Okratoksin A i omjer sfinganina i sfingozina u urinu stanovnika s područja endemske nefropatije u Hrvatskoj

The most plausible theory of the aetiology of endemic nephropathy links it with exposure to nephrotoxic mycotoxin ochratoxin A (OTA). In this study, the concentration of OTA and sphinganine/sphingosine (Sa/So) ratio, the biomarker of another nephrotoxic mycotoxin fumonisin B1 exposure, were analysed in 45 human urine samples collected in the endemic village of Kaniža in Croatia and in 18 samples from control village. Samples were collected twice from the same persons in 2000 and 2005. In both years the frequency of OTA-positive samples was higher in Kaniža (43 % and 18 %, respectively) than in the control village (28 % and 6 %, respectively). OTA concentrations in samples collected in Kaniža were higher in 2000 than in 2005 (p1 at the same time, while in Kaniža four such samples were collected in 2000 and one in 2005.Najprihvatljivija teorija o etiologiji endemske nefropatije povezuje njezin nastanak s izloženošću nefrotoksičnim mikotoksinima. Dok se izloženost mikotoksinu okratoksinu A (OTA) može dokazati njegovim nalazom u biološkim uzorcima kao što su krv i urin, vrlo kratko zadržavanje fumonizina B1 (FB1) u organizmu to onemogućava. Na pokusnim je životinjama nađeno da je porast omjera koncentracija sfi ngolipida sfi nganina i sfi ngozina (Sa/So) biološki pokazatelj izloženosti tom mikotoksinu. U ovom istraživanju mjerena je koncentracija OTA i omjer koncentracija Sa/So u urinu 45 stanovnika u endemskom selu Kaniža i 18 stanovnika u kontrolnom selu. Uzorci urina skupljeni su od istih osoba 2000. i 2005. godine. U obje godine učestalost uzoraka koji su sadržavali OTA bila je veća u Kaniži (43 % i 18 %) negoli u kontrolnom selu (28 % i 6 %). Koncentracija OTA također je bila viša u urinima skupljenim u Kaniži negoli u kontrolnom selu. Koncentracija OTA u uzorcima skupljenim u Kaniži 2000. bila je viša nego u uzorcima iz 2005. (p<0.005). Iako je u urinima iz obje godine omjer koncentracija Sa/So bio viši u Kaniži negoli u kontrolnom selu, razlika nije bila statistički značajna. Nije nađen nijedan uzorak skupljen u kontrolnom selu koji bi istodobno sadržavao mjerljivu koncentraciju OTA i omjer Sa/So veći od jedan. Za razliku od uzoraka iz kontrolnog sela, četiri uzorka skupljena u Kaniži u 2000. godini i jedan uzorak u 2005. godini upućivali su na istodobnu izloženost ovim mikotoksinima

Određivanje aflatoksina, okratoksina A, fumonizina i zearalenona u žitaricama i krmivu primjenom kompetetivnoga direktnog imunoenzimatskog testa (CD-ELISA) i tankoslojne kromatografije (TLC)

