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Design of metal-free catalysts for CO2 reduction
No full textPrateći sve intenzivnije napore znanstvene zajednice u razvoju nemetalnih katalizatora za redukciju ugljikova dioksida (CO2), potaknute rastućim izazovima klimatskih promjena, ovaj rad istražuje potencijal fosfina kao donora hidrida i istodobno kao katalizatora za reakciju redukcije CO2 u mravlju kiselinu. Koristeći računalne kvantno-kemijske metode (DFT), ispitana je sposobnost doniranja hidrida kod protoniranih difosfina supstituiranih elektron-donorskim skupinama: tris(dimetilamino)fosfazenilnom, tris(pirolidino)fosfazenilnom i tetrametilgvanidinskom. Ključan aspekt dizajna ovih difosfina je mogućnost formiranja dativne P–P veze nakon doniranja hidridnog iona, koja značajno pridonosi hidridnom karakteru i katalitičkom potencijalu spojeva. Ispitana je hidričnost ukupno 18 difosfina, a za dva od njih (spojevi 1aa i 4aa) izračunati su reakcijski putevi konverzije CO2 u mravlju kiselinu. Pri tome je utvrđeno da spoj 4aa posjeduje dobar potencijal za katalitičko djelovanje jer je cijeli reakcijski ciklus, uključujući i regeneraciju katalizatora, termodinamički i kinetički ostvariv. Ovim istraživanjem otvara se novi smjer u razvoju nemetalnih katalizatora temeljenih na fosfinima, koji su dosad bili slabo istraženi u kontekstu redukcije CO2.In response to the growing need for metal-free catalyst design for the reduction of carbon dioxide (CO₂), driven by the escalating impact of climate change, this study explores the potential of protonated phosphine compounds to act as both hydride donors and catalysts for reduction of CO2 to formic acid. Using computational quantum-chemical methods (DFT), the hydride-donating ability of protonated diphosphines substituted with electron-donating groups — tris(dimethylamino)phosphazenyl, tris(pyrrolidino)phosphazenyl, and tetramethylguanidino — was investigated. The design of diphosphines capable of forming a dative P–P bond upon hydride donation has proven crucial, as this interaction significantly enhances both the hydride-donating ability and the catalytic potential of these compounds. The hydricity of a total of 18 diphosphines was investigated, and for two of them (compounds 1aa and 4aa), reaction pathways for the conversion of CO2 to formic acid were calculated. It was found that compound 4aa has good potential for catalytic activity, as the entire reaction cycle, including catalyst regeneration, is both thermodynamically and kinetically feasible. This study opens a new direction in the development of non-metallic catalysts based on phosphines, which have so far been scarcely explored in the context of CO2 reduction
Implementation of fly-by-wire flight controls on flight simulator for modern fighter airplane
No full textU diplomskom radu prikazan je razvoj i izrada fly-by-wire (FBW) upravljačke palice koja koristi silu za određivanje zadanih komandi, za razliku od konvencionalnih palica koje mjere pomak. Opisan je proces kalibracije palice te prilagodba postojećeg Simulink model leta kako bi se palica mogla koristiti. Za procjenu primjenjivosti nove FBW palice, proveden je eksperiment s dvije skupine ispitanika koji je uključivao dva zadatka. Prvi zadatak sastojao se od praćenja zadanog kuta propinjanja, dok je u drugom zadatku potrebno pratiti zadani smjer leta. Izvedba je analizirana na dva načina. Objektivno, mjerenjem varijance pogreške od zadanih vrijednosti i mjerenjem broja ekstrema u signalu palice te subjektivno ispunjavanjem NASA-TLX upitnika i ocjenom upravljivosti prema Cooper-Harper ljestvici za ocjenu upravljivosti. Na kraju je prikazana usporedba ostvarenih varijanci pogreške s novom FBW palicom i konvencionalnom upravljačkom palicom.The topic of this master’s thesis is the development and creation of a fly-by-wire (FBW) control stick that uses force to determine input commands, unlike conventional control sticks that measure