- The Journal of the Serbian Chemical Society -JSCS (formerly Glasnik Hemijskog društva Beograd) publishes articles ori... moreThe Journal of the Serbian Chemical Society -JSCS (formerly Glasnik Hemijskog društva Beograd) publishes articles original papers that have not been published previously, from the fields of fundamental and applied chemistryedit
Rate coefficients for electron impact dissociation of the N 2 molecule under the influence of crossed radio-frequency (RF) electric and magnetic fields were calculated for field frequencies of 13.56, 100 and 200 MHz and for root mean... more
Rate coefficients for electron impact dissociation of the N 2 molecule under the influence of crossed radio-frequency (RF) electric and magnetic fields were calculated for field frequencies of 13.56, 100 and 200 MHz and for root mean square values of the reduced electric field strength of 300 and 500 Td. The root mean square values of the reduced magnetic field were varied from 0 to 2000 Hx. Тhe effects of the strength of the RF fields and their frequency on the rates for the dissociation to neutral fragments and for the dissociative ionization are discussed. The temporal evolution of the rate coefficients during one period of the RF field is shown and discussed.
Research has shown that most chemistry teachers have misconceptions about covalent bonding. This study investigates whether the cognitive conflict interview technique could persuade teachers to revise their possible misconceptions of... more
Research has shown that most chemistry teachers have misconceptions about covalent bonding. This study investigates whether the cognitive conflict interview technique could persuade teachers to revise their possible misconceptions of covalent bonding. Eight chemistry teachers from different schools participated in this study. Two validated instruments, cognitive conflict technique interview guidelines and the open-ended covalent bonding test, were employed for the data collection. The results showed that the cognitive conflict interviews could facilitate respondents to overcome their misconceptions about covalent bonding. Five of the eight respondents experienced a conceptual change from misconceptions to scientific conceptions, and three others experienced a partial conceptual change. Six concepts which previously caused misconceptions were eliminated and turned into a scientific concept instead. Of the 46 cases of misconceptions, 41 cases turned into scientific conceptions. The result of this study serves as an initial perspective for exploring the effectiveness of cognitive conflict interviews more broadly.
A three-phase foam is considered one of the promising advanced materials for fighting fires. However, the preparation conditions, cost and effect are key factors for industrial applications. In this study, new three-phase foam systems... more
A three-phase foam is considered one of the promising advanced materials for fighting fires. However, the preparation conditions, cost and effect are key factors for industrial applications. In this study, new three-phase foam systems with fly ash and a complex surfactant are proposed. Five types of surfactants alcohol polyoxyethylene ether sodium sulfate, coconut oil diethanolamine, sodium lauryl sulfate, polyacrylamide and polyether-modified silicone resin emulsion were selected as foaming agents. Through laboratory experiments, the effect on the expansion ratio and foam stability of the surfactant type/concentration, fly ash particle concentration/size and pH were investigated. The foaming condition was determined by numerical optimization. The results of this study may serve as a reference for understanding the preparation of a novel threephase foam. It is hoped that this work could provide useful guidance for the preparation of efficient three-phase fire-extinguishing foam for the safe guarding of process safety in the field of chemical production, transportation, and storage suitable for drug delivery than Al 12 P 12 and Al 12 N 12 based on their recovery times.
N-doped TiO2/carbon composites (TiO2/CN) with different nitrogen content, were obtained starting from titanium isopropoxide and glucose, and by varying the amount of melamine, added to starting reaction mixture. For comparison, an... more
N-doped TiO2/carbon composites (TiO2/CN) with different nitrogen content, were obtained starting from titanium isopropoxide and glucose, and by varying the amount of melamine, added to starting reaction mixture. For comparison, an undoped sample (TiO2/C) was also prepared. Structural and surface characteristics were determined through scanning electron microscopy, thermogravimetric analysis, elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and nitrogen adsorption–desorption isotherms. The photocatalytic activity of TiO2/CN composites was examined via photocatalytic degradation of methylene blue and multiclass pharmaceuticals from water solution. It was found that N doping of TiO2/carbon composites induced changes in structural and surface characteristics of TiO2/CN composites, improving their adsorption, but decreasing photocatalytic efficiency. Nevertheless, TiO2/CN0.05 composite obtained by the hydrothermal synthesis in the presence of glucose and 0.05 g melamine showed the highest efficiency for removing selected pharmaceuticals and methylene blue from aqueous solutions through the combined processes of adsorption in the dark, and photocatalytic degradation under UV and visible irradiation.
In this study, plasma induced by a nanosecond Nd:YAG laser on thin oil films deposited on a silica wafer was characterized by evaluating the main plasma parameters. Spatially and temporally integrated spectral measurements were performed... more
In this study, plasma induced by a nanosecond Nd:YAG laser on thin oil films deposited on a silica wafer was characterized by evaluating the main plasma parameters. Spatially and temporally integrated spectral measurements were performed under experimental conditions optimized for elemental analysis of trace metals in oil. Time-resolved values of the spectral line intensities, electron number density, and plasma temperature were obtained from time-integrated measurements by subtracting averaged spectra recorded at different time delays. The electron number density was estimated using the Stark broadened profile of the hydrogen Balmer alpha line. Ionization temperatures were derived from Mg ionic to atomic line intensity ratios. The obtained apparent values of time-resolved plasma parameters were in the range of 1.1×10 17 cm-3 (1.5 μs) to 1.5×10 16 cm-3 (4 μs) and 9400 K (3 μs) to 7200 K (5 μs), depending on the delay time. Emission spectra of C 2 and CN molecules were used to evaluate the rotational and vibrational temperature.
In this study, an agricultural waste product was used to prepare a green corrosion inhibitor based on olive leaves (Olea europaea var. syslvestris). Firstly, an optimization study of antioxidant activity of O. europaea leaves monitored by... more
In this study, an agricultural waste product was used to prepare a green corrosion inhibitor based on olive leaves (Olea europaea var. syslvestris). Firstly, an optimization study of antioxidant activity of O. europaea leaves monitored by the DPPH free radical trapping method, was carried out using full factorial design. In the second step, the extract obtained under optimal conditions was tested as a green corrosion inhibitor for steel in 0.5 mol dm-3 HCl, using gravimetric and electrochemical methods. The results obtained by various techniques showed that the extract acted as a mixed-type inhibitor. The adsorption of the inhibitor was spontaneous (ΔG ads = −12.443 kJ mol-1), through the mechanism of physical adsorption, and it obeyed the Langmuir adsorption isotherm. The highest corrosion inhibition efficiency of 92 % was obtained for 2.8 10-3 g cm-3 of inhibitor, as measured by gravimetric method.
Four novel conformationally restricted (-)-muricatacin analogues, bearing a methoxy group at the C-5 position and with an alkoxymethyl group аs the C-7 side chain, have been synthesised and their in vitro antiproliferative activity was... more
Four novel conformationally restricted (-)-muricatacin analogues, bearing a methoxy group at the C-5 position and with an alkoxymethyl group аs the C-7 side chain, have been synthesised and their in vitro antiproliferative activity was evaluated against a panel of seven human tumour cell lines, as well as a single normal cell line. All analogues (9-12) showed diverse antiproliferative effects against all tested human malignant cell lines, but were devoid of any significant cytotoxicity towards the normal foetal lung fibroblasts (MRC-5). A structure-activity relationship study reveals that the introduction of tetrahydrofuran ring, the replacement of C-8 methylene group in the side chain of muricatacin analogues with the O-8 ether functionality, as well as the length of side chain may be beneficial for the antiproliferative effects of these lactones. All novel analogues were more potent than lead compound, (-)-muricatacin, against HL-60 cell line.
