Hrčak - Portal of scientific journals of Croatia
Not a member yet
321498 research outputs found
Sort by
The use automatic syringes for injecting contrast media in the interventional cardiology
No full text
The Role of Radiotherapy in the Treatment of Lymphoma: Clinical Experience of the Clinic for Tumors, University Hospital Centre Rijeka
No full textCilj: Cilj je ovog stručnog rada prikazati jednogodišnje iskustvo našeg radioterapijskog centra u liječenju limfoma. Ispitanici i metode: Uključili smo pacijente s dijagnozom Hodgkinova (HL) ili ne-Hodgkinova limfoma (NHL) koji su započeli liječenje radioterapijom između kolovoza 2022. i rujna 2023. godine. Svi su pacijenti prethodno liječeni kemoterapijom. Podatci su uključivali dob, spol, vrstu i lokalizaciju limfoma, propisanu ukupnu dozu radioterapije, tehniku zračenja i radiološki odgovor nakon završetka liječenja. Rezultati: Prema anatomskoj lokalizaciji, kod većine pacijenata provedena je radioterapija supradijafragmalno, najčešće područja glave i vrata, potom pazušne jame i medijastinuma. Kod otprilike jedne trećine pacijenata radilo se o infradijafragmalnom limfomu, najčešće ingvinalne lokalizacije. Većina radioterapijskih tretmana provedena je 3D konformalnom tehnikom. Radioterapija zahvaćenog mjesta (ISRT) češće se provodila u odnosu na radioterapiju zahvaćenog polja (IFRT). Medijan ukupne doze radioterapije u ISRT grupi iznosio je 32,4 Gy, a u IFRT grupi 33 Gy. Medijan dnevne doze u objema grupama bio je 1,8 Gy. Kod IFRT grupe jednako su bile zastupljene IMRT i 3D CRT tehnika, dok je u ISRT grupi zastupljenija bila tehnika 3D CRT. Kod dvaju pacijenata IFRT grupe zabilježene su nuspojave gradusa I, i to kod obaju stomatitis. Dva pacijenta u ISRT grupi razvila su nuspojavu gradusa I u vidu eritema kože. Kompletan odgovor imalo je trideset pacijenata (86 %), četvero pacijenata (11 %) imalo je parcijalni odgovor, a jedna pacijentica (3 %) bila je bez odgovora na radioterapiju. Zaključci: Radioterapija i dalje ima važnu ulogu u liječenju limfoma. Smanjenje doza i volumena zračenja dovelo je do bolje lokalne podnošljivosti uz održane izvrsne stope odgovora.Aim: This paper presents the one-year experience of our radiotherapy center in treating lymphoma. Patients and methods: We included patients diagnosed with HL or NHL who began radiotherapy treatment between August 2022 and September 2023. All patients had previously received chemotherapy. Data collected included age, sex, type and location of lymphoma, prescribed total dose of radiotherapy, radiation technique, and radiological response after the treatment completion. Results: Based on anatomical localization, most patients underwent supradiaphragmatic radiotherapy, primarily targeting the head and neck region, followed by the axillary region and mediastinum. Approximately one-third of patients presented with infra-diaphragmatic lymphoma, most often in the inguinal region. The most used radiation therapy technique was 3D conformal radiotherapy. Involved site radiotherapy (ISRT) was performed more frequently than involved field radiotherapy (IFRT). The median irradiation dose in the ISRT group was 32.4 Gy, compared to 33 Gy in the IFRT group. The median daily dose in both groups was 1.8 Gy. IMRT and 3D CRT techniques were equally represented in the IFRT group, while the 3D CRT technique was more prevalent in the ISRT group. Grade I side effects were noted in two patients in the IFRT group, with both cases reporting stomatitis. Two patients in the ISRT group experienced a grade I side effect in the form of skin erythema. Thirty patients (86 %) achieved a complete response, four patients (11 %) had a partial response, and one patient (3 %) showed no response to radiotherapy. Conclusions: Radiotherapy remains a crucial modality for lymphoma treatment. Reducing doses and radiation volumes enhances local tolerability while maintaining excellent response rates
Multi Response Modelling and Optimisation of Austempering Parameters on ADI Microstructure, Hardness and Fatigue Strength
No full textIn this work, the influence of austempering temperature and time on the microstructure, hardness and fatigue strength of austempered ductile iron (ADI) is investigated. The experimental part was carried out on a total of eleven samples, nine of which were subjected to heat treatment at three temperatures (250 °C, 350 °C and 450 °C) and three time intervals (30 min, 75 min and 120 min). The tests included measurements of the fatigue strength, Vickers hardness and a microstructural analysis. The aim was to determine the optimum austempering parameters to achieve an ausferritic microstructure and improved mechanical properties. The results showed that austempering temperature had a significant effect on the properties of the treated samples, while austempering time did not show consistent statistical significance, although some samples deviated positively from the statistical model. The best result was obtained with the sample austempered at 350 °C for 120 minutes. Metallographic analysis confirmed the presence of an ausferritic microstructure, which contributed to the improved mechanical properties. The research highlights the importance of properly selecting austempering parameters to achieve an optimal combination of hardness and fatigue strength. Measured values were used to develop mathematical models which can be applied to predict analysed properties of ADI depending on austempering parameters
Analysis of the Evaluation Framework of European Union-Funded Tourism Projects
