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This study examined the nephroprotective effects of 15 different anthocyanins from the bilberry extract on the acute kidney injury caused by CCl4. The acute nephrotoxicity in rats was induced 24 h after the treatment with a single dose of CCl4 (3 mL/kg, i.p.).The nephroprotective effects of the anthocyanins were examined in the animals that had been given the bilberry extract in a single dose of 200 mg of anthocyanins/kg daily, 7 days orally, while on the seventh day, 3 h after the last dose of anthocyanins, the animals received a single dose of CCl4 (3 mL/kg, i.p.) and were sacrificed 24 h later. When the nephrotoxicant alone was administered, it resulted in a substantial increase of the pro-oxidative (TBARS, CD, H2O2, XO, and GSSG) and pro-inflammatory markers (TNF-α, NO, and MPO), as well as a noticeable reduction of the antioxidant enzymes (CAT, SOD, POD, GPx, GST, GR) and GSH when compared to the results of the control group. Moreover, the application of CCl4 significantly influenced a reduction of the renal function, as well as an increase in the sensitive and specific injury indicators of the kidney epithelial cells (β2-microglobulin, NGAL, KIM1/TIM1) in the serum and urine of rats. The pretreatment of the animals poisoned with CCl4 with the anthocyanins from the bilberry extract led to a noticeable reduction in the pro-oxidative and pro-inflammatory markers with reduced consumption of the antioxidant defence kidney capacity, compared to the animals exposed to CCl4 alone. Anthocyanins have been protective for the kidney parenchyma, with an apparent absence of the tubular and periglomerular necrosis, severe degenerative changes, inflammatory mononuclear infiltrates and dilatation of proximal and distal tubules, in contrast to the CCl4-intoxicated animals. The nephroprotective effects of anthocyanins can be explained by strong antioxidant and anti-inflammatory effects achieved through the stabilization and neutralization of highly reactive and unstable toxic CCl4 metabolites.

In this study, modified sol-gel method was employed to synthesize the pure and Zr-doped titania catalysts. Brunauer-Emmett-Teller (BET) method was applied to determine porosity, X-ray diffraction (XRD) analysis was used to study crystal structure, scanning electron microscopy (SEM) was used to investigate morphology and Fourier transform infrared spectroscopy (FTIR) was used to examine surface properties/total acidity of the obtained catalysts samples. Photocatalytic activity was tested in the reaction of crystal violet (CV) dye decolourization/degradation under UV light irradiation. The effects of several photocatalysis operational parameters were considered, such as catalyst dosage, initial dye concentrations, duration of UV irradiation treatment, as well as catalysts calcination temperatures and dopant amounts. The obtained results indicated faster dye decolourization/degradation with the increase of the catalyst dosage and the decrease of initial CV concentrations. The Zr-doping affects photocatalytic properties, i.e. CV decolourization/degradation of the prepared catalytic materials. Thus, addition of 5 wt.% of ZrO2 to titania increases photocatalytic effect for ~15% and addition of 10 wt.% of ZrO2 improves the photocatalytic efficiency of titania for nearly 30%.

Heterogeneous catalysis is in recent focus of research for biodiesel production from vegetable oils because of advantages such as easy separation and reuse of catalysts, although homogeneous catalysis is most commonly used method. The aim of this study was preparation of γ-Al2O3 support by modified sol-gel procedure, synthesis of the KI/Al2O3 catalyst and testing its activity in the transesterification of sunflower oil with methanol. Influences of different process parameters on conversion of sunflower oil to methyl esters were examined. The gained results implicate that the potassium iodide incorporation into/onto the structure of γ-Al2O3 significantly influences textural and structural properties of the catalyst. Additionally, the catalyst basic strength is increased and all together those properties are positively affecting the activity of the catalyst in the reaction of transesterification of sunflower oil with methanol. The impregnation of alumina with potassium iodide resulted in the additional formation of basic catalytically active sites. The surface properties of the catalyst have an essential impact on its catalytic performance. Under relatively mild process conditions and relatively short reaction time, the usage of the KI/Al2O3 catalyst resulted in very high conversion to fatty acids methyl esters (i.e. 99.99 %). [Projekat Ministarstva nauke Republike Srbije, br. 172061 i br. TR 34008]

