The absorption, fluorescence, and fluorescence excitation spectra of phenylthio-substituted Al-phthalocyanine in solutions, polyvinyl butyral films, and silicate gel matrices were studied at room temperature. It was found that monomeric fluorescent forms of impurity molecules are formed not only in ethanol and polyvinyl butyral, but also in inorganic and organo-inorganic silicate matrices colored by direct sol-gel synthesis. It was shown that when the tetraethoxysilane matrix is stained by the impregnation method, nonfluorescent aggregates, presumably of the H-type, are formed. The obtained solid silicate matrices can be used as multipurpose luminescent materials for the near-IR region.

The IR spectra of the free base of phthalocyanine and three of its deuterium derivatives have been studied experimentally and theoretically. Calculations of normal vibrations by the density functional theory method made it possible to carry out a detailed interpretation of the spectra and their changes upon isotope substitution. Vibrations, frequencies of which are sensitive to the isotopic substitution of various positions of the molecule, have been established. A high delocalization of plane bending vibrations of NH bonds has been noted with the greatest change in vibration frequencies not exceeding 85 cm^–1.

 Assignment of signals of the nuclei of hydrogen and carbon atoms in a group of steroids belonging to the group of 6-deoxo-24-epiteasterone and 24-epibrassinolide has been fulfilled using the two-dimensional Nuclear magnetic resonance spectroscopy methods. The effect of solvents on the chemical shift has been studied. 

 The structure of 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1Н,3Н)-dione in dimethyl sulfoxide was proved by ¹³С, ¹Н, and ¹⁵N NMR spectroscopy. It was shown that this compound has a structure similar to 5,5,6-trihydroxy-6-methyldihydropyrimidine-2,4(1Н,3Н)-dione. 

The formation of J-aggregates of 21-thia-5,10,15,20-tetra-(4-sulfonatophenyl)-porphyrin in acidified water solutions is herein revealed for the first time and their spectral-luminescent properties are measured. It is shown that the spectral-luminescent properties of J-aggregates are due to the excitonic interactions, and the number of coherent interacting monomeric porphyrin molecules in the aggregate is evaluated. It is found that J-aggregates of heteroporphyrin have fluorescence, and the fluorescence quantum yield Фfl is found to be as low as 1.8 × 10^–4. The photolability of J-aggregates is found, namely, upon J-aggregate photoexcitation to the absorption band at 503 nm they collapse to the monomeric doubly protonated molecules. The process of photomonomerisation is reversible: upon keeping the solution in the dark, J-aggregates form again.

The photo- and cathodoluminescence of the visible range from erbium-doped barium titanate xerogels obtained in the form of a powder and target pressed from it by explosive compaction method is investigated. The powder and target exhibit up-conversion luminescence of erbium ions under excitation at wavelengths in the regions of 950–1000 and 1450–1550 nm, which is characterized by intense bands at 650, 520–560 nm and a weak band at 820 nm, corresponding to the

⁴F_9/2 ® ⁴I_15/2, ²Н_11/2 ® ⁴I_15/2, ⁴S_3/2 ® ⁴I_15/2, ⁴I_9/2 ® ⁴I_15/2

 transitions of the trivalent erbium ion. The target also demonstrates cathodoluminescence at room temperature and liquid nitrogen temperature with the most intensive bands at 650, 520, and 538 nm.

The optical spectrum band positions and electron paramagnetic resonance (EPR) parameters – g factors (g_x, g_y, g_z) and the hyperfine structure constants (A_x, A_y, A_z) for Cu²⁺ doped in LiNbO₃ crystal are theoretically investigated using the perturbation formulas of these EPR parameters for a 3d⁹ ion under rhombically elongated octahedra based on the cluster approach. The doped Cu²⁺ was assumed to substitute for the host Li+ in the lattice, with a different local environment from the original Li+ due to size mismatch and the Jahn–Teller effect. Based on the calculations, the Cu-O bonds are found to suffer the axial elongation δz (~0.0611 Å) along the z-axis, and the planar bond length experiences an additional variation δr (~0.0861 Å) along the x- and y-axis respectively. Meanwhile, the ground-state wave function for the Cu²⁺ center in LiNbO₃ was also obtained.

