372 research outputs found
Uredbe Europske unije u svezi s mikotoksinima u hrani
Mycotoxins are fungal metabolites that are present in a large part of the world food supply and bear potential threat to food safety. The European Union has been working for several years now on the harmonization of some mycotoxin standards for foods based on toxicological evaluation by its Scientific Committee on Food (SCF). These standards will follow the ALARA (as low as reasonably achievable) principle and will be applied to aflatoxins in the first place followed by ochratoxin A, patulin, and several toxins from Fusarium spp. Detailed regulations (limits, methods of sampling, and analysis) for aflatoxins B, G, and M on the commodities at stake have been worked out. At the moment, a variety of interrelated approaches as to the intake and toxicity of ochratoxin A are being discussed to assess the hazards and to determine the associated risk of this toxin. The other toxins like patulin and the ones derived from Fusarium spp. such as zearalenon and fumonisins will be discussed in the years to come.Mikotoksini su potencijalno opasni gljiviÄni metaboliti koji su prisutni u mnogim prehrambenim proizvodima. Europska unija veÄ nekoliko godina radi na usklaÄivanju normi za mikotoksine u hrani koje se zasnivaju na toksikoloĆĄkoj procjeni Znanstvenog odbora za hranu (engl. Scientific Committee on Food). Ove Äe norme slijediti naÄelo razumnog minimuma te Äe se odnositi prije svega na aflatoksine, okratoksin A, patulin i nekoliko drugih toksina iz vrsta Fusarium. Upravo se donose precizne uredbe (glede ograniÄenja, metoda uzorkovanja i analize) u svezi s aflatoksinima B, G i M. Trenutno se raspravlja o razliÄitim meÄusobno povezanim pristupima unosu i toksiÄnosti okratoksina A kako bi se procijenila opasnost i rizici vezani za ovaj toksin. Tek slijedi rasprava o patulinu odnosno toksinima iz vrsta Fusarium kao ĆĄto su zearalenon i fumonizini
Chiral molecule adsorption on helical polymers
We present a lattice model for helicity induction on an optically inactive
polymer due to the adsorption of exogenous chiral amine molecules. The system
is mapped onto a one-dimensional Ising model characterized by an on-site
polymer helicity variable and an amine occupancy one. The equilibrium
properties are analyzed at the limit of strong coupling between helicity
induction and amine adsorption and that of non-interacting adsorbant molecules.
We discuss our results in view of recent experimental results
Multiscale characterization of the 3D network structure of metal carbides in a Ni superalloy by synchrotron X-ray microtomography and ptychography
Synchrotron X-ray microtomography and ptychography were used to characterize the 3D network structure, morphology and distribution of metal carbides in an as-cast IN713LC Ni superalloy. MC typed carbides were found to distribute mainly on the grain boundary between the matrix Îł and Îł' phase. The differences in solidification cooling rate had a minor influence on the volume fraction of the MC type carbides, but significantly affected the carbide size, distribution and network morphology. Depending on the local composition of the remaining liquid phase and geometric constraints, the carbides can form either spherical or strip or network morphologies. The research demonstrated clearly the advantage and technical potential of using the two complementary tomography techniques synergistically to characterize non-destructively complex multiple-phase structures in three dimensional space with a spatial resolution of ~30 nm
Preparation of amino-substituted indenes and 1,4-dihydronaphthalenes using a one-pot multireaction approach: total synthesis of oxybenzo[c]phenanthridine alkaloids
Allylic trichloroacetimidates bearing a 2-vinyl or 2-allylaryl group have been designed as substrates for a one-pot, two-step multi-bond-forming process leading to the general preparation of aminoindenes and amino-substituted 1,4-dihydronaphthalenes. The synthetic utility of the privileged structures formed from this one-pot process was demonstrated with the total synthesis of four oxybenzo[c]phenanthridine alkaloids, oxychelerythrine, oxysanguinarine, oxynitidine, and oxyavicine. An intramolecular biaryl Heck coupling reaction, catalyzed using the HermannâBeller palladacycle was used to effect the key step during the synthesis of the natural products
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Development and demonstration of a Lagrangian dispersion modeling system for realâtime prediction of smoke haze pollution from biomass burning in Southeast Asia
Abstract Transboundary smoke haze caused by biomass burning frequently causes extreme air pollution episodes in maritime and continental Southeast Asia. With millions of people being affected by this type of pollution every year, the task to introduce smoke haze related air quality forecasts is urgent. We investigate three severe haze episodes: June 2013 in Maritime SE Asia, induced by fires in central Sumatra, and March/April 2013 and 2014 on mainland SE Asia. Based on comparisons with surface measurements of PM10 we demonstrate that the combination of the Lagrangian dispersion model NAME with emissions derived from satelliteâbased activeâfire detection provides reliable forecasts for the region. Contrasting two fire emission inventories shows that using algorithms to account for fire pixel obscuration by cloud or haze better captures the temporal variations and observed persistence of local pollution levels. Including upâtoâdate representations of fuel types in the area and using better conversion and emission factors is found to more accurately represent local concentration magnitudes, particularly for peat fires. With both emission inventories the overall spatial and temporal evolution of the haze events is captured qualitatively, with some error attributed to the resolution of the meteorological data driving the dispersion process. In order to arrive at a quantitative agreement with local PM10 levels, the simulation results need to be scaled. Considering the requirements of operational forecasts, we introduce a realâtime bias correction technique to the modeling system to address systematic and random modeling errors, which successfully improves the results in terms of reduced normalized mean biases and fractional gross errors
Barriers and enablers to blood culture sampling in Indonesia, Thailand and Viet Nam: a Theoretical Domains Framework-based survey
Objective Blood culture (BC) sampling is recommended for all suspected sepsis patients prior to antibiotic administration. We examine barriers and enablers to BC sampling in three Southeast Asian countries.