A new biosorbent, abbreviated as LVB-ZrO₂, was synthesized by chemically modifying Lagenaria vulgaris shell with ZrO₂. The removal of textile dye RB19 from aqueous solution by LVB-ZrO₂was studied. Characterization by SEM, FTIR and XRD confirmed the chemical modification of the biomaterial, which showed significant improvement of removal efficiency compared with unmodified Lagenaria vulgaris shell. LVB-ZrO₂point of zero charge is 5.49. The biosorption process is highly pH dependent and the optimal pH is 2.0, at which complete dye removal was attained. The results are the best by a pseudo-second order kinetic model. The optimal adsorbent dosage is 4 mg/dm³.The RB19 biosorption follows the Langmuir isotherm model (R² = 0.9978), with the maximum sorption capacity of 75.12 mg/g. LVB-ZrO₂is a mechanically stable, easy to synthesize, cost-effective, biocompatible and environmentally-friendly biosorbent with the high potential for the removal of RB19 from aqueous solution.

Three types of functional ceramic composites were designed, synthesized and probed for effective sulfide removal from aqueous solutions. The main goal was to examine complex influence of graphite, surpluses of Fe (similar to 4%) and micro-additions of Cu (similar to 0.2%) on the functional features of the composites. The structural, textural, morphological and surface characteristics of the composites were examined in detail by XRD, nitrogen sorption, SEM and FTIR. It has been shown that all composites are solid heterogeneous systems containing amorphous and crystalline phases (graphite, hematite, montmorillonite, quartz, etc.) with pronounced redox activity in contact with sulfide aqueous solutions. Great enhancment of sulfide consumption was detected for composites which contained graphite and it was established that reaction kinetics is fitted to irreversible second-order batch reaction with two reactants. After the treatment of 1 mM S2- solution, using composite dossage of 1 g/dm(3), concentration dropped down to 0.02 mM. In addition, cyclic voltammetry at 50 mV/s revealed the key role of dopants in electrochemical aspect of the process. Obvious boost of S2- uptake is ascribed to numerous electrochemical, chemical and sorption processes on the composite's developed surface.

Titanium dioxide, as environmental (decontamination) photocatalyst, is increasingly gaining importance in the removal of organic pollutants from water and air, as well. Different methods can be used for obtaining TiO2 catalyst, but sol-gel and hydrother­mal methods are most commonly used for the synthesis and modification of TiO2. The properties of nanostructured materials such as crystal phase, surface features and electronic structures can be changed with doping. In this paper, the influence of Fe and Zn as dopants on the physico-chemical properties of TiO2 catalyst will be presented based on the reported literature data. Usually applied instrumental tech­niques for the materials characterizations are X-ray diffraction (XRD), SEM, TEM, FTIR and UV-vis spectroscopy. The removal efficiency of various organic pollutants (organic dyes, antibiotics, pesticides, xenobiotics) is determined by the characteristics and dosage of the catalyst, nature and initial concentration of pollutants.

