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The bentonite was treated in different ways and the changes in structure were monitored. Acid activation with sulphuric acid of investigated bentonite caused the increase in specific volume of micropore-mesopore. It was shown that activation by acid obtained at a constant temperature and constant period of time provides the possibility to obtain samples of bentonite of searched porosity only by changing the concentration of sulphuric and hydrochloric acid. By thermal activation of bentonite clay in the temperature range 100-1100 0C, samples of desired porosity were acquired. [Projekat Ministarstva nauke Republike Srbije, br. 174007i br. TR 34020]

Organic modification of mineral clay using the monomer ethenyl acetate was performed. The exchange of inorganic interlayer clay cations was achieved using the cationic surfactant Genamine CTAC and Asepsol. Aiming to investigate the influence of organic modifications on adsorptive clay properties, dried composites of clay/ethenyl acetate, with different percentages of clay were soaked in distilled water. The influence of the temperature on the adsorptive properties of organoclays was also followed. The adsorptive properties of the obtained composites of organoclays with Luviskol, Carbopole and purine were investigated along with their capability for removing Pb2+ from water in charged systems. [Projekat Ministarstva nauke Republike Srbije, br. TR 34020, br. 172047 i br. 174007]

Nowadays, climate changes induce deviations in the composition of honey varieties characteristic of a specific geographic region. Therefore, according to Codex Alimentarius for honey, the slight variations in values of determined parameters cannot be strictly regarded as a sign of its adulteration. Here, modified methods are presented for preparing honey samples for inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis and the high-performance liquid chromatography (HPLC) method to use them as fast and reliable methods in the food industry. ICP-OES analysis suggested that all analysed honey samples are natural, and HPLC-DAD (diode-arrray detection) analysis on the flavonoids showed that one sample is probably not natural. Invertase activity showed an overlap with this HPLC-DAD finding but suggested more samples as possibly adulterated, which can be neglected due to possible thermal treatment of those natural samples, causing a decrease in invertase activity. Therefore, results obtained from the analyses of investigated honey samples based on the mineral content, number, and quantity of flavonoids, together with the invertase activity, indicated that the combination of analyses could be a reliable tool for determining the quality of honey samples.

People with Color Vision Deficiency (CVD), which arises as a deformation of the M cones in the eye, cannot detect the color green in the image (deutan anomaly). In the first part of the paper, deutan anomalous is described. After that, the image recoloring algorithm, which enables Deutan CVD people to see a wider spectrum in images, is described. Then, the effect of the Recoloring algorithm on images with inserted watermark is analyzed. An experiment has been carried out, in which the effect of the Recoloring algorithm on the quality of extracted watermark and Recoloring image is studied. In addition, the robustness of the inserted watermark in relation to spatial transformations (rotation, scaling) and compression algorithms has been tested. By applying objective measures and visual inspection of the quality of extracted watermark and recoloring image, the optimal insertion factor α is determined. All results are presented in the form of pictures, tables and graphics.

The traditional maceration technique with a two-step solid-liquid extraction was used in this paper. After the first extraction step, an extract was separated from the exhausted plant material (elderberry flower) and then a plant material was added to the extract. Experimental parameters included different ethanol concentrations (30 %, 60 %, and 90 %), solid-to-solvent ratios (1:15, 1:30, and 1:45 w/v), pH values (3, 7, and 10), and extraction times (15, 30, and 45 minutes), while one-factor-at-a-time (OFAT) was experimental design. The results indicated that the optimal ethanol concentration in the solvent was 60 vol. % for both extraction steps. Increasing the solid-to-solvent ratio from 1:15 w/v to 1:30 w/v resulted in higher (poly)phenol content, with a slight decrease observed at higher ratios. (Poly)phenols content remained consistent in acidic and neutral environments, but decreased at pH 10. While the content of (poly)phenolic compounds increased with longer extraction times, 30 minutes was considered optimal, as further extension did not significantly increase the content. Additionally, it was observed that the content of total (poly)phenols was lower in the second extraction step, suggesting saturation of the solvent after the first extraction..