displacement. The calibration process of the stick is described, as well as the adaptation of an existing Simulink flight simulation model to enable its use. To evaluate the applicability of the new FBW control stick, an experiment was conducted with two groups of participants, involving two tasks. The first task consisted of tracking a specified pitch angle, while the second required tracking a specified flight direction. Performance was analyzed in two ways. Objectively, by measuring the variance of error from predefined values and counting the number of extrema in the control stick signal and subjectively, through the completion of the NASA-TLX questionnaire and maneuverability assessment using the Cooper-Harper rating scale. Finally, a comparison of the error variance achieved with the new FBW control stick and the conventional control stick is shown
Characterisation of silicon dioxide nanoparticles of different sizes and their modification by polyelectrolyte
No full textNanočestice silicijeva dioksida pokazuju veliki potencijal za primjenu u raznim područjima te je za njihovu primjenu važno razumjeti kako veličina utječe na njihova ostala svojstva. Nadalje, modificiranjem nanočestica adsorpcijom polielektrolita moguće je promijeniti njihova svojstva. Polielektroliti su makromolekule čije podjedinice sadrže ionske ili lako ionizirajuće skupine te ih je moguće adsorbirati na površine suprotnog naboja. U ovome radu istražen je utjecaj veličine nanočestica silicijeva dioksida na njihova svojstva te su korištene čestice promjera od 10 nm do 100 nm. Veličina čestica određena je mikroskopijom atomskih sila te pretražnom elektronskom mikroskopijom. Dinamičkim i elektroforetskim raspršenjem svjetlosti određeni su hidrodinamički promjer i ζ-potencijal nanočestica pri različitim koncentracijama natrijeva klorida. Površinski naboj određen je titracijom nanočestica otopinom polielektrolita. Zatim je na nanočestice adsorbiran poli(N-etil-4-vinilpiridinijev) bromid te je određeno kako maksimalna koncentracija polielektrolita ovisi o veličini čestica. Također su određeni veličina čestica, hidrodinamički promjer te ζ-potencijal i uspoređeni s nemodificiranim česticama.Silicon dioxide nanoparticles show great potential for application so it’s important to understand how their size affects their other properties. It is possible to modify nanoparticle properties my adsorbing polyelectrolytes on them. Polyelectrolytes are macromolecules which contain ionic or easily ionisable groups, and they can be adsorbed on oppositely charges surfaces. The influence of silicon dioxide nanoparticle size on their properties was studied for nanoparticles with a diameter of 10 nm to 100 nm. Particle size was determined by atomic force microscopy and scanning electron microscopy. Dynamic and electrophoretic light scattering was used to determine the hydrodynamic radius and ζ-potential of the particles at different concentrations of sodium chloride. Surface charge was determined by titrating nanoparticles with polyelectrolyte. Then, poly(N-ethyl-4-vinylpyridinium) bromide was adsorbed and the dependence of maximum polyelectrolyte concentration on particle diameter was shown. Particle size, hydrodynamic radius and ζ-potential were also determined and compared to unmodified particles
Determination of essential oil content and composition in cinnamon bark
No full textLjekarnička droga Cinnamomi cortex dobiva se od kore pravog, cejlonskog cimetovca (Cinnamomum verum J. Presl.) i
tradicionalni je biljni lijek za blage gastrointestinalne tegobe. S obzirom da je kora cimetovca jedan je od najstarijih i
često korištenih začina koji se zbog svog aromatičnog eteričnog ulja uvelike koristi u kulinarstvu i prehrambenoj
industriji, na tržištu nalazimo kore i nekoliko drugih vrsta cimetovaca. U okviru diplomskog rada provedena je
fitokemijska analiza u svrhu određivanja sadržaja i sastava eteričnog ulja u deset komercijalnih uzoraka kore cimetovca.
