, which indicates the viral nature of the disease.

The Features of X-Ray Phase Analysis of Rocks with Complex Mineral Composition

The article presents the results of identification and quantitative analysis of the phase composition, fine structure parameters of minerals in carbonate and terrigenous rocks by the use of modern X-ray diffraction (XRD) analysis. To make the XRD analysis, we optimized the modes of x-ray pattern shooting by changing the radius of the goniometer, the system of primary and secondary slits, Soller slits, and the system of detecting the low-content minerals. In processing the obtained x-ray patterns, we considered the size and defects of the crystal grains, the crystallographic mode of arrangements, atomic population of the crystal lattice, the Debye-Waller factor and the instrumental line broadening by the use of the Caliotti function for LaB6. So we determined the type and content of minerals, estimated the period of the crystal lattice, the size of the coherent scattering domains and micro-distortion crystal lattice of the mineral. We compared the obtained data on the presence and quantitative content of minerals with the data of X-ray fluorescence (XRF) analysis and scanning electron microscopy (SEM). Based on the obtained data, reference intensity ratio (RIR) coefficients were selected for a number of minerals typically contained in core materials for quantitative phase analysis by the use of the corundum number method.

Analysis of X-ray Patterns in Infection and Tumor

In diagnosis of bone tumor, X-ray is as important, if not more important than pathology report. However, X-ray had specific disadvantage. Tumor mimics especially infection can have same appearance as tumor in the X-ray. In this article, author analyzes the different patterns of X-ray changes common to tumor and infection and points outs that X-ray depicts the aggressiveness of the condition rather than a specific diagnosis

Scintillating Starbursts: Concentric Star Polygons Induce Illusory Ray Patterns

Here, we introduce and explore Scintillating Starbursts, a stimulus type made up of concentric star polygons that induce illusory scintillating rays or beams. We test experimentally which factors, such as contrast and number of vertices, modulate how observers experience this stimulus class. We explain how the illusion arises from the interplay of known visual processes, specifically central versus peripheral vision, and interpret the phenomenology evoked by these patterns. We discuss how Starbursts differ from similar and related visual illusions such as illusory contours, grid illusions such as the pincushion grid illusion as well as moiré patterns.

HIV-TUBERCULOSIS: A STUDY OF CHEST X-RAY PATTERNS IN RELATION TO CD4 COUNT

Background: Fight against human immunodeciency virus (HIV) is incomplete without addressing problems associated with difcult diagnosis of tuberculosis in HIV-Tuberculosis coinfected patients. Chest X-ray is a primary tool to evaluate tuberculosis in HIV. Aim: To assess and compare various radiological patterns of pulmonary tuberculosis in HIV patients and compare these patterns in relation to CD4 counts. Materials and Methods: Prospective cohort study was conducted in a tertiary hospital in J.L.N.M.C.H Bhagalpur from april 2019 to january 2021 with 200 HIV positive patients. WHO guidelines were used for diagnosis of HIV and tuberculosis. Results: 27% of the patients had sputum positive pulmonary tuberculosis, with higher incidence (33%) among CD4 less than 200 as compared to CD4 more than 200 (14%). Inltration (39%) followed by consolidation (30%), cavity (11%), and lymphadenopathy (9%) seen with CD4 less than 200. Inltration (37.5%) followed by cavity (25%) and miliary (25%) with CD4 above 200. Bilateral (68.5%) and mid and lower zones or all zone involvement more commonly seen. Conclusion: In patients with CD4 lower than 200 noncavitory inltration and consolidation predominated. Involvement of lungs was atypical; diffuse or mid and lower zone involvement was higher than classical upper lobe involvement. A high index of suspicion is necessary for the accurate and timely diagnosis of tuberculosis in HIVpositive patients.

Maghemite in Brazilian Iron Ores: Quantification of the Magnetite-Maghemite Isomorphic Series by Χ-ray Diffraction and the Rietveld Method, and Confirmation by Independent Methods

Maghemite (γ-Fe2O3) is a mineral formed from magnetite oxidation at low temperatures, an intermediate metastable term of the magnetite to hematite oxidation and could be mixed with both. It has magnetic susceptibility similar to magnetite, crystal structure close to magnetite with which it forms a solid solution, while compositionally it equals hematite. Maghemite is thus easily misidentified as magnetite by Χ-ray diffraction and/or as hematite by spot chemical analysis in iron ore characterization routines. Nonstoichiometric magnetite could be quantified in samples of Brazilian soils and iron ores by the Rietveld method using a constrained refinement of the Χ-ray patterns. The results were confirmed by reflected light microscopy and Raman spectroscopy, thus qualitatively validating the method. Χ-ray diffraction with the refinement of the isomorphic substitution of Fe2+ by Fe3+ along the magnetite-maghemite solid solution could help to suitably characterize maghemite in iron ores, allowing for the evaluation of its ultimate influence on mineral processing, as its effect on surface and breakage properties.