University of Zagreb
  • Zagreb, Grad Zagreb, Croatia
Recent publications
Background: The complex system of stressors related to the coronavirus disease 2019 (COVID-19) pandemic has affected the global population, provoking a broad range of psychological reactions. Although numerous studies have investigated the mental health impact of COVID-19, qualitative research and cross-country comparisons are still rare. Objective: This qualitative study aimed to explore self-perceived challenges and opportunities related to COVID-19 across six European countries. The overall objective was to provide a differentiated picture of individual subjective experiences in the early stages of the pandemic. Method: The present study included 7309 participants from Austria, Croatia, Georgia, Greece, Poland, and Portugal. We performed qualitative content analysis according to Mayring analyse open-ended questions regarding stressful events, positive and negative aspects of the pandemic, and recommendations to cope with the pandemic situation. MAXQDA software was used for data management and analysis. Results: Participants' accounts were moderately consistent across the countries. The most prominent themes regarding stressful and negative pandemic aspects included: Restrictions and changes in daily life, Emotional distress, and Work and finances. Answers about positive pandemic consequences were mainly centred around the themes Reflection and growth, Opportunity for meaningful/enjoyable activities, and Benefits on interpersonal level. Key themes identified from participants' recommendations to cope with the pandemic included Beneficial behavioural adjustment, Beneficial cognitive-emotional strategies, and Social support. Conclusions: Participants experienced various challenges, but also shared several positive pandemic consequences and recommendations to cope with the pandemic. These first-hand data could inform mental health practices to promote well-being during COVID-19 and similar global challenges in the participating countries and possibly beyond. Highlights: We examined COVID-19-related experiences in 7309 adults from six European countries.Besides challenges, participants identified many positive pandemic consequences.Participants' recommendations to cope with COVID-19 included behavioural and cognitive-emotional strategies.
The knowledge on how gut microbes contribute to the inflammatory bowel disease (IBD) at the onset of disease is still scarce. We compared gut microbiota in newly diagnosed, treatment-naïve adult IBD (Crohn's disease (CD) and ulcerative colitis (UC)) to irritable bowel syndrome (IBS) patients and healthy group. Mucosal and fecal microbiota of 49 patients (13 UC, 10 CD, and 26 IBS) before treatment initiation, and fecal microbiota of 12 healthy subjects was characterized by 16S rRNA gene sequencing. Mucosa was sampled at six positions, from terminal ileum to rectum. We demonstrate that mucosal microbiota is spatially homogeneous, cannot be differentiated based on the local inflammation status and yet provides bacterial footprints superior to fecal in discriminating disease phenotypes. IBD groups showed decreased bacterial diversity in mucosa at all taxonomic levels compared to IBS. In CD and UC, Dialister was significantly increased, and expansion of Haemophilus and Propionibacterium characterized UC. Compared to healthy individuals, fecal microbiota of IBD and IBS patients had increased abundance of Proteobacteria, Enterobacteriaceae, in particular. Shift toward reduction of Adlercreutzia and butyrate-producing taxa was found in feces of IBD patients. Microbiota alterations detected in newly diagnosed treatment-naïve adult patients indicate that the microbiota changes are set and detectable at the disease onset and likely have a discerning role in IBD pathophysiology. Our results justify further investigation of the taxa discriminating between disease groups, such as H. parainfluenzae, R. gnavus, Turicibacteriaceae, Dialister, and Adlercreutzia as potential biomarkers of the disease.
Gastrochilus wolongensis (Orchidaceae), a new orchid species from Sichuan Province, Southwest China, is described and illustrated. It morphologically resembles G. sinensis, but differs markedly from the latter in having black-purple stripes (vs. purplish-red spots) on the adaxial side of the petals and sepals, a reniform epichile densely covered with long papillate hairs (vs. sparsely pubescent) with purplish-red spots (vs. unspotted), and outside the sac of the hypochile with purplish-red stripes (vs. purplish-red spotted). The molecular phylogenetic analysis based on nuclear ribosome internal transcribed spacer (nrITS) and four chloroplast DNA fragments (matK, psbA-trnH, psbM-trnD, and trnL-F) of 36 Gastrochilus species showed that G. wolongensis was closely related to G. ciliaris and G. formosanus.