Metodom destilacije pomoću vodene pare utvrđeno je da uzorci cjelovite biljne droge sadrže od 16 do 30 mL eteričnog
ulja /kg, dok tržišni uzorci kore u prahu sadrže značajno manje eteričnog ulja (7 do 10 mL/kg). Metodom plinske
kromatografije spregnute s tandemskom spektrometrijom masa (GC-MS/MS) određen je kemijski profil izoliranog
eteričnog ulja kore cimetovca. Identificirane su 51 do 61 sastavnica koje su sačinjavale od 94,76 % do 99,90 % eteričnog
ulja. Glavna sastavnica je trans-cimetni aldehid (56,96-89,86 %), dok su ostale manje zastupljene eugenol (0,96-8,03
%), cinamil acetat (0,20-5,09 %) i p-metoksi-cimetni aldehid (0,25-2,59 %). Kumarin koji može biti štetan po ljudsko
zdravlje utvrđen je u previsokoj koncentraciji u samo jednom od 10 analiziranih eteričnih ulja. Dobiveni rezultati
ukazuju na važnost identifikacije izvorišne biljne vrste i kontrole kakvoće biljnih droga i pripravaka koji se primjenjuju
u suvremenoj fitoterapiji.Herbal drug Cinnamomi cortex consists of bark of the true Ceylon cinnamon tree (Cinnamomum verum J. Presl.) and is
a traditional herbal medicine for mild gastrointestinal complaints. Given that cinnamon bark is one of the oldest and
frequently used spices, which is widely used in the culinary and food industry due to its aromatic essential oil, we also
find barks of several other types of cinnamon on the market. For this graduate thesis, a phytochemical analysis was
carried out in order to determine the content and composition of essential oil in ten commercial samples of cinnamon
bark. Using the method of steam distillation, it was determined that the samples of the herbal drugs in toto contain from
16 to 30 mL of essential oil/kg, while the market samples of powdered bark contain significantly less essential oil (7 to
10 mL/kg). The chemical profile of the isolated cinnamon bark essential oil was determined by the method of gas
chromatography coupled with tandem mass spectrometry (GC-MS/MS). Between 51 and 61 components were
identified, which constituted from 94.76% to 99.90% of the essential oil. The main component is trans-cinnamaldehyde
(56.96-89.86%), while the other less abundant are eugenol (0.96-8.03%), cinnamyl acetate (0.20-5.09%) and p-methoxy
cinnamaldehyde (0.25-2.59%). Coumarin, which can be harmful to human health, was found in too high a concentration
in only one of the 10 analyzed essential oils. The obtained results indicate the importance of identification of the source
plant species and quality control of herbal drugs and preparations used in modern phytotherapy
The association between self-compassion and symptoms of eating disorders in high school students
No full textOvaj diplomski rad istražuje povezanost samosuosjećanja i simptoma poremećaja hranjenja kod adolescenata, s posebnim naglaskom na razlike između mladića i djevojaka. Samosuosjećanje, kao koncept koji se sve više prepoznaje kao vitalan za mentalno zdravlje, obuhvaća ljubaznost prema sebi, zajedničku čovječnost i usredotočenu svjesnost kada je u pitanju vlastita patnja.
Cilj istraživanja bio je ispitati razlike u razinama samosuosjećanja i simptomima poremećaja hranjenja kod mladića i djevojaka, kao i utvrditi povezanost između ovih konstrukata. Istraživanje je provedeno u sklopu većeg znanstvenog projekta „Testiranje 5c modela pozitivnog razvoja mladih: tradicionalno i digitalno mobilno mjerenje“ (P.R.O.T.E.C.T.), čiji je nositelj Edukacijsko-rehabilitacijski fakultet u Zagrebu. U istraživanju je sudjelovalo 289 srednjoškolaca, točnije 141 djevojka i 148 mladića. Učenici su pohađali 2. razrede srednjih škola, pri čemu je 127 učenika gimnazije (43,9%), 141 učenik četverogodišnje ili petogodišnje škole (48,8%) te 21 učenik trogodišnje strukovne škole (7,3%). Prosječna dob djevojaka bila je 15,92 godine (SD= 0,36) dok je prosječna dob mladića bila 15,97 godina (SD=0,42). Podaci su prikupljeni putem standardiziranih upitnika, uključujući SCOFF upitnik za simptome poremećaja hranjenja i Skalu samosuosjećanja za mlade (SCSA).
