N-Methyl D-Aspartate Receptor Antagonist Kynurenic Acid Affects Human Cortical Development

Kynurenic acid (KYNA), a neuroactive metabolite of tryptophan degradation, acts as an endogenous N-methyl-D-aspartate receptor (NMDAR) antagonist. Elevated levels of KYNA have been observed in pregnant women after viral infections and are considered to play a role in neurodevelopmental disorders. However, the consequences of KYNA-induced NMDAR blockade in human cortical development still remain elusive. To study the potential impact of KYNA on human neurodevelopment, we used an in vitro system of multipotent cortical progenitors, i.e., radial glia cells (RGCs), enriched from human cerebral cortex at mid-gestation (16-19 gestational weeks). KYNA treatment significantly decreased RGCs proliferation and survival by antagonizing NMDAR. This alteration resulted in a reduced number of cortical progenitors and neurons while number and activation of astrocytes increased. KYNA treatment reduced differentiation of RGCs into GABAergic neurons, while differentiation into glutamatergic neurons was relatively spared. Furthermore, in mixed cortical cultures KYNA triggered an inflammatory response as evidenced by increased levels of the pro-inflammatory cytokine IL-6. In conclusion, elevated levels of KYNA play a significant role in human RGC fate determination by antagonizing NMDARs and by activating an inflammatory response. The altered cell composition observed in cell culture following exposure to elevated KYNA levels suggests a mechanism for impairment of cortical circuitry formation in the fetal brain after viral infection, as seen in neurodevelopmental disorders such as schizophrenia

Wigner-Mott scaling of transport near the two-dimensional metal-insulator transition

Electron-electron scattering usually dominates the transport in strongly correlated materials. It typically leads to pronounced resistivity maxima in the incoherent regime around the coherence temperature $T^{*}$, reflecting the tendency of carriers to undergo Mott localization following the demise of the Fermi liquid. This behavior is best pronounced in the vicinity of interaction-driven (Mott-like) metal-insulator transitions, where the $T^{*}$ decreases, while the resistivity maximum $\rho_{max}$ increases. Here we show that, in this regime, the entire family of resistivity curves displays a characteristic scaling behavior $\rho(T)/\rho_{max}\approx F(T/T_{max}),$ while the $\rho_{max}$ and $T_{max}\sim T^{*}$ assume a powerlaw dependence on the quasi-particle effective mass $m^{*}$. Remarkably, precisely such trends are found from an appropriate scaling analysis of experimental data obtained from diluted two-dimensional electron gases in zero magnetic fields. Our analysis provides strong evidence that inelastic electron-electron scattering -- and not disorder effects -- dominates finite temperature transport in these systems, validating the Wigner-Mott picture of the two-dimensional metal-insulator transition.Comment: 7 page

Emergency treatment in case of cyanide poisoning during fumigation

Ovaj rad se bavi osnovnim aspektima toksikologije i klinike trovanja cijanidima, organizacije i metodologije pružanja prve pomoći kod trovanja cijanovodonikom prilikom vršenja furnigacija. Osim toga, dat je i komparativni prikaz najvažnijih antidota cijanida.The paper deals with the principal aspects of the toxicology and clinical treatment of cyanide poisoning and with the organisation of emergency medical care in cases of cyanide poisoning during fumigation. Comparative characteristics of the most important cyanide antidotes are also presented

Transmission through correlated Cun_nCoCun_n heterostructures

The effects of local electronic interactions and finite temperatures upon the transmission across the Cu$_4$CoCu$_4$ metallic heterostructure are studied in a combined density functional and dynamical mean field theory. It is shown that, as the electronic correlations are taken into account via a local but dynamic self-energy, the total transmission at the Fermi level gets reduced (predominantly in the minority spin channel), whereby the spin polarization of the transmission increases. The latter is due to a more significant $d$-electrons contribution, as compared to the non-correlated case in which the transport is dominated by $s$ and $p$ electrons.Comment: 29 pages, 7 figures, submited to PR

Emergence of classical behavior from the quantum spin

Classical Hamiltonian system of a point moving on a sphere of fixed radius is shown to emerge from the constrained evolution of quantum spin. The constrained quantum evolution corresponds to an appropriate coarse-graining of the quantum states into equivalence classes, and forces the equivalence classes to evolve as single units representing the classical states. The coarse-grained quantum spin with the constrained evolution in the limit of the large spin becomes indistinguishable from the classical system

Some clinical and biochemical parameters in workers occupationally exposed to pesticldes

U radu je ispitivana profesionalna izloženost radnika pesticidima i njihov uticaj na pojedine kliničke i biohemijske parametre. Klinički i biohemijski pokazatelji efekata pesticida praćeni su standardnim internističkim pregledom, rendgenografskim, elektrokardiografskim, spirometrijskim i laboratorijskim istraživanjima. Dobijeni rezultati su upoređeni sa rezultatima kontrolne grupe, a dobijene razlike su testirane Studentovim t-testom i x2-testom. Osim toga ispitivana je i linearna korelacija vrednosti pojedinih parametara zdravstvenog stanja i dužine izloženosti. Razmatrani su mogući mehanizmi nastajanja uočenih promena posmatranih parametara zdravstvenog stanja kod grupe radnika profesionalno Izložene pesticidima.Occupational exposure to pesticides and its effect on some clinical and biochemical parameters were studied in a group of workers. Radiographic, electrocardiographic and spirometric examinations were performed in addition to standard medical check-up. Laboratory tests included blood and urine analyses The results were compared with the data for the control group and the differences were analysed by means of Student\u27s t-test and the chi-squared test. There was a linear correlation between certain health parameters and length of exposure