Antitumor Activity and Physicochemical Properties of New Thiosemicarbazide Derivative and Its Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) Complexes

A novel biologically active thiosemicarbazide derivative ligand L (N-[(phenylcarbamothioyl)amino]pyridine-3-carboxamide) and a series of its five metal(II) complexes, namely: [Co(L)Cl₂], [Ni(L)Cl₂(H₂O)], [Cu(L)Cl₂(H₂O)], [Zn(L)Cl₂] and [Cd(L)Cl₂(H₂O)] have been synthesized and thoroughly investigated. The physicochemical characterization of the newly obtained compounds has been performed using appropriate analytical techniques, such as ¹H and ^l3C nuclear magnetic resonance (NMR), inductively coupled plasma (ICP), thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and magnetic measurements. In order to study the pharmacokinetic profile of the compounds, ADMET analysis was performed. The in vitro studies revealed that the synthesized compounds exhibit potent biological activity against A549 human cancer cell line.     

Human Remains Identification Using Micro-CT,Chemometric and AI Methods in Forensic Experimental Reconstruction of Dental Patterns after Concentrated Sulphuric Acid Significant Impact

(1) Teeth, in humans, represent the most resilient tissues. However, exposure to concentrated acids might lead to their dissolving, thus making human identification difficult. Teeth often contain dental restorations from materials that are even more resilient to acid impact. This paper aims to introduce a novel method for the 3D reconstruction of dental patterns as a crucial step for the digital identification of dental records. (2) With a combination of modern methods, including micro-computed tomography, cone-beam computer tomography, and attenuated total reflection, in conjunction with Fourier transform infrared spectroscopy and artificial intelligence convolutional neural network algorithms, this paper presents a method for 3D-dental-pattern reconstruction, and human remains identification. Our research studies the morphology of teeth, bone, and dental materials (amalgam, composite, glass-ionomer cement) under different periods of exposure to 75% sulfuric acid. (3) Our results reveal a significant volume loss in bone, enamel, dentine, as well as glass-ionomer cement. The results also reveal a significant resistance by the composite and amalgam dental materials to the impact of sulfuric acid, thus serving as strong parts in the dental-pattern mosaic. This paper also probably introduces the first successful artificial intelligence application in automated-forensic-CBCT segmentation. (4) Interdisciplinary cooperation, utilizing the mentioned technologies, can solve the problem of human remains identification with a 3D reconstruction of dental patterns and their 2D projections over existing ante-mortem records.     

Catalytic performances of Ni/mesoporous SiO2 catalysts for dry reforming of methane to hydrogen

Several mesoporous silicas with different morphologies were controllably prepared by sol-gel method with adjustable ratio of dual template,and they were further impregnated with aqueous solution of nickel nitrate,followed by calcination in air.The synthesized silica supports and supported nickel samples were characterized using N₂-adsorption/desorption,X-ray diffraction（XRD）,H₂ temperature-programmed reduction（H₂-TPR）,Scanning electron microscope（SEM）,Transmission electron microscope（TEM） and thermo-gravimetric analysis（TGA-DTG） techniques.The Ni nanoparticles supported on shell-like silica are highly dispersed and yielded much narrower nickel particle-size than those on other mesoporous silica.The methane reforming with dioxide carbon reaction results showed that Ni nanoparticles supported on shell-like silica carrier exhibited the better catalytic performance and catalytic stability than those of nickel catalyst supported on other silica carrier.The thermo-gravimetric analysis on used nickel catalysts uncovered that catalyst deactivation depends on the type and nature of the coke deposited.The heterogeneous nature of the deposited coke was observed on nickel nanoparticles supported on spherical and peanut-like silica.Much narrower and lower TGA derivative peak was founded on Ni catalyst supported on the shell-like silica.     

Analyte and system eigenpeaks in nonaqueous capillary zone electrophoresis: theoretical description and experimental confirmation with methanol as solvent

A mathematical model developed for aqueous solutions and adapted to methanol as solvent was applied to predict the electromigration characteristics of analytes and background electrolytes in capillary zone electrophoresis. These characteristics are the effective mobility, and the tendency of the analyte to undergo peak-broadening due to electromigration dispersion. The input parameters for calculation like limiting mobilities and dissociation constants were experimentally determined or taken from the literature. By the aid of the model, the molar response for conductivity detection was calculated as well as the transfer ratio when indirect UV detection was used. They allow depicting the electropherogram by computer simulation. An additional important program output is the prediction of the occurrence of system- or eigenpeaks that mimic peaks of analytes or electroosmotic flow markers. The measured electropherograms were in agreement with those theoretically predicted. Deviations were attributed to ion pairing in methanolic solutions, which was not implemented in the model.     

Determination of nitrated polycyclic aromatic hydrocarbons and their precursors in biotic matrices

Analytical method for the determination of ultra-trace levels of nitro-PAHs in various biotic matrices has been developed. Soxhlet extraction and/or solvent extraction enhanced by sonication were used for isolation of target analytes; GPC followed by SPE were employed for purification of crude extracts. GC-MS/NCI technique was utilised for identification/quantitation of target analytes. Performance characteristics of implemented method were obtained through thorough in-house validation procedure. The main sources of uncertainties were critically evaluated, possible strategies of their elimination/minimisation were considered and consequently employed. Examination of real-life samples of various foodstuffs (complete human diet, mate tea, pumpkin seed oil, parsley, sausages) was performed in this study.     

