Modern life and contemporary materials have brought ubiquitous microplastic particles into our surroundings. Many researchers have focused their research towards investigating sources, pathways, ...toxic effects and mitigation possibilities of microplastic pollution. One of the most abundant types of microplastics is microplastic fibers, mainly released from synthetic clothes. This study investigates the possibility of identifying microplastic fibers released from textiles during the laundry washing cycle by Fourier-transform infrared spectroscopy (FTIR). Microplastic fibers released from some types of synthetic clothes during the laundry washing cycle at 40°C were collected and analyzed. Thanks to FTIR spectroscopy, it has been proven that a certain amount of microplastics is separated every time synthetics are washed.
The article researches the transformation of the urban planning institutional structure in the period of the post-socialist transition in Serbia. The goal is to provide an insight into the path of ...how urban planning has been modified due to structural changes in the socio-economic and political system in the period from 2000 to the present day. The focus of the research is the change in the role and position of institutions in decision-making processes on urban development, and especially the instruments used in those processes. Through a chronological review of the urban plans of New Belgrade blocks on the Sava Quay, several aspects of the planning process are observed: (a) changes in the planned uses of areas, (b) changes in the participation of institutions in the planning process and (c) changes in the instruments used in the planning process. The results of the research show that during the two decades of the post-socialist transition, urban planning was transformed in the direction of: (a) becoming a key instrument for the redistribution of spatial resources in favor of the interests of private capital; (b) the centralization of decision-making - vertically through the expanded influence of higher levels of government, and horizontally by the concentration of power within the group of decision-makers at the city level; and (c) the elaboration of decision-making mechanisms at the very end of the planning process and within a narrow circle of city government institutions, using the institute of amendments.
This paper investigates the General urban plan (GUP), as a traditional planning instrument that can respond to the challenges of the contemporary social context. Given that in 2019 a decision was ...made to develop a new GUP of Belgrade, which should offer a strategic spatial and urban solution based on the principles of social, economic, environmental and cultural sustainability to be developed in the coming decades, the question is what is and what should be the GUP and what should it look like, but perhaps most importantly - what can be included in the GUP be today? The role and scope of the General urban plan are explored from two aspects. In the first, the role of the GUP is analyzed within the institutional framework - the Law on planning and construction and the Law on the planning system of the RS, which was adopted in 2018, as well as their connection, interaction and the possibilities that arise from it. In the second step, the scope of the GUP is explored through an assessment of contemporary planning practice in Belgrade, with the General plan of Belgrade 2021 adopted in 2003 as its cornerstone, and then analyzing the changes in planning that occurred through its further implementation and detailed elaboration. While the strategic role of the GUP is increasing with the possibility of connecting both planning systems, in practice its importance and scope are continuously weakening, leaving the planned growth and development of Belgrade to the economic interests related to individual locations.
Microplastics have reached all corners of our planet, including soil and water. Plastic-degrading bacteria are seen as a promising, environmentally friendly tool for the bioremediation of soil ...polluted with microplastics. The petroleum origin of plastics makes them candidates for bioremediation analogous to the bioremediation of soil polluted with oil and its derivatives. A mud pit, located near the village of Turija, used for mud formation for the lubrication of drill pipes for drilling rigs, ended up polluted with oil and its derivatives. It was bioremediated using the in situ procedure. The content of n-hexane extractable substance, total petroleum hydrocarbon, dry substance, and loss on ignition were analyzed.
The scientific studies on drug delivery systems that transport drugs to the targeted tissues, at a certain rate and desired time intervals, have gained popularity. The main goal of the drug delivery ...and release systems is to maintain the drug level in the blood plasma by balancing the amount of active ingredient. In this study, pH and temperature sensitive drug carriers were prepared using chitosan as a biopolymer and clay as a natural material. The characterization of the prepared materials was performed for structural analysis by FT-IR and for morphological analysis by SEM instruments. The swelling properties of the prepared materials were investigated. In this work, Ranitidine-HCl was used as a model drug. The prepared drug carriers were first loaded with Ranitidine-HCl and release properties of the materials were investigated at two different temperatures (25oC, 37oC) and various pH medium. The data obtained from the experiments indicated that the maximum release of Ranitidine–HCl from the prepared sample was observed at pH=7,6 buffer solution at both temperatures by comparing buffer solutions. It has been shown that the materials prepared in this study are suitable carriers for the Ranitidine-HCl drug active ingredient.
