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Abstract The WWE domain is a relatively under-researched domain found in twelve human proteins and characterized by a conserved tryptophan-tryptophan-glutamate (WWE) sequence motif. Six of these WWE domain-containing proteins also contain domains with E3 ubiquitin ligase activity. The general recognition of poly-ADP-ribosylated substrates by WWE domains suggests a potential avenue for development of Proteolysis-Targeting Chimeras (PROTACs). Here, we present novel crystal structures of the HUWE1, TRIP12, and DTX1 WWE domains in complex with PAR building blocks and their analogs, thus enabling a comprehensive analysis of the PAR binding site structural diversity. Furthermore, we introduce a versatile toolbox of biophysical and biochemical assays for the discovery and characterization of novel WWE domain binders, including fluorescence polarization-based PAR binding and displacement assays, 15N-NMR-based binding affinity assays and 19F-NMR-based competition assays. Through these assays, we have characterized the binding of monomeric iso-ADP-ribose (iso-ADPr) and its nucleotide analogs with the aforementioned WWE proteins. Finally, we have utilized the assay toolbox to screen a small molecule fragment library leading to the successful discovery of novel ligands targeting the HUWE1 WWE domain.

Introduction/purpose: Gunpowder is a type of explosive material (EM), a mixture of chemical compounds capable of releasing their potential energy in a very fast exothermic chemical reaction. This paper investigates the single base gunpowder samples. Methods: Microcalorimetry (MC), or heat flow calorimetry (HFC), is the only modern method that monitors the direct cause of autoignition - the rate of heat release, which is a key factor for gunpowder storage explosive safety. It is based on high-sensitivity calorimeters which allow monitoring of chemical reactions at low speeds. The microcalorimeter "TAM III" was used and the method given by the NATO standard STANAG 4582. A very reliable result was obtained on the chemical stability of the observed single base gunpowder samples, as well as an assessment of its behavior in the next 10 years. Results: The thermal activity of gunpowder depends on several factors, the most important of which are: chemical composition, size and shape of the gunpowder grain, the degree of decomposition of the gunpowder, storage conditions, etc. Namely, it is a much more exact and consistent indicator of the chemical stability of gunpowder compared to the critical diameter. Conclusion: The MC method should be used both for monitoring the chemical stability of gunpowder during storage and for the prediction of the service life of gunpowder.

Introduction/aim: This paper aims to present the methodology for creating educational content/scenarios on a ship simulator (bridge simulator) that will serve officers of river units in developing the ability to react when performing regular and military tactical tasks on the ships of the River Flotilla. Also, training on the simulator aims to train officers of river units using modern information technologies. Methods: The paper uses simulation methods, experimental methods, case studies, and operational research. Results: Specific educational content/scenarios were created, also specific methodology was developed and the principles were clearly defined according to which content/scenarios are created on the ship simulator. Conclusion: By using the ship simulator, in different teaching scenarios, cadets of river units as well as members of river units are trained and acquire the ability to react adequately in real situations in the shortest possible time.

Cadmium is one of the most dangerous pollutants found in the environment, where it exists mainly due to human activities. High cadmium concentrations can cause serious problems, which is why the detection and determination of Cd is one of the most important tasks. Electroanalytical methods provide rapid and accurate results in the detection of cadmium in various solutions. In this study, the possibility of using a bismuth film electrode deposited on a brass surface and electroanalytical techniques for the detection of cadmium is investigated. The bismuth film was deposited on the surface of the brass electrode using a chronoamperometric technique. Cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the synthesized bismuth film electrode. The current peaks obtained by anodic square-wave stripping voltammetry under optimized conditions showed a linear relationship in the investigated concentration range of cadmium. The study of the interference of different cations (Cr3+, Mn2+, Zn2+, Ca2+, K+, Mg2+ and Na+) showed that the tested cations have no influence on the determination of Cd2+ ions in the investigated solution. This finding provides a good opportunity for the use of the synthesized electrode in real samples.

Introduction/purpose: The activity of managing the budget funds of the Ministry of Defense and the Serbian Armed Forces (MoD and AF) does not accept even minimal mistakes in the procurement of weapons and military equipment (WME). Equipping the Serbian Armed Forces with weapons and military equipment must be economically justified because a large part of the budget is allocated for that purpose. The goal of the research is to look at the economic aspect of treating costs as a prerequisite for the process of equipping the defense system with weapons and military equipment. Methods: For the purposes of the research, we used analytical and descriptive methods in order to see the comprehensive costs of assets that precede the effective equipping of the Ministry of Defense and the Armed Forces with WME. The research included the analysis of 18 review and research papers, which we analyzed in accordance with the Rulebook on equipping the Serbian Armed Forces with weapons and military equipment. Results: The results of the research indicate that economic justification is expressed implicitly by the ratio of intangible benefits and achieved goals to the invested funds. The most common reason why economic justification is not expressed explicitly by the difference between the initial investment and the final asset quantity is the existence of a number of circumstances for making wrong investment decisions. Also, if the costs are not considered in detail during the entire life cycle of the investment, it can be assumed that the planned target result is not certain. Conclusion: The research indicates that not considering costs during the entire life cycle of the investment is the main reason for unplanned investments in the later stages and the emergence of numerous problems in the functioning of the defense system.

Philip K. Dick’s novels Ubik and The Man in the High Castle explore the idea of the multiplicity of realities, which can be understood better if interpreted from a cosmological point of view. The scientific principles of decoherence, as formulated by H. Dieter Zeh and Hugh Everett III, shed light on the nature of these fictional worlds, their creation and dissolution and their perception by both the protagonists and the reader. Ontological puzzles of the quantum world, based on the rejection of the special status of an observer in physical reality and fractal branching of the universe, offer insights into the mechanisms at work in these two novels. Decoherence may be the key to understanding the disintegrating borders between realities in both novels, which are manifested as worlds in superposition. However, the rules of this scientific principle are radically challenged by the emergence of what could be termed the agents of re-coherence. These agents reveal the existence of alternate realities in the novels, as well as the process of the violation of the decoherence principle. Not only are these occurrences interesting from both a scientific and artistic point of view, they also reveal the realities in the novels as being far more coherent than they seem on the surface and interpretable as literary parallels to thought experiments conceived as possible explanations of the quantum world theory.

This study investigates the perception of the implementation of the Farm to Table (F2T) concept on the sustainability of agritourism households in the Republic of Serbia. The main objective of the study is to determine how this concept affects the environmental, economic, and social sustainability of these households according to the participants. Data were collected through surveys of agritourism homestead owners in the regions of Vojvodina, Western Serbia, Southern Serbia, and Eastern Serbia. The research findings, obtained using quantitative (SEM) analyses, indicate that the F2T concept significantly contributes to the sustainable development of agritourism homesteads by increasing economic profitability, reducing environmental impact, and strengthening the social community. Moderators such as seasonal product availability, employee education, and the local community support have a significant impact on the effectiveness of F2T activities. The innovation of this study lies in the application of quantitative methods to analyze the specific impacts of the F2T concept on the sustainability of agritourism households, an area that has been poorly explored in the literature. The study has a number of implications, including providing empirical data that can help farmers, tourism operators, and policymakers to promote sustainable agritourism businesses.