We demonstrate the efficiency of the chocolate sample classification by type and manufacturer using the “spectral print” method using THz transmission spectra. To suppress the noise and the Fabry–Perot effect, spectra baselines are determined using the adaptive iteratively reweighted penalized least squares (airPLS) method. The classification was carried out by constructing a low-dimensional space of the principal components of the baselines and applying the methods of cluster analysis in this space. The precision and recall values of the classification of chocolate samples by the k-means, classification and regression tree and hierarchical cluster analysis are 0.85 and 0.83, 0.91 and 0.90, 0.94 and 0.93, respectively. The support vector machine is successfully applied to consider two cases where pairwise classification is most problematic.

TEM investigation revealed that the rapid vacuum-thermal carbidization of silicon at 1100°C leads to the formation of cubic silicon carbide (SiC) layers. The band of the IR transmission spectrum at 798 cm^–1 corresponding to the stretching vibration of Si-C and the maximum of Raman spectrum at 793 cm^–1 relating to transverse optical phonon mode of SiC confirm the formation of a layer of the cubic SiC politype. The absorption band of Si-O-Si (1100 cm^–1) was found using the IR-spectroscopy. The dependence of the transmission coefficient on the wavenumber was determined.

When plasmonic nanoparticles (PNPs) enter a biofluid, the adsorbed biomolecules on the surface form a protein corona, which has direct consequences in biomedical applications. The binding in passive adsorption is nonspecific and is governed by ionic, van der Waals, and hydrophobic forces. We describe the results of deep LED (275-nm) interaction with bovine serum albumin (BSA) containing gold nanourchin (GNU) using dynamic beam view profiling and fluorescence spectroscopy. 800-nm diode laser-induced thermal effects on the bioplasmonic solution were investigated using probe beam monitoring and an IR camera. The results indicated a consistent nonlinear and oscillatory behavior of the GNU-BSA complex due to the adsorption and desorption process of protein. Tyrosine (Tyr) fluorescence enhancement and quenching were observed, which can provide some information about the binding kinetics and protein conformational changes. After 10 min of laser heating, the Tyr fluorescence completely vanished and the He-Ne probe beam was broadened by about 4 nm owing to molecular collisions and protein denaturation. The temperature variation due to protein unfolding and denaturation exhibited a similar nonlinear pattern at different GNU volumes. However, the temperature was lower at higher GNU concentrations, indicating a higher rate of protein adsorption, which effectively mitigated the localized surface plasmon resonance heating.

In order to directly detect the concentration of glucose in milk, carbon dots (CDs) rich in phenolic hydroxyl groups were synthesized in one step as a fluorescent probe. We presented a new glucose oxidase (GOx)-mediated strategy to detect glucose, which allowed the quantitative analysis of hydrogen peroxide (H2O2) and glucose. Furthermore, it was possible to detect H2O2 and glucose directly in complex systems such as milk. The result in milk showed that the fluorescence of the CDs was quenched by H2O2 with the concentration range from 1 to 100 μM linearly, and the correlation coefficient was 0.977 with a detection limit of 0.175 μM. Similarly, a linear correlation was built between the fluorescence of the CDs and the concentration of glucose in the range from 10 to 100 μM with a correlation coefficient of 0.968 and a detection limit of 0.686 μM. The recovery rate was 97.30–101.05%, which showed high sensitivity in the detection of glucose in milk. As far as we know, this was the first time that CDs were used as a fluorescent probe to detect glucose in milk directly, which removed the step of pretreating milk and provided a supplement and extension for the detection of glucose in fluorescent spectroscopy.

The spectral and fluorescent characteristics of bovine serum albumin (BSA) molecules in the soft crown of silver nanoparticles (AgNP) were studied at different pH values. The formation of BSA + AgNP complexes was established. The coupling constants of the complex (K_ass) and the biomolecular rate constants of the BSA fluorescence quenching (K_q) were determined for different pH values. The dependences of K_ass and K_q on pH are nonmonotonic with maxima at pH 6.0. The number of binding sites (Hill coefficient (n)) and the thickness of the BSA soft crown (Dd) are also maximal at pH 6.0. At higher and lower pH values (relative to pH 6.0), these parameters decrease. Variations in the parameters of interaction between BSA and AgNP are due to changes in the conformational modifications of the protein (content of the a-helix) and the microenvironment of Tyr and Trp protein residues in the soft crown (hydrophobicity of the protein).

The migration and accumulation of iron and copper ions in the process of growing Solanum tuberosum L vial potatoes have been studied. The form and content of the metals in the tissues of potatoes grown under factorostatic conditions have been determined by elemental analysis and electron paramagnetic resonance (EPR) method. The toxic effect of the studied heavy metals has been expressed in terms of physical-chemical characteristics (change in the EPR signals and metal accumulation in plant organs) and biometric parameters with an increase in the content of metal salts in the nutrient medium. In addition, the EPR spectra showed a narrow singlet typical for stable semiquinone radicals.

