Goce Delcev University

Legacy flotation tailings from historical mining operations increasingly attract attention as secondary resources for strategic raw materials while simultaneously posing significant environmental risks. The former Sb–As–Cr mine of Lojane in North Macedonia represents one of the largest arsenic(As)- and antimony(Sb)-rich mine waste sites in the region, originating from the processing of hydrothermal vein-type mineralization hosted within the ophiolitic units of the Vadar Zone (Đorđević et al. 2019). Despite the extensive environmental concerns, the potential of these tailings as a resource has remained largely unexplored.This study aims to assess the feasibility of sustainable recovery of Sb from the Lojane flotation tailings through a detailed mineralogical and geochemical characterization. This will be achieved by using powder X-ray diffraction (PXRD), inductively coupled plasma-optical emission and -mass spectrometry (ICP-OES/MS), and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), alongside evaluating environmentally relevant processes controlling metal(loid) mobility.Bulk mineralogical analyses reveal a complex assemblage of primary and secondary Sb- and As-bearing phases, including realgar (AsS), pararealgar (AsS), arsenolite (As2O3), senarmontite (Sb2O3) and cervantite (Sb2O4) accompanied by abundant gangue minerals such as quartz (SiO2) and gypsum (CaSO4·2 H2O). This mineralogical diversity reflects the advanced oxidation and weathering processes that have affected the tailings as wells as indicating multiple mineralogical hosts for Sb and As.Detailed chemical analyses reveal very high concentrations of As (124–480 g/kg) and Sb (12–87 g/kg), and elevated concentration of Fe (7–30 g/kg) as well as traces of Cr (20–190 mg/kg), Ni (90-2.560 mg/kg), Tl (50-205 mg/kg) and Co (10-130 mg/kg).Electron microscopy investigations provide detailed insights into the micro-scale distribution of Sb- and As-bearing phases as well as their textural relationships with alteration products. The primary As–Sb sulphide assemblage, including relict realgar and stibnite, is pervasively overprinted by chemically heterogeneous cemented crusts containing shrinkage microcracks that form continuous intergranular matrices.SEM-EDS reveals the presence of two groups of secondary matrices that commonly occur as pore-filling and grain-coating phases. The first group from the Fe-As-Sb-S-O system consists mostly of oxides (arsenolite, stibioclaudetite, hydroxy iron oxides, roméite group As-bearing Sb-oxides), arsenates (scorodite) and sulphates (gypsum). The second group, which is Si–Al–O dominated, consists predominantly of amorphous to poorly crystalline Si–Al oxides with systematically detectable minor contents of As, Sb, Fe and S.Together, these observations indicate progressive supergene oxidation, element redistribution and the partial immobilisation of As and Sb within secondary phases. This exerts a key control on their environmental mobility and long-term stability.By linking mineralogical controls, bulk chemistry and leaching behaviour this study provides a comprehensive framework for evaluating both the environmental risks and resource potential of complex As-Sb flotation tailings. Tamara Đorđević acknowledges the financial support of the Austrian Science Fund (FWF) [Grant: P 36828-N]. Đorđević, T. et al. (2019): Can. Mineral., 57, 1–21.

Male infertility contributes to nearly half of infertile couples, with asthenozoospermia and oligoasthenoteratozoospermia as predominant factors. Despite advancements in sperm processing techniques, the outcomes remain limited in severe cases, particularly concerning motility, mitochondrial function, and DNA integrity. Platelet-rich plasma (PRP), an autologous concentrate rich in platelets (>1 × 106/μL) and growth factors, has recently gained attention as an adjunctive therapy in andrology and assisted reproduction. This review systematically evaluated studies published between 2015 and 2025 investigating PRP use in sperm processing, including in vitro experiments, clinical trials, animal models, and mechanistic studies. PRP demonstrated concentration-dependent benefits, with 5% PRP yielding optimal improvements: motility increased by 15-30%, mitochondrial activity increased by up to 80% (p = 0.002), and oxidative stress was significantly reduced (p < 0.001). PRP's effects on DNA integrity differ by application method: intratesticular administration improves spermatogenesis, producing sperm with reduced DNA fragmentation (~33% relative reduction after 3 months, p < 0.001), while in vitro supplementation provides limited protection against processing-induced damage. Mechanisms involve antioxidant action, mitochondrial protection via AMP-activated protein kinaseNuclear Factor kappa-light-chain-enhancer of activated B cells (AMPK/NF-κB) modulation, membrane stabilization, and the selective preservation of higher-quality spermatozoa. PRP shows consistent biological efficacy and safety but lacks methodological standardization. Fewer than 20% of studies report platelet concentrations, limiting reproducibility. Standardized protocols distinguishing leukocyte-poor from leukocyte-rich preparations and randomized trials focusing on live birth rates are recommended. This review proposes an eight-point characterization checklist for future research.

