NITRATES AND NITRITES, METABOLISM AND TOXICITY

Nitrati i nitriti su kemijski spojevi koji se koriste kao gnojivo, rodenticidi ili konzervansi. Mogu se naći u zraku, tlu, vodi ili hrani (posebice povrću) a mogu se i stvarati u ljudskom tijelu. Nitrati imaju važnu ulogu u hranjenju i metabolizmu biljaka. Nastaju oksidacijom organskog otpada djelovanjem dušičnih bakterija. Ljudi mogu biti izloženi nitratima i nitritima preko konzumacije povrća i mesnih prerađevina, a manjim dijelom preko vode ili ostale hrane. Pijenje vode sa većom koncentracijom nitrata može djelovati na ljudsko tijelo na dva načina: (i) akutno, što se najčešće manifestira methemoglobinemijom (nitrati u probavnom sustavu se reduciraju u nitrite koji potom oksidiraju željezo u hemoglobinu crvenih krvnih stanica stvarajući methemoglobin koji nije sposoban prenositi kisik po tijelu), a koja se manifestira pojavom plave boje kožw, i (ii) kronično, što se manifestira pojavom karcinoma kao rezultata izloženosti nitrozaminima (koji nastaju tijekom reakcije nitrata sa aminima u tijelu).Nitrates naturally occur in the environment and are involved in the nitrogen cycle. Nitrates and nitrites are chemical compounds used in fertilizers, rodenticides and as food preservatives. They can be found in the air, soil, water and food (especially in vegetables) and can be synthesized in the human body. Nitrates play a significant role in the diet and metabolism of plants. Nitrates are formed by oxidation of organic waste by the action of nitrogen-binding bacteria. Humans are exposed to nitrates and nitrites via consumption of vegetables and processed meat products, and to a lesser extent via water and other food. Consumption of drinking water with an increased concentration of nitrate may affect the human body in two ways: (i) acutely, most often manifested as methemoglobinemia (where nitrates in the digestive system are reduced to nitrites, which then oxidize iron in the hemoglobin of the red blood cells forming methemoglobin unable to transmit oxygen in the body), resulting in blue skin, and (ii) chronic, manifested by the occurrence of cancer as a result of organism exposure to nitrosamines (formed during the reaction of nitrates with amines in the body)

Epidemiologija problema mentalnog zdravlja u mladih s područja Osijeka, korištenjem upitnika snaga i teškoća (SDQ)

