Croatian Digital Thesis Repository
Not a member yet
259189 research outputs found
Sort by
Improving bioremediation of waste streams through exogenous microbial cultures
No full textU modernom svijetu tehnološkog napretka, antropogene aktivnosti dovode do sve većeg onečišćenja voda. Procjedne vode koje nastaju iz organske frakcije miješanog komunalnog otpada sadrže visoko opterećenje te zahtijevaju fizikalnu, kemijsku ili biološku obradu prije ispuštanja u okoliš. Tehnologija bioremedijacije postaje sve važnija u suočavanju s navedenim izazovima jer pruža održivo i visokoučinkovito rješenje za sanaciju različitih vrsta onečišćenja. Onečišćujuće tvari putem procesa biorazgradnje ili biotransformacije prevode se u netoksične produkte i nusprodukte djelovanjem enzimskog kataboličkog potencijala mikroorganizama. Kako bi se povećala brzina i djelotvornost tehnologije bioremedijacije uvode se dodatni alati kao što su optimiranje procesnih čimbenika putem biostimulacije te korištenje autohtonih ili egzogenih kultura kao inokuluma u procesu bioaugmentacije.
U ovom radu istraživana je bioremedijacija procjedne vode iz organske frakcije iz miješanog komunalnog otpada. Uspoređena je djelotvornost uklanjanja organskog onečišćenja uz bioaugmentaciju egzogenih mikrobnih kultura Pseudomonas putida te aktivnog mulja.
Pokusi su provedeni u šaržnom reaktoru pri submerznim uvjetima u periodu od 10 dana. Ukupna prosječna vrijednost učinkovitosti procesa uklanjanja organske tvari za istraživane sustave iznosila je 89 %. Provedena istraživanja pružaju uvide u praktičnu primjenu bioremedijacije i doprinose daljnjem razvoju strategija za obradu otpadnih voda.In the modern society of technological progress, anthropogenic activities are leading to increasing water pollution. Leachates originating from the organic fraction of mixed municipal waste are highly contaminated and require physical, chemical or biological treatment before being discharged into the environment. Bioremediation technology is becoming increasingly important in overcoming these challenges as it offers a sustainable and highly effective solution for the remediation of various types of pollution. Pollutants, through processes of biodegradation or biotransformation, are converted into non-toxic products and byproducts through the enzymatic catabolic potential of microorganisms. To enhance the speed and effectiveness of bioremediation technology, additional tools are introduced, such as the optimisation of process factors through biostimulation and the use of indigenous or exogenous cultures as inoculants in bioaugmentation. In this work, the bioremediation of leachate from the organic fraction of mixed municipal waste was investigated.
The effectiveness of the removal of organic pollution removal with bioaugmentation with exogenous microbial cultures Pseudomonas putida and activated sludge was compared.