Spider silk fibers, collected from Pholcus Phalangioides spider were used as a template for obtaining magnesium oxide (MgO, periclase) as well as magnesium hydroxide (Mg(OH)2, brucite) fibers. Magnesium oxide fibers were obtained in a simple manner by heat induced decomposition of magnesium salt (MgCl2) in the presence of the spider silk fibers, while magnesium hydroxidefibers were synthesized by hydration of MgO fibers at 50 °C, 70°C and 90 °C, for 48 and 96 h. According to Scanning electron microscopy (SEM), dimensions of spider silk fibers determined the dimension of synthesized MgO fibers, while for Mg(OH)2 fibers, the average diameter was increased with prolonging the hydration period. The surface of Mg(OH)2 fibers was noticed to be covered with brucite in a form of plates. X-ray diffraction (XRD) analysis showed that MgO fibers were single-phased (the pure magnesium oxide fibers were obtained), while Mg(OH)2 fibers were two- or single-phased brucite depending on incubation period, and/or incubation temperature. Vlakna paukove mreže sakupljena od Pholcus phalangioides pauka korišćena su kao matrica za dobijanje vlakana magnezijum oksida (MgO, periklas) i magnezijum-hidroksida (Mg(OH)2, brucit). Vlakna magnezijum oksida jednostavno su dobijena termičkim razlaganjem soli magnezijuma (MgCl2) u prisustvu vlakana paukove mreže, dok su vlakna magnezijum hidroksida sintetisana hidratacijom MgO vlakana na temperaturama: 50, 70 i 90 °C u trajanju od 48 i 96 h. Na osnovu rezultata skenirajuće elektronske mikroskopije (SEM), veličina sintetisanih MgO vlakana bila je određena dimenzijama vlakana pauka, dok je za Mg(OH)2 vlakna prosečan dijametar rastao sa produženjem perioda hidratacije. Na površini Mg(OH)2 vlakana uočeni su tabličasti kristali brucita. Difrakcija X zraka (XRD) pokazala je da su vlakna periklasa jednofazna (dobijen je čist magnezijum-oksid), dok su brucitna vlakna bila dvofazna ili jednofazna, u zavisnosti od inkubacionog perioda i/ili teperature na kojoj je vršena inkubacija.

Spermatogenesis is a dynamic process that is regulated by adhesive interactions between germ and Sertoli cells. Germ cells express the Junctional Adhesion Molecule-C (JAM-C, encoded by Jam3), which localizes to germ/Sertoli cell contacts. JAM-C is involved in germ cell polarity and acrosome formation. Using a proteomic approach, we demonstrated that JAM-C interacted with the Golgi reassembly stacking protein of 55 kDa (GRASP55, encoded by Gorasp2) in developing germ cells. Generation and study of Gorasp2-/- mice revealed that knock-out mice suffered from spermatogenesis defects. Acrosome formation and polarized localization of JAM-C in spermatids were altered in Gorasp2-/- mice. In addition, Golgi morphology of spermatocytes was disturbed in Gorasp2-/- mice. Crystal structures of GRASP55 in complex with JAM-C or JAM-B revealed that GRASP55 interacted via PDZ-mediated interactions with JAMs and induced a conformational change in GRASP55 with respect of its free conformation. An in silico pharmacophore approach identified a chemical compound called Graspin that inhibited PDZ-mediated interactions of GRASP55 with JAMs. Treatment of mice with Graspin hampered the polarized localization of JAM-C in spermatids, induced the premature release of spermatids and affected the Golgi morphology of meiotic spermatocytes., Author summary Spermatogenesis defects are a common cause of male sterility. Spermatogenesis occurs in the seminiferous tubules of the testes and involves adhesive interactions between developing germ cells and Sertoli cells. Knock-out mouse models identified several adhesion molecules that are critically involved in spermatogenesis. We previously demonstrated that the Junctional Adhesion Molecule-C (JAM-C) plays a crucial role in establishing spermatids polarity. The latter involves rearrangements of the Golgi apparatus in spermatids which contribute to acrosome formation. The present study demonstrated that the C-terminal cytosolic region of JAM-C interacted with the Golgi reassembly stacking protein of 55 kDa (GRASP55) encoded by Gorasp2 and that spermatogenesis was impaired in Gorasp2-deficient mice. We developed an inhibitor of GRASP55 interaction with JAM-C and demonstrated that treatment of wild-type mice with the inhibitory compound induced germ cell loss. Therefore, the male infertility-associated pathway identified in this study is important not only from a genetic point of view, but also as a potential target for male contraception.