Introduction: Mental disorders begin at an early age. Screening is the first step in early intervention for the mental health problems of children and adolescents. The aim of this study was to analyse the prevalence of mental health problems among adolescents from Osijek, to early detect the risks of possible mental disorders, and to analyse gender differences. Materials and methods: The main screening instrument was The Strengths and Difficulties Questionnaire (SDQ), which assesses the emotional and behavioural difficulties of children and adolescents, as well as the prosocial skills. Over 5 school years (2012/13-2016/17), a total of 5787 students were examined. 5514 (95.3%) first-year students from 16 high schools and 273 (4.7%) seventh-grade students from 10 elementary schools were examined in the City of Osijek. Results: 10.4% of students had the borderline or abnormal score on the Total difficulties score. Girls had higher scores on the Total difficulties score (p<0.01), Emotional symptoms subscale (p<0.01), Prosocial behaviour subscale (p<0.01), and on the Hyperactivity/inattention subscale (p<0.01). On the Conduct problems subscale and the Peer relationships problem subscale, boys scored significantly higher than the girls (p<0.01). Conclusion: In the Osijek area, girls are more affected by mental problems than boys, scoring higher on the total scale, as well as on the emotional and hyperactivity scale. Whereas boys scored higher on the conduct and peer relationship scales. The data obtained through this screening allows for further planning of public health measures, preventive activities, treatment, and mental health promotion.Uvod: Mentalni poremećaji započinju u ranoj dobi. Probir je prvi korak u ranoj intervenciji mentalnih poremećaja djece i adolescenata. Ciljevi ove studije su bili istražiti prevalencije mentalnih poteškoća adolescenata s područja grada Osijeka, pravovremeno uočiti rizike mogućih mentalnih poremećaja te istražiti razlike među spolovima. Materijal i metode: Glavni instrument probira je bio Upitnik snaga i poteškoća namijenjen procjeni emocionalnih i poteškoća u ponašanju djece i adolescenata kao i procjeni prosocijalnih vještina. Tokom pet školskih godina (2012/13 - 2016/17), ispitano je ukupno 5787 učenika, od toga 5514 (95.3%)učenika prvih razreda 16 srednjih škola te 273 (4.7%) učenika sedmih razreda osnovnih škola grada Osijeka. Rezultati: 10.4% učenika je imalo graničan ili povišen rezultat na ljestvici ukupnih poteškoća. Djevojčice su imale viši rezultat na ljestvici ukupnih poteškoća (p<0.01), na ljestvicama emocionalnih poteškoća, prosocijalnog ponašanja i hiperaktivnosti (p<0.01). Na ljestvicama problema u ponašanju i problema s vršnjacima su dječaci imali viši rezultat (p<0.01). Zaključak: Na području grada Osijeka, djevojčice su češće pogođene mentalnim poteškoćama, emocionalnim poteškoćama i hiperaktivnošću. Dječaci su češće pogođeni problemima u ponašanju i problemima u odnosu s vršnjacima. Podaci dobiveni ovim probirom služe u planiranju javnozdravstvenih mjera, preventivnih aktivnosti, liječenja i promocije mentalnog zdravlja

NITRATES AND NITRITES, METABOLISM AND TOXICITY

Nitrati i nitriti su kemijski spojevi koji se koriste kao gnojivo, rodenticidi ili konzervansi. Mogu se naći u zraku, tlu, vodi ili hrani (posebice povrću) a mogu se i stvarati u ljudskom tijelu. Nitrati imaju važnu ulogu u hranjenju i metabolizmu biljaka. Nastaju oksidacijom organskog otpada djelovanjem dušičnih bakterija. Ljudi mogu biti izloženi nitratima i nitritima preko konzumacije povrća i mesnih prerađevina, a manjim dijelom preko vode ili ostale hrane. Pijenje vode sa većom koncentracijom nitrata može djelovati na ljudsko tijelo na dva načina: (i) akutno, što se najčešće manifestira methemoglobinemijom (nitrati u probavnom sustavu se reduciraju u nitrite koji potom oksidiraju željezo u hemoglobinu crvenih krvnih stanica stvarajući methemoglobin koji nije sposoban prenositi kisik po tijelu), a koja se manifestira pojavom plave boje kožw, i (ii) kronično, što se manifestira pojavom karcinoma kao rezultata izloženosti nitrozaminima (koji nastaju tijekom reakcije nitrata sa aminima u tijelu).Nitrates naturally occur in the environment and are involved in the nitrogen cycle. Nitrates and nitrites are chemical compounds used in fertilizers, rodenticides and as food preservatives. They can be found in the air, soil, water and food (especially in vegetables) and can be synthesized in the human body. Nitrates play a significant role in the diet and metabolism of plants. Nitrates are formed by oxidation of organic waste by the action of nitrogen-binding bacteria. Humans are exposed to nitrates and nitrites via consumption of vegetables and processed meat products, and to a lesser extent via water and other food. Consumption of drinking water with an increased concentration of nitrate may affect the human body in two ways: (i) acutely, most often manifested as methemoglobinemia (where nitrates in the digestive system are reduced to nitrites, which then oxidize iron in the hemoglobin of the red blood cells forming methemoglobin unable to transmit oxygen in the body), resulting in blue skin, and (ii) chronic, manifested by the occurrence of cancer as a result of organism exposure to nitrosamines (formed during the reaction of nitrates with amines in the body)

Biocatalytic reductions by plant tissue - Green alternative to alcohol production

