Introduction. Cardiac magnetic resonance imaging (CMR) is considered the reference diagnostic method for quantifying right ventricular size and function, and pulmonary regurgitation in patients with tetralogy of Fallot surgery. The aim of this paper is to confirm the importance of magnetic resonance continuous postoperative monitoring of right and left heart function parameters as a diagnostic method that provides the most precise and accurate assessment. Methods. The prospective observational study included subjects with TOF surgery who were diagnosed with residual morphological and/or functional disorders on control postoperative echocardiographic examinations. All subjects underwent magnetic resonance imaging of the heart on a 1.5 T scanner with dedicated coils for the heart surface according to the standard protocol for a period of one year from the beginning of the study. Criteria for exclusion from the study were: significant residual pulmonary stenosis, condition after pulmonary valve replacement, existence of residual shunt lesions, contraindications for cardiac magnetic resonance imaging (pacemaker, ICD, claustrophobia). Depending on the time elapsed since the tetralogy of Fallot surgery, the subjects were divided into groups: more than 15 years, 11-15 years, 6-10 years, less than 5 years. Results. The study included 131 subjects with an average age of 24.18 ± 11.57 years with complete correction of TOF. Intergroup differences in values of right ventricular end-diastolic volume, right ventricular ejection fraction, and left ventricular ejection fraction were demonstrated, but there was no statistically significant intergroup difference in values of pulmonary regurgitation fraction. The negative interaction of the right and left ventricles intensifies during the years of follow-up of patients after TOF surgery, which is especially true fifteen years after surgery. Conclusion. CMR has the most significant role in research efforts aimed at improving the outcomes of operated patients with tetralogy of Fallot.

Introduction: Machine learning (ML) plays a significant role in the fight against the COVID-19 (officially known as SARS-CoV-2) pandemic. ML techniques enable the rapid detection of patterns and trends in large datasets. Therefore, ML provides efficient methods to generate knowledge from structured and unstructured data. This potential is particularly significant when the pandemic affects all aspects of human life. It is necessary to collect a large amount of data to identify methods to prevent the spread of infection, early detection, reduction of consequences, and finding appropriate medicine. Modern information and communication technologies (ICT) such as the Internet of Things (IoT) allow the collection of large amounts of data from various sources. Thus, we can create predictive ML-based models for assessments, predictions, and decisions. Methods: This is a review article based on previous studies and scientifically proven knowledge. In this paper, bibliometric data from authoritative databases of research publications (Web of Science, Scopus, PubMed) are combined for bibliometric analyses in the context of ML applications for COVID-19. Aim: This paper reviews some ML-based applications used for mitigating COVID-19. We aimed to identify and review ML potentials and solutions for mitigating the COVID-19 pandemic as well as to present some of the most commonly used ML techniques, algorithms, and datasets applied in the context of COVID-19. Also, we provided some insights into specific emerging ideas and open issues to facilitate future research. Conclusion: ML is an effective tool for diagnosing and early detection of symptoms, predicting the spread of a pandemic, developing medicines and vaccines, etc.

This paper proposes a novel circuit configuration for a high-voltage direct-current circuit breaker (HVDCCB) test bench that differs significantly from conventional test benches. The proposed test bench consists of a modular multilevel cascaded converter (MMCC) that is based on H-bridge cells, an output inductor, and an auxiliary capacitor bank. The proposed test bench is capable of generating controllable output currents up to several kiloamperes and output voltages up to several hundred kilovolts because each MMCC cell is operated by phase-shifted pulse-width-modulated (PSPWM) signals. Consequently, the proposed test bench can simulate a wide range of fault conditions within hardware limitations to test different HVDCCB types with various current and voltage ratings. The flexibility of the proposed test bench is complemented by a longer service lifetime with inherent circuit protection in the case of operational failure of the HVDCCB. The concept of the proposed test bench is verified experimentally on a downscaled test bench that consists of nine H-bridge cells and operates at an equivalent switching frequency of $\mathrm {92.5 kHz }$ .

The purpose of this study was to explore possible protective effects of vitamin D3 on serum glucose concentration, body weight and histopathology of pancreas and liver. Animals were divided into 3 groups: Control group (n=6), streptozotocin (STZ) group (n=6) and streptozotocin + vitamin D3 (STZ+D3) group (n=6). Rats in the STZ+D3 group starting from the 7th day of experiment were given vitamin D3 for 14 days. Glucose levels and body weight were measured on the 1, 7, 14 and 21st day of experiment. Qualitative histological analysis of pancreas and liver was done using the light microscope with a digital camera. Differences between the groups were tested by one-way analysis of variance (ANOVA) followed by Dunnett's posttest. Differences in repeated measures were tested using paired t-test. On day 14 and 21, blood glucose level in STZ+D3 group was significantly higher compared to the control group of animals but significantly lower than the glucose level registered in STZ group of rats. On day 14 and day 21, body weight in STZ rats was significantly lower compared to weight in STZ+D3 and control groups of rats. Morphological changes, such as shrinkage of islets, vacuolation of both endocrine and exocrine cells, were observed in pancreas of STZ group of animals but were nearly absent in STZ+D3 rats. Similarly, STZ+D3 group of rats showed preserved liver histoarchitecture. Obtained results suggest that vitamin D3 treatment reduces hyperglycemia, exerts beneficial effects on body weight and alleviates histopathological changes in pancreas and liver in STZ-induced diabetic rats.