Myocardial ischemia represents a state of reduced coronary perfusion with oxygenated blood, insufficient to meet the metabolic demands of the myocardium. Both acute and chronic ischemia trigger a cascade of cellular events that lead to disturbances in ionic balance, mitochondrial function and energy metabolism. During ischemia, cardiomyocytes (CMs) shift from aerobic to anaerobic metabolism, resulting in adenosine triphosphate (ATP) depletion, loss of ionic homeostasis and calcium (Ca2+) overload that activate proteases, phospholipases and membrane damage. Reperfusion restores oxygen supply and prevents irreversible necrosis but paradoxically initiates additional injury in marginally viable myocardium. The reoxygenation phase induces excessive production of reactive oxygen species (ROS), endothelial dysfunction and a strong inflammatory response mediated by neutrophils, platelets and cytokines. Mitochondrial dysfunction and opening of the mitochondrial permeability transition pore (mPTP) further amplify oxidative stress and inflammation and trigger apoptosis and necroptosis. Understanding these intertwined cellular and molecular mechanisms remains essential for identifying novel therapeutic targets aimed at reducing reperfusion injury and improving myocardial recovery after ischemic events.

Introduction: Diabetes mellitus and cardiovascular diseases remain the leading causes of death worldwide. There are approximately 366 million people with diabetes globally, and by 2030, it is projected that this number will reach 520 million, or 6.3% of the world's population, affected by diabetes. Dyslipidemia and diabetes are the main contributors to cardiovascular diseases. Diabetic dyslipidemia is characterized by disturbances in all lipid fractions (increased triglycerides, increased LDL-cholesterol, and low HDL-cholesterol levels). Purpose of the study: This study aimed to assess hyperlipidemia as a risk factor for cardiovascular disease in patients with diabetes Mellitus. Materials and Methods: The study was a prospective cohort ("cross-sectional"). Results: A total of 200 participants were included: 100 patients with diabetes mellitus (60 with type 1 and 40 with type 2), and 100 healthy individuals serving as controls. Among the diabetes patients (100), 45 (45%) were female, with a mean age of 58.00 ± 14.00 years, while 55 (55%) were male, with a mean age of 59.60 ± 12.00 years. The control group comprised 100 voluntary blood donors, 45 (45%) women and 55 (55%) men, with a mean age of 58.40 ± 13.60 years. The results are shown in the following tables (numbers 3-6). Conclusion: Dyslipidemia and hyperglycemia are the principal risk factors and are independent of the development of premature atherosclerosis and cardiovascular disease. Treating primary or secondary dyslipidemia early is crucial and can significantly help prevent early atherosclerotic processes and cardiovascular diseases. Recent studies on the treatment of dyslipidemia have shown a strong positive effect of statins (40 mg dose), which appear to help prevent cardiovascular disease.

Glyphosate (N-(phosphonomethyl) glycine) is the most widely used herbicide globally, with applications exceeding 125 million kilograms annually across more than 160 countries. Its broad-spectrum efficacy and cost-effectiveness, especially in genetically modified glyphosate-tolerant crops, have made it indispensable in modern agriculture. However, its extensive use has raised concerns regarding environmental persistence and potential health effects. Although it binds strongly to soil particles, glyphosate and its main metabolite, aminomethylphosphonic acid, are frequently detected in soil, water, and, to a lesser extent, air and food. Human exposure occurs primarily through diet, environmental contact, or occupational activities. Biomonitoring studies confirm widespread low-level exposure, with glyphosate and AMPA detected in human urine samples worldwide. Toxicological and epidemiological data remain inconsistent. While the International Agency for Research on Cancer classified glyphosate as “probably carcinogenic to humans,” other agencies, including EFSA and the U.S. EPA, found no evidence of carcinogenicity. Evidence linking glyphosate exposure to non-Hodgkin lymphoma and other cancers remains inconclusive. Environmental studies highlight adverse effects on soil microorganisms, aquatic systems, and non-target species, prompting regulatory reassessment in the EU and beyond. Future research should prioritize formulation-specific toxicity, long-term biomonitoring, and mechanistic studies addressing endocrine, metabolic, and microbiome effects. Integrating toxicological, epidemiological, and environmental data will be essential for refining risk assessment, guiding sustainable weed management, and balancing glyphosate’s agricultural benefits against its potential ecological and health risks.