This paper deals with synchronised influences of hydromechanical and hidrochemical parameters on the formation of solid deposits in geothermal and other waters which compose complex heterogeneous and micro-heterogeneous system of liquid-solid. Constituents of these waters in ionic, colloidal and micro-heterogeneous suspended state of liquid-solid are responsible for the creation of the carbonates, sulphates and other solid matters. In these processes one cannot eliminate the influence of hydromechanical parameters with flow velocity and water flow criteria (laminar or turbulent flow) as vital factors. Experiments were conducted on the laboratory pilot installation with glass pipes diameter of 2, 4, 6, 8 and 10 mm respectively, and the flow was monitored by means of digital peristaltic pump with the flow rate of 2 ml/min to 5000 ml/min. The paper gives the results of the investigation of the impact of the linear flow velocity on the relative decrease of the initial water hardness in geothermal waters of Sijarinska Banja spa, Niska Banja spa and the estuary water of Medijana, Nis. From the obtained dependences, according to the linear regression model, for each diameter critical values for linear velocities as an important parameter for the understanding of the synergism of the hydromechanical and hydrochemical parameters were determined. [Projekat Ministarstva nauke Republike Srbije, br. 33046]

The influence of the physicochemical properties of a series of CaO catalysts activated at different temperatures on the biodiesel production was investigated. These catalysts show dissimilar yields in the transesterification of triglycerides with methanol. We have found significant relationships between structural properties (the type of the pore system, the typical CaO crystal phase and the sizes of crystallites (up to 25 nm), the minimal weight percentage of CaO phase, the total surface basicity and potential existence of two types of basic active sites) of CaO prepared and activated by means of thermal treatment at highest temperature and catalytic efficiency. Benefits of this catalyst are short contact time, standard operating temperature and atmospheric conditions, relatively low molar ratios and small catalyst loading. These all together resulted in a very high biodiesel yield of high purity. The properties of different biodiesel (obtained with the use of the prepared CaO catalyst) blends with different diesel and biodiesel ratios indicate that the higher the fraction of biodiesel fuel the better the achieved fuel properties according to the EU standards. A significant reduction of CO2 and CO emissions and only a negligible NOx increase occurred when blends with an increased biodiesel portion was used. The use of biodiesel derived blends, and the eventual complete replacement of fossil fuels with biodiesel as a renewable, alternative fuel for diesel engines, would greatly contribute to the reduction of greenhouse gases emissions. [Projekat Ministarstva nauke Republike Srbije, br. ON 172061 i TR 34008]

Sorption characteristics of three Lagenaria vulgaris-based biosorbents: raw biomass (rLVB), acid–base-activated biomass (aLVB) and sulfuric acid-treated biomass (ccLVB), were compared as a function of contact time, initial methylene blue concentration, and initial pH, in order to evaluate the effect of chemical modifications. The adsorption studies of raw and chemically modified L. vulgaris biomass were compared in batch mode. The Fourier transform Infrared spectroscopy (FTIR) results of biosorbents’ characterization showed presence of different functional groups which can be responsible for sorption of MB from aqueous solutions. Moreover, FTIR analysis reveals that acid–base activation of raw biomaterial resulted in hydrolysis of esters providing more reactive sites (–COO−), while sulfuric acid-treatment method introduced new functional groups such as –SO3−. Surface functional groups containing oxygen, such as carboxylic, lactonic, and phenolic, are quantified using the Boehm’s method. The kineti...

