Presentation number: FSA 1


Filip Bulat

VII. Gymnasium, Zagreb, Croatia

The sensory receptors of vestibulocochlear organ in humans are hair cells which transmit the stimulus via nerves to the brain. Evolutionary, they are of ectodermal origin. Many diseases affect these cells resulting in degradation and loss of function in vestibulocochlear system. We were interested in knowing how starvation, i.e., malnutrition affects ciliates Paramecium sp. The purpose of the research was to experimentally test the reaction of malnourished Paramecium sp. (starving Paramecium) to spinning, which is a physiological stimulus for the vestibular organ. The same volume of Paramecium culture medium of good physiological condition with optimal concentrations of oxygen in the water was placed in 10 test tubes marked with letters A1 to A5 and B1 to B5. The culture (Paramecium sp.) that was fed was marked group A, while the malnourished culture was marked group B. The test tubes were kept on a rack. The same volume of sample was added to each test tube. Immediately before spinning each tube was tightly screwed and put in a separate small transparent bag tied at the top with the wool string 10 cm long. Bags were evenly spun for 5 minutes. The test tubes were then placed back on a rack and after 10 minutes a sample from the test tube was taken with a pipette and put in a Petri dish on the bottom of which a net for counting Paramecium sp. sized 1cm x 1cm was drawn. The Petri dish was then filled with a sample of Paramecium sp. culture medium to the 3 mm mark. The experiment was conducted in the following order: A1 and B1 were not exposed to trauma, and they represent control samples, while other samples were exposed to spinning: A2 and B2: on the 1st, 4th, and 8th day of the experiment, A3 and B3: on the 1st, 3rd, 5th, 7th, and 8th day, A4 and B4: one spin each day, A5 and B5 two consecutive spins each day. The proportion of dead Paramecium in a given sample volume during 8 days after spinning was measured in relation to the control sample. Compared to control sample in test tube A2, 18,33% specimens die. In test tube B2 20,83% specimens die. In both samples the majority of Paramecium survives and has proper mobility. The total number of live specimens in sample B2, on the eighth day of the experiment, is smaller in relation to the total number of live specimens in sample A2 on the eighth day of the experiment. 40.67% of Paramecium die in sample B3 after eight days, while 28,21% of Paramecium die in sample A3. 43,75% of Paramecium die in sample B4, and 44,83% of Paramecium die in sample A4. Test tube B5 has 50,21% of dead Paramecium, while 42,54% of Paramecium die in sample A5. Results show that better nutrition leads to better resistance to physiological, and especially to extreme stimuli, and the survival of the cells is thus greater. Since there is no data on the subject that was analyzed, it is assumed that better condition of well-nourished specimens results in better resistance to damage; therefore, sensory receptors that have proper nutrition (blood flow) are more resistant to damage and degradation of function in vestibulocochlear system.

Presentation number: FSA 2


Ante Čolak

  1. Gymnasium, Zagreb, Croatia

Detailed study and analysis of the accession literature on the basis of which the discussion of the comparison was made. Aducanumab is effective in removing β-amyloid plaque, but as an anti-AD drug it is not effective in preventing or alleviating symptoms. On the other hand, symptomatic therapies are effective in alleviating the cognitive decline caused by neurodegeneration, but are not effective in preventing the development of AD. The first, the PRIME test, showed that aducanumab reduces amyloid PET SUVR findings 15 within 54 weeks of treatment. Due to the promising results, Biogen decided to conduct two new studies: EMERGE and ENGAGE. Moreover, EMERGE met its goal: subjects treated with the highest dose, 10 mg/kg, had a significantly better result (30% better) measured on the Clinical Dementia Rating Scale (CDR-SB). Furthermore, participants in the ENGAGE study improved their cognitive performance by 27% measured by CDR-SB. Current treatments for Alzheimer’s disease vary from symptomatic treatments to the drug known as aducanumab which reduces the β-amyloid plaques that are considered to be one of the causes of this neurodegenerative disease. Due to the insufficient improvement of cognitive abilities among patients, aducanumab has proved to be insufficient treatment for cognitive manifestations of the disease. Comparatively, symptomatic treatments, like acetylcholinesterase inhibitors and NMDA receptor antagonists, help patients improve their cognitive capabilities, meaning they are more effective than aducanumab regarding the symptoms. An indirect benefit of the discovery of aducanumab is shaping the course of Alzheimer’s research.