The necessity of anti-inflammatory drugs such as glucocorticoids has been evident during the COVID-19 pandemic. Glucocorticoids, are the standard therapy for the treatment of moderate and severe COVID-19 patients. However, serious side... more
The necessity of anti-inflammatory drugs such as glucocorticoids has been evident during the COVID-19 pandemic. Glucocorticoids, are the standard therapy for the treatment of moderate and severe COVID-19 patients. However, serious side effects limit the use of these drugs, and anti-inflammatory drugs with better pharmacological properties are urgently required. Bile acids are of interest, because of their anti-inflammatory and immunomodulatory properties, facilitated through an unclear mechanism involving transmembrane and nuclear receptors. In this work, we screened the binding activity of a number of bile acid derivatives, for the ligand-binding domain of glucocorticoid receptor (GR-LBD), the most important receptor for anti-inflammatory processes. Tested compounds include oximes, lactones, lactams, tetrazoles, dienones, C-24 alcohols and cholic acid amides. Cholic acid oxime, deoxycholic acid dienone, 3-keto-24-cholic alcohol and cholic acid amide showed best binding affinities for GR-LBD among tested compounds. The in silico molecular docking explanation is provided. SAR analysis showed that expansion of B and C steroid rings or attachment of heterocycle to C ring is not beneficial for binding; side chain should contain hydrogen donor group; the GR-LBD tolerate well different functionalities on C-3 position. These results provide valuable information toward synthesis of the new glucocorticoids based on bile acids.
This study aimed to examine the effect of pictorial based learning (PcBL) on conceptual change in the topic of chemical kinetics. The four-tier instrument (FTDICK) previously developed was deployed to map conceptual change within chemical... more
This study aimed to examine the effect of pictorial based learning (PcBL) on conceptual change in the topic of chemical kinetics. The four-tier instrument (FTDICK) previously developed was deployed to map conceptual change within chemical kinetics concepts. First-year chemistry students at an Indonesian university formed an experimental and a control group. The experimental group experienced the PcBL approach while the control one experienced direct instruction (DI). The conceptual changes demonstrated by the two groups are classified into four categories, namely complete, partial, false and random. Complete conceptual change (CCC) had the highest occurrence rate among the four categories. However, generalising that PcBL and DI are influential in promoting conceptual change in the field of chemical kinetics may be too ambitious. Therefore, further research is needed to reach that conclusion. The effectiveness of PcBL and DI in promoting conceptual change in this study was almost equal. However, in answering the FTDICK questions, the PcBL students showed a better performance reflecting more sound scientific understanding than DI students did.
This research aimed to characterize the physical and chemical properties of municipal solid waste (MSW) incineration fly ash, as well as to investigate the leaching of heavy metals during toxicity characteristics leaching procedure (TCLP)... more
This research aimed to characterize the physical and chemical properties of municipal solid waste (MSW) incineration fly ash, as well as to investigate the leaching of heavy metals during toxicity characteristics leaching procedure (TCLP) process. To understand the leaching behaviour, concentrations of heavy metals, chloride, sulphate and calcium at various leaching, time was monitored together with pH of the leaching solution. Results showed that the chemical compositions of fly ashes led to differences in leaching environment. For the two fly ashes under study, one resulted in a leaching environment with pH of 10-12 while the other had pH about 6-7. Based on pH, anions and cations concentrations, Minteq software was employed to investigate the speciation of heavy metals. Results showed that the shift in precipitation/dissolution balance of carbonate and hydroxides of heavy metals could explain the fluctuation in metal concentrations during the leaching process, which indicates that leaching was probably controlled by these reactions. On the other hand, addition of EDTA changed the controlling reactions. Chelating reactions between heavy metals and EDTA led to much higher leaching toxicity due to the presence of heavy metals, showing that the presence of chelating organics in natural environment may facilitate heavy metal leaching.
The water hyacinth biomass was used for the synthesis of activated carbons in a process of chemical activation with ZnCl 2 , followed by controlled pyrolysis. The applied impregnation weight ratios ZnCl 2 and dry hyacinth biomass were in... more
The water hyacinth biomass was used for the synthesis of activated carbons in a process of chemical activation with ZnCl 2 , followed by controlled pyrolysis. The applied impregnation weight ratios ZnCl 2 and dry hyacinth biomass were in the range of 0.5-3.5. The carbonization was conducted at four different temperatures (400-700 °C) under an inert atmosphere. The highest yield of activated carbon was obtained for the impregnation ratio of 0.5 and carbonization temperature of 400 °C. The samples were characterized using elemental analysis, adsorption-desorption isotherms of nitrogen and SEM analysis. The activated carbon obtained with an impregnation ratio 2.0 and carbonization temperature of 500 °C (2.0AC 500) showed the highest values of specific surface area and total pore volume of 1317 m 2 g-1 and 0.697 cm 3 g-1 , respectively. The adsorption of glyphosate, pesticide with a strong negative environmental impact, was a fast process, with the equilibrium time of 120 min. The adsorption isotherms were fitted with Langmuir and Freundlich model. The Langmuir adsorption capacity of q max = 240.8 mg g-1 for 2.0AC 500 classified the selected adsorbent as a very efficient one. The tested adsorption process followed the kinetics of the pseudo-second-order model.
Molecularly imprinting technology was applied for preparing selective sorbents for benzophenone-4 (BP4), an organic UV filter used in sunscreens and cosmetics. Several imprinted polymers were prepared by bulk polymerization, using BP4 as... more
Molecularly imprinting technology was applied for preparing selective sorbents for benzophenone-4 (BP4), an organic UV filter used in sunscreens and cosmetics. Several imprinted polymers were prepared by bulk polymerization, using BP4 as template. Combination of stability (mechanical and chemical), selectivity and robustness of the imprinted polymers with BP4 properties resulted in a successful imprinting process (imprinting factors in range 1.05-2.60). The prepared polymers were characterised by infrared spectroscopy, elemental analysis, conductometric titrations and nitrogen physisorption at 77 K. Adsorption capacities and selectivity towards 7 other organic UV filters (benzophenone-3, benzophenone-8, homosalate, butyl methoxydibenzoylmethane, ethyl hexyl salicylate, ethyl hexyl p-dimethylamino benzoate and ethyl hexyl p-methoxycinnamate) were determined, proving high adsorption capacity and high selectivity for BP4 binding. The highest adsorption capacity was observed for 4-vinylpyridine/ethylene glycol dimethacrylate co-polymer prepared in dimethyl sulfoxide (1.108 mmol g-1). The imprinted polymer with the highest binding capacity was applied to solid phase extraction of BP4 from aqueous solutions with 98.5 % efficiency.