Nanosized Mg-doped ceria powders were obtained by self-propagating room temperature reaction without using surfactants or templates. X-ray diffraction analysis and field emission scanning microscopy results showed that the doped samples are solid solutions with fluorite-type structure and spherical morphology. Raman spectra revealed an increase in the amount of oxygen vacancies with the increase of Mg concentration. This increasing results in a narrowing of the bandgap of CeO2. The photocatalytic performances of the Mg-doped ceria solid solutions were evaluated by decomposing an organic dye, crystal violet under UV irradiation. The Mg-doped ceria solid solutions exhibit significantly better photocatalytic activity than the pure CeO2 and commercial TiO2. The higher first rate constant of the Mg-doped samples demonstrated that they are much more efficient than TiO2 and CeO2 under UV light. Mg2+ dopant ions and oxygen vacancies play a significant role in the enhancement of photocatalytic performances of the Mg-doped ceria.

Serpentinite rock collected near Kopaonik Mountain in Serbia is considered as a multiphase assemblage mostly consisting of mineral lizardite. Forsterite has been obtained by chemical-thermal treatment of grounded sample of serpentinite. Electrochemical features of these two materials were investigated by using modified carbon paste electrode (CPE) which included mixing analytes, graphite powder and parafin oil as a binder and packing the mixture in a Teflon holder. Morphological and structural characteristics of the samples were analyzed by SEM and XRD techniques which revealed presence of certain crystal phases and agregates of irregular shapes sized from 10 to 40 μm. Cyclic voltammetry was employed to study their electrochemical characteristics. The peak current height and peak-to-peak separation showed that the electrochemical reaction is quasi-reversible. Kinetic parameters were derived from Tafel analysis. Calculated kinetic parameters indicated prominent electrocatalytic effect of the minerals for ferri/ferro cyanide redox reaction in aquaeous solution Book Of Abstracts of 4th Conference of The Serbian Society for Ceramic Materials

This paper presents a complete characterization of rapeseed oil, of Banaćanka variety, as well as the potential use of oil generated after filtering, in order to obtain biodiesel. Researches are based on the fact that Banaćanka is the oldest domestic rapeseed variety, the so-called double zero "00" (low in erucic acid, below 5%, and glucosinolates below than 30 mmol g-1), suitable for use in the region, since it is low temperatures tolerant, posseses high genetic potential for seed yield of about 5.2 t/ha, and high oil content of around 45%. Transesterification was carried out in batch reactor Parr 4520, with KOH as a catalyst. Cold pressed oil without prior treatment was used as feedstock for transesterificataion. The paper analyses the effects of temperature, reaction duration, catalyst amount and rate of agitation on the synthesis of biodiesel at constant pressure and molar methanol/oil ratio.[Projekat Ministarstva nauke Republike Srbije, br. TR-31046: Improvement of the quality of tractors and mobile systems with the aim of increasing competitiveness and preserving soil and environment]

Adsorption of a cationic phenothyazine dye methylene blueonto activated carbon prepared from pine cones was investigated with the variation in parameters of contact time, dye concentration and pH. The kinetic data were found to follow the pseudo-second-order kinetic modelclosely. The equilibrium data were best represented by the Langmuir isotherm with maximum adsorption capacity of 233.1 mg g-1. Adsorption was favored by using a higher solution pH. Textural analysis by nitrogen adsorption was used to determine specific surface area and pore structure of the obtained carbon. Boehm titrations revealed that carboxylic groups are present in the highest degree on the carbon surface. The results indicate that the presented method for activation of pine cones could yield activated carbon with significant porosity, developed surface reactivity and considerable adsorption affinity toward cationic dye methylene blue.

Two series of zirconia based catalysts promoted with either sulfates or phosphates were prepared, calcined at different temperatures (600 and 700?C) and evaluated for the n-hexane isomerization reaction. The catalysts with different concentrations of sulfates or phosphates (4 or 10 wt. %) were characterized by BET, XRD, SEM methods, and total acidity was evaluated by using the Hammett indicators. Their final catalytic performances were correlated with their physical-chemical properties (surface, structural, textural and morphological). It was found that sulfated zirconia catalyst calcined at lower temperature showed the highest initial activity of all tested catalysts as the result of favorable total acidity, mesopore texture and structural properties. Somewhat lower activity of the sulfated catalyst calcined at higher temperature is related to the content of acid groups partially removed during thermal treatment, thus, lower total acidity, and also to less favorable textural and structural features. Negligible activity of phosphated zirconia catalysts is connected with low total acidity despite the positive status of particular property showing the complexity of the active phase/site formation in the catalyst.