The application of the optimal interpolation method for the assimilation of the observational data of aerosol optical thickness (AOT), which are sparse in space and time, in the chemical transport model is herein validated. Assuming the negligible error of AOT observations in the AERONET ground-based radiometric network, spatial and temporal correlation functions of the errors in the results of the AOT simulated by the GEOS-Chem chemical transport model are obtained. The optimal interpolation method is applied to the AERONET data using the GEOS-Chem results as a background field for the Eastern European region for 2015–2016. It is shown that the use of the optimal interpolation method permits to reduce the root-meansquare error of the AOT estimation by more than a third in places where there are no AERONET stations in comparison with the model results.

The photoinduced gyrotropy (nonlinear optical activity) of polarization-sensitive luminescent recording materials based on various drinking and mineral waters are herein studied by the methods of polarizationluminescent holography. Photoluminescence spectra and spectra of the degree of circularity of (circular) polarization luminescence of the reconstructed phantom object are obtained. It is shown that during the transition between the racemic to chirally pure phases, a significant modification of the spectra of dynamic multiplex luminescent Denisyuk holograms is observed in the medium, in particular, a polarizationholographic memory of the gyrotropic properties is expressed in the considered water media. The polarization-holographic analysis of the optical polarization spectra of aqueous media makes it possible to obtain additional information about anisotropic-gyrotropic holographic materials, namely, the intrinsic chirality of the components of each compound present in the medium.

We numerically investigated the features of the formation of the space-energy profile of the visibility zone by active-pulse vision systems (APVS) on inclined paths with the diffuse reflection of vertically and horizontally oriented objects. We proposed to take into account the presence of a noise threshold in APVS and introduced the concept of signal contrast that permited to bring the results of the numerical modeling of the potential capabilities of APVS closer to those realized experimentally. It is shown that the position used earlier, when the length of the visibility zone was uniquely determined by the sum of the duration of the illumination and strobing pulses, is valid if the signal contrast is close to unity. With the considered typical parameters, the maximum observation range of vertical objects is approximately 3.8 times higher than the similar value for horizontal objects. When the APVS installation height increases, the signal value for vertical objects decreases monotonically, and for horizontal objects this dependence has a maximum. For the first time, a decrease in the length of the visibility zone for fixed durations of illumination and strobing pulses with an increasing delay distance is experimentally confirmed

The terahertz (THz) absorption spectrum of orotic acid monohydrate in the crystalline phase was experimentally obtained by using THz time-domain spectroscopy and computationally simulated by using density functional theory. Four distinct peaks were observed within the range of 12–128 cm^–1, and were computationally reproduced by simulations using the Perdew–Burke–Ernzerhof functional. A comparison of the experimental and calculated data indicated that the measured peaks mostly originated from intermolecular forces in which the interactions between orotic acid molecules dominated. In addition, the feature located at 110.2 cm^–1 was attributed to the interactions between orotic acid and water molecules. These findings demonstrate that THz spectroscopy can be used to monitor molecular dehydration during industrial production.

The paper proposes a deep neural network architecture based on the integration of the convolutional neural network Faster R-CNN with the Feature Pyramid Network module. Based on this approach, an algorithm for detecting and classifying vehicles in images and a corresponding model have been developed. A cross-platform environment ML.NET was used to train the proposed model. The results of comparing the effectiveness of the proposed approach and convolutional neural networks YOLO v4 and Faster R-CNN are presented. The improvement of the accuracy of detection and localization of different types of vehicles in ultra-high resolutions images is shown. Examples of processing ultra-high resolutions remote sensing images and appropriate recommendations are given.

A simple, accurate, novel, safe, and precise method was developed for the estimation of erlotinib hydrochloride in tablet dosage form using a mixture of methanol and acetonitrile (50:50% V/V). The maximum and subsidiary peak absorption of erlotinib hydrochloride were noted at 247 and 333 nm, respectively. Erlotinib hydrochloride follows Beer’s law in the concentration range of 5–30 μg/mL (r² = 0.9992). In the proposed method, the subsidiary peak absorption wavelength of 333 nm was used to estimate the concentration of erlotinib hydrochloride in tablets. The linear regression equation was found to be y = 0.0461x + 0.0164. The developed method was validated according to the International Conference on Harmonization (ICH) guidelines, and the values of accuracy, precision, and other statistical variables were found to be in accordance with the prescribed values.