The use of biocatalysts for the industrial synthesis of chemicals has been attracting much attention as an environmental friendly synthetic method. Various plants, such as apple (Malus pumila), carrot (Daucus carota), cucumber (Cucumis sativus), onion (Allium cepa), potato (Solanum tuberosum), radish (Raphanus sativus) and sweet potato (Ipomoea batatas) were used as biocatalysts. Enzymes that plants produce are able to perform reactions under mild conditions (pH and temperature), with remarkable chemo-, regio-, and stereoselectivity. Due to this feature the number of biocatalysts used in organic synthesis has rapidly increased during the last decades, especially for the production of chiral compounds. This review presents biotechnological processes for the production of chiral alcohols by reducing prochiral ketones with whole plant tissue. Chiral alcohols are important building blocks for the synthesis of pharmaceuticals, pesticides, pheromones, flavors, fragrances and advanced materials such as liquid crystals. Reductase-catalyzed reactions are dependent on cofactors, and therefore, one major task in process development is to provide an effective method for regeneration of the cofactors consumed. The need for expensive cofactors is eliminated by using the whole plant tissue since the plant automatically provides this requirement. Depending on the vegetable used, either enantiomer may be obtained in high yield and high enantiomeric excess (ee), which could be a critical factor for drug development/bioactivity evaluation perspective. In this paper, various processes carried out on laboratory scales are presented. Attention is turned to conversion, yield, enantiomeric excess (ee)

Biocatalytic reductions by plant tissue - Green alternative to alcohol production

The use of biocatalysts for the industrial synthesis of chemicals has been attracting much attention as an environmental friendly synthetic method. Various plants, such as apple (Malus pumila), carrot (Daucus carota), cucumber (Cucumis sativus), onion (Allium cepa), potato (Solanum tuberosum), radish (Raphanus sativus) and sweet potato (Ipomoea batatas) were used as biocatalysts. Enzymes that plants produce are able to perform reactions under mild conditions (pH and temperature), with remarkable chemo-, regio-, and stereoselectivity. Due to this feature the number of biocatalysts used in organic synthesis has rapidly increased during the last decades, especially for the production of chiral compounds. This review presents biotechnological processes for the production of chiral alcohols by reducing prochiral ketones with whole plant tissue. Chiral alcohols are important building blocks for the synthesis of pharmaceuticals, pesticides, pheromones, flavors, fragrances and advanced materials such as liquid crystals. Reductase-catalyzed reactions are dependent on cofactors, and therefore, one major task in process development is to provide an effective method for regeneration of the cofactors consumed. The need for expensive cofactors is eliminated by using the whole plant tissue since the plant automatically provides this requirement. Depending on the vegetable used, either enantiomer may be obtained in high yield and high enantiomeric excess (ee), which could be a critical factor for drug development/bioactivity evaluation perspective. In this paper, various processes carried out on laboratory scales are presented. Attention is turned to conversion, yield, enantiomeric excess (ee)

Nitrate removal from water by ion exchange

High concentrations of nitrate in water, both in surface and in groundwater, is a consequence of geological composition of soil or human activity. Increased concentrations of nitrate in drinking water is a serious hazard to human health, causing abnormalities such as cancerous growth in human digestion system, while excessive nitrate intake via drinking water can cause methemoglobinemia in infants. Furthermore, the presence of nitrate in aquifers can stimulate eutrophication, which compromise the growth of algae and depletion of dissolved oxygen. Natural and chemical fertilizers in crop production, detergent manufacturing, uncontrolled land discharge of municipal wastewater, and industrial wastes have been identified as the main sources of nitrate in water sources. Nitrate is a stable, highly soluble ion that is difficult to remove by conventional water treatment methods such as coagulation and flocculation. The ion exchange is the most widely used procedure for removing nitrate from water. In this research the possibility of removing nitrate from water was examined by using commercial ion exchangers: Duolite A7 and Relite A490, respectively. The influence of the initial concentration of nitrate (10, 50 and 100 mg/l), the contact time (15 - 1440 min) and the mass of the ion exchanger (0.1 to 0.6 g) was also examined

