A theoretical study of the influence of interatomic collisions in a gaseous medium has been carried out on intra-Doppler resonances of absorption of optical radiation in a thin gas cell, which can be recorded by recently developed laser spectroscopy methods. Limitations have been determined on the pressure of the gaseous medium at which the influence of such collisions on the width of these resonances is not significant. The results obtained can find application in ultra-high-resolution atomic spectroscopy, as well as in compact optical frequency standards based on the thin gas cells under consideration.

The influence of the architecture of NH₂-peripheral substitution of porphin derivatives on the energy of the intersystem T₁→S₀ transition was studied theoretically. Using quantum chemistry methods, the molecular conformation of 15 porphine and 8 Zn-porphine derivatives in the ground singlet S₀ and lowest triplet T₁ states was optimized, the energies of molecular orbitals were determined, and the energies of the T₁→S₀ transition were calculated. It has been established that the energy of T₁→S₀ transition decreases from 11700 down to 6200 сm^–1 with an increase in the number of NH₂-groups in C_m-positions of the macrocycle, with the energy of the T₁→S₀ transition being a linear function of the weighted sum of the inductive and resonant Hammett constants 0.2σ_I + 0.8σ_R of substituents. The ratio of the inductive and resonant contributions of the NH₂-group depends on the attachment to the macrocycle, with the contribution of resonant interactions decreasing with increasing the spacer length. It has been shown that the main reason for the bathochromic shift of T₁→S₀ transition is a significant increase in the energy of b₁-orbital, which has antinodes on C_m atoms of the macrocycle. The dependence is kept also for Zn-porphyrins with the same architecture of peripheral substitution. It has been noticed that the energy of T₁→S₀ transition differs both for NH-tautomers and for conformers that differ in the position of NH₂-groups relative to the macrocycle mean plane. The calculation results show the promise of experimental studies of aminoporphyrins for obtaining new phosphors in the IR spectral region. Based on the results obtained, the method has been proposed to predict the energy of T₁→S₀ transition for the synthesis of compounds with the required spectral-luminescent characteristics.

In the spectral range of 0.6—6.0 eV at 300 K, the transmittance and reflectivity, as well as photoluminescence in the range of 0.8—1.7 eV at 300 and 77 K, of thin films of cadmium telluride synthesized on different substrates by thermal evaporation in a quasi-closed volume were studied. A strong dependence of the intensity and position of the band-band and excitonic luminescence bands on the quality of the substrate was discovered. The excitonic luminescence bands of films on silicon and glass are shifted by 10 meV to the short-wavelength region due to the presence of internal stresses in the films owing to the mismatch between the parameters of the elementary cells of the substrate and the film. The transparency region of films cleaved from glass shifts to the long-wavelength region due to the density tails of electronic states in the band gap caused by disordering of the films and the excess of the light wavelength over the roughness of the films on the growth and nucleation side. Based on the obtained dependences of the intensity and spectral position of the photoluminescence lines, the best structural perfection is characteristic of films on a cadmium-tellurium substrate.

The effect of irradiation with 4 MeV electrons of different doses on the processes of radiative recombination of nonequilibrium charge carriers in Cu(In,Ga)(S,Se)₂ thin films of solar cells was studied. It was established that near-edge photoluminescence (PL) in the energy range of ~ 0.9—1.2 eV in non-irradiated and irradiated direct-gap Cu(In,Ga)(S,Se)₂ solid solutions is caused by optical interband transitions and radiative recombination through the energy levels of acceptor and donor type structure defects in the presence of strong potential fluctuations. The effect of an energy shift of the maxima of near-edge PL bands and a redistribution of their intensity in thin films after electron irradiation depending on the irradiation dose was found based on measurements of PL spectra in the temperature range of 5—300 K. Based on the data on the quenching of PL bands intensity, the activation energies of nonradiative recombination processes were determined. The possible nature of structural defects in non-irradiated and electron-irradiated Cu(In,Ga)(S,Se)₂ solid solutions is discussed.

The correct conditions for measuring the luminescence intensities in filaments formed by the action of femtosecond laser pulses have been found for lithium fluoride crystals. The conditions determined ensure that the measured intensities are proportional to the concentrations of luminescent color centers created in crystals by laser radiation, and allow conclusions to be drawn about the processes occurring in the filaments. Near-cluster color centers have been found, indicating the presence of nanosized clusters in all areas of the filaments.