Rezultati istraživanja pokazali su da adolescentice iskazuju znatno višu razinu simptoma poremećaja hranjenja u odnosu na adolescente, pri čemu 42,1% adolescentica brine o gubitku kontrole nad hranom, u usporedbi sa 15,2% adolescenata. Također, 37,1% adolescentica smatra sebe debelima, dok taj postotak među adolescentima iznosi 15,2%. U istom istraživanju, mladići su pokazali značajno veće razine samosuosjećanja od djevojaka. Daljnja analiza pokazuje da se samosuosjećanje negativno korelira sa svim varijablama simptoma poremećaja hranjenja. Regresijska analiza potvrdila je da je samosuosjećanje značajan negativan prediktor simptoma poremećaja hranjenja, a izraženiji je njegov učinak kod adolescentica nego kod adolescenata. Zaključci ovog istraživanja ukazuju na važnu ulogu samosuosjećanja u razvoju i održavanju mentalnog zdravlja adolescenata te u prevenciji poremećaja hranjenja.This thesis investigates the relationship between self-compassion and eating disorder symptoms among adolescents, with a particular focus on differences between boys and girls. Self-compassion, as a concept increasingly recognized as vital for mental health, encompasses kindness toward oneself, understanding of the shared human experience, and mindful awareness regarding one’s own suffering.
The aim of the research was to examine differences in self-compassion levels and eating disorder symptoms between boys and girls, as well as to determine the connection between these constructs. The research was conducted as part of a larger scientific project called “Testing the 5C Model of Positive Youth Development: Traditional and Digital Mobile Measurement” (P.R.O.T.E.C.T.), led by the Faculty of Education and Rehabilitation Sciences in Zagreb. A total of 289 high school students participated in the research, specifically 141 girls and 148 boys. The students were in their second year of high school, with 127 students in gymnasiums (43.9%), 141 students in four or five-year programs (48.8%), and 21 in three-year vocational schools (7.3%). The average age of the girls was 15.92 years (SD = 0.36), while the average age of the boys was 15.97 years (SD = 0.42). Data were collected using standardized questionnaires, including the SCOFF questionnaire for eating disorder symptoms and the Self-Compassion Scale for Adolescents (SCSA).
The research results revealed that adolescent girls exhibit a significantly higher level of eating disorder symptoms compared to boys, with 42.1% of girls concerned about losing control over their eating, compared to 15.2% of boys. Furthermore, 37.1% of girls consider themselves overweight, while this percentage among boys is 15.2%. In the same study, boys demonstrated significantly higher levels of self-compassion then girls. Further analysis indicates that self-compassion negatively correlates with all variables of eating disorder symptoms. Regression analysis confirmed that self-compassion is a significant negative predictor of eating disorder symptoms, with a more pronounced effect among girls than boys.
The conclusions of this research highlight the important role of self-compassion in the development and maintenance of mental health among adolescents, as well as in the prevention of eating disorders
Analysis of cor samples and identification of Fusarium genus molds
No full textPlijesni roda Fusarium su najbrojniji rod gljivica koje kontaminiraju kukuruz. Poznat je njihov štetan učinak na zdravlje ljudi i životinja, bilo uzrokovanjem fuzarioze ili akutnim i kroničnim trovanjem mikotoksinima, a temperatura zraka i količina padalina su se pokazale kao vrlo značajni čimbenici o kojima ovisi njihova pojavnost na kukuruzu. Klimatske promjene zbog toga uvelike utječu na kontaminaciju kukuruza i prehrambenih proizvoda dovodeći do porasta koncentracija plijesni na usjevima, većih koncentracija kontaminanata u prehrambenim namirnicama i sve većem riziku za ljudsko zdravlje te smanjenoj isplativosti poljoprivrednih uzgoja.