Prion diseases are neurodegenerative disorders caused by misfolded prion proteins. Although rare, the said diseases are always fatal; they commonly cause death within months of developing clinical symptoms, and their diagnosis is exceptionally difficult pre-mortem. There are no known cures or treatments other than symptomatic care. Given the aggressiveness of prion diseases on onset, therapies after disease onset could be challenging. Prevention to reduce the incidence or to delay the disease onset has been suggested to be a more feasible approach. In this perspective article, we summarize our current understandings of the origin, risk factors, and clinical manifestations of prion diseases. We propose a PCR testing of the blood to identify PRNP gene polymorphisms at codons 129 and 127 in individuals with familial PRNP mutations to assess the risk. We further present the CRISPR/Cas9 gene editing strategy as a perspective preventative approach for these high-risk individuals to induce a polymorphic change at codon 127 of the PRNP gene, granting immunity to prion diseases in selected high-risk individuals, in particular, in individuals with familial PRNP mutations.

Purpose – During the pandemic, two types of fear were identified that occur significantly in all groups or profiles of people. The aim of this paper is to determine which of the two types of fears exist in certain psychological groups, and which of the fears strongly influence the decision to travel. Design/methodology/approach – The VALS 2 method and standardized questionnaire were used for the segmentation of the tourist market or for the determination of the psychographic profiles of the consumers, and three additional questions were joined to it as they were vital for the research of the type of fear and its impact on the decision for traveling. When the reliability of the questionnaire and the validity of the sample were determined, the data were further processed using a computer program package IMB AMOS SPSS 21.00, and then, based on the theoretical suppositions and hypotheses, the SEM structural model was created. Findings – The paper indicates the existence of established types of fears in humans, when it comes to pandemics and similar crisis situations. People are most afraid of infection during travel, and lack of funds and job loss during the critical period of the pandemic. The research conducted confirms that all groups of people, who are determined by the psychological technique VALS 2, react with a certain dose of fear and make decisions under the pressure of fears. Research limitations/implications – The research had limitations in terms of contact with people and conducting live surveys. The measures during the pandemic, which were carried out by the state, included social distance and limited movement of people. Practical implications – The work can contribute to the community, along with similar research. The results of the research will be available, and it will be possible to see the behavior of people during crisis situations, and the impact of fears on making decisions, both travel decisions and decisions related to other areas of life. Originality/value – The paper provides research results on a large sample of respondents, and can serve as a basis for further research in the field of tourism, psychology and similar fields. It is crucial to consider the type of fears, and the strength of the impact of these fears on the decision to travel, during crisis situations.

BackgroundThyroid nodules (TN) are localized morphological changes in the thyroid gland and can be benign or malignant.ObjectiveThe present study investigates the relationships between biochemical markers in serum (s) and their homologs in washout (w) after fine-needle aspiration biopsy (FNAB) of the TN of interest and their correlation with cytology specimen findings.MethodsWe investigated the relationships between serum biochemical markers nitric oxide (NO), thyroglobulin (TG), and calcitonin (CT), their homologs in washout after FNAB of the TN of interest, and cytology findings of biopsy samples classified according to the Bethesda system for thyroid cytopathology in this study, which included 86 subjects.ResultsWashout TG (TGw) level positively correlates with the cytology finding of the biopsy. A higher level of TGw correlates with higher categories of the Bethesda classification and indicates a higher malignant potential. The levels of serum NO (NOs), serum TG (TGs), serum CT (CTs), and washout CT (CTw) do not correlate with the cytology finding of the biopsy, and the higher levels of washout NO (NOw) correspond to the more suspicious ultrasound findings.ConclusionThe findings of our study suggest that TGw and NOw could be used as potential predictors of malignancy in TN.

Experimental investigations of the effectiveness of the pretreatment of the acid leaching process of a representative sample of electric arc furnace dust (EAF dust) and characterization of a representative sample were performed. As EAF dust is globally defined as hazardous solid industrial waste, and it contains a high percentage of zinc and other useful components, in this paper, the application of pretreatment will be carried out in order to increase the efficiency of the further process of acid leaching, all with the aim of using EAF dust as a secondary raw material for metal valorization. The pretreatment involved the application of a simple process of leaching the EAF dust sample with distilled water. Under the following defined optimal leaching conditions: time—30 min, ratio of solid to liquid phase—1:10, temperature—ambient, and stirring speed—500 rpm, a reduction in the content of water-soluble components was achieved, namely, 83% Cl, 92% K, 74% Na, 14% Cd, 15% Ca, and 19% F. The application of the pretreatment enables significantly better filtration of the suspension and increases the leaching efficiency of zinc and other useful components in the further process of leaching EAF dust with a sulfuric acid solution, compared with the process of direct acid leaching of EAF dust.

Local markets have been a special setting throughout human history. Apart from their important social role, they had immeasurable economic importance as primary forms of exchange of goods (trade). Nonetheless, they experienced numerous transformational changes that affected their functioning. Like other countries, Serbia has a long tradition of market activity. However, several novelties have been introduced in recent years. Among many, the process of e-fiscalization is the main issue. Therefore, the focus of our research is based on a qualitative analysis of online media content (news and comments) related to the fiscalization of market activity. The attitudes of different categories of participants (state authorities, vendors, and customers) were analyzed. LIGRE open-access software was used for this purpose. The results of the analysis showed conflicting parties. Legislators emphasize the exclusive positive effects, while vendors point to the negative side of fiscalization. As a third party, customers (service users) have an undefined attitude in relation to fiscalization (pros/cons/neutral). There is an agreement to introduce market activity into legal flows. However, the key prerequisite is the prior resolution of a number of problems (working conditions, business costs, market monopoly, etc.).

Introduction/purpose: The problem of efficient distribution of cryptographic keys in communication systems has existed since its first days and is especially emphasized by the emergence of mass communication systems. Defining and implementing efficient protocols for symmetric cryptographic keys establishment in such circumstances is of great importance in raising information security in cyberspace. Methods: Using the methods of Information Theory and Secure Multiparty Computation, protocols for direct establishment of cryptographic keys between communication parties have been defined. Results: The paper defines two new approaches to the problem of establishing cryptographic keys. The novelty in the protocol defined in the security model based on information theory is based on the source of common randomness, which in this case is the EEG signal of each subject participating in the communication system. Experimental results show that the amount of information leaking to the attacker is close to zero. A novelty in the second case, which provides security with keys at the level of computer security by applying Secure Multiparty Computation, is in the new application field, namely generation and distribution of symmetric cryptographic keys. It is characteristic of both approaches that within the framework of formal theories, it is possible to draw conclusions about their security characteristics in a formal way. Conclusions: The paper describes two new approaches for establishing cryptographic keys in symmetric cryptographic systems with experimental results. The significance of the proposed solutions lies in the fact that they enable the establishment of secure communication between comunication parties from end to end, avoiding the influence of a trusted third party. In that way, the achieved communication level security significantly increases in relation to classical cryptographic systems.