The temperature dependences of emission bands positions of the LED heterostructure and the phosphor of white LED lamps, having a linear or quasilinear character, with temperature coefficients K₁ = –0.38 meV/K, K₂ = 0.147 meV/K, K₃ = 0.27 meV/K for the bands 2.7 eV, 2.4 eV, and 2.05 eV, respectively, are determined. Estimations of the magnitude of active region of overheating of heterostructures during the test time have been carried out using spectral measurements data. The estimations are compared with the results of direct temperature measurements. It has been found that the temperature increases by about 20°C during the test period, which is less than the increase in temperature of the electronic subsystem (about 50°C), in accordance with the literature data obtained on other types of LEDs. It is shown that the main reason for the change in the color temperature of the lamp radiation during operation is the process of thermal quenching of luminescence in the phosphor material.

Triple hybrid nanocomplexes based on the selenium (Se⁰) nanoparticles, cellulose polymer carrier (CPC) and photosensitizer fotoditazine (FD) with a different sequence of the component introduction and their ratio have been synthesized. Comparative studies of the spectral characteristics of these triple nanocomplexes with similar characteristics of FD and double complexes of the variable composition (FD/Se⁰, CPC/FD and CPC/Se⁰) have been carried out using spectral methods. It has been shown that the synthesized triple hybrid selenium-containing nanocomplexes can be promising for the photodynamic therapy and diagnostics.

The light pressure of an evanescent electromagnetic wave formed due to the total internal reflection near the flat interface of a dielectric and a liquid on a dielectric spherical nanoparticle located in a liquid medium is considered. Phase portraits of a two-dimensional system of equations which is equivalent to the equation of nanoparticle transportation under the influence of the gradient force of the light pressure of the evanescent field, taking into account the resistance force of the medium, are plotted. It is shown that, depending on the parameters of the laser radiation and the material of the nanoparticle suspended in water, various phase portraits can be realized both without equilibrium points and with one equilibrium point (stable focus, stable node or saddle) on the phase plane.

The process of creating a macroporous silicon substrate on which a layer of titanium dioxide is deposited using the atomic layer deposition method is described. To form a macroporous structure of the substrate, the method of electrochemical etching was used. TiO₂ deposition was carried out using the SI PEALD setup. The morphology, structure and optical properties of the deposited TiO₂ film were assessed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, spectral ellipsometry in the range of 240–1000 nm and Raman spectroscopy. The Raman spectra revealed peaks at 144, 194, 397, 639 cm^–1, which is the characteristic of one of the modifications of TiO₂ – anatase. Based on the calculated ellipsometric parameters, the absorption coefficient and the optical band gap of the deposited film were determined.

The results of spectroscopic measurements of the equilibrium electron concentration behind a strong shock wave in argon at a shock velocity of 4.2 km/s and a pressure ahead of the wave front of 5 Torr are presented. Similar measurements are carried out in oxygen, nitrogen and air in the velocity range from 8.3 to 11.3 km/s at an initial pressure of 0.25 Torr. The measurement method is based on the analysis of the broadening of the line of the hydrogen atom H_β of the Balmer series in the spectrum of the integral radiation density of the gas under study, to which a small amount of hydrogen is added (about 1%). The dependence of the electron concentration on the shock wave velocity in oxygen, nitrogen and air has been established. The results obtained are compared with the available experimental and calculated data.

Samples of oxidized bacterial cellulose with different content of carboxyl groups have been obtained, the exchange capacity and degree of swelling of the samples have been determined. A technique has been developed for the quantitative determination of CeO₂ nanoparticles using the spectrophotometric method. The immobilization of CeO₂ nanoparticles on oxidized bacterial cellulose has been studied. A semi-empirical kinetic model describing the release of nanoparticles from the matrix is established.

The spectral and bactericidal properties of a number of biodyes such as bromophenol blue, amido black 10 B, methyl thymol blue, basic fuchsin, chrome dark blue, eosin, dye (indigo), bromophenol red were characterized. It has been shown that the inclusion of eosin, bromophenol red, indigo and rifampicin into the internal space of phospholipid nanocontainers leads to leveling of the characteristic absorption maxima in the visible or ultraviolet region for the spectra of these compounds in the form of an aqueous solution. This allows visual and spectrophotometric monitoring of the process of the prodrug incorporation into liposomes. The construction of a number of supramolecular forms of prodrugs, which are micelles and liposomes from modified forms of the bactericidal nucleoside brivudine in various combinations, showed the feasibility of using indigo as a dye marker. This made it possible to identify liposomes formed from an equimolar mixture of dimyristoylphosphatidylbrivudine lipoconjugate with dimyristoylphosphatidylcholine as a potential prodrug formulation that most effectively inhibits the growth of Staphylococcus aureus cells.