Mikološka analiza metodom razrjeđenja na hranjivim podlogama (DRBC i MGA) provedena je na 50 uzoraka kukuruza od kojih su 25 iz 2021. godine, a 25 iz 2022. godine. Istraživanje je pokazalo je da su koncentracije plijesni veće na uzorcima iz 2022. godine, za koju je prosječna vrijednost koncentracije na DRBC agaru 7,93 x 105 CFU/g dok je za 2021. srednja vrijednost koncentracije na DRBC agaru 1,32 x 105 CFU/g. Srednja vrijednost koncentracije na MGA agaru je također veća za 2022. godinu. Dobivene srednje vrijednosti su vrlo visoke, a većina uzoraka premašuje dozvoljene maksimalne koncentracije koje smiju biti prisutne u hrani.
Na svim uzorcima je došlo do porasta plijesni roda Fusarium, što pokazuje na dominaciju ovog roda kao kontaminanta kukuruza. Na DRBC agaru plijesni roda Penicillium su izrasle na 96% uzoraka, a plijesni roda Aspergillus na njih 72% što ih čini sljedećima po zastupljenosti. Od ostalih plijesni pojavljuju se vrste iz roda Cladosporium, Absidia, Trichoderma i Mucor, a na 28% uzoraka je uočen porast kvasaca. Svi uzorci s kvascima poraslih na DRBC agaru su iz 2022. godine. Na MGA agaru osim fuzarija je također došlo do porasta kvasaca na nekim uzorcima, od kojih je 84% također iz 2022. godine.
Izolacijom i identifikacijom plijesni roda Fusarium primjenom molekularne metode tj. sekvenciranjem genske regije ITS pokazano je da se u većini uzoraka radi o vrsti F. napiforme i/ili F. verticilloides dok je za samo 6% uzoraka identificirana vrsta F. fujikuroi i/ili F. proliferatum. Sve identificirane vrste pripadaju F. fujikuroi kompleksu vrsta. Genska regija ITS pokazala se nedovoljno specifična za razlučivanje srodnih vrsta unutar fuzarijskih kompleksa. Za razlučivanje vrsta unutar pojedinih fuzarijskih kompleksa potrebno je primijeniti više genskih markera kao što su tef1 i rpb2. Visoka učestalost i dominacija vrsta iz kompleksa F. fujikuroi u uzorcima kukuruza može predstavljati opasnost za zdravlje ljudi jer se radi o uzročnicima mikoza kao i o poznatim proizvođačima mikotoksina, poglavito iz skupine fumonizina.Molds of the genus Fusarium are the most prevalent fungi contaminating corn. Their harmful effects on human and animal health are well-documented, either through causing fusariosis or through acute and chronic poisoning by mycotoxins. Air temperature and precipitation levels have been identified as significant factors influencing their occurrence in corn. Consequently, climate change greatly impacts the contamination of corn and food products, leading to increased concentrations of molds in crops, higher contaminant levels in food products, an elevated risk to human health, and reduced profitability in agricultural production.
Mycological analysis using the dilution method on nutrient media (DRBC and MGA) was conducted on 50 corn samples, 25 from 2021 and 25 from 2022. The study revealed that mold concentrations were higher in the 2022 samples, with an average concentration value on DRBC agar of 7.93 x 10⁵ CFU/g, compared to an average concentration value on DRBC agar of 1.32 x 10⁵ CFU/g for 2021. The average concentration value on MGA agar was also higher for 2022. The obtained average values are very high, with most samples exceeding the maximum allowable concentrations permitted in food.