Local producers constitute a crucial segment of the local economy, playing a pivotal role in driving rural development and the progress of tourism. Their avenues for showcasing products extend beyond markets, bazaars, or food events, often being integrated into a destination’s tourism offerings. Moreover, they contribute to the culinary progress within tourism. Originating from wider rural areas or nearby villages, local producers significantly impact everyday migrations, services, and financial transactions in relationships spanning suburban–urban, village–town, and cross-border cooperation. This study aims to scrutinize the social facets of the organization and work of local producers, offering insights into contemporary market processes. It also serves to illustrate cross-border cooperation and the role of culinary tourism in local business. Through qualitative data processing, we will delve into the outcomes of cross-border projects, emphasizing ethical and sustainable values rooted in territory, landscape, local culture, authenticity, and the application of culinary elements in tourism. The results will shed light on the economic, social, and cultural ramifications on markets in border regions, influencing daily life and the economy. This study will define key aspects of rural development. These research findings can inform local governments, the economy, and communities in future strategic planning for developing this market segment. Tourism, especially in hospitality, will empower rural communities to enhance financial inflow and create local employment opportunities, such as roles for vineyard tour guides or local chefs. Simultaneously, it will bolster other sectors of the local economy, such as agriculture.

NKG2D is an activating receptor expressed by all human NK cells and CD8 T cells. Harnessing the NKG2D/NKG2D ligand axis has emerged as a viable avenue for cancer immunotherapy. However, there is a long-standing controversy over whether soluble NKG2D ligands are immunosuppressive or immunostimulatory, originating from conflicting data generated from different scopes of pre-clinical investigations. Using multiple pre-clinical tumor models, we demonstrated that the impact of the most characterized human solid tumor-associated soluble NKG2D ligand, the soluble MHC I chain-related molecule (sMIC), on tumorigenesis depended on the tumor model being studied and whether the tumor cells possessed stemness-like properties. We demonstrated that the potential of tumor formation or establishment depended upon tumor cell stem-like properties irrespective of tumor cells secreting the soluble NKG2D ligand sMIC. Specifically, tumor formation was delayed or failed if sMIC-expressing tumor cells expressed low stem-cell markers; tumor formation was rapid if sMIC-expressing tumor cells expressed high stem-like cell markers. However, once tumors were formed, overexpression of sMIC unequivocally suppressed tumoral NK and CD8 T cell immunity and facilitated tumor growth. Our study distinguished the differential impacts of soluble NKG2D ligands in tumor formation and tumor progression, cleared the outstanding controversy over soluble NKG2D ligands in modulating tumor immunity, and re-enforced the viability of targeting soluble NKG2D ligands for cancer immunotherapy for established tumors.

Abstract One of the goals of this research was to develop an electrochemical sensor that had the ability to determine the target analyte and was both cheap and non-toxic. Another goal was to influence the reduction of electronic waste. In accordance with these, a graphite rod from zinc-carbon batteries was used to prepare an electrochemical sensor for the determination of L-tryptophan in Britton–Robinson buffer solution. Two electrochemical methods were used in the experimental research, differential pulse voltammetry and cyclic voltammetry. The effect of different parameters, including the pH value of supporting solution, scan rate, as well as the concentration of L-tryptophan on the current response, was studied. The pH value of Britton–Robinson buffer influenced the intensity of L-tryptophan oxidation peak, as well as the peak potential. The intensity of the current response was the highest at pH 4.0, while the peak potential value became lower as the pH increased, indicating that protons also participated in the redox reaction. Based on the obtained data, electrochemical oxidation of L-tryptophan at the graphite electrode was irreversible, two electron/two proton reaction. In addition, it was observed that the oxidation peak increased as the scan rate increased. According to the obtained electrochemical data, it was suggested that the oxidation of L-tryptophan was mixed controlled by adsorption and diffusion. The linear correlation between oxidation peak and L-tryptophan concentration was investigated in the range 5.0–150.0 µM and the obtained values of limit of detection and limit of quantification were 1.73 µM and 5.78 µM, respectively. Also, the prepared electrochemical sensor was successful in determination of target analyte in milk and apple juice samples.

The implementation of novel coaxial dipole antennas has been shown to be a satisfactory diagnostic platform for the prediction of orthopaedic bone fracture healing outcomes. These techniques require mechanical deflection of implanted metallic hardware (i.e., rods and plates), which, when loaded, produce measurable changes in the resonant frequency of the adjacent antenna. Despite promising initial results, the coiled coaxial antenna design is limited by large antenna sizes and nonlinearity in the resonant frequency data. The purpose of this study was to develop two Vivaldi antennas (a.k.a., “standard” and “miniaturized”) to address these challenges. Antenna behaviors were first computationally modeled prior to prototype fabrication. In subsequent benchtop tests, metallic plate segments were displaced from the prototype antennas via precision linear actuator while measuring resultant change in resonant frequency. Close agreement was observed between computational and benchtop results, where antennas were highly sensitive to small displacements of the metallic hardware, with sensitivity decreasing nonlinearly with increasing distance. Greater sensitivity was observed for the miniaturized design for both stainless steel and titanium implants. Additionally, these data demonstrated that by taking resonant frequency data during implant displacement and then again during antenna displacement from the same sample, via linear actuators, that “antenna calibration procedures” could be used to enable a clinically relevant quantification of fracture stiffness from the raw resonant frequency data. These improvements mitigate diagnostic challenges associated with nonlinear resonant frequency response seen in previous antenna designs.

Simultaneous ipsilateral “floating-hip” and “floating-knee” injuries are very rare and severe, and they occur in high-velocity road traffic accidents. A 55-year-old man presented with posterior wall fracture – dislocation of the acetabulum, complete fracture – dislocation of the femoral head, ipsilateral femoral shaft fracture, open patellar fracture, Gustilo type II, tibial fracture, and traumatic sciatic nerve injury/peroneal division. Given the fact that hip dislocation is an orthopedic emergency, we first did closed external tibial fixation, femoral head reduction, osteosynthesis of the acetabular fracture, and partial patellectomy. After 2 days, the patient underwent a second surgery; fixation of the neck and femoral shaft fractures was done, with a self-dynamic internal fixator. After 14 months from the injuries, radiographs show complete healing of all fractures, the patient walks independently without crutches, and the peroneal nerve is partially recovered. Despite the seriousness of the presented injuries, we did not have any complications, and 14 months after the injury, the femoral head is still viable, with no signs of femoral head osteonecrosis.