No full textThis paper examines the evaluation frameworks applied to tourism-related interventions funded by the European Union (EU), focusing on their effectiveness in promoting accountability, learning, and sustainable outcomes. Through content analysis of evaluation reports, audits, and programme assessments from the EU’s Cohesion Policy data platform, the study identifies key methodological patterns and recurring challenges. Despite progress in adopting participatory and mixed-method approaches, evaluations remain limited in number and scope, with tourism accounting for less than 1% of all assessments. Persistent challenges include fragmented data, a lack of standardised indicators, inconsistent methodologies, and limited capacity to assess regional diversity and long-term impacts. Poor dissemination practices further restrict knowledge transfer and reduce the learning potential. By highlighting these gaps, the paper contributes to the underexplored field of tourism evaluation in EU policy and advocates for more harmonised and transparent evaluation protocols. Strengthening these foundations is critical to enhance the impact of EU funding and supporting evidence-based policymaking in the tourism sector
From Written to Digital Commands in German Railway Operations – Challenges and Opportunities
No full textSafe communication between dispatchers and train drivers is a central element of railway operations, especially in disruption scenarios where commands ensure the continuation of safe operations. Traditionally, this process has been carried out in written or telephone form according to clearly standardised rules set out in DB Guideline 408. With the introduction of digital command, a profound change is taking place in this safety-critical communication. The aim of this study is to systematically examine the effects of digitalisation on comprehensibility, usability and safety. Methodologically, the research employs both qualitative and quantitative approaches, including simulator studies, task analyses, guided interviews, questionnaires, mock-ups and thinking-aloud techniques. Initial assessments indicate that digital commands provide significant benefits in terms of time savings, standardisation and documentation, but also introduce new challenges related to human-machine interaction and increased demands on cognitive processes. Factors such as stress, time pressure and user habits significantly influence acceptance and error proneness. The study shows that digital commands can only unfold their full potential if technical innovation and human factors are equally addressed. This research contributes to a deeper understanding of how digitalisation can enhance safety and efficiency in railway operations without compromising the existing high safety standards
Women in the Railway Sector – A Bibliometric Analysis of the Last Ten Years’ Scientific Production
No full textGender equality has become a priority for governments, institutions and companies that are fostering inclusive environments. In this context, the historically male-dominated railway sector has begun a process of transformation. However, women continue to encounter persistent barriers to working, accessing and utilising rail transport. These challenges are closely linked to the complexity of travel chains, safety concerns, and mobility constraints that are shaped by prevailing social and gender structures. Considering this, the study employs a quantitative bibliometric analysis of scientific production on women in the railway sector (2015–2024), using data from the Web of Science Core Collection and Scopus, to map the status, identify research gaps, and inform future studies and policies. The analysis reveals a growth in research on women in the railway sector over the past decade, though the field remains in consolidation. Output is diverse and multidisciplinary but often fragmented, underscoring the need for stronger international collaboration. Impact is concentrated in a few publications, highlighting the importance of more effective dissemination strategies. While quantitative approaches predominate, greater use of qualitative and mixed methods is needed to capture women’s experiences. Future research should enhance collaboration, diversify methodologies, and strengthen dissemination to achieve greater influence on policies and practices
The Meshing Stiffness Characteristics of Variable Hyperbolic Circular Arc Tooth Trace Cylindrical Gears under Installation Errors
No full textTo investigate the impact of installation errors on the meshing performance of variable hyperbolic circular arc tooth trace (VH-CATT) cylindrical gear transmission systems, this study examines the time-varying meshing stiffness characteristics under the influence of such errors. First, based on the VH-CATT cylindrical gear forming principle, a precise three-dimensional model was established after deriving tooth surface equations. Second, the tooth face load and meshing stiffness of VH-CATT cylindrical gears were calculated using tooth contact analysis (TCA) and load tooth contact analysis (LTCA) models. Finally, the effects of different mounting errors on the meshing stiffness of VH-CATT cylindrical gears were examined. The study conclusively shows that the centre distance installation error, the axial installation error, and the rotational installation error around the gears’ centre line direction (for the y-axis) exert a pronounced effect on both the single-tooth stiffness and the meshing stiffness characteristics of VH-CATT cylindrical gears. The rotational installation error around the normal direction of the gear centre line (for the x-axis) notably affects the single-tooth stiffness characteristics of the VH-CATT cylindrical gears, yet it exhibits limited sensitivity towards the meshing stiffness characteristics. These findings provide a technical basis for reducing vibration and noise, improving load carrying capacity, and optimising the tooth surface design of VH-CATT cylindrical gears
Kemijska karakterizacija i antibakterijska aktivnost matične mliječi spram multirezistentnih patogena
No full textResearch background. Given the known antibacterial properties of royal jelly (RJ), we hypothesize that royal jelly could inhibit priority multidrug-resistant (MDR) bacteria, including different strains of vancomycin-resistant Enterococcus faecium (VRE), methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Klebsiella pneumoniae (CRKP) and Acinetobacter baumannii (CRAB). We further propose that the antibacterial efficacy of royal jelly may be influenced by its chemical composition and by inter- and intraspecies variability among MDR pathogens.