Influence of solvent on temperature and thermal peak broadening in capillary zone electrophoresis

The present paper deals with the role of the solvent on thermal peak broadening. One main solvent property that determines the magnitude of the temperature gradient due to the generation of Joule heat in capillary zone electrophoresis is the thermal conductivity. As organic solvents have lower thermal conductivity than water (methanol and acetonitrile, e.g., nearly by a factor of 3) it can be hypothesized that the temperature gradient inside the capillary is more pronounced in organic solvents compared to an aqueous solution. On the other hand, the temperature dependence of the ion mobility (which is responsible for the velocity profile and thus for thermal peak broadening) is smaller in organic solvents. To get insight into the thermal effect of the solvent, first the temperature of a solution in a cylindrical tube was calculated utilizing the heat balance equation. It was shown that the two theoretical models most common in the literature (based on the analytical solution or on an assumption of the parabolic temperature profile in the tube, respectively) give the same results. The latter model was chosen for the further calculations, adding a quadratic term to express the electric conductivity as a function of the temperature. The temperature at the inner capillary wall and center as function of the capillary dimensions and the electric power was computed for electrolytes with a given conductivity at 25.0 degrees C with water, methanol, and acetonitrile as solvents. Capillary cooling systems used were circulating liquid cooling, enforced air-cooling, and natural convection in still air. The mean temperature (averaged over the cross section) resulting from Joule heating was compared with experimentally determined temperatures established upon application of an electric field; the latter temperature was derived from the measurement of the electric conductance of the background electrolyte solution and its (measured) temperature dependence. All investigations were carried out with solutions of the same initial electric conductivity (about 0.5 S.m(-1) at 25.0 degrees C). Agreement is found for natural convection conditions, and the deviation between theoretical and experimental results for the forced air and circulated liquid cooling systems can be related to the poorly defined thermal conditions of the capillaries in commercial instrumentation (with a part in a thermostated cassette and a part outside). For given conditions the temperature gradients in the organic solvents exceed largely those in water, independent of the type of cooling. As a consequence, the thermal plate height is significantly larger in organic solvents, at least under conditions where the deviation from the Nernst-Einstein limiting case is not too high. However, even for the maximum applicable field strengths the thermal plate height contributions are negligible compared to longitudinal diffusion in all solvents.     

Conductivity detection in capillary zone electrophoresis: inspection by PeakMaster

A simple rule stating that the signal in conductivity detection in capillary zone electrophoresis is proportional to the difference between the analyte mobility and mobility of the background electrolyte (BGE) co-ion is valid only for systems with fully ionized electrolytes. In zone electrophoresis systems with weak electrolytes both conductivity signal and electromigration dispersion of analyte peaks depend on the conductivity and pH effects. This allows optimization of the composition of BGEs to give a good conductivity signal of analytes while still keeping electromigration dispersion near zero, regardless of the injected amount of sample. The demands to achieve minimum electromigration dispersion and high sensitivity in conductivity detection can be accomplished at the same time. PeakMaster software is used for inspection of BGEs commonly used for separation of sugars (carbohydrates, saccharides) at highly alkaline pH. It is shown that the terms direct and indirect conductivity detection are misleading and should not be used.     

Optimization of background electrolytes for capillary electrophoresis I. Mathematical and computational model

A mathematical and computational model is introduced for optimization of background electrolyte systems for capillary zone electrophoresis of anions. The model takes into account mono- or di- or trivalent ions and allows also for modeling of highly acidic or alkaline electrolytes, where a presence of hydrogen and hydroxide ions is significant. At maximum, the electrolyte can contain two co-anions and two counter-cations. The mathematical relations of the model are formulated to enable an easy algorithmization and programming in a computer language. The model assesses the composition of the background electrolyte in the analyte zone, which enables prediction of the parameters of the system that are experimentally available, like the transfer ratio, which is a measure of the sensitivity in the indirect photometric detection or the molar conductivity detection response, which expresses the sensitivity of the conductivity detection. Furthermore, the model also enables the evaluation of a tendency of the analyte to undergo electromigration dispersion and allows the optimization of the composition of the background electrolyte to reach a good sensitivity of detection while still having the dispersion properties in the acceptable range. Although the model presented is aimed towards the separation of anions, it can be straightforwardly rearranged to serve for simulation of electromigration of cationic analytes. The suitability of the model is checked by inspecting the behavior of a phosphate buffer for analysis of anions. It is shown that parameters of the phosphate buffer when used at neutral and alkaline pH values possess singularities that indicate a possible occurrence of system peaks. Moreover, if the mobility of any analyte of the sample is close to the mobilities of the system peaks, the indirect detector signals following the background electrolyte properties will be heavily amplified and distorted. When a specific detector sensitive on presence of the analyte were used, the signal would be almost lost due to the excessive dispersion of the peak.     

System peaks in micellar electrophoresis: I. Utilization of system peaks for determination of critical micelle concentration

A new way to determine the critical micelle concentration (CMC) based on the mobilities of system peaks is presented. A general approach for the CMC determination is based on the change of the slope or on finding the inflection point in the plot of a physical property of solution as a function of surfactant concentration. The determination of CMC by system peaks in CE utilizes a "jump" instead of a continuous change in the measured quantity. This phenomenon was predicted by the program PeakMaster, which was modified for simulation of micellar systems. The simulation of the steep change in mobilities of the anionic system peaks showing the CMC value was verified experimentally in a set of measurements, where the concentration of the surfactant was varied while the ionic strength was kept constant. The experimental work fully proved our model. A comparative electric current measurement was carried out. The proposed method seems to offer easier CMC determination as compared to the standard methods.