The analysis of pressure changes in water and steam flow along the entire once-through steam boiler tube system at the 650 MWe lignite fired Unit was carried out after the long operational period of almost 30 years without a chemical cleaning of the pipe system. A significant increase of the hydraulic resistance was recorded in comparison to the design values in the evaporator tubes, both in the water heating zone and in the evaporation zone with the two-phase mixture flow. The cause of this adverse effect is the formation of a wavy surface of the magnetite layer deposited on the inner wall of tubes. The significantly increased absolute roughness on the inner wall of tubes was determined on the basis of measured pressure drops at sections of the tube system and numerical calculation performed with a thermal-hydraulic model of single-phase and two-phase water and steam tube flows. The model is based on the steam-water two-fluid model with mass, momentum and energy balance equations and mechanistic correlations for the steam-water interface transfer processes. The model is suitable for the single and two-phase flow parameters prediction in the span from subcritical to supercritical and near critical pressure conditions. Conducted calculations provide detailed insight in the fluid pressure, velocity and temperature change in the boiler tube system. After the long operational period the pressure drop in evaporating tubes almost doubles in comparison to the design values. The presented results are a support to boiler's design, operational procedures and maintenance.

BackgroundLate reconnections (LR) of pulmonary veins (PVs) after wide antral circumferential ablation (WACA) using point-to-point radiofrequency (RF) ablation are common. Lesion size index (LSI) is a novel marker of lesion quality proposed by Ensite Precision mapping system, expected to improve PV isolation durability. This study aimed to assess the durability of LSI-guided PVI and the risk factors for LR of PVs.MethodsThe prospective study included 33 patients with paroxysmal atrial fibrillation (PAF) who underwent (1) the index LSI-guided WACA procedure (with target LSI of 5.5-6.0 for anterior and 5.0-5.5 for posterior WACA segments) and (2) the 3-month protocol-mandated re-mapping procedure in all patients, irrespective of AF recurrence after the index procedure. Ablation parameters reported by Ensite mapping system were collected retrospectively. The inter-lesion distance (ILD) between all adjacent WACA lesions was calculated off-line. Association between index ablation parameters and the LRs of PVs at 3 months was analyzed.ResultsThe median patient age was 61 (IQR: 53–64) years and 55% of them were males. At index procedure, the first-pass WACA isolation rate was higher for the left PVs than the right PVs (64 vs. 33%, p = 0.014). In addition, a low acute reconnection rates were observed, as follows: in 12.1% of patients, in 6.1% of WACA circles, in 3.8% of WACA segments and in 4.5% of PVs. However, the 3-month remapping study revealed LR of PV in 63.6% of patients, 37.9% of WACA circles, 20.5% of WACA segments and 26.5% of PVs. The LRs were identified mostly along the left anterior WACA segment. Independent risk factors for the LR of WACA were left-sided WACA location (OR 3.216 [95%CI: 1.065–9.716], p = 0.038) and longer ILD (OR 1.256 [95%CI: 1.035–1.523] for each 1-mm increase, p = 0.021). The ILD of > 8.0 mm showed a predictive value for the LR of WACA, with the sensitivity of 84% and specificity of 46%. A single case of cardiac tamponade occurred following the re-mapping invasive procedure. No other complications were encountered.ConclusionAlthough the LSI-guided PVI ensures a consistent PVI during the index procedure, LRs of PVs are still common. Besides the LSI, the PVI durability requires an optimal ILD between adjacent lesions, especially along the anterior lateral ridge.

The results of this research on the electrochemical behavior of Cu24Zn5Al alloy in a 0.1 mol/dm3 sodium sulfate (Na2SO4) solution containing 1-phenyl-5-mercaptotetrazole (PMT) are presented in this paper. The influence of PMT concentration, chloride ion concentration, and pre-treatment were examined. The influence of pre-treatment was studied in terms of the effect of the immersion time of the electrode in the appropriate inhibitor solution. After selecting the optimal immersion time, its effect on the behavior of the Cu24Zn5Al alloy was tested in a 0.1 mol/dm3 solution of sodium sulfate in the presence of different concentrations of chloride ions. Research shown that with the increase of PMT concentration, the anodic current density around the corrosion potential decreases, indicating that PMT behaves as a corrosion inhibitor for Cu24Zn5Al alloy.

Research on chalcopyrite leaching represents a great challenge, given its importance as one of the most abundant copper minerals and its significant role in global copper extraction. This study aimed to evaluate the effects of different parameters on chalcopyrite leaching by hydrogen peroxide as a strong oxidizing reagent in sulfuric acid solution. A series of leaching tests were carried out to investigate the effect of the solid/liquid ratio, stirring speed, temperature, oxidant and acid concentrations, and lixiviant dosing method on copper extraction from chalcopyrite concentrate. The catalytic decomposition of hydrogen peroxide occurred in the investigated leaching system, as reflected in the obtained metal extraction values. Copper extraction was increased in the first 60 min of the reaction, after which it essentially ceased. The maximum final copper extraction of 64.5% was attained with 3.0 mol/L H2O2 in 3.0 mol/L H2SO4 at a temperature of 40 °C after 120 min of reaction. Due to the catalytic decomposition of hydrogen peroxide in the examined leaching system, the leaching experiment was performed with the periodic addition of lixiviant at specific time intervals as well. The dissolution process was described by the first-order kinetics equation with an apparent activation energy of ~39 kJ/mol. Finally, XRD and SEM-EDS analyses were used to characterize the leached residue, and the results showed that the formation of elemental sulfur on the chalcopyrite surface affected the dissolution process.

Study is aimed at solving the problem of developing a strategy for the formation and arrangement of cultural landscapes in the Republic of Mordovia on the basis of geoinformation support for the tourist and recreational development of the cultural landscape. The study of the formation of cultural landscapes of the region was carried out through the use of databases of spatio-temporal organization of geosystems and cartographic modeling of the patterns of economic development of geosystems. The regional GIS "Mordovia" and geoportal "Natural and Historical Heritage of the Republic of Mordovia" developed by the authors contain an interactive system of thematic maps and databases that reveal the peculiarities of nature, population, economy, cultural heritage, and the development of environmental situations of the region. The article shows that the cultural landscapes of Mordovia were formed in the process of centuries-old economic development of geosystems, and include high landscape diversity, cultural objects of peoples with unique development paths as the most important components.

As one of the oldest documented mines in Europe, Rudna Glava should be at the very top when it comes to geotourist visits in Serbia and the Balkans. The research goal is to point out the possibilities of geotourism development in this part of Serbia, while the findings aim to identify the existing problems for geotourism development in the area. Тhe study will analyze the geotourism potential of this archaeological site by using the Geosite Assessment Model (GAM), combining the main and additional values. The GAM involves grades given by experts and provides a relatively actual image of the geoheritage state based on which it is practicable to plan and enhance the activities for the observed sites. The outcomes showed that the observed site has a high score of the main, and a low score of additional values. This means that the site should be additionally protected, and included in various tourist programs.