A series of polyurethanes (PU) were synthesised via one-step polymerisation without a chain extender, using toluene diisocyanate as well as a variety of soft segments composed of different ...macrodiols. Poly(D,L-lactide) (PDLLA) and polycaprolactone diol (PCL) were synthesised as a polyester type polyols to obtain soft segments. The process of varying the molar ratio of newly synthesised PDLLA in soft segments has been confirmed as a powerful tool for fine-tuning the final properties of PU. Fourier-transformed infrared spectroscopy was used for evaluation of molecular structures of synthesised PDLLA polyol and final PU. Nuclear magnetic resonance spectrometry was used to confirm the presumed structure of PU. The influence of soft segment composition on polyurethane thermal characteristics was examined using thermogravimetric analysis and differential scanning calorimetry. The composition of soft segments had little impact on the thermal stability of PU materials, which is explained by the comparable structures of both polyester polyols. Wide-angle X-ray scattering was utilised to evaluate the effect of amorphous PDLLA on the degree of crystallinity of PCL in soft PU segments. It was discovered that not only did the PDLLA ratio in the soft segment have a substantial influence on the degree of microphase separation in the soft and hard segments, but it also influenced the crystallisation behaviour of the materials. Furthermore, the restriction of crystallisation of the PCL soft segment has been verified to be dependent on the hard segment concentration and the ratio of PDLLA/PCL polyols. The sample with pure PCL as the polyol component achieved the highest degree of crystallinity (34.8%). The results demonstrated that the composition of soft segments directly affected the properties of obtained polyurethane films. These results can be utilised to easily achieve a desirable set of properties required for application in biomaterials.
Clays are widely used in controlled drug delivery systems due to their strong adsorption properties and natural origin. In this study, a drug carrier was prepared using chitosan, a natural polymer, ...mixed with bentonite clay. Then, poly(acrylic acid) was added to improve its swelling properties. Pantoprazole was chosen as the model drug. The swelling properties of the prepared samples were investigated at two different temperatures: 25 and 37 °C. The prepared samples were examined by Fourier-transform infrared spectroscopy and scanning electron microscopy. The controlled release of the pantoprazole from the drug carriers indicated that the release of the pantoprazole is temperature-sensitive. In order to study the effect of bentonite on the drug carrier system, drug release was also investigated in the samples without adding clay. It was observed that the drug release profiles of the prepared sample containing bentonite fitted better than the sample without clay. The release kinetics analysis showed that the first-order and the Korsmeyer-Peppas models fit the best, and that pantoprazole was transported via Fickian diffusion. The prepared samples showed the capability of pantoprazole loading and, thus, its possibility to be used in drug delivery systems.
An active packaging based on the composite film was developed by incorporation of oregano oil as an antimicrobial agent into a cellulose acetate/polycaprolactone diol blend (CA/PCL-diol). A novel ...plasticizer based on polyethylene terephthalate (PET) glycolysis product (bis(hydroxyethyl terephthalate)) and tartaric acid was synthesized and its influence on the structural, surface, mechanical, barrier, and thermal properties were investigated. The obtained results have shown that plasticizer also has a compatibilizing effect, improving the miscibility of polymers in a blend. A sample with the optimal amount of plasticizer (30 wt%), as well as the best mechanical and barrier properties, was used for the preparation of series with different amounts of oregano oil (3, 6, and 9 wt%). The synthesized azo dye—5-(4-bromo-phenyl azo)-3-amido-6-hydroxy-4-methyl-2-pyridone, soluble in acetone, as well as a blend and plasticizer, has been shown as an adequate one for this composition, due to its ability to achieve a good pigmentation in a low amount (0.3 wt% per polymer blend weight), to absorb UV light, and decrease the aging of the material. Contemporary lifestyle has imposed a need for ready-to-eat (RTE) meals which saves consumers time. RTE food packaging should meet certain requirements such as the ability to prolong shelf-life and preserve the freshness of the food product, and at the same time to make a minimal amount of waste after usage, considering the fact that it is mostly single-use plastic food packaging. Optimal mechanical properties, biodegradability, and additional functions make these films suitable for the packaging of ready-to-eat (RTE) food such as fresh salad.
The hydro-geomorphological background in microplastic (MP) deposition and mobilization is often neglected, though the sampling environment is the key point in a monitoring scheme. The aim of the ...study was to analyze the environmental driving factors of MP transport over three years (2020–2022) along a 750 km-long section of the Tisza River, Central Europe. The mean MP content of the fresh clayey sediments was 1291 ± 618 items/kg in 2020, and then it decreased (2021: 730 ± 568 items/kg; 2022: 766 ± 437 items/kg). The upstream and downstream sections were the most polluted due to improper local sewage treatment. In 2020, 63% of the sites were hotspot (≥2000 items/kg), but their number decreased to one-third in 2021 and 2022. MP pollution is influenced by highly variable environmental factors. (1) The geomorphological setting of a site is important, as most of the hotspots are on side bars. (2) The tributaries convey MP pollution to the Tisza River. (3) The bankfull or higher flood waves effectively rearrange the MP pollution. (4) The dams and their operation influence the downstream trend of MP pollution in the reservoir. (5) Downstream of a dam, the clear-water erosion increases the proportion of the pristine sediments; thus, the MP concentration decreases.
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