2 research outputs found
Dioksini i njihova toksiÄnost za ljude
The term dioxins usually refers to polychlorinated dibenzo-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). As 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) has the highest toxic potential, the toxic potentials of other PCDDs and PCDFs are defined in comparison with it. Human exposure to dioxins can be environmental (background), occupational, or accidental pollution. In the human body, dioxins are in part metabolised and eliminated, and the rest is stored in body fat. People vary in their capacity to eliminate TCDD, but it is also dose-dependent; the elimination rate is much faster at higher than lower levels. The liver microsomal P4501A1 enzyme oxygenates lipophilic chemicals such as dioxins. It is encoded by the CYP1A1 gene. Cytosolic aryl hydrocarbon receptor (AhR) mediates their carcinogenic action. It binds to dioxin, translocates to nucleus and together with hydrocarbon nuclear translocator (ARNT) and xenobiotic responsive element (XRE) increases the expression of CYP1A1. Dioxins are classified as known human carcinogens, but they also cause noncancerous effects like atherosclerosis, hypertension, and diabetes. Long-term exposures to dioxins cause disruption of the nervous, immune, reproductive, and endocrine system. Short-term exposure to high levels impairs the liver function and causes chloracne. The most sensitive population to dioxin exposure are the foetuses and infants. A large number of health effects have been documented in the scientific literature, and they all place dioxins among the most toxic chemicals known to man.Dioksini su skupina kemijskih spojeva koji obuhvaÄaju poliklorirane dibenzo-dioksine (PCDD) i poliklorirane dibenzo-furane (PCDF). NajveÄi toksiÄni potencijal (faktor ekvivalentne toksiÄnosti) ima
2,3,7,8-TCDD, dok su toksiÄni potencijali drugih PCDD i PCDF odreÄeni u odnosu na njega. Izloženost dioksinima može biti izravna: izloženost dioksinima emitiranim u okoliÅ” kao posljedica nesreÄe,
profesionalna izloženost te neizravna, tzv. pozadinska. Nakon ulaska u ljudski organizam dioksini se djelomiÄno metaboliziraju i eliminiraju, a ostatak se pohranjuje u adipozno tkivo. Postoji odreÄena varijabilnost izmeÄu ljudi u kapacitetu eliminacije TCDD. Eliminacija TCDD ovisna je o dozi ā kod veÄe izloženosti (izloženost viÅ”im koncentracijama) brzina eliminacije je viÅ”a nego kod manje izloženosti (izloženost nižim koncentracijama). Enzim P4501A1 najvažniji je u oksigenaciji lipofi lnih supstrata poput dioksina. Kodiran je genom CYP1A1.
AhR je staniÄni receptor koji djeluje kao transkripcijski faktor koji posreduje u njihovu karcinogenom uÄinku. AhR veže dioksin te se premjeÅ”ta u jezgru gdje zajedno s ARNT (engl. aryl hydrocarbon nuclear translocator) i XRE (engl. xenobiotic responsive element), smjeÅ”tenim u promotorskoj regiji gena za CYP1A1, uzrokuje poveÄani izražaj CYP1A1.
Dioksini su karcinogeni spojevi, ali imaju i nekarcinogene uÄinke poput ateroskleroze, hipertenzije, dijabetesa, poremeÄaj živÄanog, imunosnog, reproduktivnog i endokrinog sustava, posebice kod kroniÄne izloženosti. Akutna izloženost uzrokuje oÅ”teÄenja jetre i klorakne. Najosjetljivija skupina izloženosti dioksinu je dojenÄad u prenatalnom i postnatalnom razdoblju. U znanstvenoj i struÄnoj literaturi dokumentirani su brojni zdravstveni uÄinci kao posljedice izloženosti dioksinima te ih svi istiÄu kao jedne od najtoksiÄnijih kemijskih spojeva
Spatial Segregation of Roma Settlements Within Serbian Cities. Examples from Belgrade, Novi Sad, and KruŔevac
This chapter focuses on the spatial segregation of Roma settlements within Serbian cities, shaped by the long-standing ethnic distance and social exclusion. In order to understand the broader context, the historical background against which Roma settlements emerged in Serbia, as well as their current demographic, legislative, and urban characteristics, are briefly presented. Several forms of segregation of Roma settlements are analysed, including segregation as a consequence of racist hostility, institutional discrimination by city administration, and development-based conflicts. Examples of setting up a wall enclosing a Roma settlement in KruŔevac, racist pressures that prevent the construction of housing for Roma in Belgrade and the reluctance to improve and legalise Roma settlements in Novi Sad, illustrate the various manifestations of segregation and division of urban space in Serbia.The Urban Book Serie