Digital media has led to significant changes in the behavior of young people. A significant contribution to the further development of the tourism sector is particularly noteworthy. These digital media facilitate the process of making decisions about choosing and planning trips and are an inevitable means of searching, collecting and marketing information and content for members of Generation Z. Social networks significantly simplified the way of communication between users and thus became an easily accessible source of data. Photos, videos, comments as well as reviews or ratings of other travelers are the most frequently searched content formats. Visual representations and recommendations give potential travelers a better idea of what kind of experience they can expect when visiting a particular destination. The essence of recommendations is that they come from other travelers, and this type of content rarely causes suspicion among users, considering that they represent the sharing of their own subjective experience. In order to understand how social media and the content shared on them influence travel planning among Generation Z, research was conducted using the Pearson correlation test on the territory of the Republic of Serbia. The results of the research confirmed the connection between how photos, videos, comments and reviews on social networks have a significant relationship and influence on the search for the necessary information about tourist services through social media. Taking into account the obtained research results, it is possible to adapt and create better content on social networks that will encourage tourists who are members of Generation Z to make a decision. The results of the conducted research can act as an incentive for further analysis of the behavior of members of Generation Z when planning trips with the use of social media, especially if future research is conducted on respondents outside the territory of the Republic of Serbia.

Background/Aim. There is limited data on the frequency of intracranial hemorrhage (ICrH) in the first wave [beta variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] and second wave (delta variant of SARS-CoV-2) coronavirus disease 2019 (COVID-19) pandemic. The aim of this study was to analyze the appearance of ICrH in COVID-19 patients (CP). Methods. Among 505 CP treated at the Special Hospital for Cerebrovascular Diseases “Sveti Sava” intermittently during the 2020–2021 period, ICrH was diagnosed in 76 (15.1%) patients. The available information from the medical records regarding clinical, demographic, as well as radiological data (multislice computed tomography examination of the endocranium) was collected and analyzed. Results. In the first wave, out of 308 CP, 63 (20.5%) were diagnosed with ICrH. In the second wave, out of 1 97 CP, ICrH was diagnosed in 13 (6.6%) patients, which was a statistically significant difference (p < 0.002). There was no statistically significant difference for the presence of hyper-tension (p = 0.271), diabetes mellitus (p = 0.558), and chronic obstructive pulmonary disease (p = 0.794) among CP with ICrH comparing the two waves of the pandemic. However, a statistically significant difference was proven in the frequency of patients with atrial fibrillation and anticoagulant drug therapy (p = 0.021 each). There was no statistically significant difference in the frequency of patients with fever ( p = 0.637), fatigue (p = 0.587), hemiparesis (p = 0.831), respiratory symptoms (p = 0.289), and loss of consciousness (p = 0.247). D-dimer values in the second pandemic wave were statistically significantly lower (p = 0.003). The combination of ischemic stroke and ICrH was six times more common in the second wave (p = 0.003). However, cerebral parenchymal hemorrhage was two times less frequent (p = 0.001) in the second wave but with statistically higher frequencies of multifocal (23.1%) and diffuse type (36.4%) of ICrH (p = 0.007). Combined hemorrhages, as well as subarachnoid and subdural sub-types, were more common in the second wave (23.1% each). Fatal outcomes occurred in 38.1% of patients in the first wave compared to 69.2% in the second wave (p = 0.039). Conclusion. In the first pandemic wave of COVID-19, ICrH in CP was significantly more frequent and D-dimer was singled out in laboratory analyses, the values of which were statistically significantly higher in comparison with second wave. In the second wave of COVID-19, parenchymal ICrH was less frequent and multifocal and diffuse ICrH were more common in CP with ICrH. The mortality rate was very high in the second wave.

Background/Aim. Prostate carcinoma (PCa) is second occurring carcinoma that affects the male population. Although PCa incidence rates are high, most cases have a favorable prognosis, with comfortable long-term life quality. The aim of the study was to compare long non-coding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5) plasma levels between healthy individuals and patients with PCa, and also between PCa patients with different prognostic scores. Methods. The present study included a total of 40 patients with PCa and a control group of 20 healthy individuals. PCa patients were divided into two subgroups (20 patients each) based on the prognostic criteria of the American Joint Committee on Cancer. The patient data were collected and analyzed; lncRNA GAS5 levels were quantified using the re-al-time polymerase chain reaction method. Statistical analysis was conducted using the IBM SPSS Statistics 26.0 computer program (IBM, USA, 2019). Results. The relative quantification of lncRNA GAS5 expression levels showed down-regulation in PCa patients compared to healthy individuals; however, the difference was marginally statistically significant (p = 0.056). With further analysis of the given results, we concluded that the expression level of lncRNA GAS5 was not significantly different in the first patient subgroup and the healthy individuals (p = 0.268). Patients from the second subgroup had significantly lower plasma levels of lncRNA GAS5 than healthy individuals (p = 0.033). The difference in the level of lncRNA GAS5 expression between patients with favorable prognoses (Group 1) and the ones with worse prognostic scores (Group 2) did not indicate statistical significance (p = 0.275). In both Group 1 (p = 0.805) and Group 2 (p = 0.454), the plasma levels of lncRNA GAS5 were not significantly different in comparison to the age (≤ 65 vs. > 65 years). Conclusion. One of the main objectives of PCa research is identifying novel and more efficient biomarkers. Conducted research provides strong evidence about the significance of lncRNAs GAS5 in PCa, as well as the correlation between decreased expression of lncRNA GAS5 and poor prognosis in various tumors.