The experiments were carried out in a batch reactor under submerged conditions for 10 days. The average overall efficiency of the organic matter removal in the investigated systems was 89 %. The conducted research provides insights into the practical application of bioremediation and contributes to the further development of wastewater treatment strategies
Equilibrium adsorption of copper ions from copper (II) nitrate on humus : diploma thesis
No full textU ovom diplomskom radu ispitivana je ravnoteža adsorpcije bakrovih iona iz otopina bakrovih iona različitih početnih koncentracija na humusu u šaržnom reaktoru pri stalnoj temperaturi od 308 K, brzini miješanja od 200 okr min-1 te trajanju eksperimenta od 96 h. Porast početnih koncentracija otopine bakrovih iona ne utječe značajno na ravnotežnu koncentraciju adsorbiranih bakrovih iona na humusu jer se ona neznatno mijenja. Maksimalni kapacitet adsorpcije bakrovih iona na humusu postignut je pri koncentraciji od 8,016 mmol dm-3 te iznosi 0,518 mmol g-1 za zadane uvjete provedbe eksperimenta. Učinkovitost adsorpcije bakrovih iona na humusu opada s porastom početne koncentracije bakrovih iona te je maksimalan učinak adsorpcije bakrovih iona na humusu postignut pri najnižoj odabranoj početnoj koncentraciji od 4,049 mmol dm-3 i iznosi 60,320 %. Dobiveni eksperimentalni podatci testirani su Langmuirovom, Freundlichovom, Tothovom, Redlich-Petersonovom i Sipsovom izotermom. Procjenom kvalitete slaganja adsorpcijskih modela s eksperimentalnim podatcima, usporedbom izračunatih vrijednosti statističkih parametara za RMSE i χ2 te maksimuma kapaciteta adsorpcije i eksperimentalno dobivenog može se zaključiti da najbolje slaganje s eksperimentalnim podatcima pokazuje Tothova izoterma koja je razvijena kako bi proširila primjenu Langmuirovog modela u heterogenim sustavima.In this diploma thesis, the equilibrium adsorption of copper ions from the copper ions solutions of various initial concentrations was investigated in a batch reactor on the humus at a constant temperature of 308 K, a stirring speed of 200 rpm for 96 h. The increase in the initial concentrations of copper ions solutions does not significantly affect on the equilibrium amount of copper ions adsorbed on the humus because it slightly changes. The maximum adsorption capacity of copper ions on the humus was achieved at a concentration of 8.016 mmol dm-3 with the value of 0.518 mmol g-1 for the given experimental conditions. The adsorption efficiency of copper ions on the humus decreases with an increase in the initial concentration of copper ions, and the maximum adsorption capacity of copper ions on the humus was achieved at the lowest selected initial concentration of 4.049 mmol dm-3 with the value of 60.320 %. The experimental data obtained were tested on Langmuir, Freundlich, Toth, Redlich-Peterson and Sips isotherms. By estimating the quality of the agreement of adsorption models with the experimental data, comparing the calculated values of statistical parameters for RMSE and χ2 and the maximum adsorption capacity with the experimentally obtained, it can be concluded that the best agreement with experimental data is shown by the Toth isotherm, which was developed to extend the application of the Langmuir model in heterogeneous systems
Molecular characterization of ribosomal group 16SrV phytoplasma isolates from north-western Croatia
No full textFitoplazme su biljne patogene bakterije bez stanične stijenke koje pripadaju rodu 'Candidatus Phytoplasma'. Nastanjuju floem biljaka i prenose se kukcima-vektorima koji su ujedno i njihovi domaćini. Fitoplazme predstavljaju veliku opasnost u poljoprivredi uništavanjem usjeva raznih poljoprivrednih kultura, a u Europi su poznate po uništavanju usjeva vinovih loza uzrokujući bolesti žutica vinove loze (eng. grapevine yellows; GY). S tom bolesti povezane su fitoplazme flavescence dorée (FDp; ribosomska skupina 16SrV) te bois noir (ribosomska podskupina 16SrXII-A; 'Ca. P. solani'). Cilj ovog diplomskog rada je bila molekularna karakterizacija izolata FDp dobivenih iz uzoraka vinove loze, crne johe i kupine prikupljenima na sjeverozapadnom području Hrvatske. Nakon potvrde prisustva fitoplazmi u izolatima triplex real‐time PCR‐om, napravljena je filogenetska analiza gena map i vmpA umnoženih PCR-om. Utvrđena je velika genetska varijabilnost oba gena, a otkriveno je potencijalnih šest novih genotipova FDp te je po prvi put napravljena molekularna karakterizacija fitoplazmatskih izolata iz