The method of quantum chemical modeling using the level of Hartree–Fock theory HF-3c/MINIS/MINIS11 theory(d)(Cl)/def2-SV(P)ECP(Pt), considering intermolecular interaction within the ORCA 5.03 software package, studied the electronic structure and binding energy of cisplatin, quinine and fullerenol adducts and their three-component systems. By analyzing the total energies of the systems and the calculated energy diagrams of the higher occupied and lower unoccupied molecular orbitals for the initial components and the molecular ensembles formed by them, we drew conclusions about the most probable their combinations in terms of stability. The nature of synergistic effects is assumed and the prospects for using the three-component cisplatin-quinine-fullerenol С₆₀(OH)₂₄ system during chemotherapy in oncological practice are outlined.

The proposed method for analyzing photon counting distributions (PCD), calculated over the space (pixels) of a stack of fluorescent images obtained in the process of scanning measurement in fluorescence fluctuation spectroscopy, makes it possible to determine the characteristic brightness and number of molecules of the investigated substance. The method is valid for ergodic systems and is based on the theory of analysis of photon count histograms PCH (Photon Counting Histogram), developed for the analysis of single-point measurements. The method has been tested on the experimentally obtained images of green fluorescent protein. The results are compared with the results of a single-point experiment and the N&B (Number and Brightness) method, which is most often used for numerical analysis of a stack of fluorescent images obtained in scanning experiments. The resulting estimates of the characteristic brightness and number of molecules of the calculated substance are in good agreement with the estimates obtained using analysis methods in this area, which allows us to conclude that it is possible to use the theory of the PCH method for the analysis of spatial PCD calculated based on a stack of images. The developed method makes it possible to obtain estimates of the observed parameters based on a selected subregion of one image frame.

Fredholm’s integral equations of the second kind are formulated to describe the anomalous skin effect in metal films on dielectric substrates. An algorithm for numerical solution of equations based on the quadrature method is developed. As a result of its application to the processing of experimental data on the spectral ellipsometry of gold films of various thicknesses on a silicon substrate known from the literature, the density, relaxation time of the electron gas and the dielectric constant of gold are determined unambiguously. It is shown that the dependence of the dielectric constant of gold films on their thickness, noted in a number of experimental studies, can be associated with the use of the Drude’s normal skin model, which does not take into account the excitation of a space charge in the film. Optical fields in gold films are studied at different probabilities of specular reflection of electrons from the film boundaries. It is shown that among sensors of biological solutions with the Kretschmann configuration, structures in which the probability of specular reflection of electrons from the metal film-liquid interface tends to 1 are preferred.

An express and simple method for identification of oil and fatty products of plant origin by their own fluorescence and diffuse reflection of IR radiation using colorimetry and near-IR spectroscopy is proposed. To record the analytical signal, we used 3D printed devices with built-in UV and IR LED matrices (390 and 850 nm), and a smartphone with the PhotoMetrix PRO® application installed, as well as FT-IR spectroscopy in the near-IR region (10000–4000 cm^–1) with the NIRA attachment, used for the analysis of solid samples. Processing of diffuse reflectance spectra was carried out using the TQ Analyst and The Unscrambler X applications. Identification and differentiation of the studied objects was carried out using chemometric algorithms – principal component analysis (PCA) and hierarchical cluster analysis (HCA). The determination of the mass fraction of fat in the declared products was carried out using univariate and multivariate (PLS algorithm) analyzes. It has been established that on the PCA and HCA graphs, adulterated butter is located separately from natural products and does not intersect with each other on the dendrogram. To construct a calibration relationship and determine the milk fat concentration using the PLS method and one-dimensional analysis, we took samples of butter with different milk fat mass fractions: 61.5, 72.5, 82.5, and 99.0%. At the same time, the calibration error (RMSEC) did not exceed 1.31% and the predictive properties (RMSEP) – 4.45%. The methods under consideration were tested with samples of butter and vegetable oil products from different manufacturers. When multivariate analysis was used, the RMSEP values for dairy products did not exceed 4.97%, and for margarine it was more than 10%. When using univariate analysis, the relative deviation of the results from the values of the mass fraction of fat presented on the packaging did not exceed 4.8%. As a result of the study of margarine, this indicator was in the range of 96.3–96.5%. The data obtained were correlated with the results of Fourier transform infrared spectroscopy.

