Dioksini i njihova toksičnost 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 obuhvaćaju poliklorirane dibenzo-dioksine (PCDD) i poliklorirane dibenzo-furane (PCDF). Najveći toksični potencijal (faktor ekvivalentne toksičnosti) ima 2,3,7,8-TCDD, dok su toksični potencijali drugih PCDD i PCDF određeni u odnosu na njega. Izloženost dioksinima može biti izravna: izloženost dioksinima emitiranim u okoliš kao posljedica nesreće, profesionalna izloženost te neizravna, tzv. pozadinska. Nakon ulaska u ljudski organizam dioksini se djelomično metaboliziraju i eliminiraju, a ostatak se pohranjuje u adipozno tkivo. Postoji određena varijabilnost između ljudi u kapacitetu eliminacije TCDD. Eliminacija TCDD ovisna je o dozi – kod veće izloženosti (izloženost višim koncentracijama) brzina eliminacije je viša nego kod manje izloženosti (izloženost nižim koncentracijama). Enzim P4501A1 najvažniji je u oksigenaciji lipofi lnih supstrata poput dioksina. Kodiran je genom CYP1A1. AhR je stanični receptor koji djeluje kao transkripcijski faktor koji posreduje u njihovu karcinogenom učinku. AhR veže dioksin te se premješta u jezgru gdje zajedno s ARNT (engl. aryl hydrocarbon nuclear translocator) i XRE (engl. xenobiotic responsive element), smještenim u promotorskoj regiji gena za CYP1A1, uzrokuje povećani izražaj CYP1A1. Dioksini su karcinogeni spojevi, ali imaju i nekarcinogene učinke poput ateroskleroze, hipertenzije, dijabetesa, poremećaj živčanog, imunosnog, reproduktivnog i endokrinog sustava, posebice kod kronične izloženosti. Akutna izloženost uzrokuje oštećenja jetre i klorakne. Najosjetljivija skupina izloženosti dioksinu je dojenčad u prenatalnom i postnatalnom razdoblju. U znanstvenoj i stručnoj literaturi dokumentirani su brojni zdravstveni učinci kao posljedice izloženosti dioksinima te ih svi ističu kao jedne od najtoksičnijih kemijskih spojeva

Salona II. Recherches archéologiques franco-croates à Salone. Ecclesiae dalmatiae. L'architecture paléochrétienne de la province romaine de Dalmatie (IVe- VIIe S.) [En dehors de la capitale, Salona] Tome 2 - Illustrations et conclusions

Pascale Chevalier, qui était déjà l'un des principaux auteurs de Salona I, a dressé l'inventaire - avec l'aide de tous ses collègues de Croatie, de Bosnie-Herzégovine et, pour une région limitée, du Monténégro - des 264 édifices cultuels actuellement connus (sans compter ceux de la capitale, Salone) dans la province de Dalmatie, à l'intérieur des frontières postérieures à la réforme de Dioclétien. Chaque fiche, normalisée, comporte les éléments essentiels de la description architecturale, du décor et du mobilier liturgique, une bibliographie raisonnée, et un commentaire sur la chronologie. Le deuxième volume contient une analyse globale de ces édifices, dont l'architecture est rarement ambitieuse, mais représente une variante régionale originale, tributaire à la fois de l'Italie, de la Grèce et de Constantinople. Sont particulièrement nombreux les groupes « complexes », formés soit de deux églises parallèles soit d'une seule encadrée d'annexes symétriques. Les installations liturgiques sont souvent bien conservées, en particulier pour les baptistères, les dépôts de reliques et les banquettes presbytérales. L'illustration comporte en général un plan redessiné à échelle constante (reproduit au 1/200e) et quelques photographies quand le monument est bien conservé. Des planches comparatives (avec des cartes de répartition) illustrent chaque chapitre de la synthèse. Tous les sites sont localisés dans un atlas de six cartes.Chevalier Pascale. Salona II. Recherches archéologiques franco-croates à Salone. Ecclesiae dalmatiae. L'architecture paléochrétienne de la province romaine de Dalmatie (IVe- VIIe S.) [En dehors de la capitale, Salona] Tome 2 - Illustrations et conclusions. Rome : École Française de Rome, 1995. 282 p. (Publications de l'École française de Rome, 194-2

Salona II. Recherches archéologiques franco-croates à Salone. Ecclesiae dalmatiae. L'architecture paléochrétienne de la province romaine de Dalmatie (IVe- VIIe S.) [En dehors de la capitale, Salona] Tome 2 - Illustrations et conclusions