Organomodified bentonites were obtained by modification of bentonite clay from local mine Bogovina, with four different alkylammonium ions in the amounts that correspond to cation exchange capacity. Carbonized bentonites, obtained by... more
Organomodified bentonites were obtained by modification of bentonite clay from local mine Bogovina, with four different alkylammonium ions in the amounts that correspond to cation exchange capacity. Carbonized bentonites, obtained by pyrolyzing the organomodified bentonites in the flow of nitrogen, were characterized using XRD, low-temperature N 2 physisorption and Raman spectroscopy. Structural and textural properties of carbonized bentonites depended on the arrangement of alkylammonium cations in the paternal organomodified bentonite, while the Raman spectroscopy confirmed the presence of amorphous carbon. The obtained carbonized bentonites were used for modification of the carbon paste electrode. The modified electrodes were investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The electrosorption of chloride and sulfate anions on carbonized bentonites was studied by chronocoulometry. The results were interpreted in the terms of surface groups and textural properties of the carbonized bentonites.
LORCA et al. heterocyclic structure. These models can be used for the rational proposal of new inhibitors.
The present work reports the synthesis of three new nitrogen-containing heteronuclear molecules (two pyrimidines and one pyrrolopyrimidine). Based on the 12 principles of green chemistry, chemical methodologies are planned and executed.... more
The present work reports the synthesis of three new nitrogen-containing heteronuclear molecules (two pyrimidines and one pyrrolopyrimidine). Based on the 12 principles of green chemistry, chemical methodologies are planned and executed. Various phase transfer catalysts were examined in the crucial step to execute C-N bond formation (through the SnAr mechanism), TBAI was found to be a better option than those of TBAB and CTAB. The one-pot synthetic methodology was optimized involving Wittig olefination and bromination to achieve a key precursor for the synthesis of a new pyrrolopyrimidine.
This study aimed to show aromatic profile of wines produced from two autochthonous grape cultivars Krstač (K) and Žižak (Z). During the wine production two enzymatic preparations (EP) Lallzyme cuvee blanc (CB) and Lallzyme enzymatic... more
This study aimed to show aromatic profile of wines produced from two autochthonous grape cultivars Krstač (K) and Žižak (Z). During the wine production two enzymatic preparations (EP) Lallzyme cuvee blanc (CB) and Lallzyme enzymatic preparation β (EB) and different time of skin contact (4 and 8 h) were applied. Aromatic compounds were detected by GC/FID-MS analysis. Significantly higher content of total detected aromatic compounds compared to appropriate controls (168.54 and 161.72 mg L-1) was observed for K EB4h (176.33 mg L-1) and Z CB4h (177.29 mg L-1) wines. Skin contact and usage of EP mostly increased content of 2-phenylethyl and isoamyl alcohols. Wines from both varieties showed higher content of hexanoic and octanoic acids compared to the control. It is interesting to emphasize that content of esters that are responsible for fruity aroma of wine which is important for pleasant taste (isoamyl acetate-banana, ethyl hexanoate-ripe banana, 2-phenylethyl acetate-powerful fruity rose like) were increased in all samples compared to the controls. The highest grades, after sensory evaluation, were obtained for K EB 8h (18.0 out of 20.0) and Z CB 8h (18.2 out of 20.0).
Anti-cancer drug delivery based on nanocages is important step in drug development process due to reducing side effects and drug-releasing near the tumor cell. We have studied the interaction of the bendamustine anti-cancer drug with the... more
Anti-cancer drug delivery based on nanocages is important step in drug development process due to reducing side effects and drug-releasing near the tumor cell. We have studied the interaction of the bendamustine anti-cancer drug with the Al/B-N/P nanocages with utilization density functional theory (DFT) approach both in gas and water phases at the B3LYP/6-31G (d,p) level of theory. Results show that the nanocages quantum parameters were somewhat varied by the adsorption of the bendamustine drug. The bendamustine drug operates as an electrons donor and can adsorb in the site of the electron's acceptor of nanocages. The changes in Gibbs energy correspond to a chemisorption in both phases. The results indicated that the bond between studied nanocages and bendamustine is covalent. However, all studied nanocages may be favorable candidates for detecting the bendamustine drug. Yet, pristine B 12 P 12 and B 12 N 12 nanocages appeared to be more suitable for drug delivery than Al 12 P 12 and Al 12 N 12 based on their recovery times.
Iron homeostasis is altered in tumours in response to a perturbation in the expression of iron-dependent proteins. Therefore, iron chelators make cancerous cells more vulnerable to iron deficiency. Compounds having thiosemicarbazide... more
Iron homeostasis is altered in tumours in response to a perturbation in the expression of iron-dependent proteins. Therefore, iron chelators make cancerous cells more vulnerable to iron deficiency. Compounds having thiosemicarbazide scaffold with the ability to metal complex formation have the potential to act as anticancer. A series of thiosemicarbazide derivatives were designed, synthesized successfully and their cytotoxicity was then tested on some cancerous as well as laboratory normal model systems by using colorimetric assay based on WST-1 reagent. According to the cytotoxicity results, some compounds showed high toxicity effect on both the cancerous and healthy cell lines. The results of toxicity assays on U87 and A549 cell lines showed the survivability less than 50 % at all concentrations higher than 10 ppm for all the synthesized compounds. The MCF-7 cell line exhibited approximately the same behaviour and had survivability less than 60 %. The 3T3 in compared with HUVEC cell line showed a completely different behaviour against the synthesized compounds and had survivability more than 50 %. The selectivity index was also measured and based on the study results it could be concluded that the cytotoxicity profile of the synthesized compounds on 3T3 cell line shows a significant difference, indicating a good anticancer effect of these compounds.
Methods for determination of bisoprolol and related substances mostly use UV detection and a phosphate buffer and are not suitable for MS detection. In this study, LC-UV-MS/MS for separation and characterization of bisoprolol related... more
Methods for determination of bisoprolol and related substances mostly use UV detection and a phosphate buffer and are not suitable for MS detection. In this study, LC-UV-MS/MS for separation and characterization of bisoprolol related substances was developed, validated and applied for studying the degradation products of bisoprolol when exposed to hydrolytic stress, heat and light. The method uses a C18 column, formic acid in water and acetonitrile as mobile phases, gradient elution and UV and MS detection. Forced degradation revealed that acid hydrolysis produces the most intensive transformation of bisoprolol to its impurity A, along with impurities L and D. Alkaline hydrolysis produced impurities A, L, Q, G and K; oxidative and thermal degradation produced impurities A, L and K, while photodegradation produced impurities A, L, G and K, all characterized by their mass spectral data. The developed method using two detection systems was demonstrated as efficient since mass spectra allowed identification of the related substances of bisoprolol and quantification was possible using absorbance measurements at 270 nm. The obtained results will fill in the lack of data on the fragmentation patterns of bisoprolol and related substances that could be used by researchers and practitioners in research and quality control laboratories.
In this work, the molecular interaction between the carbamazepine and alizarin in methanol has been represented in terms of limiting apparent molar volumes and viscosity coefficients. Before further proceeding, the validity and... more
In this work, the molecular interaction between the carbamazepine and alizarin in methanol has been represented in terms of limiting apparent molar volumes and viscosity coefficients. Before further proceeding, the validity and applicability of the calculation of apparent molar volumes have also been checked by considering the available five types of frequently used equations, where the required modifications have proposed by the addition of hypothetical mass and concentration of the solute. After that, the limiting apparent molar volume and viscosity coefficients have been calculated using Masson equation and Jones-Dole equation respectively to predict and cross-check the interactions occurring between the molecules in ternary system. The equation marked with (1) has been found the best-fit equation, and the carbamazepine and alizarin in methanol are strongly bound (φ V o = 23104 m 3 mol-1 and B = = 18.10 kg mol-1) to each other at the concentration 0.003 mol kg-1. The results have been interpreted in favour of the solute-cosolute interactions, which is dominant over the solute-solute and cosolute-cosolute interactions. The interpretations have been discussed with the help of intermolecular forces and noncovalent interactions.