All samples showed an increase in molds of the genus Fusarium, and in the majority of samples, they were the dominant genera. On DRBC agar, molds of the genus Penicillium grew on 96% of samples, and molds of the genus Aspergillus on 72%, making them the next most prevalent. Other molds present included species from the genera Cladosporium, Absidia, Trichoderma, and Mucor, with 28% of the samples showing yeast growth. All samples with yeast growth on DRBC agar were from 2022. On MGA agar, in addition to Fusarium, yeast growth was also observed on some samples, 84% of which were from 2022.
Isolation and identification of molds of the genus Fusarium using molecular methods, specifically sequencing of the ITS gene region, demonstrated that most samples contained the species F. napiforme and/or F. verticillioides, while only 6% of the isolates were identified as F. fujikuroi and/or F. proliferatum. All identified species belong to the F. fujikuroi species complex. The ITS gene region proved to be insufficiently specific for distinguishing closely related species within the Fusarium complexes. To differentiate species within specific Fusarium complexes, the application of multiple genetic markers, such as tef1α and rpb2, is required. The high prevalence and dominance of species from the F. fujikuroi complex in corn samples may pose a risk to human health, as they are known pathogens causing mycoses and are recognized producers of mycotoxins, particularly fumonisins
INFLUENCE OF TEMPERATURE EXTREMES ON ZOOPLANKTON DEVELOPMENT DURING THE SPRING – SUMMER PERIOD
No full textPlanktonski rakovi zauzimaju ključni trofički poloţaj unutar slatkovodne hranidbene mreţe, a njihov razvoj
ovisan je o temperaturi. Cilj provedenog istraţivanja bio je utvrditi imaju li zabiljeţene normalne i ekstremne
temperature u proljetnom (travanj – lipanj) i ljetnom razdoblju (srpanj – rujan) 2012., 2013. i 2016. godine
utjecaj na kvalitativni i kvantitativni sastav zajednice planktonskih rakova u jezeru Sakadaš (Park prirode
Kopački rit). Uzorci vode za hidrobiološke analize prikupljeni su iz površinskog sloja jezera Sakadaš
mjesečnom dinamikom. Struktura zajednice zooplanktona opisana je indeksima, a vrijednosti mjerenih
fizikalno – kemijskih čimbenika usporeĎene su statistički primjenom t-testa i jednosmjerne analize varijance.
Zajednicom rašljoticalaca dominirale su manje forme, dok su zajednicom veslonoţaca dominirali ciklopoidni
veslonošci i njihovi razvojni stadiji. Brojnost i biomasa planktonskih rakova značajno su se razlikovale
izmeĎu proljeća i ljeta pri čemu su veće vrijednosti zabiljeţene u proljeće. Istraţivanjem je utvrĎeno da
temperatura utječe na sezonske sukcesije i moţe doprinositi meĎugodišnjim varijabilnostima u sastavu
zajednice, no značajniji je indirektan utjecaj kroz dostupnost hranjivih tvari i predaciju. Istovremeno s
temperaturom značajan utjecaj su imali prozirnost, koncentracija klorofila a te koncentracija dušika.Microcrustacean zooplankton constitutes a major component of freshwater food webs and their development depends on temperature. The aim of this study was to determine whether the recorded normal and extreme temperatures have an impact on the qualitative and quantitative composition of the microcrustacean community in Lake Sakadaš (Kopački rit Nature Park) during spring (April – June) and summer (July – September) of 2012., 2013. and in 2016. Water samples for hydrobiological analyses were collected monthly from the upper layer of Lake Sakadaš. The structure of the zooplankton community was described using indexes and the values of the measured physico – chemical parameters were compared using a statistical application of the t-test and one – way ANOVA. Small forms dominated in the cladoceran community, while cyclopoid copepods with juvenile forms were dominant in the copepod community. The abundance and biomass were significantly different between spring and summer with higher numbers recorded in spring.
