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•Stable Co(II)-RLMP complexes were synthesized and isolated in the solid state.•Co(II)-RLMP complex formation is confirmed by UV-Vis and ATR-FTIR spectroscopy.•MALDI-TOF/TOF MS ...results confirmed d-Glcp as the RLMP repeating unit.•XRD results show a low crystallinity form of Co(II)-RLMP.•Different model structures of synthesized Co(II)-RLMP complexes are proposed.
Complexes of Co(II) ion with reduced low-molar pullulan (RLMP) (Mw 6000 g/mol) were synthesized in aqueous solutions at boiling temperature in the pH range from 7.5 to 13.5. Obtained Co(II)-RLMP complexes, with cobalt content ∼2–8% (AAS), were characterized by UV-Vis spectrophotometry, FTIR spectroscopy (ATR-FTIR, FT-IRIS), MALDI-TOF/TOF MS, and XRD. Tetragonally distorted Oh coordination of Co(II) ions with O ligand atoms in synthesized complexes is suggested based on the spectrophotometric data. No influence of complexation process on the 4C1 chair conformation of the d-glucopyranose units of pullulan was detected by ATR-FTIR measurements and FT-IRIS showed high homogeneity of synthesized complexes. Some additional depolymerization of pullulan during complex synthesis was indicated by MALDI-TOF/TOF MS but it also revealed good stability of complexes with much weaker binding of Co(II) ion in low molar mass fragments. Even in complexes with highest Co(II) ion content a low degree of crystallinity was detected by XRD analysis.
Synthesis, UV–vis, ATR-FTIR, FT-IRIS, EPR spectroscopic and different physicochemical techniques are described for the direct analysis of bioactive copper(II)–pullulan complexes which permits the ...important anti-hypocupremic and anti-microcitary anemic preparation to be obtained.
Bioactive copper(II) complexes with polysaccharides, like pullulan and dextran, are important in both veterinary and human medicine for the treatment of hypochromic microcitary anemia and hypocupremia. In aqueous alkaline solutions, Cu(II) ion forms complexes with the exopolysaccharide pullulan and its reduced low-molecular derivative. The metal content and the solution composition depend on pH, temperature, and time of the reaction. The complexing process begins in a weak alkali solution (pH >7) and involves OH groups of pullulan monomer (glucopyranose) units. Complexes of Cu(II) ion with reduced low-molecular pullulan (RLMP,
M
w
6000
g
mol
−1) were synthesized in water solutions, at the boiling temperature and at different pH values ranging from 7.5 to 12. The Cu(II) complex formation with RLMP was analyzed by UV–vis spectrophotometry and other physicochemical methods.
Spectroscopic characterizations (ATR-FTIR, FT-IRIS, and EPR) and spectra–structure correlation of Cu(II)–RLMP complexes were also carried out.
The grid-connected inverter is the key component for the reliable and safe operation of grid-interconnected renewable energy systems. In order to ensure that the inverter output current is in-phase ...synchronized with the grid voltage, a highly efficient and fast control strategy is required. This paper proposes an algorithmically driven approach for designing the adaptive controller for a grid-connected DC/AC inverter. The controller consists of two adaptive IIR filters based on the LMS algorithm and has two modes of operation. During the learning mode, the controller uses the filters to estimate the coefficients of the inverse transfer function of the PWM-driven inverter at several grid frequencies within a specific range. During the online mode, the controller generates the driving signal for the inverter block using a set of learned coefficients corresponding to the current grid frequency. By constantly monitoring the grid voltage and reconfiguring the controller accordingly, a fast adaptation of the inverter output current to grid frequency variations is achieved. For grid frequency variations in the range of 48 to 52 Hz, the MATLAB simulation results show that the phase difference between the grid voltage and inverter output current waveforms becomes less than 1 degree after at most four periods.
SMILES notation based optimal descriptors as a universal tool for the QSAR analysis with further application in drug discovery and design is presented. The basis of this QSAR modeling is Monte Carlo ...method which has important advantages over other methods, like the possibility of analysis of a QSAR as a random event, is discussed. The advantages of SMILES notation based optimal descriptors in comparison to commonly used descriptors are defined. The published results of QSAR modeling with SMILES notation based optimal descriptors applied for various pharmacologically important endpoints are listed. The presented QSAR modeling approach obeys OECD principles and has mechanistic interpretation with possibility to identify molecular fragments that contribute in positive and negative way to studied biological activity, what is of big importance in computer aided drug design of new compounds with desired activity.