Background This study aims to present long-term results, preoperative classification, and surgical approach in the therapy of vesicovaginal fistulas (VVF) and neovesicovaginal fistulas (NVVF). Unlike developing countries, where fistulas are mainly the result of delivery trauma, in the modern world, the main causes are urogynecological surgery and irradiation therapy. Methods Data of 36 woman who underwent surgical treatment of VVF and NVVF were collected retrospectively. After clinical assessment, fistulas were categorized by the Goh classification system, which led to the choice of surgical approach: transvaginal or transabdominal. Follow-up period was 60 to 108 months. Results Out of 36 patients evaluated, 23 were operated transabdominal, and 13 were operated transvaginal. Patients selected for the transabdominal approach were mainly categorized as Goh 1 and 2, including patients after radiotherapy and patients with large fistulas. Patients selected for the transvaginal approach were mainly Goh 3 and 4. There were no statistical differences between groups regarding the success of the operation (83.3%) and complication rate. Complications included fistula recurrence (16.6%), stress urinary incontinence (22.2%), urinary tract infections (11.1%), overactive bladder (13.9%), and urosepsis (2.8%). There was a statistical difference in the duration of the hospital stay in favor of the transvaginal approach (12.00 ± 5.8 vs 16.27 ± 4.65). Conclusions Success in the surgical treatment of VVF and NVVF can be achieved by careful preoperative classification, selection of surgical approach, assessment of local tissue status, taking into consideration the characteristics of the fistulas, and adhering to the basic surgical principles. Regardless of the surgical approach, conducting such a preoperative stratification can achieve similar long-term outcomes. Most fistula recurrence (83.3%) appeared within 6 months after the surgery.
Background The development of liver cirrhosis is usually an asymptomatic process until late stages when complications occur. The potential reversibility of the disease is dependent on early diagnosis of liver fibrosis and timely targeted treatment. Recently, the use of non-invasive tools has been suggested for screening of liver fibrosis, especially in subjects with risk factors for chronic liver disease. Nevertheless, large population-based studies with cost-effectiveness analyses are still lacking to support the widespread use of such tools. The aim of this study is to investigate whether non-invasive liver stiffness measurement in the general population is useful to identify subjects with asymptomatic, advanced chronic liver disease. Methods This study aims to include 30,000 subjects from eight European countries. Subjects from the general population aged ≥ 40 years without known liver disease will be invited to participate in the study either through phone calls/letters or through their primary care center. In the first study visit, subjects will undergo bloodwork as well as hepatic fat quantification and liver stiffness measurement (LSM) by vibration-controlled transient elastography. If LSM is ≥ 8 kPa and/or if ALT levels are ≥1.5 x upper limit of normal, subjects will be referred to hospital for further evaluation and consideration of liver biopsy. The primary outcome is the percentage of subjects with LSM ≥ 8kPa. In addition, a health economic evaluation will be performed to assess the cost-effectiveness and budget impact of such an intervention. The project is funded by the European Commission H2020 program. Discussion This study comes at an especially important time, as the burden of chronic liver diseases is expected to increase in the coming years. There is consequently an urgent need to change our current approach, from diagnosing the disease late when the impact of interventions may be limited to diagnosing the disease earlier, when the patient is asymptomatic and free of complications, and the disease potentially reversible. Ultimately, the LiverScreen study will serve as a basis from which diagnostic pathways can be developed and adapted to the specific socio-economic and healthcare conditions in each country. Trial registration This study is registered on ( NCT03789825 ).
Given the importance of the environment around the world and its accelerating destruction brought on by the increase in emissions resulting from the growing use of various forms of transportation, this paper shall aim to eliminate this research gap via a thorough investigation of the literature. These goals include the effect of greenhouse gases emitted by the transportation industry on the environment, the impact of pollutants on transportation mode choice, a study of the obstacles to reducing pollution in transportation, and the presentation of solutions and suggestions. In the research, papers related to this topic in various transportation industries, including road, rail, marine, air, and multimodal transportation, and the variables affecting the control of greenhouse gas emissions in any mode of transportation were collected. Afterward, fundamental analysis was carried out, conclusions drawn, and the presentation of suggestions and solutions in this area addressed. Reducing greenhouse gases in transportation is a challenge that requires examining numerous influential variables and factors. The studies presented in this research are expected to be useful, especially for the energy activists, researchers, and policymakers who would like to conduct long-term studies of pollutants in the transportation industry and the variables influencing the control of greenhouse gas emissions.