The present study found an impact of temperature on seasonal succession and contribution to interannual variability in community structure and an indirect impact through nutrient availability and predation. Simultaneously with the temperature, transparency, chlorophyll – a concentration and nitrogen concentration influenced the microcrustacean zooplankton community
ANTIBACTERIAL PROPERTIES OF SUBCUTANEOUS TISSUE EXTRACTS OF DIFFERENT VARIETIES OF WHITE GRAPES (Vitis Vinifera L.)
No full textPrisutnost polifenola u pokožici predmet je brojnih istraživanja zbog njihovih pozitivnih učinaka na ljudsko
zdravlje. Polifenolni spojevi u grožđu zastupljeni su u dvije osnovne kategorije: flavonoidi i neflavonoidi. U
skupinu flavonoida ubrajaju se flavan-3-oli, flavonoli, flavanoli i antocijani, a u kategoriji neflavonoida
zastupljeni su stilbeni, te fenolne kiseline (hidroksibenzojeve i hidroksicimetne). Najznačajniju razliku između
crnog i bijelog grožđa čini prisutnost antocijanina u polifenolnom sastavu crnog grožđa. Pokožica bijelog
grožđa nije dovoljno proučena u usporedbi s crvenim sortama, zbog nižeg sadržaja antocijanina i
proantocijanidina. Međutim, pokožica bijelog grožđa bogat je izvor flavonoida i stilbena s važnim svojstvima
za promicanje zdravlja. Sadržaj ukupnih fenolnih spojeva ovisi o raznolikosti prisutnih čimbenika kao što su
svijetlost, temperatura, okoliš i agrotehničke metode. Za izolaciju fenolnih spojeva služe raznolike metode
ekstrakcije koje se biraju prema određenim čimbenicima za pojedinu sortu.The presence of polyphenols in the epidermis has been the subject of numerous studies due to their positive
effects on human health. Polyphenolic compounds in grapes are represented in two basic categories: flavonoids
and nonflavonoids. The group of flavonoids includes flavan-3-ols, flavonols, flavanols and anthocyanins, and
the category of non-flavonoids includes stilbenes and phenolic acids (hydroxybenzoic and hydroxycinnamic).
The most significant difference between red and white grapes is the presence of anthocyanins in the
polyphenolic composition of red grapes. The skin of white grapes has not been sufficiently studied compared
to red varieties, due to the lower content of anthocyanins and proanthocyanidins. However, the skin of white
grapes is a rich source of flavonoids and stilbenes with important health-promoting properties. The content of
total fenolic compounds depends on the variety of factors present such as light, temperature, environment and
agrotechnical methods. A variety of extraction methods are used to isolate phenolic compounds, which are
selected according to certain factors for each variety
The impact of noise pollution on marine invertebrates
No full textAntropogeni izvori buke pod morem te njihovi učinci na
morske beskralježnjake rastući su globalni problem. U radu je opisano širenje zvuka u morskoj
vodi te temeljne komponente podvodne buke. Morski beskralježnjaci gotovo isključivo
percipiraju komponentu gibanja čestica, a u tome im pomažu osjetilni receptori u vidu
osjetilnih dlačica i statocista. Eksperimentalno izlaganje zvuku može biti akutno i kronično.
Iako je većina dosadašnjih studija bazirano na istraživanju obrazaca ponašanja i kretanja, u
novije vrijeme raste broj studija koje proučavaju fiziološke, biokemijske i genetičke odgovore
morskih beskralježnjaka prilikom izlaganja buci sa rastućim dokazima o štetnosti
antropogenog zvuka u moru.Anthropogenic sources of underwater noise and their effects on sea
invertebrates have grown into global problem. This thesis describes the propagation of sound
in seawater and the underlying components of underwater noise. Sea invertebrates almost
exclusively perceive the particle movement component which is assisted by sensory receptors
such as sensory hair and statocysts. Experimental exposure to sound can be acute and chronic.