kupine i crne johe u Hrvatskoj. Također, velik broj pozitivnih izolata iz crne johe pokazuje značajan potencijal širenja zaraze ovom fitoplazmom. Dobiveni rezultati omogućuju bolji uvid u epidemiologiju FDp na području sjeverozapadne Hrvatske.Phytoplasmas are plant-pathogenic bacteria lacking cell wall that belong to the genus ‘Candidatus Phytoplasma’. They inhabit the phloem of plants and are transmitted by insect vectors that are also their natural hosts. They pose a significant threat to agriculture by destroying crops from various cultures and are known in Europe for affecting grapevine crops by causing grapevine yellows (GY) disease. This disease is associated with flavescence dorée phytoplasmas (FDp; 16SrV ribosomal group) and bois noir phytoplasmas (16SrXII-A ribosomal subgroup; ‘Ca. P solani’). This study was focused on the molecular characterization of FDp isolates obtained from samples of grapevines, black alders and blackberries collected in north-western Croatia. After confirming the presence of phytoplasmas in isolates by using triplex real‐time PCR, a phylogenetic analysis of the map and vmpA genes amplified by PCR was performed. Significant genetic variability of both genes was determined, and six potential new FDp genotiypes were discovered, along with the first molecular characterization of phytoplasma isolates from blackberries and black alders in Croatia. Moreover, numerous positive isolates from black alders indicate a significant potential for the infection spread of this phytoplasma. The obtained results provide better insight into the epidemiology of FDp in the north‐western part of Croatia
Analysis and improvement of metal parts manufacturing process
No full textU ovom radu prikazana je analiza i unaprjeđenje procesa proizvodnje metalnih dijelova,
posebice fokusirajući se na prakse unutar tvrtke Metal Product. Cilj je bio razumjeti postojeće
procese, načine identificije područja za potencijalna poboljšanja te prijedloge koraka
optimizacije proizvodnje. U suradnji s timom i kolegama, prikupiljeni su prijedlozi i
identificirane su ključne potrebe za promjenama. Ti prijedlozi poslužili su kao osnova za
temeljitiju analizu i razvoj strategija za unaprjeđenje.
Tijekom rada u Metal Productu, posebna pažnja posvećena je prikupljanju relevantnih
podataka koji će poslužiti kao temelj za ovaj rad. Analizirani su različiti aspekti proizvodnje,
uključujući dizajn proizvodnih ciklusa, implementaciju novih kapaciteta, digitalne sustave
upravljanja, inovacije u procesima recikliranja i smanjenje otpada. Rad je podijeljen u više
poglavlja, gdje svako poglavlje odgovara određenom segmentu unaprjeđenja procesa.
Jasno je da unaprjeđenje procesa zahtijeva sveobuhvatan pristup, koji uključuje: dizajn novog
prostornog rasporeda (Eng. Layout) proizvodnog ciklusa, implementaciju novih proizvodnih
kapaciteta, novi digitalni sustav za upravljanje proizvodnjom, inovacije u procesima
recikliranja, smanjenje nesukladnih proizvoda i otpada, redizajn radnih mjesta, optimizaciju
tokova sirovina i gotovih proizvoda, stvaranje novih procedura proizvodnje, primjenu
proizvodnje bez papira, uvođenje ekološki prihvatljive ambalaže, smanjenje potrošnje maziva
i vode u proizvodnji, analizu disipacije energije, uvođenje brojila energije te nabavu opreme za
automatizaciju i robotizaciju.
Svaki od ovih segmenata detaljno je analiziran s ciljem identificiranja optimalnih rješenja koja
će pridonijeti efikasnosti, ekološkoj održivosti i ekonomičnosti proizvodnje. Pri tome su
korišteni podatci prikupljeni tijekom prakse i rada u tvrtki, kao i znanstvena literatura i studije
slučaja koje su relevantne za temu. Ovaj pristup omogućio je da se pruži teorijski okvir za
unaprjeđenje procesa proizvodnje u Metal Productu te praktično demonstrira kako se
predložene promjene mogu implementirati u stvarnom poslovnom okruženju. Na kraju, sve
stavke su potkrijepljene izračunima ključnih pokazatelja i cjelokupnom analizom podataka o
uskim grlima i uštedi vremena.This paper presents an analysis and improvement of the metal parts production process,
focusing particularly on practices within the Metal Product company. The aim was to
understand existing processes, identify areas for potential improvements, and propose steps for
optimizing production. In collaboration with the team and colleagues, suggestions were
gathered, and key needs for changes were identified. These suggestions served as the basis for
a thorough analysis and development of strategies for improvement.