New cyanide-bridged heteronuclear compounds, [Cd(NH₃)(μ-ampy)M(μ-CN)₄]_n [ampy = 3-aminomethylpyridine, M: Pd(II) or Pt(II) (hereafter abbreviated as Cd-M-ampy)] have been prepared in powder form and investigated by utilizing elemental analysis, vibrational (FT-IR and Raman) spectroscopy, and thermal analysis. In our previous work, we synthesized the [Cd(NH₃)(μ-ampy)Ni(μ-CN)₄]_n compound and determined its crystal structure. The results of thermal analysis and vibrational spectroscopic show that the structural characteristics of Cd-Ni-ampy and Cd-M-ampy [M: Pd(II) or Pt(II)] compounds are analogous to each other. In these compounds, while the sphere of the center of the M(II) ion has a square pyramidal geometry, the coordination sphere of the Cd(II) ion is identified to have a distorted octahedral geometry. While one amine, one ampy, and four cyanide ligands coordinate to the Cd(II) ion, a three-dimensional coordination polymer forms by the coordination of these ligands to the Cd(II) and M(II) ions. Thermal degradation of the compounds occurs in two steps: degradation of ampy and amine ligands and release of the cyanide groups.

Spectroscopic studies of Ho³⁺-doped SrF₂ crystals were performed regarding applications in solid-state lasers. The crystal structure of the Ho:SrF₂ crystal was investigated using single-crystal X-ray diffraction. SrF₂ exists as a cubic structure with an Fm3m space group. A Raman shift of 288 cm^–1 was observed for the Ho:SrF₂ single crystal. SrF₂ hosts with low-frequency vibrational modes are suitable for reducing nonradiative emissions while maximizing radiative emissions. The absorption spectrum was recorded in the visible region from 400 to 800 nm, yielding absorption lines at 416, 450, 468, 473, 484, 536, 638, and 643 nm. The fluorescence spectrum recorded at an excitation wavelength of 450 nm shows two emission bands at 546 and 656 nm, which correspond to green and red emission, respectively. The intensity parameters Ω_λ (λ = 2, 4, and 6) were estimated using the Judd–Ofelt theory. For Ho:SrF₂ single crystal, the calculated Ω_λ are Ω₂ = 0.14×10^-20 cm², Ω₄ = 3.14×10^-20 cm², and Ω₆ = 3.74×10^–20 cm². The radiative transition probabilities, radiative lifetimes, and branching ratios β_R for Ho:SrF₂ were determined using the Judd-Ofelt parameters. The ⁵S₂ + ⁵F₄ → ⁵I₈ transition is more effective for population-building processes because of its lifetime (0.26 ms) and higher branching ratios (~82.86%). Ho:SrF₂ is, therefore, a promising solid-state laser crystal for green and red spectral regions.

A new class of BaLiZn₃(BO₃)₃:RE (RE = Sm³⁺, Tb³⁺, Dy³⁺, and Pb²⁺) phosphors were synthesized with a solid-state reaction method. The minor concentrations of various rare earth (Tb³⁺, Dy³⁺, and Sm³⁺) ions and transition metal (Pb²⁺) ions activated in the BaLiZn₃(BO₃) host matrix were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy. The XRD results of BaLiZn₃(BO₃)₃:RE (RE = Sm³⁺, Tb³⁺, Dy³⁺, and Pb²⁺) phosphors confirmed that all the samples have a monoclinic phase. SEM studies revealed that the morphology of BaLiZn₃(BO₃)₃:RE (RE = Sm³⁺, Tb³⁺, Dy³⁺, and Pb²⁺) phosphors was irregular. The photoluminescence emission and excitation spectra show that these phosphors can be effectively excited by near-ultraviolet light-emitting diodes (n-UV), and they all exhibit an efficient orange-red (Sm³⁺, ⁴G_5/2 → ⁶H_7/2), green (Tb³⁺, ⁵D₄ → ⁷F₅), yellow (Dy³⁺, ⁴F_9/2 → ⁶H_13/2), and blue (Pb²⁺ ,³P₁ → ¹S₀) emission. All of the above results confirmed that the obtained phosphors could be a potential candidate for n-UV-excited WLEDs.