Thermoplastic poly(urethane-siloxane)/organoclay nanocomposites (TPU NCs) with different hard segment content (20-55 wt. %) were prepared by in situ polymerization in the presence of organically modified montmorillonite as a nanofiller... more
Thermoplastic poly(urethane-siloxane)/organoclay nanocomposites (TPU NCs) with different hard segment content (20-55 wt. %) were prepared by in situ polymerization in the presence of organically modified montmorillonite as a nanofiller (Cloisite 30B; 1 wt. %). Hydroxyl-terminated ethoxypropyl-poly(dimethylsiloxane) was used as soft segment, while 4,4'-methylenediphenyl diisocyanate and 1,4-butanediol were the hard segment components. The study of the influence of the hard segment content on the functional properties of TPU NCs was performed by Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), dynamic mechanical thermal analyses (DMTA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), water contact angle and water absorption tests. The results revealed that TPU NCs with the increasing hard segment content exhibit higher values of degree of microphase separation, melting temperature of the hard segments, degree of crystallinity, storage modulus (except for TPU NC-55), but lower thermal stability and hydrophobicity. TPU NC films were hydrophobic and their free surface energy was in the range from 17.7 to 24.9 mJ m-2. This work highlights how the composition of TPU NCs would affect their functional properties and provide an additional composition intended for designing advanced TPU NC materials for special biomedical applications.
The influence of temperature, reaction time, and type of the catalyst on the yield of the 2,3,5-trimethylpyridine (collidine) from 3-amino-2-methylpropenal and methylethylketone was investigated. 3-Amino-2-methylpropenal was synthesized... more
The influence of temperature, reaction time, and type of the catalyst on the yield of the 2,3,5-trimethylpyridine (collidine) from 3-amino-2-methylpropenal and methylethylketone was investigated. 3-Amino-2-methylpropenal was synthesized from 3-ethoxy-2-methylacrolein previously synthesized from methylmalondialdehyde tetraethyl acetal, obtained from triethyl orthoformate and propenyl ether. The optimal conditions for the investigated synthesis were temperature of 150 °C, reaction time 24 h, and the CH 3 COOH/pTsOH catalyst. This synthesis is the first successful attempt to synthesize 2,3,5-trimethylpyridine in an acid medium.
Tire pyrolytic oil (TPO) obtained from thermal pyrolysis of scrap tires is not a diesel equivalent fuel which can be used directly in vehicles due to its high density, viscosity, sulfur content, low flash point and low cetane index. It... more
Tire pyrolytic oil (TPO) obtained from thermal pyrolysis of scrap tires is not a diesel equivalent fuel which can be used directly in vehicles due to its high density, viscosity, sulfur content, low flash point and low cetane index. It can only be used in a limited way by mixing with diesel fuel (DF) in amounts less than 30 %. In this study, the pyrolysis of scrap tires was carried out at a heating rates of 5 and 10 °C min-1 in the range of 450-600 °C, using a mixture of hierarchical zeolite (HZSM-5), mesoporous silica (MCM-41) and quicklime (CaO) as the catalyst. The obtained TPO and catalytic pyrolytic oil (CPO) were upgraded by pre-treatment, and distillation consisting of a mixture of Cu(I)-loaded mesoporous aluminosilicate (Cu(I)-MAS) and MCM-41, desulfurization and decolourization steps, respectively. To obtain diesel-like fuel, the upgraded catalytic pyrolytic oil (UCPO) and biodiesel (PBD) obtained from palm oil were blended in certain proportions. Density, viscosity, flash point and cetane index of the obtained diesel-like fuels were found within the limit values of diesel fuel.
Previously, the cytotoxic actions of five Pd(II) complexes with biden¬tate N-heteroaromatic chelators (complexes 1–5) on a palette of several cancer cell lines were investigated. However, the results of the cytotoxic activity did not... more
Previously, the cytotoxic actions of five Pd(II) complexes with biden¬tate N-heteroaromatic chelators (complexes 1–5) on a palette of several cancer cell lines were investigated. However, the results of the cytotoxic activity did not correlate with the hydrophobic character of the complexes. To gain further insight into the structure–activity relationship, essential for the design of novel potential drugs, other factors, such as non-specific interactions with cellular proteins, have to be taken into account. To explore the potential non-specific influence of the complexes on protein structures, ovalbumin (OVA) was chosen as a model system to mimic cellular non-specific crowding environ¬ments with high protein concentrations. A Fourier-transform infrared spectro¬scopy study implied that the binding of 3 and 4 led to only moderate alter¬nat¬ions in the secondary structures of the protein, without the possibility to penet¬rate into hydrophobic core of the protein and disruption of protein native fold. Contrary, the effect of complex 5 on OVA secondary structures was concen¬tration-dependent. While the lower concentration of complex 5 had no effect on OVA structure, a doubled concentration of complex 5 led to complete dis¬ruption of the content native-like secondary structures. The concentration-dep¬endent effect of complex 5 on the changes in secondary structures and con¬siderable increase in the exposure of OVA hydrophobic surfaces to water may be related to a potential crosslinking that leads to OVA aggregation.
A series of novel fluorinated 1,5-benzothiazepine derivatives were synthesized, characterized and evaluated for in vitro anticancer and antibacterial activity. The in vitro anticancer activity of the synthesized compounds 4a-h was... more
A series of novel fluorinated 1,5-benzothiazepine derivatives were synthesized, characterized and evaluated for in vitro anticancer and antibacterial activity. The in vitro anticancer activity of the synthesized compounds 4a-h was evaluated against four human cancer cell lines namely lung (A549), breast (MCF-7), liver (HEPG2) and prostate (PC-3). Compounds 4c, 4d, 4g and 4h exhibited good activity with GI 50 <10 µg ml-1 against all four human cancer cell lines which was comparable to standard drug adriamycin. Additionally, antibacterial activity of synthesized compounds was estimated using Resazurin Microtiter Assay (REMA) and compared with standard drug ampicillin. Among the synthesized compounds, 4c, 4d, 4g and 4h showed good antibacterial activity and all the synthesized compounds were found to be more active towards gram negative than gram positive bacteria. These promising results obtained from in vitro anticancer and antibacterial activity, inferred that the synthesized compounds are capable of being anticancer as well as antibacterial agents.