Background/Aim. Since 2014 and the publication of the results of the first study on the accumulation of gadolinium contrast, we have witnessed a growing body of evidence on the deposition and retention of gadolinium in the brain after the use of gadolinium-based contrast agents (GBCAs). However, there is still no strong clinical evidence of the adverse effects of GBCAs on the brain parenchyma. The aim of the study was to determine the existence of gadolinium deposits in the brain of patients with relapsing-remitting multiple sclerosis after a ten-year follow-up period. During this period, the patients have regularly, each year, undergone magnetic resonance imaging (MRI) with the administration of gadolinium contrast (gadopentetate dimeglumine – Magnevist®) in order to follow the course of the disease. Methods. A cohort of 20 patients was formed for the purpose of this study. The ratio of the values of the signal intensity (SI) of different regions of the brain-to-cerebrospinal fluid (CSF) was com-pared for each patient on the initial MRI examination and the MRI examination ten years later. Results. Frontal cortex-to-CSF (p < 0.01), occipital cortex-to-CSF (p < 0.01), the white matter of the corona radiata-to-CSF (p < 0.01), parietal cortex-to-CSF (p < 0.05), thalamus-to-CSF (p = 0.051), putamen-to-CSF (p = 0.06), and anterior and posterior limb of the capsula interna-to-CSF (p = 0.062) SI ratios increased after multiple gadopentetate administrations. An increase in the absolute values of the T1- weighted (T1W) signal in three-quarters of patients was registered in the frontal and occipital cortex and cerebellar hemispheres. A slightly smaller increase in SI, but still greater than 55–65%, was registered in structures of the parietal cortex, putamen, cornu anterior and posterior of the capsula interna, corpus callosum (CC) splenium, pons, thalamus, nucleus caudatus, substantia nigra, CC genu, and temporal cortex. Conclusion. In the cohort of 20 patients, there was a statistically significant increase in SI in the pre-contrast T1W sequence in the following structures: frontal, parietal, and occipital cortex, as well as supratentorial white matter. This result speaks in favor of the existence of chronic accumulation of gadolinium contrast agent gadopentetate dimeglumine in brain structures.

It is known that the temperature of crystallization during the synthesis of zeolite is one of the most important process parameters. However, during the research work on the synthesis of zeolite 13X and the introduction of this material into regular industrial production, it was noticed that the heating rate of the starting reaction suspension can have an equally important influence. This influence can be so pronounced that a difference of just a few minutes in reaching the crystallization temperature can make a significant difference in product quality, affect the presence of other phases in the crystal, or even determine the direction of zeolite crystallization. Therefore, the aim of this work was to show the influence of the heating rate on the quality of the obtained 13X zeolite powders. The obtained samples were analysed in terms of crystallinity (by X-ray diffraction), chemical composition, granulometry and specific surface area (by Brunauer-Emmett-Teller analysis), and regarding water and CO2 adsorption capacities. Additionally, scanning electron microscopy analysis of the samples showed the morphological characteristics of different 13X zeolite powders. The analysis results of the obtained powders confirmed the influence of the heating rate and helped to define the optimal synthesis parameters i.e. the initial temperature and heating time, that resulted in stable product quality.

Traumatic brain injury is a severe condition frequently complicated with infections, hypermetabolism, and augmented renal clearance (ARC). The ARC is a phenomenon characterized by increased creatinine clearance above 130 mL/min/1.73m2. This phenomenon has been associated with decreased blood concentrations of selected antibiotics, like vancomycin, probably causing treatment failure. Despite ARC's possible fatal consequences in our local medical community, it is rarely assessed. Patient with traumatic brain injury accompanied with secondary infection and augmented renal clearance accompanied with subtherapeutic vancomycin concentrations in the time of treatment is presented. Since concentrations of antibiotics are not routinely measured in Serbian hospitals, clinical practice adjustment and widely accepted method of antibiotics blood concentration measurement which is particularly important in critically ill patients is suggested. The clinical pharmacologist is a significant team member for the treatment of critically ill patients due to his/her expert knowledge of pharmacokinetics and drug interactions, especially important in this category of patients, contributing to positive clinical outcomes.