Throughout the work at Metal Product, special attention was given to gathering relevant data
to serve as the foundation for this paper. Various aspects of production were analyzed, including
the design of production cycles, implementation of new capacities, digital management
systems, innovations in recycling processes, and waste reduction. The paper is divided into
several chapters, each corresponding to a specific segment of process improvement.
It is evident that process improvement requires a comprehensive approach, including the design
of a new spatial layout of the production cycle, implementation of new production capacities,
a new digital production management system, innovations in recycling processes, reduction of
non-compliant products and waste, redesign of workstations, optimization of raw material and
finished product flows, creation of new production procedures, implementation of paperless
production, introduction of environmentally friendly packaging, reduction of lubricant and
water consumption in production, analysis of energy dissipation, introduction of energy meters,
and procurement of automation and robotics equipment.
Each of these segments was analyzed in detail with the aim of identifying optimal solutions that
would contribute to the efficiency, environmental sustainability, and cost-effectiveness of
production. Data collected during internships and work at the company, as well as relevant
scientific literature and case studies, were used for this purpose. This approach allowed for the
provision of a theoretical framework for improving the production processes at Metal Product
and practically demonstrating how the proposed changes can be implemented in a real business
environment. Finally, all items were supported by calculations of key indicators and a
comprehensive analysis of bottleneck data and time savings
Testing of weld joints according to standard HRN EN ISO 14555
No full textU teorijskom dijelu rada opisani su postupci zavarivanja svornjaka s detaljnim uvidom u
postupak elektrolučnog zavarivanja svornjaka s odmakom luka uz primjenu keramičkog prstena
ili zaštitnog plina (postupak 783). Također, detaljno su opisane metode ispitivanja zavarenih
spojeva svornjaka prema zahtjevima norme HRN EN ISO 14555 ovisno o razini kvalitete,
promjeru svornjaka i radnoj temperaturi.
U eksperimentalnom dijelu rada prvotno su postupkom 783 zavarena dva tipa uzoraka
svornjaka koja se sastoje od 12 zavarenih svornjaka promjera Ø22 mm i 12 zavarenih svornjaka
promjera Ø19 mm, te su zatim na njima provedena ispitivanja definirana prema normi HRN
EN ISO 14555 što uključuje vizualni pregled, test savijanja, makroanalizu i test vlačne čvrstoće.
Kriteriji prihvatljivosti dobivenih rezultata ispitivanja definirani su prema normi HRN EN ISO
3834-2, te se daje analiza rezultata i procjena razine kvalitete zavarenih spojeva. Na kraju je
određena prikladnost provedenih ispitivanja za primjenu ovih dvaju tipova zavarenih svornjaka
u radnim uvjetima i za različite načine opterećenja.The teoretical part of this thesis covers stud welding processes with detailed insight in stud arc
welding using ceramic ferrule or shielding gas (process 783). Investigation methods of those
welding joints according to HRN EN ISO 14555 standard in terms of quality levels, stud
diameter and ambient temperature are also described in detail.
In experimental part, two types of samples were welded using process 783. Samples were
consisted of 12 welded studs of diameter Ø22 mm and 12 welded studs of diameter Ø19 mm.