Aspergillus, Penicillium, and Fusarium species frequently contaminate crops. For this reason mycotoxins such as afl atoxins (AFs), ochratoxin A (OTA), fumonisins (FBs), and zearalenone (ZEA) are found in food and feed in a wide range of concentrations, depending on environmental and storage conditions. Consumption of mycotoxin-contaminated food and feed has been associated with acute and chronic poisoning and carcinoma. The aim of this study was to determine the incidence and co-occurrence of AFs (B1+B2+G1+G2), OTA, FBs (B1+B2+B3), and ZEA in 37 samples of cereals and feed randomly collected in 2007 from households of an endemic nephropathy (EN) area in Croatia. The mycotoxins were determined using the competitive direct ELISA test (CD-ELISA) in combination with thin-layer chromatography (TLC). The most frequent mycotoxin was ZEA (92 %, mean 318.3 μg kg-1), followed by FBs (27 %, 3690 μg kg-1), AFs (24.3 %, 4.6 μg kg-1), and OTA (16.2 %, 9.8 μg kg-1). Levels of AFs, ZEA, and FBs detected by CD-ELISA signifi cantly correlated with the TLC results. However, only one OTA-positive sample was confi rmed by TLC due to its high limit of detection. The levels of these mycotoxins were below the permissible limit for animal feed. Twenty-nine percent of cereals were contaminated with FBs, OTA, or ZEA in mass fractions above the permissible limit for humans. Co-occurrence of two toxins varied between 4.2 % and 54 % and of three between 4.2 % and 7.6 %. Prolonged co-exposure to AFs, OTA, FBs, and ZEA might increase the risk of various chronic diseases.Vrste plijesni iz rodova Aspergillus, Penicillium i Fusarium česti su kontaminanti usjeva te na takvim supstratima tvore mikotoksine. Stoga su žitarice i krmiva često kontaminirana afl atoksinima (AFs), okratoksinom A (OTA), fumonizinima (FBs) i zearalenonom (ZEA) u različitim koncentracijama ovisno o mikroklimatskim uvjetima na polju i u skladištu. Konzumiranje hrane kontaminirane mikotoksinima često je povezano s akutnim ili kroničnim trovanjima, ali i s razvojem karcinoma. Cilj ovog rada bio je odrediti istodobnu pojavnost AFs (B1+B2+G1+G2), OTA, FBs (B1+B2+B3) i ZEA u uzorcima žitarica i krme (N=37) koji su nasumično skupljeni u individualnim domaćinstvima na području endemske nefropatije (EN) u Hrvatskoj (2007). Za određivanje navedenih mikotoksina korišten je kompetitivni direktni ELISA-test (CD-ELISA) u kombinaciji s tankoslojnom kromatografi jom (TLC). Najzastupljeniji mikotoksin bio je ZEA (92 %, srednja koncentracija 318.3 μg kg-1), nakon čega slijede FBs (27 %, 3690 μg kg-1), AFs (24.3 %, 4.6 μg kg-1) te OTA (16.2 %, 9.8 μg kg-1). Koncentracije AFs, FBs i ZEA određene CD-ELISA-testom statistički značajno koreliraju s rezultatima dobivenim s TLC. OTA je potvrđen metodom TLC samo u jednom uzorku zbog visokog limita detekcije. Dokazane koncentracije su ispod razina dopuštenih za krmiva, dok je 29 % uzoraka žitarica sadržavalo FBs, OTA ili ZEA u koncentracijama iznad dopuštenih u hrani za ljude. Kokontaminacija s dvama odnosno trima toksinima varirala je između 4.2 % i 54 % odnosno između 4.2 % i 7.6 %. Dugotrajni unos AFs, OTA, FBs i ZEA putem hrane može povećati rizik od razvoja različitih kroničnih bolesti zbog njihova mogućega sinergističkog djelovanja

Kontaminacija zrna pšenice, kukuruza, soje i graška vrstama Fusariuma u Hrvatskoj

From 2002 to 2008, 203 samples of wheat, maize, soybean, and pea were analysed for the presence of Fusarium species. Contamination with Fusarium spp., expressed as the percentage of seeds with Fusarium colonies, ranged from 5 % to 69 % for wheat, from 25 % to 100 % for maize, from 4 % to 17 % for soybean, and from 3 % to 17 % for pea. 187 isolates were collected and the following 19 species determined: F. graminearum, F. poae, F. avenaceum, F. verticillioides, F. sporotrichioides, F. heterosporum, F. crookwellense, F. tricinctum, F. semitectum, F. oxysporum, F. proliferatum, F. solani, F. equiseti, F. pseudograminearum, F. chlamydosporum, F. sambucinum, F. compactum, F. scirpi, and F. culmorum. Dominant species were F. graminearum on wheat (27 % of isolates), F. verticillioides on maize (83 % of isolates), F. sporotrichioides on soybean (34 % of isolates), and F. proliferatum on pea (29 % of isolates). Among species identifi ed, F. heterosporum, F. crookwellense, F. pseudograminearum, F. sambucinum, and F. compactum have been reported for the fi rst time in Croatia.U periodu od 2002. do 2008. g. analizirana je prisutnost vrsta Fusariuma na 208 uzoraka zrna pšenice, kukuruza, soje i graška. Kontaminacija vrstama Fusariuma, izražena kao postotak sjemenki s kolonijama Fusarium spp., kretala se od 5 % do 69 % na pšenici, od 25 % do 100 % na kukuruzu, od 4 % do 17 % na soji te od 3 % do 17 % na grašku. Prosječna kontaminacija vrstama Fusariuma u različitim godinama varirala je od 10 % do 46 % na pšenici, od 50 % do 91 % na kukuruzu, od 5 % do 9 % na soji te od 7 % do 10 % na grašku. Vrste Fusariuma koje se javljaju na zrnu izolirane su i determinirane s odabranih uzoraka pšenice, kukuruza, soje i graška. Skupljeno je 187 izolata, a utvrđeno je 19 vrsta: F. graminearum, F. poae, F. avenaceum, F. verticillioides, F. sporotrichioides, F. heterosporum, F. crookwellense, F. tricinctum, F. semitectum, F. oxysporum, F. proliferatum, F. solani, F. equiseti, F. pseudograminearum, F. chlamydosporum, F. sambucinum, F. compactum, F. scirpi i F. culmorum. Dominantne vrste bile su F. graminearum na pšenici (27 % izolata), F. verticillioides na kukuruzu (83 % izolata), F. sporotrichioides na soji (34 % izolata) te F. proliferatum na grašku (29 % izolata). U Hrvatskoj su prvi put utvrđene vrste F. heterosporum, F. crookwellense, F. pseudograminearum, F. sambucinum i F. compactum