Presentation number: FSA 3


Mei Đulabić Chalfe

  1. Gymnasium, Zagreb, Croatia

The aim was to determine how everyday and ubiquitous disinfectants affect different types of bacteria and whether different cosmetic ingredients in some antibacterials such as hand gel affect the growth of different types of bacteria positively or negatively. Recognize if the resistance of different bacteria to the same disinfectants differs. Also, the aim of the study was to determine whether Salmonella’s resistance to disinfectants differs from other gram-negative bacteria. Collecting swabs from 7 places then applying diluted solutions of these swabs to various selective and differential nutrient substrates (Plate Count agar, Mac Conkey agar, BD Salmonella Shigella Agar). Placing Petri dishes in an incubator and calculating the CFU before and after using the disinfectant. Gram-negative bacteria were on average more susceptible to disinfectants than other bacteria. The most effective disinfectant was 70% ethanol alcohol. The least effective disinfectant was antibacterial wipes. Salmonella was more resistant to disinfectants than other gram-negative bacteria. The main conclusion of the study is that all types of bacteria have shown some kind of resistance to the disinfectants used, which coincides with the read literature and hypothesis.

Presentation number: FSA 4


Robertina Filković

  1. Gymnasium, Zagreb, Croatia

This research is carried out to confirm the fact that social networks and school have negative influence on adolescents’ mental health.  The fact is proven by two hypotheses: 1. Social networks have negative influence on high school students’ mental health. 2. The pressure made for better academic accomplishment leads to higher number of suicidal high school students. The research is carried out with two questionnaires. First questionnaire, which was carried out at the end of the January, was solved by 374 high school students. Second questionnaire is carried out to establish how much does school affect students’ mental health.  It was carried out in mid-April and was solved by 238 students. Results from first questionnaire show that today many high school students have symptoms of mental illnesses. The main cause is technology. According to answers social networks cause development of anorexia nervosa and bulimia nervosa. On average, school success is important to examinees and among those who said that school success is very important 23 think about suicide and 14 resort to self-harm. Depression symptoms mostly appear at the examinees who engage with sport. The results show that high school students are getting suicidal, and they are finding help in illicit substances. They are isolating themselves and their social life and academic success are failing. To reduce the number of high school students who are suffering from mental illnesses, parents and students’ education is needed.

Presentation number: FSA 5


Lucija Glavičić Marović

  1. Gymnasium, Zagreb, Croatia

This essay aims to review the current body of knowledge on the effects of microplastics and nanoplastics on human health. The additional objective is to discuss the possible impact of microplastics and nanoplastics on human epigenetic modifications. An electronic search of published articles was conducted in PubMed and Google Scholar using the following keywords: “microplastics human health”, “microplastics epigenetic”, and “microplastics epigenetic modification human”. Microplastics can pose risks to human health in three ways: as physical particles, chemicals, or microbial pathogens found in biofilms on microplastic particles. The most important entry route to the human body is ingestion. Only small microplastic particles can be absorbed (<150 μm can penetrate the gastrointestinal epithelium, <100 nm can penetrate the dermal barrier, <10 μm can be absorbed through the alveolar epithelium). Potential harmful pathways to human health include gut and lung inflammation, oxidative stress and cytotoxicity, translocation, metabolism and energy homeostasis, neurotoxicity, reproductive toxicity and carcinogenicity. Prenatal and neonatal exposure to certain chemicals forming plastics (bisphenol A, phthalates, and others) can cause not only epigenetic changes, but also genetic and morphological changes. The potentially harmful effects are determined mainly by levels of exposure, concentration and individual susceptibility. Growing evidence suggests that increased exposure to microplastics can increase incidence in gut and lung inflammation, obesity, immunological disorders, neurological diseases, cardiovascular diseases and cancer.  The increasing exposure of humans to microplastics calls for further research to understand its impact better.