Experimental approach. Royal jelly samples were collected from five beekeepers (RJ1–RJ5) in the Mediterranean and continental regions of Croatia. Chemical profiling was conducted using solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME/GC-MS) and Fourier-transform infrared (FTIR) spectroscopy, together with separate assays to measure antioxidant capacity (ABTS) and quantify the content of bioactive compounds. Antibacterial activity was assessed by agar well diffusion assay and by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against 20 MDR strains of VRE, MRSA, CRKP and CRAB, selected from 85 isolates using repetitive sequence-based PCR (rep-PCR) genotyping. MDR status was confirmed by standard susceptibility testing.
Results and conclusions. All royal jelly samples showed strong antioxidant activity and high amounts of bioactive compounds, with RJ1 consistently exhibiting the highest contents of ABTS, polyphenols, flavonoids and proteins. FTIR analysis revealed variations in carbohydrate and lipid composition among samples, while protein content remained relatively uniform, and indicated the highest mass fractions of sugars, lipids and proteins in RJ1. GC-MS identified octanoic acid (48.09–83.07 %) as the predominant volatile compound, especially abundant in RJ1 and RJ4. Despite some variability in chemical profiles, both chemical composition and antibacterial activity were comparable between samples from the Mediterranean and continental regions. All royal jelly samples inhibited MDR bacteria, suggesting a potential synergistic effect of crude royal jellies, with inhibition zones ranging from 11.8 (CRKP) to 16.8 mm (MRSA). A. baumannii was most susceptible (MIC/MBC=27.2 µg/mL), while E. faecium was the most resistant (MIC=96.6 µg/mL, MBC=126.4 µg/mL). Beyond interspecies differences, pronounced strain-level variability in antibacterial response was also observed.
Novelty and scientific contribution. This is the first study to simultaneously evaluate the antibacterial activity of royal jelly against multiple strains of clinically relevant MDR pathogens alongside comprehensive chemical profiling. Importantly, it reveals for the first time that the efficacy of royal jelly varies not only between species but also among strains within the same species, emphasizing the need to consider strain-level differences in future assessments.Pozadina Istraživanja. S obzirom na poznata antibakterijska svojstva matične mliječi, svrha je ovog istraživanja bila utvrditi utjecaj matične mliječi na inhibiciju rasta prioritetnih, višestruko rezistentnih (eng. multidrug-resistant, MDR) bakterija, uključujući različite sojeve vankomicin-rezistentnog Enterococcus faecium (VRE), meticilin-rezistentnog Staphylococcus aureus (MRSA), karbapenem-rezistentne Klebsiella pneumoniae (CRKP) i Acinetobacter baumannii (CRAB), te procijeniti utjecaj kemijskog sastava i međuvrsne i unutarvrsne varijabilnosti MDR patogena na antibakterijsku učinkovitost matične mliječi.
Eksperimentalni pristup. Uzorci matične mliječi (RJ1–RJ5) prikupljeni su od pčelara iz mediteranskog i kontinentalnog područja Hrvatske. Kemijski sastav ispitan je pomoću mikroekstrakcije vršnih para na čvrstoj fazi koja je prethodila plinskoj kromatografiji spregnutoj s masenom spektrometrijom (HS-SPME/GC-MS) te infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), uz određivanje antioksidacijske aktivnosti (ABTS) i udjela bioaktivnih spojeva. Antibakterijska aktivnost određena je metodom difuzije u agaru te određivanjem minimalne inhibicijske (MIC) i minimalne baktericidne (MBC) koncentracije spram 20 MDR sojeva (VRE, MRSA, CRKP i CRAB), odabranih među 85 izolata na osnovi rep-PCR genotipizacije. Višestruka rezistencija je potvrđena pomoću metode određivanja osjetljivosti bakterija.