Bentonite is mainly composed of clay minerals from smectite group, therefore it has a well developed and chemically active surface area and high cation exchange capacity. Moreover, an interlayer space of smectite has unusual hydration properties, which manifest as swelling of bentonite in water. These properties make bentonite as a commonly used raw material in chemistry and industry, and it is very important in environmental protection and water treatment as an effective sorbent of heavy metals. The results of X-ray diffraction, a cationic exchange capacity, specific surface area, acid-base properties of the surface and the swelling index showed that the bentonite sample contains mostly montmorillonite. The aim of this study was to test the efficacy of bentonite in the removal of Mn2+ from aqueous systems. The experimental results of Mn2+ adsorption on the bentonite were interpreted by Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherms. The adsorption isotherm studies indicate that the adsorption of Mn2+ follows Langmuir isotherm very well. Theoretical monolayer saturation capacity according to Langmuir model was 12.41 mg/g. The removal of Mn2+ is achieved by ion exchange mechanism with naturally occurring cations in bentonite, as well as by forming the inner- and outer-sphere complexes with bentonite surface.

The heavy metals (Fe, Cu, Zn and Mn) contents of selected plant species, grown in Southeast region of Serbia, that are traditionally used in alternative medicine were determined. Among the considered metals, iron content was the highest one and varied from 137.53 up to 423.32 mg/kg, while the contents of Cu, Zn and Mn were remarkably lower, and ranged from 8.91 to 62.20 mg/kg. In addition, an analysis of plants extracts showed a significant transfer of heavy metals during extraction procedure; therefore, the corresponding extraction coefficients reached values up to 88.8%. Those were especially high in the ethanol based extracts. Moreover, it is established that such coefficients mostly depend on the solvent nature and also on the treated plant species. The obtained results impose that medicinal plants from Southeast region of Serbia due to rather low content of heavy metals are appropriate for preparation of teas and medicinal extracts.

Cones of the European Black pine and Horse chestnut kernel, regarded as brown municipal waste, was utilized in this work as a precursor for powdered activated carbons. Chemical activation was employed at 500?C in inert atmosphere of nitrogen. Standard physico-chemical analyses were performed to examine obtained products. FTIR method was employed to determine fuctional groups which were found to be typical for activated carbons. Acidic oxygen groups were quantitatively determined using Boehm titrations. It was established that carboxylic groups on pine cone activated carbon, and phenolic groups on chestnut kernel activated carbon were dominant from all acidic oxygen groups. Since both contact pH and pHPZC were determined to be fairly acidic, it could be concluded that obtained activated carbons belong to L-type. Shape and layout of micrometer dimensioned particles were observed by scanning electron microscopy. Particles of different shapes and dimensions along with small cracks and wide crevices and voids were noticed. Textural analysis was used to determine specific surface area and pore distribution of obtained activated carbons. Obtained products possess highly developed surface area and wide pore distribution.

Fruits and vegetables constitute the cheapest source of essential trace elements for the majority of people living in developing countries. The Cu, Fe and Zn contents in twenty selected wine samples produced in the South-East region of Serbia were determined by flame atomic absorption spectrometry. The Cu concentrations varied from 0.07 to 0.57 ppm in wines, and the Fe concentrations fluctuated from 2.93 to 36.2 ppm, while the Zn levels were in the range from 0.21 to 0.67 ppm. The established contents of Cu and Zn showed that wines from this part of the world could serve as good dietary sources of the essential trace metals, and the determined values were within the allowed me¬tals levels in wines for human consumption.