Feedback Enhances Feedforward Figure-Ground Segmentation by Changing Firing Mode

In the visual cortex, feedback projections are conjectured to be crucial in figure-ground segregation. However, the precise function of feedback herein is unclear. Here we tested a hypothetical model of reentrant feedback. We used a previous developed 2-layered feedforwardspiking network that is able to segregate figure from ground and included feedback connections. Our computer model data show that without feedback, neurons respond with regular low-frequency (∼9 Hz) bursting to a figure-ground stimulus. After including feedback the firing pattern changed into a regular (tonic) spiking pattern. In this state, we found an extra enhancement of figure responses and a further suppression of background responses resulting in a stronger figure-ground signal. Such push-pull effect was confirmed by comparing the figure-ground responses withthe responses to a homogenous texture. We propose that feedback controlsfigure-ground segregation by influencing the neural firing patterns of feedforward projecting neurons

Accuracy versus precision in boosted top tagging with the ATLAS detector

The identification of top quark decays where the top quark has a large momentum transverse to the beam axis, known as top tagging, is a crucial component in many measurements of Standard Model processes and searches for beyond the Standard Model physics at the Large Hadron Collider. Machine learning techniques have improved the performance of top tagging algorithms, but the size of the systematic uncertainties for all proposed algorithms has not been systematically studied. This paper presents the performance of several machine learning based top tagging algorithms on a dataset constructed from simulated proton-proton collision events measured with the ATLAS detector at √s = 13 TeV. The systematic uncertainties associated with these algorithms are estimated through an approximate procedure that is not meant to be used in a physics analysis, but is appropriate for the level of precision required for this study. The most performant algorithms are found to have the largest uncertainties, motivating the development of methods to reduce these uncertainties without compromising performance. To enable such efforts in the wider scientific community, the datasets used in this paper are made publicly available

Test of lepton flavour universality in W-boson decays into electrons and τ-leptons using pp collisions at s \sqrt{s} = 13 TeV with the ATLAS detector

A measurement of the ratio of the branching fractions, Rτ/e = B(W → τν)/B(W → eν), is performed using a sample of W bosons originating from top-quark decays to final states containing τ-leptons or electrons. This measurement uses pp collisions at s =13TeV, collected by the ATLAS experiment at the Large Hadron Collider during Run 2, corresponding to an integrated luminosity of 140fb−1. The W → τντ (with τ → eνeντ) and W →eνe decays are distinguished using the differences in the impact parameter distributions and transverse momentum spectra of the electrons. The measured ratio of branching fractions Rτ/e = 0.975±0.012(stat.)±0.020(syst.), is consistent with the Standard Model assumption of lepton flavour universality in W-boson decays

Measurement of single top-quark production in association with a W boson in pp collisions at root s = 13 TeV with the ATLAS detector

The inclusive cross section for the production of a single top quark in association with a W boson is measured using 140 fb-1 of proton-proton collision data collected with the ATLAS detector at root s = 13 TeV. Events containing two charged leptons and at least one jet identified as originating from a b-quark are selected. A multivariate discriminant is constructed to separate the tW signal from the t⁢ tbar background. The cross section is extracted using a profile likelihood fit to the signal and control regions and it is measured to be sigma t W = 7⁢5 + 15 - 14 pb, in good agreement with the Standard Model prediction. The measured cross section is used to extract a value for the left-handed form factor at the Wtb vertex times the Cabibbo-Kobayashi-Maskawa matrix element mod(fLV Vtb) of 0.97 +- 0.10