Synthesis, structural and photoluminescence studies of p-(n-heptyl) benzoic acid (7ba) liquid crystalline (LC) compound with the homogeneous dispersion of ZnO nanoparticles (NPs) in different weight concentrations (i.e., 1–2.5 wt.%) were undertaken. The synthesized samples were subsequently characterized by different characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible (UV-Vis) spectroscopy, differential scanning calorimetry (DSC), optical polarising microscopy (POM), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectroscopy. From the XRD studies, the diffraction peaks observed were well resolved indicating the presence of ZnO NPs. The particle size was found to be 60 nm. SEM studies revealed the uniform dispersion and the presence of ZnO NPs in the LC samples. From the DSC analysis, the temperatures at which the phase changes take place and the corresponding enthalpy values were estimated. FTIR spectra gave information about the various functional groups present in the samples. PL studies showed the peak at 663 nm due to the presence of point defects within the bandgap-like vacancies and interstitials known as deep-level emission.

A series of MnFe_2–xYb_xO₄ powder nanoparticles (for x = 0, 0.025, 0.075, 0.1, and 0.2) of different crystallite sizes were synthesised using the co-precipitation method. The effect of Yb³⁺ dopant on the properties of manganese ferrite was characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman measurements, and photoluminescence spectroscopy (PL). The crystallite size and density of the samples have a cubic structure with an Fd3m space group. Their sizes and densities were found to be in the range of 24.8–34.7 nm and 5.07–5.49 g/cc³. FT-IR analysis indicates the presence of two absorption bands in the range 400–600 cm^–1, which is a fingerprint region of ferrites. The v₂ band (Fe-O stretching mode of the octahedral site) shifts towards the lower wavenumber, which confirms the occupancy of larger-size Yb³⁺ ions at the octahedral site. The Raman peaks were observed at 228, 295, 405, 502, and 634 cm^–1 for undoped manganese ferrite. Based on Raman observations, it has been observed that Mn²⁺ ions exhibit a preference for occupying octahedral (B) sites by substituting Fe³⁺ ions. Additionally, rare earth ions have been preferentially observed to occupy octahedral sites. The primary cause for the displacement of Raman bands was ascribed predominantly to the greater radii of rare earth ions in comparison to Fe³⁺ and Mn²⁺ ions, and the shifting of the peaks indicates the presence of Yb³⁺ at the octahedral site. The PL spectrum shows emission at 560 nm with a rise in intensity with an increase in dopant Yb³⁺, which could be because of the incorporation of Yb³⁺ in the spinel structure, leading to radiative recombination in the yellow region of the electromagnetic spectrum.

One of the inherent limitations associated with laser-induced breakdown spectroscopy (LIBS) in the identification of elements lies in the strength of the emission signals. Several approaches exist to enhance the emission capacity of LIBS. In this particular investigation, our focus was on amplifying the signal intensity of LIBS through the utilization of two techniques. These techniques include the application of a low-power electric field within the zone where plasma is formed, in conjunction with the utilization of nanoparticles on the surface of the sample. Specifically, our analysis involved the examination of samples consisting of metallic Zn powder as the matrix element, with the incorporation of small quantities of Ca in the form of CaCO₃. The combination of these two methods resulted in unprecedented outcomes, demonstrating a 3.5-fold increase in samples containing 0.05% w/w of CaCO₃ when subjected to an electric field of 60 V/cm, while bearing nanoparticles on their surface.

Umifenovir, an antiviral drug that is used to treat influenza, has recently been used in regards to COVID-19 infection. According to a literature survey, no UV technique for the estimation of umifenovir has yet been established; hence, there is an imperative need for a simple analytical method. Additionally, we developed an alternative reverse phase high performance liquid chromatography (RP-HPLC) method for the estimation of umifenovir. UV spectrophotometry was carried out at 223 nm absorption maxima using the solvent methanol. A concentration range of 2–12 µg/mL was found to obey Beer's law, with a correlation coefficient (r²) of 0.9995. A C-18 column (250 mm, 4.6 µm, 5 µm) was used for chromatographic separation using the isocratic mode. The mixture consisted of acetonitrile: 0.1% trimethylamine (pH adjusted to 2.7 by the addition of orthophosphoric acid) 60:40 as the mobile phase with a flow rate of 1 mL/min. The temperature was kept at 25ºC, and detection at 223 nm was performed using a PDA detector. The estimated percentage of the drug was close to 100%, corresponding to the label claim of the tablet made in the laboratory. The results and statistical study demonstrated the utility of the current methods in the routine evaluation of umifenovir bulk and formulation.