Fruits and vegetables constitute the cheapest source of essential trace elements for the majority of people living in developing countries. The Cu, Fe and Zn contents in twenty selected wine samples produced in the South-East region of Serbia were determined by flame atomic absorption spectrometry. The Cu concentrations varied from 0.07 to 0.57 ppm in wines, and the Fe concentrations fluctuated from 2.93 to 36.2 ppm, while the Zn levels were in the range from 0.21 to 0.67 ppm. The established contents of Cu and Zn showed that wines from this part of the world could serve as good dietary sources of the essential trace metals, and the determined values were within the allowed metals levels in wines for human consumption.

Macrophages are central players in both lipid metabolism and innate immunity. Their determinant role in the pathogenesis of atherosclerosis is under the control of the ATP-binding cassette transporter (ABCA1), which by minimizing cellular lipid content, limits development of pro-inflammatory foam cells. Considering the differential contribution of monocyte subsets to the generation of vascular lesions we analyzed the immunophenotype of ABCA1-expressing cells in the myeloid lineage, by the combined use of flow cytometry and real-time quantitative RT-PCR. ABCA1 expression is limited to "non-inflammatory" Ly6C(lo) circulating monocytes and tissue-resident macrophages expressing markers of alternative activation. In ABCA1(-/-) peritoneal macrophages the transcriptional programs induced by LPS/IFN-gamma or IL-4 cytokines are altered and deviated phosphorylation patterns of STAT transcriptional regulators in response to stimuli are observed.

Medical diagnostics and therapy use an extensive amount of electronics, optoelectronics, and laser devices. For their reliable functioning, calibration is unavoidable. Biochemical analyzers, which work on principles of absorptional spectrophotometry, became most widely present in medical biochemical laboratories. Construction of these devices is such, that in most cases, it does not allow calibration by usual methods, using neutral density (ND) filters as standards. For this reason, it was necessary to create a solution that could be used as a mean of comparison or even as a standard solution for methods of calibration of biochemical analyzers. In this article, the metrological characterization of solutions that are developed is presented, and the measuring uncertainty (ISO 1993) of methods used for calibration is estimated. The method that is developed provides metrological traceability to the primary spectrophotometric standard. With this method, metrological assurance in the field of the spect...

Using sulfuric acid as the sulfating agent, two catalyst series were obtained from hydroxide and nitrate precursor with a sulfate loading identical to commercial sulfated hydroxide, i.e., 4.2 mass%. After calcination at 500, 600 and 700?C, all nine samples had various contents of residual sulfates depending on the origin of the catalyst. Accordingly, their surface properties were different, which, together with various textural properties, govern the formation of the active phase and their catalytic activity in the n-hexane isomerization reaction. The dominant activity and yield of mainly mono-branched isomers were attained in reaction at 200?C with a commercially sulfated zirconia catalyst calcined at 500?C. Among the SZ catalyst series synthesized from hydroxide and nitrate, the second according to its activity profile was similar to that of the commercially sulfated one, while samples originating from hydroxide showed some activity only after calcination at 600?C. This is due to the poorer textural properties of the hydroxide series, necessitating a higher calcination temperature in order to promote the simultaneous decomposition of S-containing species and their re-adsorption into the zirconia matrix following interaction and active phase formation. It seems that the tetragonal zirconia phase was not responsible for the catalytic activity but a synergistic effect of the textural properties of the samples and the sulfate loadings, which determine different acid strengths on the catalyst surface.

Spider silk poses excellent mechanical properties, tenacity and elasticity and it has been used as a template for calcite mineralization to improve load bearing strength of osteoconductive calcite. The samples were obtained by mimicking biomineralization for five days in order to follow formation and growth of calcite on the surface of spider silk. Crystal phase was detected by XRD and FTIR spectroscopy. Microstructure, crystal size and its morphology were studied by means of FESEM. After two days of processing, pure calcite phase was obtained, and a size of the formed crystals increased with prolongation of biomineralization.