Design A Theoretical Domains Framework (TDF)-based survey, comprising a case scenario of a patient presenting with community-acquired sepsis and all 14 TDF domains of barriers/enablers to BC sampling.
Setting Hospitals in Indonesia, Thailand and Viet Nam, December 2021 to 30 April 2022.
Participants 1070 medical doctors and 238 final-year medical students were participated in this study. Half of the respondents were women (n=680, 52%) and most worked in governmental hospitals (n=980, 75.4%).
Outcome measures Barriers and enablers to BC sampling.
Results The proportion of respondents who answered that they would definitely take BC in the case scenario was highest at 89.8% (273/304) in Thailand, followed by 50.5% (252/499) in Viet Nam and 31.3% (157/501) in Indonesia (p<0.001). Barriers/enablers in nine TDF domains were considered key in influencing BC sampling, including âpriority of BC (TDF-goals)â, âperception about their role to order or initiate an order for BC (TDF-social professional role and identity)â, âperception that BC is helpful (TDF-beliefs about consequences)â, âintention to follow guidelines (TDF-intention)â, âawareness of guidelines (TDF-knowledge)â, ânorms of BC sampling (TDF-social influence)â, âconsequences that discourage BC sampling (TDF-reinforcement)â, âperceived cost-effectiveness of BC (TDF-environmental context and resources)â and âregulation on cost reimbursement (TDF-behavioural regulation)â. There was substantial heterogeneity between the countries. In most domains, the lower (higher) proportion of Thai respondents experienced the barriers (enablers) compared with that of Indonesian and Vietnamese respondents. A range of suggested intervention types and policy options was identified.
Conclusions Barriers and enablers to BC sampling are varied and heterogenous. Cost-related barriers are more common in more resource-limited countries, while many barriers are not directly related to cost. Context-specific multifaceted interventions at both hospital and policy levels are required to improve diagnostic stewardship practices
Accumulation of an Antidepressant in Vesiculogenic Membranes of Yeast Cells Triggers Autophagy
Many antidepressants are cationic amphipaths, which spontaneously accumulate in natural or reconstituted membranes in the absence of their specific protein targets. However, the clinical relevance of cellular membrane accumulation by antidepressants in the human brain is unknown and hotly debated. Here we take a novel, evolutionarily informed approach to studying the effects of the selective-serotonin reuptake inhibitor sertraline/ZoloftÂź on cell physiology in the model eukaryote Saccharomyces cerevisiae (budding yeast), which lacks a serotonin transporter entirely. We biochemically and pharmacologically characterized cellular uptake and subcellular distribution of radiolabeled sertraline, and in parallel performed a quantitative ultrastructural analysis of organellar membrane homeostasis in untreated vs. sertraline-treated cells. These experiments have revealed that sertraline enters yeast cells and then reshapes vesiculogenic membranes by a complex process. Internalization of the neutral species proceeds by simple diffusion, is accelerated by proton motive forces generated by the vacuolar H+-ATPase, but is counteracted by energy-dependent xenobiotic efflux pumps. At equilibrium, a small fraction (10â15%) of reprotonated sertraline is soluble while the bulk (90â85%) partitions into organellar membranes by adsorption to interfacial anionic sites or by intercalation into the hydrophobic phase of the bilayer. Asymmetric accumulation of sertraline in vesiculogenic membranes leads to local membrane curvature stresses that trigger an adaptive autophagic response. In mutants with altered clathrin function, this adaptive response is associated with increased lipid droplet formation. Our data not only support the notion of a serotonin transporter-independent component of antidepressant function, but also enable a conceptual framework for characterizing the physiological states associated with chronic but not acute antidepressant administration in a model eukaryote
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