An advanced chemometric model based on ratiometric surface-enhanced Raman scattering (SERS) was developed for the quantification of glucose in serum samples. In the absence of glucose, it was mainly the SERS signal of silver nanoparticles (AgNPs)-o-phenylenediamine (OPD). When glucose was added, glucose oxidase catalyzed glucose to produce hydrogen peroxide (H₂O₂), which oxidized OPD to produce 2,3-diaminophenazine (DAP) in the presence of AgNPs. The generated DAP exhibited a new strong SERS signal and changed the Raman peak ratio between DAP and OPD. Without using any internal standard, the advanced chemometric model mitigated the fluctuations in SERS intensity and achieved accurate concentration predictions for glucose in serum samples with recoveries in the ranges of 92.8–104.8%. The accuracy of the quantitative results obtained using the proposed method is comparable with that of the reference method – glucometer. The proposed sensor showed high sensitivity and selectivity in detecting glucose with a limit of detection (LOD) of 0.28 μM. Additionally, the presented SERS sensor demonstrated great promise in determining H₂O₂-related metabolites in real serum samples.

TiN-Ag@Ag composite substrates were prepared via ammonia reduction nitridation followed by electrochemical deposition. Fabricated TiN-Ag@Ag substrates were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and ultraviolet-visible spectrophotometry. The surface-enhanced Raman spectroscopy activity of these substrates was evaluated using ibuprofen as the probe molecule. The size of the Ag particles prepared via electrochemical deposition was approximately 1 µm, and Ag nanoparticles with an average particle size of 100 nm were uniformly distributed on the surface of TiN-Ag films. The Raman signal of ibuprofen was significantly enhanced, and the minimum detection concentration of ibuprofen was 10^–5 M. The mechanism by which the TiN-Ag@Ag composite substrate enhanced the Raman signals was analyzed using ultraviolet photoelectron spectroscopy and density functional theory implemented in the Gaussian software. Overall, charge transfer and the local electromagnetic field effect enhanced the Raman signals of ibuprofen.

Plants play an important role in nanoparticle preparation because they are easily accessible, environmentally friendly, and inexpensive. In this study, we used an ethanolic extract of Mangifera indica seed as a reducing and stabilising agent to create zinc oxide (ZnO) nanoparticles (NPs). The ZnO NPs were examined using characterization techniques such as UV-Vis, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The interaction of phytochemical constituents from plant extracts providing the biological reduction of zinc metal ions to ZnO had been identified by the UV-visible absorption studies. According to the FT-IR results, metal oxides exhibited interatomic vibration-driven absorption in the fingerprint area below 1000 cm^–1. Particles appeared to be crystalline and also a rice-grain shape of ZnO NPs was confirmed by XRD, SEM, and TEM, respectively. In addition, the cytotoxic effect of ZnO NPs was checked using the SKMEL-28 cell line, showing an IC50 value of 32.686 μg/mL in the SKMEL-28 cell line, and 49.011 μg/mL in the typical L6 cell line. Furthermore, the synthesized NPs were subjected to (AO/EB) double staining approach to examine the apoptotic activity. The acridine orange/ethidium bromide method made strong evidence for demonstrating chromatin condensation and membrane blebbing.

Exploring new material structures of low photocatalytic degradation activity for ultraviolet screening is one of the important methods for improving polyvinylchloride (PVC) performance. As an important kind of ultraviolet (UV) shielding agent material, nano zinc oxide (ZnO) has been applied extensively in many fields due to its outstanding properties. However, the severe aggregation behavior between nanoparticles (NPs) and photocatalytic activity greatly limits the application. In this work, surface modification of ZnO with hydroxyapatite and chitosan (ZnO-Hap/CS) was fabricated. Then via a solution casting technique dispersed within the PVC matrix. The results demonstrated that the obtained composite exhibited the best ultraviolet screening performance greatly decreasing the photocatalytic degradation activity of ZnO. It is expected that this approach is prospective for the large-scale preparation of nano ZnO with excellent UV-blocking performance and low photocatalytic degradation activity.