The heating sector of the European Union covers 80% of the household’s final energy consumption, which shows its relevance for the energy transition to the carbon neutral society, as set out in the Green Deal. Since most of the heat demand is located in the high heat density areas, district heating shows to be a promising solution for reducing the environmental impact of this sector, as it enables the utilisation of renewable energy sources and the use of high efficiency production technologies. An especially interesting source for district heating is excess heat from various industries and tertiary sector buildings, which has a significant technical potential. However, to enable excess heat producers to supply their heat to district heating, third-party access needs to be granted, which calls for a deregulated heat market. This work consists of analysing two different bidding strategies which can be applied on the heat market: total cost and marginal cost biding. The focus here is to research the feasibility of the excess heat sources when different bidding strategies are used, especially when low temperature excess heat is considered, which has variable hourly costs due to the electricity demand for operating a heat pump. The results show that, despite the increased capacity factor of low temperature excess heat when marginal cost biding is used, it remains infeasible when supplying heat to the high temperature district heating networks through a heat market. Therefore, lower temperature district heating is a necessity for a feasible utilisation of low temperature excess heat. Finally, the effect of the power market prices on the low temperature excess heat feasibility was analysed and it was shown that it is significant, which led to the conclusion that introducing a higher share of renewables into the power market could foster the utilisation of these heat sources.
The use of mannequins to practice different clinical procedures in undergraduate students complies with the 3R principle (Replacement, Reduction, Refinement) without affecting professional competencies. However, commercial solutions are often expensive and therefore, not available for many schools. The main aim of this study was to describe the development and validation of an economical Do-It-Yourself mannequin for jugular blood collection from dogs. The use of the mannequin was evaluated by (1) assessment of the opinion of students and experts and (2) by conducting a pilot study where salivary biomarkers of stress were determined in students and dogs. The costs of the materials needed for the mannequin confection were less than 60 Euros and it was easily built in less than 1 h. The mannequin was very well accepted and scored by both, students and experts, being mostly liked a lot and considered it to be very useful for the practices (Scored 8, 9 or 10/10). Students that could first practice with the mannequin reported a self-perceived higher level of confidence and had lower levels of alpha-amylase in saliva after the procedure. Overall, the mannequin enables the initiation of blood sampling skills in agreement with 3R principles and is easy to perform, economically affordable and sustainable. This model could be adapted to other vein simulations and animal species, and has the potential to help students deal with stressful situations such as taking blood samples from a live animal.
As one promising high-efficiency equipment, flat-plate heat pipes show an important influence on the thermal management of energy systems. This research experimentally investigates the effects of working fluids (acetone, ethanol, and 1.0 wt% Al2O3 water-based nanofluid), liquid filling ratios (30%, 45%, 60%, and 80%), and inclination angles (0°, 30°, 60°, and 90°) on thermal resistance and equivalent heat transfer coefficient of flat-plate heat pipes under input powers of 15 W, 30 W, 45 W, and 60 W. Results indicate that the flat-plate heat pipe with filling ratio of 60% has the minimum thermal resistance of 2.50 °C/W. Compared with filling ratios of 30%, 45%, and 80%, thermal resistance for 60% filling ratio decreases by 42.8%, 27.8%, and 50.7%. The thermal resistances for inclination angles of 0°, 30°, and 90° increase by 88.9%, 2.97%, and 11.8% compared to that with an inclination angle of 60°. The equivalent heat transfer coefficient of the flat-plate heat pipe increases by 90.8% when the inclination angle increases from 0° to 60° due to an effect of gravity. The heat transfer coefficient of the flat-plate heat pipe decreases by 7.2% when the inclination angle increases from 60° to 90°. The thermal resistance of the flat-plate heat pipe using Al2O3 nanofluid as the working medium decreases by 15.2% and 58.7% compared to those with acetone and ethanol. It is observed that partial dryout occurs when the input power is above 30 W. The evaporator with 5 cm length shows the best heat transfer performance of the flat-plate heat pipe.