UTJECAJ MIJEŠANJA NA UČINKOVITOST PROCESA KOAGULACIJE I FLOKULACIJE PRI KONDICIONIRANJU VODE VODOCRPILIŠTA „JARČEVAC“

Najvažniji izvori vode za piće na području istočne Hrvatske su podzemne vode koje karakterizira visoka tvrdoća i povišene koncentracije željeza, amonija, mangana, arsena i organskih tvari, što negativno utječe na organoleptička svojstva i zdravstvenu ispravnost vode za piće. Jedan od procesa koji se često primjenjuje pri kondicioniranju vode je koagulacija i flokulacija uz naknadnu filtraciju. Na učinkovitost navedenog procesa utječu čimbenici poput fizikalno-kemijskih karakteristika sirove vode, doza i vrsta koagulanta te brzina i vrijeme miješanja u pojedinim fazama navedenog procesa. U ovom radu ispitan je utjecaj brzine i vremena miješanja koagulanata i vode na učinkovitost koagulacije i flokulacije pri obradi aerirane podzemne vode vodocrpilišta „Jarčevac“ s dva željezova koagulanta – željezov klorid i željezov(II) sufat te je praćen utjecaj brzine i vremena miješanja na učinak procesa kroz dva seta, uz početnu pH vrijednost vode od 7.5 i početnu koncentraciju ukupnog željeza od 4 mg/l. Učinkovitost je praćena mjerenjem polaznih i završnih vrijednosti količine organskih tvari, ukupne tvrdoće, alkaliteta i koncentracije ukupnog željeza te pH vrijednosti i vodljivosti vode. S obzirom na dobivene rezultate moguće je zaključiti da je učinkovitija obrada podzemne vode vodocrpilišta „Jarčevac“ postignuta pri doziranju željezova klorida

NITRATE REMOVAL FROM WATER USING SURFACE-MODIFIED ULTRAFILTRATION MEMBRANES

Elevated nitrate concentrations in natural water sources are a worldwide concern due to the extensive levels of soil N-fertilization. This study investigates three commercially available polyethersulfone (PES) ultrafiltration (UF) membranes with different molecular weight cut-offs (5, 10, and 30 kDa), which we modified with a cationic surfactant, cetylpyridinium chloride to improve their nitrate removal. The nitrate removal efficiency of these membranes was examinated as functions of initial nitrate concentration, pH, and permeate flux. The best nitrate removal efficiency was obtained with a 5 kDa surface-modified UF membrane

Water preparation for industrial brewing

Voda je vrlo važna sirovina za proizvodnju piva jer pivo sadrži 85 – 95 % vode. Prema Pravilniku o temeljnim zahtjevima za pivo i pivu slične proizvode (NN 6/98), tehnološka voda koja se koristi za proizvodnju piva mora u fizikalnom, kemijskom i mikrobiološkom smislu odgovarati kvaliteti vode za piće, čije karakteristike su propisane Pravilnikom o parametrima sukladnosti i metodama analize vode za ljudsku potrošnju (NN 125/13). Kako bi pivovare bile neovisne o gradskim vodovodima često imaju svoje vlastite izvore - bunare. U prirodnim vodama uvijek postoje određene količine raznih otopljenih tvari. Ovisno o otopljenim mineralnim tvarima, vode se dijele na meke, srednje tvrde i tvrde. Tehnologija obrade voda u pivarstvu je vrlo važna jer kvaliteta, odnosno vrsta piva značajno ovisi o njoj, stoga u većini slučajeva pivovare provode obradu vode u svrhu dobivanja tehnološke vode za proizvodnju piva određenih karakteristika. Kada govorimo o obradi vode u pivovarama s vlastitim izvorima vode koje sadržavaju veće količine željeza, mangana i arsena, tada bi obrada vode svakako uključivala uklanjanje manganovih odnosno feratnih bikarbonata putem pješčanih filtera i aeracije; uništavanje mikroorganizama doziranjem klora, uklanjanje slobodnog klora i ostalih primjesa adsorpcijom na aktivnom ugljenu te pročišćavanje vode putem membranskih metoda odnosno mikrofiltracije, nanofiltracije i reverzne osmoze. Navedenom obradom vode može se dobiti voda s optimalnim vrijednostima koja je spremna za proizvodnju piva.Water quality for beer production is very important, because beer contains 85-95% of water. Water for beer production due to physical, chemical and microbiological characteristics must comply with the Regulations on the basic requirements for beer and beer like products (NN 6/98) and the Regulations on the parameters of assessment and methods of analysis of water for human consumption (NN 125/13). Breweries often use water from their own wells. In natural water certain amount of dissolved matter are present. Depending on dissolved minerals, water can be divided into soft, medium hard and hard water, respectively. Water treatment for beer production is very important because the quality or type of beer depend on it. Water treatment for beer production with elevated concentrations of iron, manganese and arsenic in water, certainly would include removal of manganese and ferric bicarbonate by sand filter and aeration, removal of microorganisms with chlorine, removal of free chlorine and other impurities by adsorption on activated carbon and water treatment with membrane processes such as reverse osmosis. This technologies for water treatment are promising for production of high quality beer products