Although most of the studies so far have been based on looking into patterns of behavior and
movement, in recent time there has been an increase of studies studying the biochemical,
physiological and genetic responses of sea invertebrates during the sound exposure with the
growing evidence of the detrimental effects of anthropogenic noise in the sea
PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF COMMON DUCKWEED (LEMNA MINOR L.) EXPOSED TO SODIUM CHLORIDE AND 6-BENZYLAMINOPURINE
No full textOsmotski stres izazvan povišenim salinitetom predstavlja ozbiljan problem u svim prirodnim ekosustavima.
Zbog osjetljivosti na toksične supstance, brzog rasta i lakog uzgoja, Lemna minor L., mala plutajuća
makrofitska vrsta, prikladan je model za proučavanje utjecaja različitih stresnih čimbenika. Cilj ovog rada bio
je ispitati fiziološki i biokemijski odgovor male vodene leće tijekom desetodnevnog izlaganja natrijevom
kloridu (50, 100 i 150 mM NaCl) i 6-benzilaminopurinu (10-3 mM 6-BAP). Povišeni salinitet inhibira prirast
broja biljaka i prirast mase biljaka, dok 6-BAP djeluje stimulativno na veličinu frondova i prirast mase.
Nepromijenjeni sadržaj malondialdehida i prolina ukazuje na izostanak stresnog efekta ispitivanih tretmana.
Unatoč smanjenju koncentracije klorofila a i b i karotenoida pri višim koncentracijama soli, omjeri Chl a/b i
Chl a+b/Car ukazuju na izostanak oksidacijskog oštećenja. Fluorescencija klorofila a je pokazala da u
uvjetima solnog stresa L. minor zadržava i poboljšava aktivnost i funkcionalnost fotosintetskog aparata
povećavajući stabilnost OEC i elektronskog transporta sa PSII na PSI. Egzogeno dodani sintetski citokinin,
6-BAP, uzrokovao je smanjenje energetske povezanosti i stabilnosti OEC što dugoročno može uzrokovati
disfunkcionalnost fotosustava II. Povećanjem koncentracije soli u kombinacijama s hormonom umanjen je
negativan utjecaj hormona na fotosintetski aparat. Rezultati ovog istraživanja pokazali su da mala vodena
leća ima razvijeni mehanizam tolerancije povišenog saliniteta, što ju čini dobrom potencijalnom sirovinom za
proizvodnju biogoriva u umjereno zaslanjenim ekosustavima.Osmotic stress caused by increased salinity is a severe problem in natural ecosystems. Due to its sensitivity
to toxic substances, rapid growth, and easy cultivation, Lemna minor L., a small floating macrophyte, is a
model species for researching the influence of various stressors. This study aimed to investigate the common
duckweed's physiological and biochemical response during ten-day-long exposure to sodium chloride (50,
100, 150 mM NaCl) and 6-benzylaminopurine (10-3 mM 6-BAP). Increased salinity inhibited plant growth
rate and size, while 6-BAP had a stimulating effect on growth rate and frond size. Unchanged
malondialdehyde and proline content indicated the absence of the stress effect. Despite the decrease in
chlorophyll a and b and carotenoids at higher salt concentrations, Chl a/b and Chl a+b/Car ratios indicated
the lack of oxidative damage. The chlorophyll a fluorescence has shown that under salt stress conditions, L.
minor retains and improves the photosynthetic apparatus's activity and functionality by increasing the
stability of OEC and electronic transport from PSII to PSI. Added synthetic cytokinin, 6-BAP, caused a
decrease in the energy connectivity and stability of the OEC, which may, in the long run, cause dysfunction
of PS II. Increasing the salt concentration in combination with the hormone reduces the hormone's negative
impact on the photosynthetic apparatus. This study indicated that L. minor has an efficient salt-stress
tolerance mechanism, making it an excellent plant for biofuel production in moderately saline ecosystems