Background/Aim. About 1.8 million new lung cancer cases are diagnosed worldwide every year, and about 1.6 million cases have a fatal outcome. Despite improvements in treatment in the previous decades, the survival of patients with lung cancer is still poor. The five-year survival rate is about 50% for patients with localized disease, 20% for patients with regionally advanced disease, 2% for patients with metastatic disease, and about 14% for all stages. The median survival of patients with untreated non-small cell lung carcinoma (NSCLC) in the advanced stage is four to five months, and the annual survival rate is only 10%. The aim of the study was to determine the results of treatment with concomitant chemoradiotherapy (CHRT) in terms of efficacy and toxicity in selected patients with advanced inoperable NSCLC. Methods. The study included data analysis of 31 patients of both sexes who were diagnosed and histopathologically verified with NSCLC in inoperable stage III and were referred by the Council for Malignant Lung Diseases to the Radiotherapy Department of the Military Medical Academy in Belgrade, Serbia for concomitant CHRT treatment. Upon expiry of the three months from the performed radiation treatment (RT), the tumor resonance was assessed based on multislice computed tomography (MSCT) examination of the chest and upper abdomen according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. According to the same criteria, progression-free survival (PFS), as well as overall survival (OS), was assessed every three months during the first two years, then every 6 months or until the onset of disease symptoms. Results. The median PFS was 13 months, and the median OS was 20 months. During and immediately after RT, 9 (29%) patients had a grade 2 or higher adverse events. Conclusion. The use of concomitant CHRT in patients in the third stage of locally advanced inoperable NSCLC provides a good opportunity for a favorable therapeutic outcome with an acceptable degree of acute and late toxicity and represents the standard therapeutic approach for selected patients in this stage of the disease.

Introduction. Neuromyelitis optica spectrum disorder (NMOSD) represents an immune-mediated neuroinflammatory syndrome, classified as a separate entity after the discovery of aquaporin-4 immunoglobulin G (anti-AQP4-IgG). The magnetic resonance neuroimaging spectrum of NMOSD classically consists of bilateral optic neuritis and longitudinally extensive transverse myelitis (LETM), recently broadened with lesions in area postrema, diencephalon, brainstem and cerebellum, and extensive cord atrophy. Case report. The case presents an anti-AQP4 autoantibody-positive 65-year-old female patient who initially presented with underestimated LETM and developed multiple cerebral and cerebellar lytic demyelinating lesions associated with acute long segment op-tic nerve involvement two years later. Two new imaging findings were described in this case: the involvement of a complete cross-sectional area of pons and microhemorrhage in the pons and corpus callosum. Conclusion. Raising suspicion of NMOSD is of crucial importance in cases with isolated LETM in order to prevent relapses in anti-AQP4-IgG positive cases and improve patient outcomes and recovery.

Background/Aim. Paragongliomas are rare hypervascular neoplasms. The aim of this study was to present the experience in the treatment of paragangliomas using preoperative embolization. Methods. This retrospective cross-sectional study included 10 patients (7 women and 3 men; median age 55 years) with paragangliomas that were embolized before surgery. Results. Three patients had tympanicum paragangliomas, two carotid bodies, three jugular and two jugulare-tympanicum paragangliomas. During the operation, only one out of 10 patients had bleeding which required blood transfusion. This patient received 1,130 mL of blood transfusion due to surgical complication. Conclusion. Adequate preoperative selective embolization of paragangliomas is essential in the preoperative preparation of these patients, because this strategy is feasible with low complication rates.

Background/Aim. Treatment options for cervical spondylotic myelopathy (CSM) are the topic for discussion due to the lack of controlled randomized prospective studies. Also, the natural history of CSM is unpredictable and the efficacy of surgical decompression is still controversial. The aim of this prospective study was to describe the results of surgical treatment of patients with CSM in a single institution. Methods. Fifty-nine patients with symptomatic CSM were enrolled in this single-center prospective study. At the end of the follow-up period of 12 months, 50 patients were analyzed. All patients were operated on; surgical decompression was performed by anterior or posterior surgical approach. Outcome evaluations were obtained preoperatively and 12 months postoperatively by using the following outcome measures: the modified Japanese Orthopedic Association (mJOA) scale, the Nurick score and the Neck Disability Index (NDI). The functional recovery ratio was calculated postoperatively by using Hirabayashi’s formula. Results. According to our results, significant improvements were detected in all outcome variables (mJOA score, Nurick score and NDI). Also, a statistically significant improvement was observed in all three categories of patients according to the preoperative mJOA score (mild, moderate, severe). Twenty-three patients (46%) had a satisfactory functional recovery, while twenty-seven (54%) had an unsatisfactory functional recovery rate. Conclusion. Surgical treatment of CSM is a very effective treating method and it resulted in a significant improvement in all outcome measures for a 1-year follow-up period. New studies could be recommended to evaluate the course of the disease, define the optimal surgical strategy, and better determine surgical outcome predictors.