Growing number of controllable generation, load and storage in distribution networks, have created an opportunity for ancillary services provision to the network operators to more effectively manage everyday grid operation, flexibility provision being one such service. The system operator’s role is to exploit this service effectively while ensuring no grid constraints will be violated. This is often precluded by the lack of measurements deployed in a typical distribution grid. This paper develops a deterministic, optimization-based approach to pre-detect the permissible range of nodal flexibility provision in a distribution network with limited observability where only ranges of nodal power injections are known. Feasibility for the entire permissible range of flexibility with respect to network voltage constraints is ensured by design. Furthermore, we identify and describe a problem stemming from having multiple flexibility providers that influence each others’ ability to provide the service. The method is extended to aggregating the flexibility where special attention is given to establishing fairness among the service providers. We test the efficacy of the proposed method on a modified IEEE 33 and three real world distribution networks.
New 1,2,3-triazolo(thieno)stilbenes were synthesized by Wittig reaction and photochemically transformed to corresponding substituted thienobenzo/naphtho-triazoles in high isolated yields. They were prepared to study the acetyl- and butyrylcholinesterase inhibition associated with the inhibition of TNFα cytokine production and anti-inflammatory activity. The best experimental results were achieved with the allyl-thienobenzotriazole and isopropyl, p-methoxybenzyl, and hydroxybutyl substituted naphthotriazoles bearing additional chloro or methoxy groups. The allyl-thienobenzotriazole photoproduct is twice as potent an inhibitor of eqBChE compared to the standard galantamine. At the same time, this compound strongly inhibited TNFα production in PBMCs in response to the LPS stimulus. The complexes between selected compounds with the active site of BChE and AChE are assessed by docking, providing insight into the stabilizing interactions between the potential inhibitor and the active site.
The high relative accuracy of the Hari–Zimmermann method for solving the generalized eigenvalue problem Ax=λBx has been proved for a set of well-behaved pairs of real symmetric positive definite matrices. These are pairs of matrices (A,B) such that the spectral conditions κ2(AS) and κ2(BS) are small, where AS=DA−1/2ADA−1/2, BS=DB−1/2BDB−1/2 and DA=diag(A), DB=diag(B). The proof is made for one step of the method. It uses a very detailed error analysis and shows that the method computes the eigenvalues of the problem to high relative accuracy. Numerical tests agree with the obtained theoretical results.
Slash-pile burning is a frequent land management practice implemented across the Mediterranean. However, the impact of this practice on runoff waters has often been neglected. To address this issue, two experimental burns were conducted: one with moderate (MS) severity, and another with high (HS) severity, to evaluate the impact of different types of slash–pile on the quality of runoff waters. An unburned (UB) treatment was also considered in this study, to evaluate the impacts of slash–pile burning per se. Treatments were established on a slope terrain (∼18°) characteristic of the Adriatic coast. During the two-year study, runoff and erosion samples were collected 22 times after major rainfall events. Aside from runoff, erosion, and total carbon in sediments (TC) were determined, as well as various water quality parameters, including, pH, electrical conductivity (EC), and Br¯, Cl¯, SO4²¯, PO4³¯, F¯, K⁺, Na⁺, Ca²⁺, and Mg²⁺. Overall, water quality parameters were more affected shortly after burning, while runoff and erosion were more dependent on precipitation patterns. TC in sediments was higher in HS than in MS, the highest values being observed in the last sampling events for both burned treatments. Regarding runoff water quality, the effects were more pronounced at HS, even if the hydrological response was stronger at the MS. The UB treatment showed significant changes in runoff water quality following major rain events, which was attributed to soil saturation. Our results suggest that slash pile burning has adverse effects on runoff waters, so it is recommended for biomass to be used in other ways, especially in the context of soil and water conservation.