Presentation number: FSA 6


Đurđica Kovačić

III. Gymnasium, Split, Croatia

The aim of the research was to determine which of the agents used has antibacterial properties and which disinfectant is the most effective when it comes to bacterial growth inhibition. An experiment was conducted comparing the effects of commercial disinfectants (soap, antibacterial soap, antibacterial hand gel) and natural disinfectants (aqueous clove extract, aqueous garlic extract, lavender oil, immortelle oil) on bacterial growth and development. Samples were taken from the classroom handle. Swabs were inoculated into tripton soy broth, after incubation decimal dilutions were made which were then inoculated on nutrient agar. After incubation of nutrient agar, colonies were counted. The following parameters were changed in the experiments: incubation time of tripton soy broth and nutrient agar, type of disinfectant and volume of disinfectant. The results showed that lavender oil was the most effective in inhibiting the growth of bacterial colonies, while antibacterial hand gel was the least effective. Disinfectants are more effective when placed in a larger volume (1 ml) than in a smaller one (0.2 ml), and pentanol-based antibacterial soap inhibits bacterial growth better than regular sodium benzoate-based soap. In conclusion, all disinfectants used showed antimicrobial properties. In further research, it would be desirable to investigate the disinfectant effect of lavender oil on specific species of bacteria and compare the results with other natural disinfectants. The impact of the active substance on soap effectiveness could also be researched in the future.

Presentation number: FSA 7


Nika Adriana Marijanović

Classical Gymnasium, Zagreb, Croatia

Sunlight consists of different spectrums of radiation such as visible light, ultraviolet (UV) and infrared light. Light is measured in wavelengths (λ), and the unit of measurement is nanometer (nm) and millimeter (mm). Different light radiations in the spectrum have different wavelengths. Sunlight can have positive and negative effects on human health. Negative effects can overshadow the positive effects with a lack of caution when exposed to sunlight for longer periods of time. Some of the consequences can be burns, premature skin aging, hyperpigmentation, allergic reactions and more serious conditions such as skin cancer. These kind of skin damages caused by the sun are mainly due to UV rays. There are many different products on the market that can protect our skin from damaging rays. The sun protection factor rating (SPF) system for sunscreens is based on the level of UVB protection offered by the product. SPF multiplied by natural skin protection in minutes determines the maximum length of time you can expose your skin to the sun without the risk of UVB-induced skin damage. However, SPF protection depends on the use of the right amounts (2 mg/cm2) of the product, therefore 60% of the time allowed by SPF is recommended. The aim of this experiment was to examine the effectiveness and quality of different sunscreens. The hypothesis of this research was that sunscreens with a higher factor will provide better cell protection. For this experiment, a total of 6 different sunscreens was used, of which 3 with a factor of 50 and the other 3 with a factor of 30. The MTT test, a standard test that measures the survival (viability) of cells after a treatment was used in the study to measure cell survival after exposure to UVB radiation. The best cell protection was provided by Eucerin 30 cream with a viability of 111.35%, followed by Vichy 50 (101.39%), the third Avon 50 (98.59%), followed by Eucerin 50 (95.64). %) and with lower viability Nivea 30 (79.3%) and Clarins 30 (78.02%). After all the information gathered from this experiment, I can conclude that the sunscreen Eucerin 30 provides the best protection against UV radiation, and Clarins 30 the worst, even though it is the most expensive product. I have also noticed that creams with a thicker composition also have a better effect. Spray sunscreens such as Nivea 30 and Clarins 30 provided the weakest protection.

Presentation number: FSA 8


Frane Marušić

Jure Kaštelan High School, Omiš, Croatia

The aim of the study was determining the effects of anthropological eutrophication on microorganisms in the Cetina River. Methods used were the following: smear method, incubation, rapid KOH test (determination per gram), flow cytometry and morphological characterization of bacteria. Compared to the data from the water sample collected five kilometers before the mouth of Cetina, quantitative data from the flow cytometer showed a decrease in the total amount of bacteria at the mouth of the river Cetina, where the city of Omis is located, but also a marked increase in bacterial predators (HNF) and cyanobacteria. Comparing these data with other research, it was found that eutrophication is a possible impact on the differences observed in the entire aquatic ecosystem and the food chain of the Cetina River. On the other hand, the characterization of bacteria showed that there is no significant difference between the types of bacteria at the stations, which leads to the conclusion that eutrophication does not affect the diversity of bacteria at the Cetina river. Humans have a great impact on the ecosystem of the Cetina river and are one of the causes of significant changes in the community of microorganisms. Although eutrophication is not yet strongly expressed in the Cetina River, it is necessary to protect Cetina so that more negative consequences do not follow, such as the development of infectious diseases, algae blooms, and degradation of recreational opportunities.