Therefore, they were investigated with visual examination, bend test, macro examination and
tensile test according to HRN EN ISO 14555 standard. Furthermore, acceptance criteria was
defined and analysis of results was carried out as well as evaluation of quality levels of welding
joints according to HRN EN ISO 3834-2 standard. Finally, suitability of experiments done was
defined for use in working ambient for both types of welded studs as well as their use with
different types of stress
Dynamics of multispecies biofilm growth at the water-air interface
No full textViševrsni biofilm mikrobna je zajednica koja se sastoji od više različitih mikrobnih vrsta. Na granici voda-zrak mikroorganizmi formiraju biofilm. U istraživanju se prati stvaranje viševrsnog biofilma kvasca Saccharomyces cerevisiae te bakterija Acinetobacter baumannii, Acinetobacter junii, Staphylococcus aureus i Bacillus cereus. Svi organizmi iz istraživanja sudjelovali su u stvaranju biofilma. Stvoreni biofilmovi bili su kod određenih organizama izraženiji i formirani u kraćem vremenskom periodu. Iz formiranog biofilma mikroorganizmi su se kretali duž staklene, nehranjive podloge. Bakterije Acinetobacter junii, Acinetobacter bauamnnii, Bacillus cereus i Staphylococcus aureus duž stakalca su se kretale samostalno ili zajedno s bakterijom druge vrste. Kvasci Saccharomyces cerevisiae duž stakalca se kreću zajedno s drugim bakterijama. Istraživala se ovisnost organizama u pokretljivosti te interakcije prokariota i eukariota unutar viševrsnog biofilma. Kod fosfat-akumulirajućih bakterija pomoću fluorescencijskog mikroskopa proučavala se brojnost polifosfata u stanici te njihov utjecaj na pokretljivost bakterija.A multispecies biofilm is a microbial community consisting of various microbial species. Microorganisms at the water-air interface form biofilms. The research focuses on observing the formation of multispecies biofilm involving yeast Saccharomyces cerevisiae and bacteria Acinetobacter baumannii, Acinetobacter junii, Staphylococcus aureus, Bacillus cereus. All organisms in the study contributed to the biofilm formation. Biofilms created by certain organisms were more present and formed in a shorter time frame. Microorganisms within the formed biofilm moved along the glass, non-nutritive surface. The bacteria Acinetobacter junii, Acinetobacter baumannii, Bacillus cereus and Staphylococcus aureus moved along the glass independently or together with bacteria of another species. Yeast Saccharomyces cerevisiae along the glass moves with other bacteria. The research investigated the dependence of organisms on mobility and the interaction between prokaryotes and eukaryotes within the multispecies biofilm. Using a fluorescence microscope, the study examined the abundance of polyphosphates in the cell and their impact on bacterial mobility in phosphate-accumulating bacteria
Functional structure of testate amoeba community at Trstenik peatbog
No full textCretovi predstavljaju prijelazna podruĉja izmeĊu vodenih i kopnenih ekosustava s bogatom bioraznolikońću. Na cretu Trstenik, ombrotrofnom cretu iz ledenog doba smjeńtenog iznad Klane u Gorskom kotaru, utvrĊene su sukcesijske promjene zbog ńirenja trave modre beskoljenke koje su dovele do isuńivanja creta. Okućene amebe su jednostaniĉni heterotrofni eukarioti ĉija je stanica zańtićena vanjskom kućicom. Zbog kozmopolitske rasprostranjenosti te kratkog ņivotnog vijeka, okućene amebe posebno su osjetljive na promjene u okolińu, a na cretovima sluņe kao bioindikatori promjene okolińnih uvjeta. Ciljevi ovog diplomskog rada su: i) odrediti funkcionalnu strukturu okućenih ameba; ii) usporediti funkcionalnu strukturu cretnog stanińta s rubnim stanińtima i sukcesijskim stanińtem; iii) povezati funkcionalnu strukturu s mikroklimatskim uvjetima na cretu Trstenik. Funkcionalne znaĉajke na temelju kojih je odreĊena funkcionalna struktura okućenih ameba su: tip pseudopodija, sastav kućice, spljońtenost kućice, oblik kućice, veliĉina otvora, poloņaj otvora, oblik otvora te miksotrofija. Rezultati ovog