Wood ash is a complex mixture of inorganic and organic compounds. It is heterogeneous in composition, which can vary considerably. Ash is mainly disposed of in landfills, which creates a risk for air, soil and groundwater contamination by... more
Wood ash is a complex mixture of inorganic and organic compounds. It is heterogeneous in composition, which can vary considerably. Ash is mainly disposed of in landfills, which creates a risk for air, soil and groundwater contamination by trace elements. In order for wood biomass ash to be used as a secondary raw material, it is necessary to perform leaching tests, to determine which microelements it contains, and which of them could be released into the environment during the ash disposal. Sequential extraction (SE) showed that in the exchangeable and carbonate fraction, the most volatile metals As, Cd, Zn and Pb are released the most from the ash of deciduous trees, while the leaching of ash from coniferous trees is significantly lower. The evaluation of risk assessment code (RAC) for the tested biomass ash samples, indicates that Pb is a high-risk leaching element due to its condensation on the ash particles. By performing toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) tests, it was established that the released concentrations of tested metals are below the maximum allowable concentration, given by the regulation. The leaching tests of composites, prepared from wood ash in combination with cement, indicate that the leaching of ash is reduced to a minimum, and that all heavy metals are bound in a cement matrix, which indicates the possibility of using wood ash for construction purposes.
Due to favourable properties layered double hydroxides (LDHs) have been widely investigated for organic dye removal processes. In order to study the adsorption of methyl orange, bimetal (ZnAl and MgAl) and trimetal (ZnCuAl and MgCuAl)... more
Due to favourable properties layered double hydroxides (LDHs) have been widely investigated for organic dye removal processes. In order to study the adsorption of methyl orange, bimetal (ZnAl and MgAl) and trimetal (ZnCuAl and MgCuAl) adsorbents were synthesized and thermally treated. The influence of adsorbent metal nature and content on structural (X-ray diffraction, Raman analysis), textural (low temperature nitrogen adsorption) and adsorption properties was investigated. Adsorption behaviour, mechanisms, and stability of synthesized LDHs and their calcined mixed oxides were studied with the aim to elucidate the adsorbent-dye interactions, enabling optimization of experimental design. All LDH adsorbents and LDH derived mixed oxide adsorbents had high removal efficiency rate, especially Zn-containing mixed oxides where complete decolourization (100 % of dye removal) was achieved almost instantly due to super-fast adsorbent-adsorbate interaction. Two possible adsorption mechanisms initiated by interfacial phenomena were in correlation with the structural and textural properties, as well as with the "memory effect" reconstruction phenomenon. These results present a solid base for further investigation and design of LDH-based adsorbents for the Methyl orange removal, considering their favourable structural and textural properties and excellent adsorption capacities.
A case study is given of dendritic growth during zinc electrolysis in conditions that promote it. Subject of the main interest was how the electrolysis parameters affect the duration of dendrites life. The selected set of parameters did... more
A case study is given of dendritic growth during zinc electrolysis in conditions that promote it. Subject of the main interest was how the electrolysis parameters affect the duration of dendrites life. The selected set of parameters did provide a surprisingly regular dendrite's life, i.e., period from start of the electrolysis until dendrites detachment from the cathode. Dendrite's growth did proceed with lowering of the zinc current efficiency, and the end of life was manifested by intensive hydrogen evolution due to corrosion of detached zinc deposit in the acid electrolyte. Current efficiency was successfully followed by the bubble counting technique, invented especially for kinetic studies of gas including reactions. The acquired results on dendrites' life duration were so exact that it was easy to unify all five mono-variable dependencies into one five-variable expression. The calculated values of life duration did differ from the measured ones by only ±3%! This is a proof that the developed expression accurately presents the real nature of dendritic growth under the applied conditions, i.e., 0.5 to 2 M zinc (II) ions, 0.41 to 3.06 M H 2 SO 4 , 10 to 2500 mg dm-3 copper (II) ions, 0.14 to 14 g dm-3 hexamethylenetetramine, and 4.25 to 103 mA dm-2 current density. The eventual broader region of Zn dendrites' strict regular growth is not excluded.
The present study reports the potential application of star-shaped poly(ε-caprolactones) with different number of arms as new drug delivery matrix. Linear and star-shaped PCL ibuprofen loaded microspheres were prepared using oil-in-water... more
The present study reports the potential application of star-shaped poly(ε-caprolactones) with different number of arms as new drug delivery matrix. Linear and star-shaped PCL ibuprofen loaded microspheres were prepared using oil-in-water (o/w) solvent evaporation technique and characterized with FTIR, DSC, XRD and SEM analysis. High yield, encapsulation efficiency and drug loadings were obtained for all microspheres. FTIR analysis revealed the existence of interactions between polymer matrix and drug, while the DSC analysis suggested that drug was encapsulated in an amorphous form. SEM analysis confirmed that regular, spherical in shape star-shaped microspheres, with diameter between 80 and 90 μm, were obtained, while quite larger microspheres, 110 μm, were prepared from linear PCL. The advantage of using starshaped PCL microspheres instead of linear PCL was seen from drug release profiles which demonstrated higher amount of drug released from star-shaped polymer matrix as a consequence of their branched, flexible structure. Microspheres prepared from the polymers with the most branched structure showed the highest amount of the released drug after 24 h. Finally, cytotoxicity tests, performed using normal human fibroblasts (MRC5), indicated the absence of cytotoxicity at lower concentrations of microspheres proving the great potential of star-shaped PCL systems in comparison to linear ones.
The knowledge on the general population health is important for creating public policies and organization of medical services. However, personal data are often limited, and mathematical models are employed to achieve a general overview.... more
The knowledge on the general population health is important for creating public policies and organization of medical services. However, personal data are often limited, and mathematical models are employed to achieve a general overview. Cluster analysis was used in this study to assess general trends in population health based on laboratory data. Metabolic indicators were chosen to test the model and define population cohorts. Data on blood analysis of 33,049 persons, namely the concentrations of glucose, total cholesterol and triglycerides, were collected in a public health laboratory and used to define metabolic cohorts employing computational data clustering (CLARA method). The population was shown to be distributed in 3 clusters: persons with hypercholesterolemia with or without changes in the concentration of triglycerides or glucose, persons with reference or close to reference concentrations of all three analytes and persons with predominantly elevated all three parameters. Clustering of biochemical data, thus, is a useful statistical tool in defining population groups in respect to certain health aspect.
Steroids are good candidates for drug development, thanks to their low general toxicity and possibility for structure modifications connected with change of their activity. Several 16,17-secoandrost-4-ene-16,17a-dinitrile compounds were... more
Steroids are good candidates for drug development, thanks to their low general toxicity and possibility for structure modifications connected with change of their activity. Several 16,17-secoandrost-4-ene-16,17a-dinitrile compounds were synthesized and screened for anticancer effect previously, including 6-oxo and 6-hydroxyimino compounds. This research is continued with the attempts for different synthetic strategy and evaluation of anticancer effect mechanism. Synthesis of 3-hydroxyimino compounds was successful, but inseparable mix of isomers was excluded from biological tests. Tested secodinitriles expressed cytotoxic effect on HeLa cervix cancer cells as a model system, with submicromolar to molar IC 50 values, where 6-substituted derivatives were more effective. After 72 h treatment with equitoxic concentrations equal IC 50 values of test compounds the mechanism of this effect was studied using flow cytometry and specific fluorescent dyes. Modest change in both G0/G1 and G2/M resting phases and change in mitochondrial membrane potential were noticed, while the most pronounced effect was apoptosis induction. Total apoptosis was in range 50.72-58.31 % in all cell samples treated with secodinitriles, compared to 7.44 % in control samples. Total percent of dead cells, including both apoptotic and necrotic, ranged from 55.24 to 65.34 %, compared to 10.68 % in control. Selectivity towards cancer cells is very important feature of these compounds indicating their potential use as lead compounds in the drug development for the treatment of cancers of steroid hormone-dependent tissues.