The main objective of present study was to evaluate inter-rater reliability and concurrent validity of Side Hop Test stopwatch vs. force plates timing, and to determine the number of sessions and trials required to minimize the effects of learning on Side Hop Test total time and limb symmetry index. Fifteen healthy male physical education students (mean ± SD: age, 23 ± 3 years; height, 181 ± 9 cm; and weight 72 ± 6 kg) participated. Side Hop Test total time (stopwatch and force plates) of left and right leg, and limb symmetry index (force plates) were obtained over seven sessions conducted 5–7 days apart. Time recordings of two raters were similar (t = −0.56, p > 0.05) with high reliability (all ICC >0.99 and CV% 0.05; for rater 1 and 2, respectively). Total time improved across the Sessions (F = 25.87, p < 0.01, ω2 = 0.18) and Trials (F = 68.15, p < 0.01, ω2 = 0.10), with no significant interaction between factors. No between-leg differences were detected (F = 0.52, p > 0.05, ω2 = 0.001). Limb symmetry index ranged from 0.999 to 1.055 across all sessions and trials (all p > 0.05 and ω2 < 0.00). Due to low coefficient of correlation, high interclass correlation coefficient, and the lack in heteroscedasticity, stopwatch measurements are valid to measure total time in the Side Hop Test. Moreover, stopwatch measurements could be reliably used to measure total time in the Side Hop Test, while the test could be administrated with only one experienced rater. Unlike total times, findings on limb symmetry index suggest it could be reliably assessed after seven familiarization sessions.

The aim of the study was to identify which tour guide's competencies can be predictors of environmentally sustainable behavior of visitors of national parks. Authors gathered answers through questionnaires from 305 visitors of two national parks located in Serbia. The results showed that guide's knowledge and telling stories in an engaging and interesting way were predictors for almost all learning outcomes. Also, guides who are energetic and show that they enjoy doing their job, can arouse visitors' interest in the presented topic, create pleasant memories and serve as a role model for sustainable behavior after the tour ends.

Introduction/purpose: The Modulation Transfer Function (MTF) is a useful tool for an imaging system performance analysis. It is used in Electro-Optical (EO) system design, verification of targeted system parameters, but also in optimization tasks for systems under test. This methodology based on the linear systems theory allows the performance analysis of complicated EO systems to be divided into subsystems. In this paper, the MTF methodology will be presented and explained, followed by the measurements performed in the electro-optical laboratory. The MTF measurements were performed on three types of cameras in different spectral bands, after which the results were compared to the model expectations and theoretical limits for the imaging system. For one of the sensors, the limiting frequency was also measured using the USAF 1951 test target which allowed the comparison between the methods. Methods: Laboratory measurements and theoretical mathematical calculations. Results: Based on the laboratory and theoretical results, the measurement results were further analyzed. Conclusion: The measurements have proven that the calculated cutoff frequency and the MTF curve represent the limit for the real measured system performance. Therefore, this study has confirmed that the MTF can be convenient for finding system limitations and bottlenecks and for increasing the overall performance of the system. / Введение/цель: Функция модуляции передачи (MTF) является полезным инструментом для анализа эффективности системы формирования изображений. Она используется при разработке электрооптических систем (EO), проверке целевых параметров системы, а также в задачах оптимизации тестируемой системы. Данная методология основана на теории линейных систем и обеспечивает возможность разделения анализа эффективности сложных систем ЭО на подсистемы. В настоящей статье представлена и объяснена методология MTF, а также приведены примеры измерений, произведенных в электрооптической лаборатории. Измерения MTF проводились с помощью трех видов камер в разных спектральных диапазонах, после чего результаты сравнивались с прогнозируемыми моделями и теоретическими пределами системы формирования изображения. Методы: Лабораторные измерения и теоретическая математическая статистика. Результаты: Результаты измерений были дополнительно проанализированы на основании проведенных лабораторных и теоретических результатов. Выводы: Проведенные измерения показали, что рассчитанная предельная частота и кривая MTF представляют собой границу реальных измеренных характеристик эффективности системы. Таким образом, исследование подтвердило, что MTF может способствовать выявлению системных ограничений и узких мест, а также повышению общей эффективности системы. Разработаны рекомендации по дальнейшей оптимизации систем формирования изображений. / Uvod/cilj: Modulaciona funkcija prenosa (MTF) koristan je alat za analizu performansi sistema za obradu slike. Koristi se u dizajniranju elektrooptičkih (EO) sistema, pri proveri ciljanih parametara sistema, ali i u zadacima optimizacije testiranih sistema. Ova metodologija, zasnovana na teoriji linearnih sistema, omogućava da se analiza performansi složenih EO sistema podeli na podsisteme. MTF metodologija najpre je predstavljena i objašnjena, a zatim je prikazano merenje izvršeno u elektrooptičkoj laboratoriji. MTF merenja izvedena su na tri tipa kamera, u različitim spektralnim opsezima, nakon čega su rezultati upoređeni sa očekivanim modelima i teorijskim ograničenjima sistema za obradu slike. Metode: Laboratorijska merenja i teorijska matematička izračunavanja. Rezultati: Na osnovu laboratorijskih i teorijskih rezultata dodatno su analizirani rezultati merenja. Zaključak: Merenja su dokazala da izračunata granična frekvencija i krivulja MTF predstavljaju granicu za stvarne performanse sistema. Potvrđeno je da MTF može biti pogodan za pronalaženje ograničenja i uskih grla sistema, kao i za poboljšanje ukupnih performansi sistema.

The study analyses the role and impact of the event "Danube Fair" (Eastern Serbia) in the tourism progress of the less-advantaged border area. The aim of this paper is to emphasize the significance of the role of events in the tourism development of rural settings and the attraction of domestic and foreign visitors with the specific offer of this part of Serbia. The tourism valorization of the event “Danube Fair” was done according to the geographical and economic criteria, and it was determined that it belongs to the category of regional events. In the paper, special attention was paid to the analysis of tourists’ satisfaction with this event as a geographical criterion, especially in dependence with the visitors’ origin, since it is what the positioning of an event on the tourism market depends on, both on the local and on the international level. “Danube Fair” presents the example of a relatively small-scale event, which can become a basis of tourism growth, with proper valorization and affirmation of local products and services, and their introduction to the international tourism market.