In view of astrophysical application, the ground state molecular parameters such as bond length, dipole moment, rotational constant, harmonic frequency, IR intensity, vibrational temperature of the astrophysically significant diatomic molecule of carbon mono-fluoride (CF) were derived using B3LYP hybrid density functional theory with three basis sets of 3-21G, 6-31G, and 6-311G. The computed data were collectively compared with the values reported in the literature. It was found that the vibrational temperature obtained using the density functional theory approach resembles the favorable temperature for the formation of the CF molecule in an interstellar medium. The transition probability parameters, namely Franck–Condon factors and r-centroids were evaluated for A–X, B–X, and D–X band systems of the CF molecule, using a more reliable numerical integration procedure. The molecular parameters of ground state obtained in the present study was compared with the reported values for better justification. The results of Franck–Condon factors and r-centroids were also discussed in view of astrophysical application.

A titanium-doped ZnO nanopowder was prepared with different wt% ratios using a simple solution technique. Structural and spectroscopic characterization was done for the prepared samples. The X-ray powder diffraction pattern showed that the prepared nanopowder was in the nanoscale range, the crystallite size of the ZnO nanopowder being 41.67 nm. By increasing the dopant concentration in the host lattice, the crystalline size was decreased to 20.84 nm. The morphological surface stated that the formatting of ZnO was marginally impacted by Ti-doping. The optical properties and identification of assimilation groups were determined by UV-Vis spectroscopy. The photoluminescence spectrum indicated that the outflow groups were in the UV and red regions. Electron paramagnetic resonance displayed a reverberation signal at g = 1.35. The distinction in the magnetization values within the range from 0.04 to 0.02 was 1.092 emu/g, demonstrating an even expansion of Ti in ZnO.

Lentinan, a therapeutic bioactive molecule obtained from Lentinus edodes (Shitake mushrooms), possesses various pharmacological activities. A literature survey reveals that no simple UV-visible technique for the estimation of lentinan has yet been established; hence, there is a pressing need for a simple, yet precise and robust analytical method. We have developed a UV-visible spectrophotometric method for the estimation of lentinan in complex with Congo red azo dye in different concentrations of alkaline solutions. Lentinan was found to be freely soluble in deionized water, and the absorption maximum (λmax) was found to be 486 nm. The validation of the developed method gave satisfactory results, the lentinan–Congo red solution complex gave acceptable linearity within the concentration range 2–10 μg/mL and the correlation coefficient (r²) was found to be >0.99. The developed method was found to be accurate because the mean recovery value at various concentrations gave higher results than 90%. LOD and LOQ for lentinan were reported and found to be 0.014 and 0.0431 μg/mL, respectively. The developed method was found to be simple, specific, economic, reliable, accurate, precise, reproducible, and it could be used as a quality control tool for the analysis of pure lentinan and lentinan in formulations.

Elimination and distribution of drugs are affected by human serum albumin (HSA) interaction. In children and adults, specific types of seizures are controlled by oxcarbazepine (OXZ) alone or in combination with other medications. However, the OXZ interaction with HSA was probed through 3D fluorescence, emission fluorescence, UV-Vis spectroscopy, and molecular docking. OXZ statically quenched the HSA fluorescence spontaneously and exothermically. Thermodynamic parameters revealed the involvement of hydrogen bonds together with van der Waals forces. Molecular docking inspections confirmed that OXZ is bound to site I of HSA. Strong binding with OXZ (of Kb order 10⁵ L/mol) reduced the secondary, microenvironmental, and conformational structures of HSA, suggesting that it unfolds. Thus, the assessment of such conformational details of OXZ–HSA binding is pivotal in surveying the efficacy of OXZ as a therapeutic operator and interpreting its pharmacokinetic properties.

Simple, rapid, and sensitive spectroscopic methods have been proposed to determine the antifungal drug mebendazole. These methods adapted the reduction of ferric into ferrous in a 1,10 phenanthroline–iron complex in an acidic medium giving an orange–red ferroin complex. In the first method, the spectrofluorimetric assay was based on mebendazole quenching for the fluorescence of ferric–phenanthroline complex at pH 3.7. The fluorescence difference was quantitated at 409 nm after excitation at 254 nm. The second method involved the spectrophotometric measurement of the formed complex at 510 nm. A linear correlation was found over the concentrations 3.0–17.0 and 5.0–20.0 μg/mL respectively for methods I and II. The correlation coefficient (r) of the two methods is 0.9998. The two methods were successfully utilized for mebendazole determination in tablets. The mechanism of the reaction pathway is represented. Statistical comparison revealed no significant differences between the findings achieved by the proposed and comparison methods.