The present study investigated the valorisation of oil-rich residues of coconut oil mill effluent (COME) as a potential growth medium for the microbial production of extracellular lipase. The bacterial species isolated from oil mill... more
The present study investigated the valorisation of oil-rich residues of coconut oil mill effluent (COME) as a potential growth medium for the microbial production of extracellular lipase. The bacterial species isolated from oil mill effluent, Acinetobacter sp. KSPE71 was tested for its efficiency to grow and produce lipase in undiluted COME and 0.2 % yeast extract and 0.2 % NH 4 Cl supplemented COME. In this connection, the process parameters such as pH, temperature, agitation speed, and inoculum size were optimized to maximize the production using a central composite design in the Response surface methodology. At the optimized state of pH 7.5, 35 °C, 150 rpm with 0.6 % inoculum size, a maximum of 3.95 U mL-1 activity was obtained, four-fold higher than the basal condition. At this stage, 73 % of the lipid content was degraded. The present work results imply that the oil mill effluent can be used as a cheaper production medium for lipase and the new isolate Acinetobacter sp. KSPE71 as a potential lipase producer. The degradation of oil waste along with the production of the valuable product has multiple advantages of cost reduction of lipase and environmental concern.
The preparation and properties of oxide coatings with immobilized ZSM-5 zeolite obtained by plasma electrolytic oxidation on aluminum support were investigated and discussed. Pure and Ce-exchanged ZSM-5 were immobilized on aluminum... more
The preparation and properties of oxide coatings with immobilized ZSM-5 zeolite obtained by plasma electrolytic oxidation on aluminum support were investigated and discussed. Pure and Ce-exchanged ZSM-5 were immobilized on aluminum supports from a silicate-based electrolyte under ultra-low duty cycle pulsed direct current conditions. The obtained composite coatings were characterized with respect to their morphology, phase and chemical composition, as well as photocatalytic activity and anti-corrosion properties. All mentioned properties of the obtained coatings were dependent on the processing time. The coatings with Ce-exchanged ZSM-5 showed higher photocatalytic activity and more effective corrosion protection than those with pure ZSM-5. The highest photocatalytic activity was observed for coatings processed for 30 min. It is suggested that the surface morphology, Ce-content and number of defects influenced the photocatalytic activity of the composite coatings.
BUGEJA DOUGLAS et al. knowledge, this is the first scientific work dealing with a detailed chemical analysis of Maltese honey.
The aim of this study was to develop and validate a sensitive RP-HPLC method for the determination of usnic acid, as a potential marker substance of the herbal product for oromucosal use being a complex mixture of plant extracts and an... more
The aim of this study was to develop and validate a sensitive RP-HPLC method for the determination of usnic acid, as a potential marker substance of the herbal product for oromucosal use being a complex mixture of plant extracts and an essential oil, including the extract of Usnea barbata. Analysis of usnic acid in the tested formulation was performed through an extraction with methanol, prior to injection onto the HPLC column (Zorbax Eclipse XDB-C18 600 Bar (4.6 mm×100 mm, 1.8 μm)). The employed gradient procedure of the solvents (phosphoric acid (pH 2.5) and acetonitrile), at flow rate of 0.1 mL min-1 allowed for the efficient and reproducible separation of usnic acid from the other compounds present in the investigated complex mixture. The established suitability, linearity, precision, accuracy and selectivity/specificity of this assay implied its applicability for the reliable examination in the stability study of the investigated multi-ingredient herbal preparation.
Presented research aimed to develop an alternative approach for the estimation of biosorption capability of sunflower husk. The acid-pretreated sunflower biomass was characterized by scanning electron microscopy combined with energy... more
Presented research aimed to develop an alternative approach for the estimation of biosorption capability of sunflower husk. The acid-pretreated sunflower biomass was characterized by scanning electron microscopy combined with energy dispersive X-Ray spectroscopy (SEM-EDX) analysis and Fourier transform infrared (FTIR) spectroscopy. Biosorption efficiency has been evaluated using inductively coupled plasma optical emission spectroscopy (ICP-OES) and laser-induced breakdown spectroscopy (LIBS). The adsorption capacity of the adsorbent was determined as the function of the pH of the solution, the initial concentration of heavy metal solutions, and contact time. The optimal conditions were achieved after 15 min of contact at pH 6, while the percentage of the removal was from 80.0–98.7 %, depending on the element. The results obtained from the kinetic and isotherm studies show that maximum adsorption of ions was quickly reached and followed the pseudo-second-order kinetic model. Real samples were tested and obtained Ni values by LIBS method were 3100±200 and 1240±100 mg kg-1, while estimated values by the ICP-OES were 2995±20 and 1130±10 mg kg-1, respectively. The obtained results prove that LIBS method can be used as a “green alternative“ for the evaluation of biosorption efficiency.
In this work the theoretical model for heat transfer from a wall to a liquid-solid fluidized bed by liquid convective mechanism has been proposed and developed. The model is based on thickness of boundary layer and film theory. The key... more
In this work the theoretical model for heat transfer from a wall to a liquid-solid fluidized bed by liquid convective mechanism has been proposed and developed. The model is based on thickness of boundary layer and film theory. The key parameter in the model is the distance between two adjacent particles which collide with the wall. According to the proposed model, the liquid convective heat transfer in a fluidized bed is 4 to 5 times more intense than in a single-phase flow. Additionally, the wall-to-bed heat transfer coefficient has been measured experimentally in water-glass particles fluidized bed, for different particle sizes. Comparison of the model prediction with experimental data has shown that size of the particles strongly influences the mechanism of heat transfer. For fine particles of 0.8 mm in diameter, the liquid convective heat transfer model represents adequately the experimental data, indicating that particle convective mechanism is negligible. For coarse particles of 1.5-2 mm in diameter, the liquid convective heat transfer mechanism accounts for 60 % of the overall heat transfer coefficient.
This study was carried out in the central district of Kirklareli province in Turkey. It presents the chemical composition of three deposition types, namely wet, bulk and dry. In this study, 150 deposition samples (wet + bulk + dry) were... more
This study was carried out in the central district of Kirklareli province in Turkey. It presents the chemical composition of three deposition types, namely wet, bulk and dry. In this study, 150 deposition samples (wet + bulk + dry) were collected for a year in the urban and suburban areas in the central district of Kirklareli. The concentrations of the main cations (Ca 2+ , K + , Na + , Mg 2+ , NH 4 +) and main anions (SO 4 2-, Cl-, NO 3-) in the collected deposition samples were determined. The seasonal variations of the concentrations of the major ions in the three deposition types were studied. The wet and dry deposition fluxes of major ions were calculated. Among the major ions, the ion with the highest annual mean flux values in the wet deposition is Ca 2+ in the urban area, while it is Clin the suburban area. In the wet deposition, the annual mean flux values of Ca 2+ in the urban area and Clin the suburban area were 65.40 and 38.09 mg m-2 h-1 , respectively. The relationship between ion concentrations and acid deposition was also investigated and the sources of ions were determined. The arithmetic mean pH values of the samples in the urban and suburban areas were 6.39 and 6.14 in wet deposition, 6.75 and 6.41 in bulk deposition, and 7.36 and 6.56 in dry deposition, respectively. The backward trajectories arriving at the region during the study period were divided into two groups. In the first cyclone group, SO 4 2was to 97 % of anthropogenic origin in both the urban and suburban areas.