Pascale Chevalier, qui était déjà l'un des principaux auteurs de Salona I, a dressé l'inventaire - avec l'aide de tous ses collègues de Croatie, de Bosnie-Herzégovine et, pour une région limitée, du Monténégro - des 264 édifices cultuels actuellement connus (sans compter ceux de la capitale, Salone) dans la province de Dalmatie, à l'intérieur des frontières postérieures à la réforme de Dioclétien. Chaque fiche, normalisée, comporte les éléments essentiels de la description architecturale, du décor et du mobilier liturgique, une bibliographie raisonnée, et un commentaire sur la chronologie. Le deuxième volume contient une analyse globale de ces édifices, dont l'architecture est rarement ambitieuse, mais représente une variante régionale originale, tributaire à la fois de l'Italie, de la Grèce et de Constantinople. Sont particulièrement nombreux les groupes « complexes », formés soit de deux églises parallèles soit d'une seule encadrée d'annexes symétriques. Les installations liturgiques sont souvent bien conservées, en particulier pour les baptistères, les dépôts de reliques et les banquettes presbytérales. L'illustration comporte en général un plan redessiné à échelle constante (reproduit au 1/200e) et quelques photographies quand le monument est bien conservé. Des planches comparatives (avec des cartes de répartition) illustrent chaque chapitre de la synthèse. Tous les sites sont localisés dans un atlas de six cartes.Chevalier Pascale. Salona II. Recherches archéologiques franco-croates à Salone. Ecclesiae dalmatiae. L'architecture paléochrétienne de la province romaine de Dalmatie (IVe- VIIe S.) [En dehors de la capitale, Salona] Tome 2 - Illustrations et conclusions. Rome : École Française de Rome, 1995. 282 p. (Publications de l'École française de Rome, 194-2

Kinetics and sintering mechanisms of hydro-thermally obtained hydroxyapatite

In this paper, the kinetics and sintering mechanism of hydro-thermally synthesized hydroxyapatite in the temperature range 900-1100 degrees C are presented. It was found that at 900 degrees C, the sintering process is very slow, whereas at 1000, 1050, and 1100 degrees C is much faster, caused by activated sintering with liquid phase/phase of solution on spots with concentrated material impurity and the formation of reaction/polyeutectic mixtures dominates. The activation energies of sintering were also determined. At all the investigated sintering temperatures, an approximate value of 90 kJ mol(-1) was found. (c) 2008 Elsevier B.V. All rights reserved

Removal of Heavy Metals from Aqueous Solutions by using Natural and Fe(III)-modified Zeolite Alginate Composites

6th International Symposium on Mining and Environmental Protection : June 21-24, Vrdnik, 2017

Implicitly Heterogeneous Multi-Stage Programming

Previous work on semantics-based multi-stage programming (MSP) language design focused on homogeneous designs, where the generating and the generated languages are the same. Homogeneous designs simply add a hygienic quasi-quotation and evaluation mechanism to a base language. An apparent disadvantage of this approach is that the programmer is bound to both the expressivity and performance characteristics of the base language. This paper proposes a practical means to avoid this by providing specialized translations from subsets of the base language to di#erent target languages. This approach preserves the homogeneous "look" of multi-stage programs, and, more importantly, the static guarantees about the generated code. In addition, compared to an explicitly heterogeneous approach, it promotes reuse of generator source code and systematic exploration of the performance characteristics of the target languages

Biodiversity at multiple trophic levels is needed for ecosystem multifunctionality.

Many experiments have shown that loss of biodiversity reduces the capacity of ecosystems to provide the multiple services on which humans depend. However, experiments necessarily simplify the complexity of natural ecosystems and will normally control for other important drivers of ecosystem functioning, such as the environment or land use. In addition, existing studies typically focus on the diversity of single trophic groups, neglecting the fact that biodiversity loss occurs across many taxa and that the functional effects of any trophic group may depend on the abundance and diversity of others. Here we report analysis of the relationships between the species richness and abundance of nine trophic groups, including 4,600 above- and below-ground taxa, and 14 ecosystem services and functions and with their simultaneous provision (or multifunctionality) in 150 grasslands. We show that high species richness in multiple trophic groups (multitrophic richness) had stronger positive effects on ecosystem services than richness in any individual trophic group; this includes plant species richness, the most widely used measure of biodiversity. On average, three trophic groups influenced each ecosystem service, with each trophic group influencing at least one service. Multitrophic richness was particularly beneficial for 'regulating' and 'cultural' services, and for multifunctionality, whereas a change in the total abundance of species or biomass in multiple trophic groups (the multitrophic abundance) positively affected supporting services. Multitrophic richness and abundance drove ecosystem functioning as strongly as abiotic conditions and land-use intensity, extending previous experimental results to real-world ecosystems. Primary producers, herbivorous insects and microbial decomposers seem to be particularly important drivers of ecosystem functioning, as shown by the strong and frequent positive associations of their richness or abundance with multiple ecosystem services. Our results show that multitrophic richness and abundance support ecosystem functioning, and demonstrate that a focus on single groups has led to researchers to greatly underestimate the functional importance of biodiversity