Magnesium-orthotitanate (Mg2TiO4) nano-powder was synthesized using a Pechini-type polymerized complex route. Microstructural characterization involving transmission electron microscopy, X-ray diffraction analysis and nitrogen adsorption-desorption isotherms indicated that well-crystallized Mg2TiO4 nanoparticles are small in size (about 10 nm) with large specific surface area (72 m(2) g(-1)). The surface modification of Mg2TiO4 nano-powders with 5-amino salicylic acid and catechol induced a significant shift of absorption to the visible spectral region due to charge transfer complex formation. It should be emphasized that tunable optical properties of Mg2TiO4 nano-powders have never been reported in the literature. Degradation reactions of an organic dye (crystal violet) were used to test the photocatalytic ability of pristine and surface-modified Mg2TiO4 nano-powders under illumination in different spectral regions. Excitation with UV light indicated, for the first time, photocatalytic ability of Mg2TiO4. Also, improved photocatalytic performance of surface-modified Mg2TiO4 nano-powders was found in comparison to unmodified ones.

The preparation of y-Al2O3 catalyst support by the modified hydrothermal method and synthesis of KI/y-AI203 catalyst, as well as the investigations of their activities in the reaction of transesterification of sunflower oil were performed in this study. The effect of various process parameters on the transesterification reaction of sunflower oil with methanol and their impacts on the reaction conversions were examined. The y-Al2O3 support and KI/y-AI203 catalysts were characterized by BET, XRD and SEM methods. The physico-chemical properties (surface, textural, structural and morphological) of the catalyst were correlated with its catalytic efficiency. The obtained results implicate that textural and structural properties of the catalyst and also the catalyst activity in the reaction of transesterification essentially depend on textual and structural properties of the y-Al2O3 support. From the optimization of the process parameters, it was found that the optimal conditions for transesterification reaction are: molar ratio of methanol to oil 12:1; stirring speed 600 rpm; the reflux temperature of methanol; the reaction time 5h; the amount of catalyst in the reaction 3 wt.%.

Preparation, characterization and application of materials modified with TiO2 nanoparticle have been reviewed. Chitosan, bacterial biomass and dendrimers were the starting material for modification. Sorbents characterization was performed by scanning electron microscopy (SEM). In order to investigate the sorption capabilities of sorbents, we used them for removal of heavy metal ions from aqueous solution. The effect of contact time on heavy metal ions sorption and maximum sorption capacities of biosorbents are shown. As a very important parameter of the sorption process, the effect of initial pH values on heavy metal removal was examined. This paper indicates that sorption using the material modified with TiO2 is becoming a promising alternative to conventional adsorbents in removing heavy metal ions.

Due to its biocompatibility, biodegradability, hydrophility, technological properties and vast availability, polysaccharides are widely used as natural non-toxic polymers in different branches of industry (food, cosmetic, textile, construction industries). Exopolysaccharides (as dextran, pullulan) have recently taken up a significant position in pharmaceutical industry. Alginate has an irreplaceable role in biomedicine, since its hydrogel form is successfully applied for immobilization of a wide range of enzymes, therapeutics, biochemical agents and different kinds of microorganisms and cells (herbal, animal or human). Alginate microspheres and microcapsules are used for controlled release of biologically active molecules, as well as cell carriers in tissue engineering. Special benefits are brought by the simplicity of configuration of alginate hydrogel, including the possibility of the controlled production of micro- and nanoparticles. Taking into account a very important role of alginates in the form of hydrogel in biomedicine, in this paper a specific attention is paid on the preparation and application of alginate matrices, microspheres and microcapsules that may have essential and unexchangeable usage/application. This paper therefore displays various possibilities of use of polysaccharide matrices for biomolecules, polysaccharide as excipients of pharmaceutical products for oral or local application, and provides a review of the examples of innovative applications.