The paper presents an analytical overview of the occurrence, movement, and accumulation of both natural and anthropogenic radionuclides in food of animal origin. The research encompasses the main pathways through which these substances enter animal organisms, together with the environmental and agricultural factors influencing their distribution in soil, vegetation, and animal tissues such as meat, milk, eggs, and fish during the period 1989 to 2025. The review was conducted based on a literature search performed in the Elsevier, Hinari, PubMed, and other relevant scientific databases. The study focuses on isotopes including uranium-238, thorium-232, potassium-40, cesium-137, and strontium-90 as key indicators of naturally occurring and technologically induced radioactivity within the biosphere. The analysis demonstrates the interconnection between geological, climatic, and agricultural conditions that determine the levels and variability of radionuclides in animal-derived food. It was established that radionuclide concentrations in North Macedonia fall within internationally accepted limits and correspond with values observed in other European countries. The study emphasizes the importance of continuous monitoring of both natural and anthropogenic sources of radioactivity to enable timely detection of fluctuations in radiological balance and to ensure the long-term safety of food and public health protection.

In modern industrial plants, timely and accurate information about process parameters is essential. For those reasons in modern technological and industrial development, the application of electronics in measuring, processing, storing and transferring process data in industrial facilities is increasing. Guided by the need for measurement, visualization and storage of process parameters, modern electronic systems provide the ability to process and store measurement data on-site and transfer it to the GSM and IoT network. On the other hand, the application of sophisticated electronic systems is noticeable not only in power plants, but also in healthy and quality food industries, such as agriculture. We witness daily tribunes and panel discussions sponsored by companies and even governments for the introduction of the terminology of digital agriculture, i.e. the introduction of smart electronic solutions in agriculture. In addition to the commitment to so-called green energy, i.e. obtaining energy from renewable sources, the development of digitization in agriculture is an area in which an enormous application of smart electronic systems is expected in the future. Guided by these reasons, in this paper an electronic system is designed that provides a solution to a problem in hydro melioration system, i.e. the development, design and practical implementation of the Smart electronic system which enables the measurement of the process parameters of an agro-industrial facility and their transfer to the GSM and IoT network. The solution enables the visualization of process parameters locally on LCD displays and remotely on an mobile device in GSM and IoT network. A data log file is also provided for store the value on the process parameters on a local computer.

The innovation ecosystem represents a complex network of institutions, companies, policies, and individuals who jointly create the conditions for the development of new technologies, entrepreneurship, and economic competitiveness. North Macedonia, as a small transitional economy, has gradually been developing its innovation potential over the past decade through the introduction of government programs for supporting start-ups, strengthening the IT industry, establishing business incubators, and stimulating research activity within academic institutions. Despite these positive trends, the system faces significant challenges, such as limited investment in research and innovation, insufficient private capital, and the emigration of highly qualified professionals. This paper analyses the structural elements of the innovation ecosystem in North Macedonia, current achievements, and potential directions for improvement.

In the contemporary tourism industry, digitalization has become an inevitable part of everyday processes — from online reservations to automated shift management. Although digital tools have the potential to facilitate work processes, they simultaneously bring new challenges, such as constant exposure to online reviews and the feeling of 24/7 availability. The aim of this paper is to examine how digitalization affects the level of stress and well-being of employees in tourism. The research is conducted through a quantitative method — a survey designed to measure sources of stress, perceptions of digitalization, and the level of job satisfaction. The results will provide insight into which digital solutions reduce and which increase stress among personnel. Based on the findings, recommendations will be proposed to improve work organization and strengthen the mental well-being of employees. The paper aims to contribute to the creation of more sustainable and human-centered working conditions in tourism in the digital era.

In this study, electrospinning was successfully employed to fabricate membranes based on polylactic acid (PLA), a polymer known for its biodegradability, containing varying amounts of opalized tuff (0, 2, 5, and 10 wt%). The addition of tuff introduced active mineral sites within the fibrous network, while the PLA matrix ensured mechanical stability, environmental sustainability, and prevention of secondary pollution. The electrospun membranes exhibited a uniform fibrous morphology with well-developed surface porosity, as confirmed by scanning electron microscopy. X-ray powder diffraction and Fourier-transform infrared spectroscopy verified the preservation of the characteristic structural features of both PLA and tuff, indicating successful incorporation of the filler without chemical alteration of the polymer matrix. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy analysis demonstrated effective adsorption of nickel (Ni2+) and lead (Pb2+) ions from aqueous solutions, attributed to the high surface activity of the silicate mineral phase. These findings highlight the synergistic combination of a renewable, environmentally friendly polymer and a naturally occurring mineral filler to produce efficient and eco-friendly adsorptive membranes for heavy metal removal from aqueous solution.