diplomskog rada potvrdili su sukcesijske promjene kojima je zahvaćen cret Trstenik te pokazali da struktura funkcionalnih znaĉajki okućenih ameba odraņava prilagodbe cretnom stanińtu za većinu funkcionalnih znaĉajki. Funkcionalna struktura okućenih ameba cretnog stanińta, razlikuje se od funkcionalne strukture okućenih ameba rubnog stanińta i sukcesijskog stanińta, a ista odraņava mikroklimatske uvjete na razliĉitim stanińtima creta Trstenik, posebice uvjete vlaņnosti supstrata.Peatbogs, which serve as transition zones between aquatic and terrestrial ecosystems, are characterized by great biodiversity. In Trstenik petabog, an ombrotrophic peatbog from the Ice Age above Klana in Gorski Kotar, successional changes were observed due to the spread of purple moor-grass, which led to the drying out of the peatbog. Testate amoebae, unicellular eukaryotes with a protective outer shell, are particularly sensitive to environmental changes and serve as bioindicators of changing environmental conditions in peatbogs. This study aims to: i) determine the functional structure of testate amoebae; ii) compare the functional structure in peatbog habitat with edge and successional habitat; iii) establish connections between functional structure with microclimatic conditions in the Trstenik peatbog. Functional traits, including pseudopod type, test composition, test flatness, test shape, aperture size, aperture position, aperture shape and mixotrophy, were analyzed. The results confirm changes in succession and show that the functional structure of testate amoebae reflects adaptations to habitat, with variations observed between typical peatbog habitat, edge and successional habitat, particularly in response to substrate moisture conditions
RECOVERY OF WINTER WHEAT SEEDLINGS SUBJECTED TO DROUGHT INDUCED BY POLYETHYLENE GLYCOL
No full textSuša je važan okolišni stres koji ograničava biljnu proizvodnju širom svijeta, a pšenica (Triticum aestivum L.) je
jedna je od glavnih prehrambenih žitarica pogođenih sušom. Cilj je bio istražiti na koji način se šest sorti ozime
pšenice suočavaju s dehidracijom i oporavkom na morfološkoj, fiziološkoj i biokemijskoj razini. Tri dana stari
klijanci izloženi su fiziološkoj suši tijekom šest dana (-0,3 MPa), nakon čega je uslijedio jedan dan rehidracije do
oporavka. Visoki sadržaj prolina, minimalno smanjenje relativnog sadržaja vode i zadržavanje stabilnosti staničnih
membrana istraživanih kultivara u uvjetima suše usko su povezani i ukazuju na visoku sposobnost tolerancije na
dehidraciju. Fluorescencija klorofila a listova klijanaca pokazala je visoku stabilnost kvantnog prinosa primarne
fotokemije PS II u uvjetima blagog stresa ukazujući da mlađa fotosintetska tkiva imaju visoku toleranciju na sušu.
Kultivar L459-2012 zadržao je visoku stabilnost fotosintetskog aparata tijekom dehidracije i rehidracije. Kod
ostalih kultivara, a najviše kod Osk 4.40/7-82 i 381/06 promjena amplitude iz pozitivne u negativnu sugerira da
dolazi do povećanja grupiranosti jedinica PSII te veće razmjene energije rehidracijom ukazujući da je kod tih
kultivara prethodna dehidracija imala u osnovi pozitivan efekt na fotosintetski aparat i da ukupna stabilnost sustava
nije oštećena. Zaključno, kratkotrajno izlaganje suši može biti korisno za rast pšenice u ranoj fazi razvoja, što u
konačnici može pridonijeti našem razumijevanju načina na koji biljke maksimalno iskorištavaju ograničene vodne
resurse.Drought is an important environmental stress, limiting crop production worldwide, and wheat (Triticum aestivum
L.) is one of the main cereals affected by drought. The aim was to investigate how six winter wheat cultivars face
dehydration and recovery at the morphological, physiological, and biochemical levels. Three-day-old seedlings
were exposed to physiological drought (-0,3 MPa) for six days, followed by one day of rehydration treatment for
recovery. High proline content, a minimal decrease of relative water content, and the stability of cell membranes