The method for using concentration plants tailings is proposed for the first time in this study. These tailings contain a number of valuable metals, such as Cu, Fe, Zn, etc., and are a potential raw material for obtaining concentrates of... more
The method for using concentration plants tailings is proposed for the first time in this study. These tailings contain a number of valuable metals, such as Cu, Fe, Zn, etc., and are a potential raw material for obtaining concentrates of some elements. An electrohydropulse discharge was used to intensify the process of copper leaching and other metals. Ammonium bifluoride, the most effective of the ammonium salts used in copper leaching by the ammonization method, was chosen as the reagent. The influences of significant leaching parameters were studied and optimized using probabilistic deterministic planning of experiment. Based on the study findings, the following process conditions were found to be optimal: mass ratio of solid to liquid (S:L) of 1:1; Cu:F = 1:6; sulphuric acid concentration 40 g L-1 ; experiment duration 30 min; discharge voltage 10 kV and a leaching efficiency of 80-85 % could be achieved. Comparative features of tailings samples from the Karagaily (Republic of Kazakhstan) concentration plant were studied using X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic emission spectral analysis. The study results showed that copper was maximally transferred to the aqueous phase.
The influence of different hydroxides, applied to activate carbon black, on the electrochemical properties of activated carbon was investigated. The carbon material was prepared by hydrothermal treatment of sucrose and afterwards... more
The influence of different hydroxides, applied to activate carbon black, on the electrochemical properties of activated carbon was investigated. The carbon material was prepared by hydrothermal treatment of sucrose and afterwards thermally activated using KOH, NaOH and LiOH. The electrochemical properties of the obtained samples were examined by cyclic voltammetry and electrochemical impedance spectroscopy and correlated to their physicochemical properties. All samples showed characteristic capacitor-like behaviour. The highest specific capacitance was obtained for the KOH-treated sample, while the increase in capacitance follows the sequence of the growth of ionic radius of a metal from an alkali which is used for activation. It was found that the dependence on the type of hydroxide is due to differences in the radii of a metal. The alkalies of larger radii of metal generated make pores wider and consequently the structure of a porous layer become more accessible to the charge transfer of capacitive response.
In this study, a novel procedure, based on application of the Chicot-Lesage (C-L) composite hardness model, was proposed for the determination of an absolute hardness of electrolytically produced copper coatings. The Cu coatings were... more
In this study, a novel procedure, based on application of the Chicot-Lesage (C-L) composite hardness model, was proposed for the determination of an absolute hardness of electrolytically produced copper coatings. The Cu coatings were electrodeposited on the Si(111) substrate by the pulsating current (PC) regime with a variation of the following parameters: the pause duration, the current density amplitude and the coating thickness. The topography of produced coatings was characterized by atomic force microscope (AFM), while a hardness of the coatings was examined by Vickers microindentation test. Applying the C-L model, the critical relative indentation depth (RID) c of 0.14 was determined, which is independent of all examined parameters of the PC regime. This RID value separated the area in which the composite hardness of the Cu coating corresponded to its absolute hardness (RID < 0.14) from the area in which the application of the C-L model was necessary for a determination of the absolute coating hardness (RID ≥ 0.14). The obtained value was in a good agreement with the value already published in the literature.
The paper presents results of the study of the electrochemical reduction of tungsten(VI) oxide in a melt of the eutectic composition 52 mol% CaCl 2 and 48 mol% NaCl at a liquid gallium electrode. Scanning electron microscopy and X-ray... more
The paper presents results of the study of the electrochemical reduction of tungsten(VI) oxide in a melt of the eutectic composition 52 mol% CaCl 2 and 48 mol% NaCl at a liquid gallium electrode. Scanning electron microscopy and X-ray diffraction methods were used to study the microstructures of the obtained powders. The Rietveld method which is based on diffraction patterns were used to calculate the quantitative content of phases in WO 3 reduction products. The thermodynamic properties of the electrolysis process were investigated by voltammetry. It is shown that a necessary condition for the electrochemical reduction of WO 3 is electrolysis at potentials higher than the standard electrode potential of decomposition of calcium tungstate, which is formed by the interaction of tungsten oxide with calcium chloride. The reduction can take place by both electrochemical and metallothermic mechanisms depending on the conditions of electrolysis. The reduction product is fine tungsten with a particle crystallite size of up to 1 μm.
Glycerol (G) is the major co-product in the transesterification process of biodiesel. As clean energy demand increases, the production of G also increases and new ways of re-using it are needed. In the last decade, some experimental... more
Glycerol (G) is the major co-product in the transesterification process of biodiesel. As clean energy demand increases, the production of G also increases and new ways of re-using it are needed. In the last decade, some experimental studies claimed that G and its derivative, malonic acid (MA), could be used as corrosion inhibitors. Yet, presently, there is little evidence of it and more studies are needed to confirm that G and MA could have a good performance in metal protection. The present work aims to study the reactivity of G and MA, since reactivity and inhibition are intimately linked. The density functional theory (DFT) at the B3YLP/6-31G** level of theory was used to study the reactivity of both molecules. The global and local quantum parameters derived were used to assess the reactivity of both molecules. Analysis of the calculated reactivity descriptors suggest that G and MA should exhibit an acceptable corrosion efficiency, but MA showed have a greater potential as a corrosion inhibitor.
The influence of intensity of the γ-irradiation on commercial high and low density polyethylene (LDPE and HDPE) granules (Kazanorgsintez PJSC, Kazan, Tatarstan, Russia) on their rheological and morphological properties at irradiation... more
The influence of intensity of the γ-irradiation on commercial high and low density polyethylene (LDPE and HDPE) granules (Kazanorgsintez PJSC, Kazan, Tatarstan, Russia) on their rheological and morphological properties at irradiation doses of 5 and 10 kGy was studied. Experiments in the oscillation mode revealed an increase in the dynamic moduli values with increasing radiation dose compared to the initial samples. At the same γ-irradiation doses, the HDPE samples compared to the LDPE ones showed the greatest changes in rheological properties, while the zero shear viscosity of HDPE increased by order of magnitude compared to the initial one at the irradiation dose of 10 kGy. Morphology analysis of supramolecular structures revealed an increase in cobweb-type structures for the irradiated sample in comparison with the initial sample, which may indicate the formation of branched structures under γ-irradiation.
Ocular drug delivery in hydrogel forming film form has several benefits over conventional dosage forms. An ophthalmic anti-inflammation study was undertaken using topically applied aspirin in a hydrogel film formulation. A hydroxypropyl... more
Ocular drug delivery in hydrogel forming film form has several benefits over conventional dosage forms. An ophthalmic anti-inflammation study was undertaken using topically applied aspirin in a hydrogel film formulation. A hydroxypropyl methylcellulose (HPMC) matrix film formulation was prepared by the solvent casting and evaporation technique by taking triethanolamine (TEA) as a plasticizer. Ex vivo corneal permeation as well as anti-inflammatory potential of aspirin was studied on carrageenan induced rabbit eye model. Moisture uptake was found to be in the range of 17.1 and 19.1 % for all the film formulations. The film with the higher HPMC content exhibited both increased moisture uptake and amount of swelling. Among the formulations, the swelling order was found to increase with increasing amount of HPMC in the film. Presence of the hydrogel matrix forming polymer sustained the drug release and corneal permeation for more than 6 h and controlled the process by the diffusion mechanism. The signs of carrageenan induced acute inflammation was inhibited completely within just 2 h of placing the film in the rabbit eye whilst the positive control continued showing redness and increased tear secretion. Aspirin ocular film formulation could be utilized for ocular anti-inflammation for an extended period of time with better patient compliance.