Phthalates are often used as plasticizers in the production of plastic food contact materials (FCMs) and pharmaceutical contact materials (PCMs), and having in mind that they are not bound to ...plastics, phthalates may easily leach from plastics under certain conditions. The aim of this research is determination of phthalates leaching potential from different plastic materials and quantitative determination of 5 phthalates (dimethyl phthalate (DMP), di-n-butyl phthalate (DnBP), benzyl butyl phthalate (BBP), diethyl hexyl phthalate (DEHP), and di-n-octyl phthalate (DOP)) in 44 different plastic articles of 7 different plastic polymers used as FCMs and PCMs by FTIR, GC-MS, and gravimetric methods. The FTIR technique is shown to be rapid method for determination of phthalate content in PVC articles. Comparing of FTIR method with GC-MS and gravimetric showed that separation and quantitative determination of each phthalate separately favor the GC-MS method, because FTIR method determines the total amount of phthalate content. However, the FTIR method is less expensive and demanding in terms of sample preparation, which is suited for use in pre-screening analysis. The results of GC-MS phthalates determination showed that PVC articles used as PCMs contain DEHP in significant amount, from 5.19 to 28.76% by weight and could be a potential risk to human health.
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•α-ZnMoO4 catalyst was synthesized electrochemically, followed by thermal treatment.•Catalyst was used in atmospheric pressure corona plasma degradation of reactive dye.•Catalyst ...enhanced plasma-generated H2O2 decomositon into dye-degrading ·OH radicals.•Dye degradation followed pseudo-first order kinetics.•TOC removal was 85.4% after 180 min of the treatment.
Microcrystalline α-ZnMoO4 catalyst for degradation of Reactive Black 5 by self-made open air atmospheric pressure pulsating corona plasma reactor was synthesized by electrodeposition, followed by thermal treatment. The effect of electrodeposition current density on the catalyst’ characteristics was examined by SEM, EDX, FTIR XRD and TG. The catalyst enhanced plasma decolourization rate by 7.5 times. The role of the catalyst in the consumption of plasma generated H2O2 and in dye degradation was examined in details for the first time to the best of our knowledge; the catalyst enhanced the generation of ⋅OH radical, a principle dye degradation reagent, by enhancing decomposition of plasma–generated H2O2. The catalyst’ excitation mostly proceeded by the strikes of plasma–generated active species accelerated by electric field, which transferred their energy to the catalyst, causing the creation of electron – holes pairs which attacked H2O2. Decolourization followed pseudo – first order kinetics. Decolourization rate increases with the increase of discharge current density and reactor input voltage. The ratio between cylindrical reactor cell’s diameter and the liquid level in it didn’t affect the decolourization rate. Relatively high energy yield of 1.86 gkWh−1 was achieved for 50% decolourization. TOC removal was 85.4% after 180 min of the treatment.
Curcumin comes from the plant species
and shows numerous pharmacological activities. There are numerous curcumin formulations with gels or cyclodextrins in order to increase its solubility and ...bioavailability. This paper presents the formulation of complex of curcumin with 2-hydroxypropyl-β-cyclodextrin in a thermosensitive hydrogel, based on N-isopropylmethacrylamide and N-isopropylacrylamide with ethylene glycol dimethacrylate as a crosslinker. The product was characterized by chemical methods and also by FTIR, HPLC, DSC, SEM, XRD. The results show that synthesis was successfully done. With an increase in the quantity of crosslinker in the hydrogels, the starting release and the release rate of curcumin from the formulation of the complex with hydrogels decreases. The release rate of curcumin from the gel complex formulation is constant over time. It is possible to design a formulation that will release curcumin for more than 60 days. In order to determine the mechanism and kinetics of curcumin release, various mathematical models were applied by using the DDSolver package for Microsoft Excel application. The Korsmeyer-Peppas model best describes the release of curcumin from the gel formulation of the complex, while the values for the diffusion exponent (0.063-0.074) shows that mechanism of the release rate is based on diffusion.
Abstract Introduction There is a concerning trend of emigration among highly educated individuals in Montenegro. This includes medical professionals who seek better job opportunities abroad. The aim ...of the present study was to identify the primary motivational factors driving Montenegrin medical students to pursue a career in medicine, and whether these factors undergo changes over the course of their studies. Methods A cross-sectional study included 210 medical students in Montenegro, 27.62% were males, and 72.38% were females. The mean age of the students was 21.90 years (SD=3.05) (range 19–39). Their academic motivation was analysed using the Academic Motivation Scale, previously validated in various cultural contexts. Results The results showed that autonomous motivation levels were higher than controlled motivation levels (p<0.001) among students in Montenegro, which has been previously associated with better learning outcomes. Students with medical doctors among their family members had higher extrinsic motivation related to rewards and punishments (extrinsic motivation with external regulation p=0.018). Amotivation showed a trend of increasing as the students got closer to graduation (p=0.057). Only 8.1% of students planned a career in primary healthcare, and 1% wished to specialize in family medicine. Conclusions This study’s findings, which indicate high levels of autonomous motivation among medical students, are of significant importance. They contribute to a comprehensive understanding of the motivation factors among medical students and young healthcare professionals in Montenegro. Moreover, they provide a basis for the implementation of strategic interventions to retain highly skilled medical professionals within the country’s workforce, thereby addressing the concerning trend of emigration among this group.
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