were closely related and indicated the high ability of dehydration tolerance. High efficiency of PSII primary
photochemistry under mild stress conditions obtained by fluorescence measurement also indicated high drought
tolerance of young photosynthetic tissues. Cultivar L459-2012 retained high stability of the photosynthetic
apparatus during both dehydration and rehydration treatment. In other cultivars, especially in Osk 4.40/7-82 and
Osk 381/06, an amplitude changed from positive to negative, suggesting that the PSII units had better excitation
energy utilization upon recovery and the overall system stability was not damaged. To conclude, despite the
variabilities in cultivars' response to water deficit and recovery, the results showed the beneficial effect of shortterm drought for early-stage wheat growth, which can ultimately contribute to our understanding of how plants
make maximum use of limited water resources
GENOTYPIC DIFFERENCES IN THE PHYSIOLOGICAL RESPONSE OF MAIZE SEEDLINGS TO WATER WITHHOLDING
No full textOgraničena dostupnost vode jedan je od glavnih čimbenika oksidativnog stresa u biljkama, a u takvim uvjetima
nastaju reaktivne kisikove jedinke (ROS) koje oštećuju biološke membrane i stanične strukture. Cilj ovog
istraživanja bio je odrediti kako stres uvjetovan zasušivanjem utječe na fiziološki odgovor različitih genotipova
klijanaca kukuruza (Zea mays L.). Zasušivanje je u većini genotipova izazvalo povećanje koncentracije lipidne
peroksidacije, vodikovog peroksida i sadržaja prolina. Rezultati ovog istraživanja ukazuju da je odgovor na stres
zasušivanjem ovisan o genotipu kukuruza te da možemo razlikovati genotipove kukuruza s većom tolerancijom
na zasušivanje i one osjetljivije. Potrebna su daljnja istraživanja antioksidacijskog sustava i mjerenja drugih
komponenti oksidacijskog stresa kako bi se utvrdila povezanost između količine ROS-a i antioksidacijskog
odgovora.Limited water availability is one of the main factors of oxidative stress in plants. In such conditions formation of
reactive oxygen species (ROS) can damage biological membranes and cell structures. The aim of this study was
to determine how water withholding stress affected the physiological response of different maize seedlings (Zea
mays L.) genotypes. Water withholding caused an increase in the concentration of lipid peroxidation, hydrogen
peroxide and proline content in most genotypes. The results of this study indicate that the response to water
withholding stress in maize is genotype-dependent and that we can distinguish maize genotypes with higher
tolerance and those more sensitive to stress. Further studies of the antioxidant system and measurements of other
components of oxidative stress are needed in order to determine the relationship between the amount of ROS and
the antioxidant response
Synthesis of coumarin-3-carboxylic acid derivatives in deep eutectic solvents
No full textZelena kemija relativno je nov koncept na polju kemije koji je u proces sinteze uveo
alternativna otapala. Vrsta alternativnog otapala koje je korišteno za sintezu derivata kumarin-
3-karboksilne kiseline bilo je eutektičko otapalo sintetizirano od dvije komponente kolinklorida i mliječne kiseline. Za sintezu derivata kumarin-3-karboksilne kiseline primijenjenaje i
mehanokemijska sinteza. Mehanokemijska sinteza temelji se na primjeni mehaničke sile koja
potiče kemijske reakcije između reaktanata, a provedena je korištenjem kugličnog mlina,uz
octenu kiselinu kao katalizator.Green chemistry is a relatively new concept in the chemistry,which introduced alternative
solvents in the synthesis. The type of alternative solvent which was used for the synthesis of
coumarin-3-carboxylic acid derivatives was a deep eutectic solvent composed of two
components, choline chloride and lactic acid, namely. Mechanochemical synthesis was also
used for the synthesis of coumarin-3-carboxylic acid derivatives. Mechanochemical synthesis
is based on the use of mechanical force which stimulates chemical reactions between reactants
and it was carried out using a ball mill, with acetic acid as a catalyst