The mechanism of the insertion reaction between the phosphenium cation and azirane has been investigated theoretically in order to better understand the reactivity for the valence isoelectronic of carbene. The phosphenium cation acts as... more
The mechanism of the insertion reaction between the phosphenium cation and azirane has been investigated theoretically in order to better understand the reactivity for the valence isoelectronic of carbene. The phosphenium cation acts as an electrophilic reagent and accepts the σ electrons of azirane to form a complex in the first combination step. The greater the positive charge on the phosphorus in the phosphenium cation, the more stable is the formed complex. Introduction of substituents will decrease the positive charge on the phosphorus in the phosphenium cation. The order of positive charge on phosphorus is HP +-F > HP +-OH > HP +-NH 2 , which is consistent with their Lewis acidities. The complex transforms to a four-membered ring product via a transition state in the second insertion step. The product is more stable than the complex due to the decrease of the ring extension.
The traditional concept of drug discovery is based on the occupancy-driven pharmacology model. It implies the development of inhibitors occupying binding sites that directly affect protein functions. Therefore, proteins that do not have... more
The traditional concept of drug discovery is based on the occupancy-driven pharmacology model. It implies the development of inhibitors occupying binding sites that directly affect protein functions. Therefore, proteins that do not have such binding sites are generally considered as pharmacologically intractable. Furthermore, drugs that act in this way must be administered in dosage regimens that often result in high systemic drug exposures in order to maintain sufficient protein inhibition. Thus, there is a risk of the onset of off-target binding and side effects. The landscape of drug discovery has been markedly changed since proteolysis targeting chimera (PROTAC) molecules emerged twenty years ago as a part of the event-driven pharmacology model. These are bifunctional molecules that harness the ubiquitin-proteasome system, and are composed of a ligand that binds the protein of interest (POI), a ligand that recruits E3 ubiquitin ligase (E3UL) and a linker that connects these two parts. Pharmacologically, PROTACs bring POI and E3UL into close proximity, which triggers the formation of a functional ternary complex POI–PROTAC–E3UL. This event drives polyubiquitination and subsequent POI degradation by the 26S proteasome. The development and exceptional properties of PROTAC molecules that brought them to clinical studies will be discussed in this paper.
A rapid and high yield microwave assisted synthesis of a series of novel 7,9-bis-(arylidene)-4-methyl-2,6,10-triphenyl-2,3-diazaspiro[4,5]dec-3-ene-1,8-dione has been explored. The spiro diarylidene derivatives having nitrogen atom and... more
A rapid and high yield microwave assisted synthesis of a series of novel 7,9-bis-(arylidene)-4-methyl-2,6,10-triphenyl-2,3-diazaspiro[4,5]dec-3-ene-1,8-dione has been explored. The spiro diarylidene derivatives having nitrogen atom and α,β-unsaturated ketone moiety were synthesized by aldol condensation between 4-methyl-2,6,10-triphenyl-2,3-diazaspiro[4,5]dec-3-ene-1,8-dione and corresponding aryl aldehydes followed by dehydration. The synthesized series of novel spirodiarylidene derivatives were characterized using IR, 1H- and 13C-NMR and mass spectra. Density functional theory (DFT) study was performed by Gaussian 09 software. The antimicrobial activities of the synthesized derivatives were evaluated against two pathogenic Gram-positive and Gram-negative bacterial strain and three pathogenic fungal species by disk diffusion method. The minimum inhibitory concentration was determined by the microbroth dilution technique. The results of the present study demonstrated that the examined compounds marked 5a and 5c, possessing 4-NO2 and 5-Br-2-OH substituents, are found to be more active against Gram-positive bacterium Staphylococcus aureus, 8 and 16 µg mL-1, respectively, and moderately active against Gram-negative bacteria Pseudomonas aeruginosa and Escherichia coli, compared to other synthetic derivatives. However, none of the synthesized derivatives showed any activity against Streptococcus pyrogenes. Compound 5e, possessing 2,4,6-(OCH3)3C6H3 moiety, exhibited broad spectrum activity against all fungal strains under study, but showed no antibacterial activity.
The supercritical extraction process is a technique that has increasingly been applied in various industries in recent years. Solubility determination in the supercritical region is the key feature for this process. However, high expenses... more
The supercritical extraction process is a technique that has increasingly been applied in various industries in recent years. Solubility determination in the supercritical region is the key feature for this process. However, high expenses and time consuming experiments for this task obligates the need for process modeling. In this study, a thermodynamic model is proposed to correlate the solubility of solid hydrocarbons, namely, 1-hexadecanol, 1-octadecanol, anthracene, benzoin, fluorene, hexamethylbenzene, mandelic acid, naphthalene, palmitic acid, phenanthrene, propyl 4-hydroxybenzoate, pyrene and stearic acid in supercritical conditions, using Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) equations of state with one-parameter van der Waals (vdW1) and two-parameters (vdW2) and covolume dependent (CVD) mixing rules. For the above combination of equations of state and mixing rules, binary interaction parameters were determined, utilizing the differential evolution optimization strategy. The validity of the model was assessed by comparing the experimental solubility data with the results obtained from thermodynamic model based on average absolute relative deviation (AARD). An empirical correlation was proposed for the correlation of the solid solubilities in supercritical CO 2. For each compound, the constants of this equation were obtained in such a manner to correlate the solubility at different temperatures and pressures.
The regioselective synthesis of a potent antiviral sugar nucleoside isoxazole analogue in the [3+2] cycloaddition (32CA) reaction of acetonitrile-N-oxide (ANO) and acetyl-protected 5-ethynyl-2'-deoxyuridine (EDU) has been studied at the... more
The regioselective synthesis of a potent antiviral sugar nucleoside isoxazole analogue in the [3+2] cycloaddition (32CA) reaction of acetonitrile-N-oxide (ANO) and acetyl-protected 5-ethynyl-2'-deoxyuridine (EDU) has been studied at the MPWB1K/6-311G(d,p) level within perspective of the molecular electron density theory (MEDT). From an electron localization function (ELF) analysis, ANO is classified as a zwitterionic species devoid of any pseudoradical or carbenoid centre. The ortho regioisomer is energetically preferred over the meta one by the activation enthalpy of 21.7-24.3 kJ mol-1 , suggesting complete regioselectivity in agreement with the experiment. The activation enthalpy increases from 53.9 kJ mol-1 in the gas phase to 71.5 kJ mol-1 in water, suggesting more facile reaction in low polar solvents. The minimal global electron density transfer (GEDT) at the TSs suggests non-polar character and the formation of new covalent bonds has not been started at the located TSs, showing non-covalent intermolecular interactions from an atoms-in-molecules (AIM) study and in the independent gradient model (IGM) isosurfaces. The AIM analysis shows more accumulation of electron density at the CC interacting region relative to the CO one, and earlier CC bond formation is predicted from a bonding evolution theory (BET) study.