Presentation number: FSA 9


Nika Miličević

  1. Gymnasium, Zagreb, Croatia

The aim of the research is to determine whether the application of different types of synesthesia will improve the performance of three tasks related to memory, concentration, and visual perception in high school students. The intention is also to compare the effects of synesthesia exercises in 1st and 3rd-grade students and to compare the results of girls and boys in the experimental groups. The study involved 200 high school students: 100 1st grade students and 100 3rd grade students with equal proportions of boys and girls. Students were divided into control and experimental groups and solved tasks for examining memory, concentration, and visual perception in separate classrooms. The first experiment examined whether colors help with grapheme memorization, the second whether drawing and eating candy help concentrate-, and the third experiment whether sound and touch improve visual perception.  Each experiment lasted 60 seconds. The results were processed by a two-way t-test in Excel. Processing the results, it turned out that the differences between the 1st-grade groups were not, and between the 3rd-grade groups were statistically significant, and that the 1st-grade girls in the concentration and visual perception experiments had higher results than the 1st-grade boys. Synesthesia was found to help 3rd graders solve tasks, but not the 1st graders. It turned out that only older boys were significantly better in all experiments compared to younger 1st graders and that 1st-grade girls were significantly better only in memory and concentration experiments than 1st-grade boys.

Presentation number: FSA 10


Goran Narančić

  1. Gymnasium, Zagreb, Croatia

The aim of this investigation is to establish the presence of metric trends in hominid dental evolution by comparing the teeth measurements of gypsum jaw models of modern humans from Western Balkans with the measurements of Australopithecus from Wolpoff’s data. The method of measuring the dimensions of the teeth is based on the Lundstrom’s method. Mesiodistal (in the direction of the tongue, “from the back to the front”) width of tooth’s crown and its breadth (from right to left) were measured with a caliper. For the teeth in the same part of the jaw (upper and lower) and of the same type and position (for instance the second incisor or first molar) the arithmetic mean of all measurements for that tooth was calculated and the standard deviation as well. The incisors in the modern human samples were significantly smaller than the ones in Australopithecus, while the difference was significantly larger in the second incisor than in the first one. In Australopithecus the canines are as much as 18% larger than in the modern human sample. The premolars of Australopithecus are significantly greater than those of the modern man, but the second premolar is much smaller than the first one in modern human. The first molar is significantly larger in Australopithecus than in the modern man. There is a clear metric trend of a decrease in teeth size in the evolution of the human jaw on the sample of the people from the Western Balkans and some teeth have shrunk more than others. It is to be assumed that the same trend will keep up in the future if the assumed causes of this trend are true and if the sedentary lifestyle carries on as it is.

Presentation number: FSA 11


Rea Pešušić

Vladimir Prelog Science School, Zagreb, Croatia

The aim of the study was designing a preparation with a therapeutical effect on coeliac disease based on genetically modified lactobacilli in mixture with bifidobacteria. The methods used were genetic modification of selected LABs (e.g. L. gasseri, L. johnsonii L. reuteri, L. acidophilus) caring genes for gluten proteases and preparation of mixture ratios of modified LABs and bifidobacterial BIF with prebiotic (Bifidobacterium longum and Bifidobacterium bifidum) for testing in mice animal model for coeliac disease. The results included genetic modification of LABs: cloning gene for gluten processing proteases; expression vector (such as an RCR – rolling cycle replication, which rapidly synthesizes plasmids – replicon) containing cloned gene; inducible promotor nisin-controlled gene expression system (NICE), transcriptional terminator and ribosome binding site to ensure optimal transcription and translation; cloned genes for glycosylation to enable post-translational modifications and functionality of produced enzymes. Mixtures of LABs and BIF in different ratios together with prebiotic for their metabolic stimulation orally applied in mice should be tested over time tracking the changes of the gut microbiome and gluten degradation, as well as regular blood tests to check the antigen levels. Genetically modified LABs orally inserted into the gut biome could be the best and safest step in the direction of developing a drug for celiac disease. I propose a cloning vector based on a RCR replicon, inserted by electroporation, with a promoter belonging to NICE, which would allow LABs to produce gluten-specific proteases, and would possibly help replenish the gut biome, if they were introduced in a cocktail with bifidobacteria.



Published: June 21st, 2022;

Copyright: © 2022 ISABS & IAR Publishing. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.