Background/Aim. For the first time, we evaluated and presented the socio-demographic characteristics, clinical manifestations and laboratory findings of hospitalized coronavirus disease 2019 (COVID-19) patients from Canton Sarajevo, Bosnia and Herzegovina. Methods. This retrospective, single-centre study included 159 RT-PCR verified COVID-19 patients (92 mild/moderate; 67 severe/critical) consecutively hospitalized at the General Hospital "Prim. dr Abdulah Nakaš" in Sarajevo, Bosnia and Herzegovina. Socio-demographic, clinical, and laboratory data on admission were retrospectively obtained from each patient's electronic medical record and patient files by two experienced physicians. Results. 43.4% of the patients belonged to the age range of 46-65 years; 71.1% were men, and 68.6% had comorbidities; hypertension was the most prevalent comorbidity (100%), followed by diabetes (91.7%) and ischemic heart disease (35.8%). The leading clinical symptoms were fever (87.44%), tiredness (77.8%), and body/muscle aches (70.3%). There was significant reduction of blood oxygen saturation (p = 0.005), and significant elevation of D-dimer (p = 0.003), CRP (p = 0.044), and fasting plasma glucose (p = 0.047) in the severe/critical patients group compared to mild/moderate group. Conclusion. Older age, the male gender, confirmed comorbidities, decreased blood oxygen saturation, increased levels of CRP, D-dimer, and fasting plasma glucose, together with symptoms of chest pain/shortness of breath and/or diarrhea occurred more frequently in severe/critical than mild/moderate COVID-19 patients.

Purpose: The aim of this paper is to provide an overview and analysis of literature dealing with the possibilities for applying augmented reality (AR) in marketing and the impact of AR on marketing in the era of digital transformation of business. Though attractive, this topic is still insufficiently explored. Methodology: The paper uses a bibliometric method - citation and co-citation analysis in the Web of Science and Scopus citation databases. Data analysis was performed using the VOSviewer software tool for information construction, analysis and visualization. Results: The conducted research revealed that there is an increasing trend in the number of research papers dealing with the AR and marketing topics. The specific topics dealt with in the papers are primarily related to the impact of AR on business, creating customer loyalty, sales increase and other marketing activities. Conclusion: AR is a powerful and influential tool the use of which improves communication with customers and, at the same time, sales strategies and processes. AR is based on immersing customers into a new experience, by showing virtual objects in the users’ real-world environment and creating harmony between the digital and the real-world environment so that the boundaries between them disappear. It is manifested as a form of experiential marketing, since it focuses both on a product and a service, and on the entire experience created for customers.

Introduction: Over the past 15 years, direct oral anticoagulant (DOAC) drugs have replaced vitamin K antagonists in a number of indications requiring oral anticoagulant therapy. Review work: The article written is an overview of the most important information related to the use of DOAC drugs in the secondary prevention of venous thromboembolism (VTE). The first randomized studies with dabigatran, rivaroxaban and apixaban are presented, which introduced these drugs into clinical practice in the first step, and then enabled the prolonged safe use of these drugs in the secondary prevention of VTE. Studies have also been described as current attitudes for the use of DOAC in patients with VTE associated with malignancy and antiphospholipid syndrome. An assessment of the risk of bleeding in patients with DOAC is also presented. Finally, we briefly presented the results of the use of DOAC in the treatment of pulmonary embolism in a group of patients from the regional PE registry.

Background / Aim: Hidradenitis suppurativa (HS) is a chronic inflammatory disease that most often affects apocrine gland-bearing areas of the skin. The treatment depends on the severity of the clinical presentation. The paper objective was to present new modalities in management and treatment of HS. Methods: The subjects in this research included the patients suffering from the severe form of HS, who were treated in the University Clinical Centre of the Republic of Srpska for the past three years. The effect of treatment of HS were monitored. In four patients, biologic therapy with adalimumab or adalimumab biosimilars was administered, while four patients received radiotherapy and 17 of them, were treated surgically. Depending on the type of treatment, the effects of therapy were monitored after 6-12 weeks by using clinical examination and by assessing the disease stage according to the Hurley staging. Due to a small number of subjects, especially in patients treated with biologic and radiotherapy, it was not possible to perform any statistical analysis and the results were presented by description, in tables and photographs. Results: Biologic therapy: Adalimumab was administered subcutaneously 80 mg, twice a month. After 12 weeks, in 4 patients was observed a regression of changes by 60-70 % when compared to previous skin changes. Radiotherapy: the total radiation dose was 5 Gy, distributed in 5 or 10 fractions. After 12 weeks an improvement by 60-70 % was observed. Surgical treatment: after 6-8 weeks, the patients were fully recovered. Conclusions: Application of biologic and radiotherapy after 12 weeks had similar results, ie it brought to regression of changes by 60-70 %. The best results were achieved after surgical treatment of HS.