A reproducible, sensitive, and cost-effective spectrofluorimetric method has been developed for quantification of the drug ibrutinib in bulk and in its oral capsule formulation. The method was validated in accordance with the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use guidelines with respect to linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), and robustness. The method was found to be extremely sensitive, and excellent linearity was noted within the concentration range 0.1–7.5 μg/mL with a correlation coefficient (r²) of 0.9961. The LOD and LOQ values for the proposed method were found to be 0.224 and 0.680 μg/mL, respectively. Excellent recoveries of the drug were observed from the marketed capsule formulation by the proposed method (97.59, 1.42% relative standard deviation).

The concentration of heavy metals in drinking water is an important standard for water quality evaluation and water pipeline corrosion detection. This research reports the development of a new method based on cloud point extraction for the separation, preconcentration, and detection of lead (Pb), cadmium (Cd), and iron (Fe) using flame atomic absorption spectrometry. This method was used because the concentration of metallic trace elements in the samples was lower than the limits of detection (LOD). The experimental LODs for Pb, Cd, and Fe, were 0.01, 0.01, and 0.3 ppm respectively, which were determined based on a significant sensitivity change in the slope of the standard curve. By using both 2,6-diamino-4-phenyl-1,3,5-triazine and 3-amino-7-dimethylamino-2-methylphenazine (Neutral Red) as chelating agents, and Triton X-114 as a surfactant, these metallic elements were enriched in water samples. The preconcentration procedure was optimized by varying the experimental factors such as temperature, equilibrium time, pH, and the concentration of the chelates and surfactant. After optimization, this method allowed the determination of these three trace elements with 20-times lower LODs and yielded recoveries of 99.8, 97.3, and 99.3% for Pb, Cd, and Fe, respectively.

Plant-mediated synthesis of nanoparticles (NPs) is an efficient and safe alternative to the conventional synthetic route. In this study, silver and gold NPs (AgNPs and AuNPs, respectively) were synthesized via a green route using Ficus sycomorus extract. Tuning the experimental parameters (namely, extract quantity, metal ion concentration, and pH value) allowed control over the size, shape, and size distribution of the NPs. UV-visible spectroscopy has been utilized to monitor the spectral profile changes of the surface plasmon resonance of the NPs under various conditions. The successful preparation of monodispersed spherical AgNPs (4 nm) and AuNPs (11 nm) was confirmed by transmission electron microscopic analysis. Fourier transform infrared spectroscopic data indicated that flavonoid glycosides played a major role in the reduction and stabilization of metal ions. The as-prepared AgNPs and AuNPs were then used as green catalysts for efficient degradation of methylene blue in the presence of sodium borohydride.

This study aimed to determine the β-lactam antibiotics (ampicillin, amoxicillin, penicillin G, oxacillin, and carbenicillin) using conjugated antibody along with gold nanorods (AuNRs). For this purpose, XRD, ATR-FTIR spectroscopy, transmission electron microscopy, and dynamic light scattering were utilized to detect the crystallinity, to identify functional groups involved in the synthesis of AuNRs, and to measure the size of the AuNRs, respectively. In this regard, pH of 9 and a concentration of 9.6 μg of antibody at 1 mL poly (4-styrenesulfonic acid (PSS))-modified AuNRs solution were selected as the best levels of pH and concentration of antibody for the conjugation of antibody with PSS-modified AuNRs. Thereafter, the maximum wavelength rates of the PSS-modified AuNRs, conjugation of antibody with PSS-modified AuNRs, and detection of antibiotics (from 1 nM to 1 mM) with PSS-modified AuNRs-PAb were recorded using a micro-volume spectrophotometer system. The results indicate that the LSPR absorption wavelength of PSS-modified AuNRs is red-shifted by increasing the concentration of β-lactam antibiotics. By increasing the concentrations of ampicillin, penicillin G, and carbenicillin, the maximum wavelength changed, and after the saturation of the antibiotic concentration, the curve reached a plateau. Correspondingly, this indicated that the antibody had a similar behavior in the detection of these antibiotics. However, regarding amoxicillin, the saturation concentration is much higher, which indicate that the antibody is more specific for its detection. In contrast, for oxacillin, saturation occurred immediately, demonstrating that the antibody had an extremely low detection capability for this antibiotic. Finally, the findings showed that the antibody was sensitive to 1 nM of five studied β-lactam antibiotics.