This study has analyzed the traffic-related change in atmospheric pollutants levels (PM2.5, PM10, CO, NO2, SO2, and O3) caused by the COVID-19 restrictive measures, based on traffic ground-based stations data in urban areas in Serbia. The possible influence of several meteorological factors (temperature, wind, pressure, and humidity), and mobility on the pollutants’ levels were also considered. The obtained results showed a positive correlation of daily NO2 concentrations with mobility and its significant reduction during restrictive measures at all selected monitoring stations. The reduction of NO2 was higher than in other countries (71.1–111.5% for measured, and 49.3–92.6% for “deweathered” data), indicating a high traffic impact on NO2 levels in Serbia. The PM, CO, and SO2 showed a weak correlation with mobility during the period with restrictive measures, which, besides traffic, indicates the significant influence of other sources of their concentration. The O3 concentrations were increased at all measuring stations and are negatively correlated to mobility. Comparison of pollutant concentrations during restriction with the equivalent period in preceding years showed reductions in NO2 and SO2 concentrations. However, compared to previous years, the concentrations of PM2.5, PM10, and CO increased in the period with restrictive measures, indicating lower sensitivity to population mobility and higher dependence on other emission sources. The findings suggest the justification for the use of traffic reduction strategies to improve air quality.

Rural tourism in Serbia had its chance to shine with the advent of the COVID-19 pandemic. The aim of this study was to determine to what extent the quality of rural service can contribute to improving rural tourism, and predictions for the continuation of the trend in terms of increasing the number of overnight stays in rural households. The obtained results show a small number of services in the sector could be improved, but that all elements except price value can influence the future development of rural tourism and that the number of overnight stays is expected to continue to grow. The importance and innovativeness of the research is reflected in the specific methodology that was applied, and the results complement those of previous research. It has been shown that villages in Serbia can create a barrier against COVID-19 through tourism.

Background: Atrial fibrillation (AF) is associated with the development and progression of chronic kidney disease (CKD). This study evaluated the impact of long-term rhythm outcome after catheter ablation (CA) of AF on renal function. Methods and results: The study group included 169 consecutive patients (the mean age was 59.6 ± 10.1 years, 61.5% were males) who underwent their first CA of AF. Renal function was assessed by eGFR (using the CKD-EPI and MDRD formulas), and by creatinine clearance (using the Cockcroft–Gault formula) in each patient before and 5 years after index CA procedure. During the 5-year follow-up after CA, the late recurrence of atrial arrhythmia (LRAA) was documented in 62 patients (36.7%). The mean eGFR, regardless of which formula was used, significantly decreased at 5 years following CA in patients with LRAA (all p < 0.05). In the arrhythmia-free patients, the mean eGFR at 5 years post-CA remained stable (for the CKD-EPI formula: 78.7 ± 17.3 vs. 79.4 ± 17.4, p = 0.555) or even significantly improved (for the MDRD formula: 74.1 ± 17.0 vs. 77.4 ± 19.6, p = 0.029) compared with the baseline. In the multivariable analysis, the independent risk factors for rapid CKD progression (decline in eGFR > 5 mL/min/1.73 m2 per year) were the post-ablation LRAA occurrence (hazard ratio 3.36 [95% CI: 1.25–9.06], p = 0.016), female sex (3.05 [1.13–8.20], p = 0.027), vitamin K antagonists (3.32 [1.28–8.58], p = 0.013), or mineralocorticoid receptor antagonists’ use (3.28 [1.13–9.54], p = 0.029) after CA. Conclusions: LRAA after CA is associated with a significant decrease in eGFR, and it is an independent risk factor for rapid CKD progression. Conversely, eGFR in arrhythmia-free patients after CA remained stable or even improved significantly.

Background Established MRI and emerging X-ray contrast agents for non-invasive imaging of articular cartilage rely on non-selective electrostatic interactions with negatively charged proteoglycans. These contrast agents have limited prognostic utility in diseases such as osteoarthritis (OA) due to the characteristic high turnover of proteoglycans. To overcome this limitation, we developed a radiocontrast agent that targets the type II collagen macromolecule in cartilage and used it to monitor disease progression in a murine model of OA. Methods To confer radiopacity to cartilage contrast agents, the naturally occurring tyrosine derivative 3,5-diiodo-L-tyrosine (DIT) was introduced into a selective peptide for type II collagen. Synthetic DIT peptide derivatives were synthesised by Fmoc-based solid-phase peptide synthesis and binding to ex vivo mouse tibial cartilage evaluated by high-resolution micro-CT. Di-Iodotyrosinated Peptide Imaging of Cartilage (DIPIC) was performed ex vivo and in vivo 4, 8 and 12 weeks in mice after induction of OA by destabilisation of the medial meniscus (DMM). Finally, human osteochondral plugs were imaged ex vivo using DIPIC. Results Fifteen DIT peptides were synthesised and tested, yielding seven leads with varying cartilage binding strengths. DIPIC visualised ex vivo murine articular cartilage comparably to the ex vivo contrast agent phosphotungstic acid. Intra-articular injection of contrast agent followed by in vivo DIPIC enabled delineation of damaged murine articular cartilage. Finally, the translational potential of the contrast agent was confirmed by visualisation of ex vivo human cartilage explants. Conclusion DIPIC has reduction and refinement implications in OA animal research and potential clinical translation to imaging human disease.

Podunavlje region in Serbia comprises 16.6% of the territory and 38.9% of the total population of the country. Due to its attractive natural values, cultural-historical monuments, ethnographic features, etc., Serbian Podunavlje has favorable conditions for the development of excursion, nautical, stationary, event, youth, rural, hunting, transit, and other kinds of tourism. Since the climate as a tourism resource and the factor of tourist migrations in the observed area has not been analyzed yet, the aim of this paper is the tourism valorization of the significance of climate using the two tourism climatic indexes: tourism climate index (TCI) and tourism climate comfort index (TCCI). To achieve it, the climate elements were first analyzed at five meteorological stations in Serbian Podunavlje: Sombor, Novi Sad, Belgrade, Veliko Gradište, and Negotin for the period 1990–2010. Then the periods favorable for tourism activities were determined according to the mentioned indexes at the given stations. The research results show that summer is certainly the most favorable season for tourism activities in the observed area since the maximum TCI values were recorded during summer, and the minimum ones during winter at all the stations. Regarding the TCCI, the most optimal values of this index were recorded in September and May. These results can further serve the tourism organizations in the municipalities in Serbian Podunavlje when considering the construction of the tourism infrastructure, marketing activities, and further affirmation of the resources for the purpose of sustainable development of tourism.

The main component of error minimization in operating rooms (ORs) is to maintain high reliability of surgical teams. The analysis of adverse events in the OR reveals deficiencies in cognitive and interpersonal skills as the main factors influencing surgeons’ errors. Therefore, research of these additional factors is necessary, besides factors related to surgeons’ clinical knowledge and technical skills. In this paper, the key factors for evaluating activities in surgical operating rooms are identified. Fuzzy analytic hierarchy process is used for identification of key factors. Fifteen key factors are identified for evaluating activities in surgical operating rooms to improve the efficiency of surgical operations. For each group of activities (surgical “capabilities,” operating room characteristics, and non-technical skills), five factors are identified. As the most important, the following factors are obtained: communication, indoor environment standardization, and tool handle design. The aim of the analysis of these key factors is surgeons’ work capability enhancement, rational design of operating rooms, and advancement of operators’ cognitive and interpersonal skills.