We consider quasi-static nonlinear poroelastic systems with applications in biomechanics and, in particular, tissue perfusion. The nonlinear permeability is taken to be dependent on solid dilation, and physical types of boundary conditions (Dirichlet, Neumann, and mixed) for the fluid pressure are considered. The system under consideration represents a nonlinear, implicit, degenerate evolution problem, which falls outside of the well-known implicit semigroup monotone theory. Previous literature related to proving existence of weak solutions for these systems is based on constructing solutions as limits of approximations, and energy estimates are obtained only for the constructed solutions. In comparison, in this treatment we provide for the first time a direct, fixed point strategy for proving the existence of weak solutions, which is made possible by a novel result on the uniqueness of weak solutions of the associated linear system (where the permeability is given as a function of space and time). The uniqueness proof for the associated linear problem is based on novel energy estimates for arbitrary weak solutions, rather than just for constructed solutions. The results of this work provide a foundation for addressing strong solutions, as well as uniqueness of weak solutions for nonlinear poroelastic systems.
This paper investigates the pandemic impact on electric vehicle (EV) monitoring framework designed for analysing and tracking of EV charging data in the Croatian electric vehicle charging station grid. The developed framework encompasses multiple features of the EV charging grid behaviour, notably: (i) global predictions of the utilized energy, (ii) number of charging vehicles, and (iii) total time spent while charging. In this paper, we analyse framework performance and key performance indicator (KPI) values during the pre-lockdown period, soft-lockdown period, and post-lockdown lift-off period to show how the pandemic situations and governmental lockdown regulations can impact EV grid performance and EV charging business. In addition to that, we test a daily framework anomaly detection flow that tracks the global predictive performance of the predictive models on the EV grid, to detect if the framework detects this to be a situation that is novel (anomalous) during the soft-lockdown period. Results show that changes in the behaviour during the lockdown period reduce electric demand on EV charging spots, with customers having lower demand and similar behaviour as in other European countries. Furthermore, the soft-lockdown period is detected as a period with more extreme anomalous values for supervised models, and this is shown as an increase in residual anomaly values, flagging 3 times more days as an extreme anomaly than in the normal periods.
In Arabidopsis thaliana (L.) Heynh., a major part of MATH-BTB protein family (BPM proteins) participate in the ubiquitin‐proteasome pathway as substrate-specific adaptors of Cullin 3 dependent E3 ligase. Through targeting of specific proteins for degradation, BPMs are involved in various developmental processes, as well as in the plant’s ability to adapt to changing environmental conditions. The aim of this research was to investigate the oxidative stress response of Arabidopsis with modified BPMs expression to moderate heat stress. Seedlings of wild type, line overexpressing BPM1 gene (oeBPM1), and line with down-regulation of BPM1, 4, 5, and 6 genes (amiR bpm) were exposed to 37 °C for six hours. Seedlings were sampled immediately after stress and after a recovery period of 24 h. Control seedlings were grown at 24 °C and were collected at the same time points as treated ones. The level of lipid peroxidation, H2O2 and proline content, as well as the activity of antioxidant enzymes (G POD, APX, CAT, and SOD) were evaluated. Control amiR bpm and oeBPM1 seedlings generally had lower H2O2 and proline content, respectively, than wild type. After exposure to 37 °C, oeBPM1 and amiR-bpm lines showed reduced proline content, while no change in lipid peroxidation level and H2O2 content was observed. Further, seedlings with modified BPMs expression showed differences in the activity of G POD, APX, and SOD, while no change was observed in the activity of CAT. The results obtained suggest involvement of BPM proteins in the response of Arabidopsis to moderate heat stress.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
15,326 members
Suncica Bosak
  • Department of Biology
Markus Schatten
  • Artificial Intelligence Laboratory
Miroslav Bača
  • Centre for forensic, biometrics and privacy
Zlatko Stapic
  • Faculty of Organization and Informatics (FOI)
Ljiljana Serman
  • Department of Medical Biology
Trg Republike Hrvatske 14, HR-10000, Zagreb, Grad Zagreb, Croatia
Head of institution
prof. dr. sc. Damir Boras
+385 1 4564 111
+385 1 4830 602