The background differences in water content of different samples have a very strong influence on the robustness of near-infrared spectroscopy (NIRS). For this reason, this study simulated typical biological water matrix samples with formulated hemoglobin (Hb), glucose (Glc), and distilled water, and attempted to use four different intelligent spectral variable selection algorithms (Competitive Adaptive Re-weighted Sampling (CARS), Randomized Frog Hopping Algorithm (RF), Genetic Algorithm (GA), and Variable Projection Importance Algorithm (VIP)) to perform the Hb water interference-resistant feature band preferences, while combining partial least squares (PLS) in parallel to build a robust quantitative model of Hb. In addition, the applicability and validity of the model were validated using three prediction sets P₁, P₂, P₃ with different water backgrounds (the formulation method and composition were kept the same, and only the water content increased sequentially). The results showed that RF, GA, and VIP could effectively screen out the characteristic wavelengths of Hb with low sensitivity to water changes and successfully correct the water effect, but due to the large number of characteristic variables they screened out and the existence of a large number of redundant and water interference variables, this ultimately made the model’s robustness less than ideal. The CARS algorithm performed the best, and the RMSEP of the three prediction sets were 0.016, 0.017, and 0.038, which is closer to the RMSECV of the calibration set. Therefore, NIRS combined with the variable selection can reduce the effect of water on model robustness and improve the prediction accuracy of the model by the method of selecting effective wave number intervals, and CARS may be one of the ideal algorithms to solve such problems.

To classify and detect the type and content of petroleum hydrocarbon contaminants in the soil surface layer, fluorescence spectrometry is commonly used. The experimental oils were selected from three common engine oils available in the market: Loxson L-CKC220 gear oil, APSIN 10W-40 engine oil and Jaguar 200 SF MA 15W-40 motorcycle oil. The fluorescence spectra of the oils were obtained using the fluorescenceinduced technique, the spectral wavelengths were selected using a genetic algorithm (GA), and the detection models were constructed by combining RF (Random Forest), AdaBoost, and Gradient Enhanced Decision Tree (GBDT) regression algorithms for classification, identification, and concentration prediction analysis. The experimental results show that the average accuracy of classification and identification of gear oil, engine oil and motorcycle oil reach 83.9, 97.8, and 92.2%, respectively. Comparative analysis of the prediction results of the three concentration regression models shows that while all algorithms have high model prediction accuracy, GA combined with GBDT regression model has the best prediction performance for gear oils, engine oils and motorcycle oils, and improves the prediction accuracies by 62.7, 42.3, and 48.3% compared to the prediction accuracies of the wavelength selection without the use of GA, respectively. In summary, GA-based spectral wavelength selection combined with machine learning algorithms has high prediction accuracy and precision for the classification and prediction of motor oil contaminants in selected specific soils, and can be used as an effective detection method.

The α-nBACoPc/SnO₂ composites were prepared using the in situ synthesis method and characterized by Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and confirmed by the loading of amino cobalt phthalocyanine on SnO₂. Conduct photocatalytic degradation experiments used rhodamine B as a simulated pollutant. The composite exhibited a photo-catalytic degradation rate of 83.3%, which was higher than that of α-nBACoPc and SnO₂ alone. The Co-O bond in the composite material enhances the transfer of electrons from phthalocyanine to the SnO₂ conduction band, improving light utilization and strengthening the synergistic impact of cobalt phthalocyanine and SnO₂. Furthermore, the composites demonstrated good stability and recyclability.

Remote detection of trace explosives and hazardous chemicals has been an ongoing challenge and a critical issue in defense science, public safety, and counterterrorism. Raman spectroscopy, a form of inelastic scattering, acts as a “fingerprint” analysis method for substance identification with high confidence in the detection of chemicals based on their vibrational modes. Here, we present a portable stand-off timegated Raman spectroscopy, which consists of a passive Q-switched pulsed laser, a designed gated ICMOS, a spectrometer, and a telescope, with an overall size of 476.5×321.5×219.3 mm and a weight of 23.2 kg, which is much more compact and portable than reported previously. To confirm the effectiveness of the designed portable time-gated Raman spectroscopy, detections at different working distances and various amounts of substances are carried out. High levels of Raman identification are acquired even for 0.1 mg at a 10 m distance. Furthermore, we simulate realistic encounters in a possible war-zone scenario by testing the system’s ability to recognize urea samples on different substrates such as an aluminum plate, woodblock, cardboard, black cloth, and leaf; good characteristic recognition is shown.