Rezultati i zaključci. Svi su uzorci matične mliječi imali izrazitu antioksidacijsku aktivnost i znatan udjel bioaktivnih spojeva, pri čemu je RJ1 imao najveće vrijednosti ABTS, polifenola, flavonoida i proteina. FTIR analiza otkrila je varijabilnost u sastavu ugljikohidrata i lipida, dok je udjel proteina bio otprilike jednak u svim uzorcima, pri čemu je uzorak RJ1 imao najveće udjele ugljikohidrata, lipida i proteina. Metodom GC-MS identificirana je oktanska kiselina (48,09–83,07 %) kao dominantnu hlapljivu komponentu, naročito u uzorcima RJ1 i RJ4. Usprkos razlikama u kemijskim profilima uzoraka, uzorci matične mliječi iz mediteranskih i kontinentalnih dijelova imali su usporediv kemijski sastav i antibakterijsku aktivnost. Svi su uzorci inhibirali rast MDR bakterija, upućujući na mogući sinergistički učinak svježe matične mliječi, s inhibicijskim zonama promjera od 11,8 mm (CRKP) do 16,8 mm (MRSA). A. baumannii bio je najosjetljiviji patogen (MIC/MBC=27,2 µg/mL), dok je E. faecium bio najotporniji patogen (MIC=96,6 µg/mL, MBC=126,4 µg/mL). Uočene su izražene razlike u osjetljivosti ne samo između bakterijskih vrsta, već i među sojevima iste vrste.
Novina i znanstveni doprinos. Ovo je prvo istraživanje koje istodobno procjenjuje antibakterijsku aktivnost matične mliječi spram više sojeva klinički relevantnih MDR patogena, uz sveobuhvatnu kemijsku karakterizaciju. Nadalje, po prvi put pokazuje da učinkovitost matične mliječi ne varira samo između različitih bakterijskih vrsta, već i među sojevima unutar iste vrste, čime se naglašava potreba za razmatranjem razlika na razini soja u budućim istraživanjima
Impacts of Hydrological and Climatological Indicators on the Ecological Values of Mura-Drava Regional Park
No full textPodručje uz rijeku Muru i Dravu proglašeno je Regionalnim parkom 2011. godine da bi se zaštitila prirodna močvarna staništa (npr. poplavne šume, napuštena meandri korita rijeka), kao i vrste koje ih nastanjuju. Pored hidrotehničkih zahvata provedenih u povijesti, u novije vrijeme posljedice klimatskih promjena predstavljaju sve važniji čimbenik u očuvanju vlažnih staništa tog područja koja ovise o hidrološkom režimu rijeke Mure i Drave. Stoga su analizirane meteorološke i hidrološke značajke tog područja u razdoblju od 1981. do 2022. odnosno od 1960. do 2024. s ciljem predikacije njihova ponašanja u narednih 10 godina. Srednje godišnje temperature zraka i količine oborina kao osnovni pokretači komponenti vodne bilance, ponajprije površinskog otjecanja opažane na postajama Varaždin i Osijek pokazuju kontinuirani porast temperatura zraka i homogenost nizova oborina bez statistički značajnog trenda. Godišnji maksimalni i minimalni protoci rijeka Mure i Drave također ne pokazuje statistički značajne promjene u promatranom razdoblje. Na nizove opažanih minimalnih i maksimalnih promjena primijenjena je metoda pokretnih srednjih vrijednosti (engl. moving average) s korakom od 10 godina i rezultati su pokazali da na Muri i maksimalni i minimalni godišnji protoci imaju statistički značajan trend opadanja, a na rijeci Dravi samo maksimalni godišnji protoci. Takve promjene hidroloških prilika na području Regionalnog parka u svakom slučaju nisu povoljne i u budućnosti mogu ugroziti njegove ekološke vrijednosti.The Mura-Drava Regional Park was established in 2011 to preserve natural swampy habitats, including flooded forests, abandoned river branches, and oxbows, as well as species that inhabit the area. In addition to the hydrotechnical structures built in the past, climate change has become an increasingly important factor in the preservation of wetlands such as the Mura-Drava Regional Park, which is strongly dependent on the hydrological regimes of the Mura and Drava rivers. This paper examines the meteorological and hydrological characteristics of the area, observed over the periods 1981–2022 and 1960–2024, respectively, to predict potential trends over the next decade. Mean annual air temperatures and precipitation, which act as driving forces of water balance components, specifically run-off, were observed at the Varaždin and Osijek stations. The results show a continuous increase in air temperature and a homogeneous precipitation data series, with no statistically significant trends detected. Similarly, annual maximum and minimum discharges of the Mura and Drava rivers do not exhibit statistically significant trends. However, when applying a 10-year moving average, statistically significant decreasing trends are observed in the maximum and minimum discharges of the Mura River and in the maximum discharges of the Drava River. These changes in the Regional Park area are considered unfavourable and may seriously threaten its ecological values in the future