Važnost znanstveno utemeljenih činjenica u kriznom komuniciranju: Dokazi iz zagrebačkog i petrinjskog potresa

Earthquakes are natural phenomena that can strongly affect the human population, infrastructure, and the environment. Croatia is part of a tectonically and seismically active area so its habitants and relevant institutions should be aware of possible hazardous events, which can be devastating. Therefore, crisis communication is extremely important, and in the event of natural disasters such as earthquakes, it must be clear, timely and concise. Scientific institutions dealing with earthquakes should also be involved in crisis communication. The information on two strong earthquakes in 2020 that shocked the area of Zagreb and Petrinja and the wide surrounding area, have shown how relevant institutions can deal with information on earthquakes and their consequences and share them publicly. This paper adopts a mixedmethods research design, combining both qualitative, and quantitative data on the Zagreb and Petrinja earthquakes from various sources of scientific and professional institutions in the field of geology, geophysics, seismology and civil engineering in Croatia. Empirical data suggest that interactive communication that strives to address local contextual concerns, explain actions, and provide honest, timely, accurate and reliable information is most effective. In the future, institutions have to find a way to react or share their information to help in the crisis.Potresi su prirodni fenomeni koji mogu snažno utjecati na zajednice, infrastrukturu i okoliš. Hrvatska je dio tektonski i seizmički aktivnog područja, tako da bi njezini stanovnici i nadležne institucije trebali biti svjesni mogućih opasnih događaja, koji mogu biti razorni. Stoga je krizna komunikacija izuzetno važna, a u slučaju prirodnih katastrofa poput potresa mora biti jasna, pravodobna i sažeta. Znanstvene institucije koje se bave potresima također bi trebale biti uključene u krizno komuniciranje. Podaci o dva snažna potresa 2020. godine koji su potresli područje Zagreba i Petrinje te širu okolicu, pokazali su kako se relevantne institucije mogu nositi s informacijama o potresima i njihovim posljedicama i javno ih dijeliti. Ovaj rad usvaja mješoviti dizajn istraživanja, kombinirajući i kvalitativne i kvantitativne podatke o potresima u Zagrebu i Petrinji iz različitih izvora znanstvenih i stručnih institucija iz područja geologije, geofizike, seizmologije i građevinarstva u Hrvatskoj. Empirijski podaci sugeriraju da je najučinkovitija interaktivna komunikacija koja nastoji riješiti lokalne kontekstualne probleme, objasniti radnje i pružiti iskrene, pravodobne, točne i pouzdane informacije. Ubuduće institucije moraju pronaći način da reagiraju ili podijeliti svoje informacije kako bi pomogle u krizi