Soil erosion is a global environmental and economic problem that is significantly related to land-use changes. Over the last decades, several mountain areas in Serbia were exposed to strong human pressure caused by winter tourism development. The largest ski center in Serbia is situated on Kopaonik Mountain within the boundaries of Kopaonik National Park, where the conflict between economic and conservation goals is rapidly growing. In this study, we calculated the sedimentation and surface runoff in three sub-basins in the area of the Kopaonik ski resort for two years (1984 and 2018) using the SWAT and analyzed the changes that occurred during the observed period. The results show an increase in surface runoff and sediment yield in sub-basins 1 and 3 and a decrease in sub-basin 2. Analysis of land cover change shows an expansion of evergreen forests, appearance of barren soil and urban areas, reduction of mixed forests and pastures, and appearance of deciduous forests. These findings indicate that in the area studied, the dominant processes are the development of tourism and natural revegetation of abandoned agricultural land. Application of remote sensing techniques and SWAT contributes to identifying and monitoring land degradation problems and improving conservation and management practice.

This research is devoted to the determination of hidden dependencies between the flow of particles that come from the Sun and precipitation-induced floods in the United Kingdom (UK). The analysis covers 20 flood events during the period from October 2001 to December 2019. The parameters of solar activity were used as model input data, while precipitations data in the period 10 days before and during each flood event were used as model output. The time lag of 0–9 days was taken into account in the research. Correlation analysis was conducted to determine the degree of randomness for the time series of input and output parameters. For establishing a potential causative link, machine learning classification predictive modeling was applied. Two approaches, the decision tree, and the random forest were used. We analyzed the accuracy of classification models forecast from 0 to 9 days in advance. It was found that the most important factors for flood forecasting are proton density with a time lag of 9, differential proton flux in the range of 310–580 keV, and ion temperature. Research in this paper has shown that the decision tree model is more accurate and adequate in predicting the appearance of precipitation-induced floods up to 9 days ahead with an accuracy of 91%. The results of this study confirmed that by increasing technical capabilities, using improved machine learning techniques and large data sets, it is possible to improve the understanding of the physical link between the solar wind and tropospheric weather and help improve severe weather forecasting.

The study focuses on the present state and the assessments of geotourism development of the two most representative tufa deposits in the Djerdap National Park—the first UNESCO Global Geopark in Serbia. The findings were designated through implementing the freshly upgraded methodology—M-GAM-1-2 based on an early modified geosites assessment model (M-GAM). To overcome the limitations of the previous model, the authors implemented additional enhancements and involved members of the local community (residents and authorities) in the study to comprehensively evaluate the observed sites. The outcomes revealed that the attitudes of all stakeholders should be taken into consideration in order to develop geotourism properly, additionally attract visitors, and preserve tufa deposits for future generations of locals and visitors. Moreover, geotourism at the observed sites can be one of the vital activities of the population, as well as a type of compensation for various limitations in the development, which are imposed by the regimes of natural and cultural heritage protection within the recently established UNESCO Global Geopark.

The article proposes a solution for the problem of high-resolution remote sensing data classification by applying deep learning methods and algorithms in conditions of labeled data scarcity. The problem can be solved within the geosystem approach, through the analysis of the genetic uniformity of spatially adjacent entities of different scale and hierarchical level. Advantages of the proposed GeoSystemNet model rest on a large number of freedom degrees, admitting flexible configuration of the model contingent upon the task at hand. Testing GeoSystemNet for classification of EuroSAT dataset, algorithmically augmented after the geosystem approach, demonstrated the possibility to improve the classification precision in conditions of labeled data accuracy by 9% and to obtain the classification precision with a larger volume of training data (by 2%) which is slightly inferior in comparison with other deep models. The article also shows that synthesis of the geosystem approach with deep learning capabilities allows us to optimize the diagnostics of exogeodynamic processes, owing to the calculation of landscape differentiation regularities. Application of the presented approach enabled us to improve the accuracy in detecting landslides at the testing site “Mordovia” by 5% in comparison with the classical approach of using deep models for remote sensing data analysis. The authors advocate that application of the geosystem approach to improve the efficiency of remote sensing data classification through methods, proposed in the article, requires an individual project-based approach to source data augmentation.

A modern challenge in electrical engineering education is to keep the math at a sufficient level, with a goal to find an optimal balance between calculus competence and operative skills needed for real-life technical applications. It is not uncommon that some gaps emerge during this quest, which makes it difficult for undergraduates to entirely understand topics related on prior knowledge. This paper aims to draw attention to several important moments concerning total response of Continuous Linear Time Invariant systems, which are superficially or incorrectly explained in many textbooks, and to offer logical arrangement which can be easily understood and accepted by students. The base of discussion relies on classical calculus background, particularly on Picard's theorem on existence and uniqueness. This theorem is rarely mentioned in signals and systems textbooks. However, mathematical models of many types of signals don't satisfy the condition for continuity, which can easily produce difficulties in the learning process. It is shown that some reported disagreements and issues related to initial conditions, can be easily cleared out by using the smooth transition from classical calculus to mathematics used in system theory. It is also shown that the classical method is always the primary tool, even for determining the impulse response, while the impulse response is unnecessary or sufficient to determine the total system response, regardless of whether the convolution integral is used.

A technique for realizing electrically erasable photonics devices using micro-heaters for localized annealing of lattice defects in silicon is presented. The lattice defects have previously been introduced by ion implantation in order to cause a refractive index change. This technique can be used to fabricate electrically erasable on-chip directional couplers (DCs) and Mach-Zehnder Interferometer (MZI) switches. These devices can be used for wafer scale testing of photonics circuits, allowing testing of individual optical components in a complex photonic integrated circuit, or components for programmable optical circuits, whilst inducing negligible additional optical loss when erased electrically. In this paper, we report the designs and experimental results of fully, rapidly annealing of these devices.

Abstract We introduce a hyperuniform-disordered platform for the realization of near-infrared photonic devices on a silicon-on-insulator platform, demonstrating the functionality of these structures in a flexible silicon photonics integrated circuit platform unconstrained by crystalline symmetries. The designs proposed advantageously leverage the large, complete, and isotropic photonic band gaps provided by hyperuniform disordered structures. An integrated design for a compact, sub-volt, sub-fJ/bit, hyperuniform-clad, electrically controlled resonant optical modulator suitable for fabrication in the silicon photonics ecosystem is presented along with simulation results. We also report results for passive device elements, including waveguides and resonators, which are seamlessly integrated with conventional silicon-on-insulator strip waveguides and vertical couplers. We show that the hyperuniform-disordered platform enables improved compactness, enhanced energy efficiency, and better temperature stability compared to the silicon photonics devices based on rib and strip waveguides.

The research analyzes attitudes and habits of the visitors in the National Park (NP) Taganay on South Urals in Russia. The survey method was applied on a sample of 305 respondents in order to investigate visitors’ travel habits, as well as their perceptions regarding different experiences they were exposed to. The results identified a strong positive perception regarding overall experiences from visiting the NP. Specific permanent patterns of behavior were observed and compatibility between visitors’ habits and the environment was determined. The most significant variables affecting perceptions are the frequency of visits and the age. The study has identified certain concerns regarding environmental issues. Respondents were found sensitive to garbage production in public areas and the presence of noise in protected territory. The results of the study provide inputs for solving the long-standing conflict between nature conservation and mass tourism in Russian protected areas.

The determination of target analytes at very low concentrations is important for various fields such as the pharmaceutical industry, environmental protection, and the food industry. Caffeine, as a natural alkaloid, is widely consumed in various beverages and medicines. Apart from the beneficial effects for which it is used, caffeine also has negative effects, and for these reasons it is very important to determine its concentration in different mediums. Among numerous analytical techniques, electrochemical methods with appropriate sensors occupy a special place since they are efficient, fast, and entail relatively easy preparation and measurements. Electrochemical sensors based on carbon materials are very common in this type of research because they are cost-effective, have a wide potential range, and possess relative electrochemical inertness and electrocatalytic activity in various redox reactions. Additionally, these types of sensors could be modified to improve their analytical performances. The data available in the literature on the development and modification of electrochemical sensors for the determination of caffeine are summarized and discussed in this review.

Five plum hybrids (38/62/70, IV/63/81, 32/21/87, 34/41/87 and 22/17/87) and newly released cultivar ‘Nada’, obtained by planned hybridisation and singled out within breeding programme at Fruit Research Institute, Čačak, were assessed for the main physical (fruit and stone weight and flesh percentage), chemical (soluble solids content, total and inverted sugars content, sucrose content, total acids content, pH value of fruit juice, ratio of soluble solids and total acids content and ratio of total sugars and total acids content) and sensorial (attractiveness, taste, aroma and consistency) traits compared with the standard cultivar ʻČačanska Lepoticaʼ. Results showed that the studied plum genotypes differed significantly in all of the assessed traits. Regarding the physical features, the best results were shown by hybrid 38/62/70, which had the highest fruit weight (56.92 g) and flesh percentage (96.91%), as well as by the new cultivar ‘Nada’, for which a larger fruit was observed in comparison to the standard (45.54 g and 42.24 g, respectively). Also, ‘Nada’ had better sensorial properties such as attractiveness, taste, aroma and consistency in relation to the other promising hybrids and the standard cultivar. From the aspect of all the studied sensorial characteristics, in addition to ‘Nada’, only hybrid 38/62/70 was aligned with the standard cultivar. Out of the studied genotypes, late ripening hybrid 22/17/87 had the best values of parameters of fruit chemical composition such as the soluble solids content (17.01%), total and inverted sugars contents (12.31% and 8.96%, respectively). The highest sucrose content (3.39%), pH value of fruit juice (3.51), as well as the highest ratio between soluble solids and total acids content (43.72) and ratio between total sugars and total acids content (32.58) were found in cultivar ‘Nada’. The highest total acids content (1.42%) was recorded in hybrid 32/21/87. Compared to ʻČačanska Lepoticaʼ, the same or better results in terms of the fruit chemical composition were determined in cultivar ‘Nada’ and hybrids 34/41/87 and 22/17/87. The study revealed existence of significant correlations between individual studied parameters of the fruit physical, chemical and sensorial properties.

Electrochemical methods used for analysis and detection of chemical compounds have significant advantages, such as simplicity and speed of work and low limits of detection. Methods of choice include cyclic, adsorptive stripping, differential pulse and square wave voltammetry. From the point of view of health sciences, environmental sciences and pharmaceutical industry, it is important to develop reliable techniques of pharmaceutical compounds determination. Paracetamol, as one of the most frequently prescribed analgesic medications, is widely present in households and environment. Therefore, it is of scientific and practical interest to test possible ways of its determination in order to find the most suitable ones. In order to provide economic means of detection, numerous authors tested pencil graphite electrodes, as widely available and low cost material suitable for surface modifications, and proved that they can be efficiently used to detect very low concentrations, around 10−9 M, of paracetamol.

Metals stability and corrosion resistance are very important factors that influence the possibility of their applications. In order to study and foresee the behavior of metals during various applications in all kinds of conditions and media, numerous approaches and techniques are developed and applied. Among those techniques, electrochemical measurements nowadays have a dominant role since they are proved to be highly efficient, reliable, fast, relatively low-cost, and easy regarding the preparation and execution of measurements. Besides that, they also provide quite a good amount of data regarding the effect and the mechanism of the reactions that metals interact in. Metals corrosion is reduced by various methods, one of the most frequently used ones is the application of corrosion inhibitors. Usually, organic compounds are studied as potential corrosion inhibitors, and at the moment the focus is on the effect on the environment. Hence, environmentally friendly and non-toxic inhibitors are important research topics. Purines, since they are the group of bioorganic compounds found in numerous biochemical structures such as DNA and RNA, present a very interesting possible solution and are studied as inhibitors of corrosion for copper, steel, aluminum, etc., as well as for some metal alloys. Data obtained and available up until the present are presented and discussed in this review.

Indigo carmine is a commonly used industrial blue dye. To determine its concentration in a commercially available food dye composed of a mixture of indigo carmine and D-glucose, this paper characterizes it through (ATR, KBr) FTIR micro-Raman as well as UV/Vis and clock: Briggs–Rauscher (BR) oscillatory reaction methods. The indigo carmine was detected in the bulk food dye only by applying micro-Raman spectroscopy, indicating a low percentage of the indigo carmine present. This research provides an improvement in the deviations from the experimental Raman spectrum as calculated by the B97D/cc-pVTZ level of theory one, resulting in a better geometrical optimization of the indigo carmine molecule compared to data within the literature. The analytical curves used to determine indigo carmine concentrations (and quantities) in an aqueous solution of food dye were applied by means of UV/Vis and BR methods. BR yielded significantly better analytical parameters: 100 times lower LOD and LOQ compared to commonly used UV/Vis. The remarkable sensitivity of the BR reaction towards indigo carmine suggests that not only does indigo carmine react in an oscillatory reaction but also its decomposition products, meaning that the multiple oxidation reactions have an important role in the BR’s indigo carmine mechanism. The novelty of this research is the investigation of indigo carmine using a clock BR reaction, opening new possibilities to determine indigo carmine in other complex samples (pharmaceutical, food, etc.).