Synthèse des pyrido[2,3-d] el [3,2-d] -s-triazolo[3,4-f] pyrimidines el de (pyrazolyl-1')-4 pyrido[2,3-d] et [3,2-d] pyrimidines

The synthesis of two new heterocycles is described: pyrido-[2,3-d]-.s-triazolo[ 3,4-f] pyrimidine and pyrido[3,2-d]-.s-triayzolo-[3,4-f] pyrimidine. 4-[I'-Pyrazolyl]pyrido[2,3-d]pyrimidines and 4-[1′-pyrazoly1] pyrido[ 3,2-d] pyrimidine are obtained by the action of 4-hydrazinopyrido[2,3-d]pyrimidine and 4-hydrazinopyrido-[3,2-d]pyrimidine with several β-diketones.     

The developmental pattern of stimulus and response interference in a color-object Stroop task: an ERP study

Background

Several studies have shown that Stroop interference is stronger in children than in adults. However, in a standard Stroop paradigm, stimulus interference and response interference are confounded. The purpose of the present study was to determine whether interference at the stimulus level and the response level are subject to distinct maturational patterns across childhood. Three groups of children (6–7 year-olds, 8–9 year-olds, and 10–12 year-olds) and a group of adults performed a manual Color-Object Stroop designed to disentangle stimulus interference and response interference. This was accomplished by comparing three trial types. In congruent (C) trials there was no interference. In stimulus incongruent (SI) trials there was only stimulus interference. In response incongruent (RI) trials there was stimulus interference and response interference. Stimulus interference and response interference were measured by a comparison of SI with C, and RI with SI trials, respectively. Event-related potentials (ERPs) were measured to study the temporal dynamics of these processes of interference.

Results

There was no behavioral evidence for stimulus interference in any of the groups, but in 6–7 year-old children ERPs in the SI condition in comparison with the C condition showed an occipital P1-reduction (80–140 ms) and a widely distributed amplitude enhancement of a negative component followed by an amplitude reduction of a positive component (400–560 ms). For response interference, all groups showed a comparable reaction time (RT) delay, but children made more errors than adults. ERPs in the RI condition in comparison with the SI condition showed an amplitude reduction of a positive component over lateral parietal (-occipital) sites in 10–12 year-olds and adults (300–540 ms), and a widely distributed amplitude enhancement of a positive component in all age groups (680–960 ms). The size of the enhancement correlated positively with the RT response interference effect.

Conclusion

Although processes of stimulus interference control as measured with the color-object Stroop task seem to reach mature levels relatively early in childhood (6–7 years), development of response interference control appears to continue into late adolescence as 10–12 year-olds were still more susceptible to errors of response interference than adults.     

Transition Metal Ion-binding Properties of a 14-Membered N2O2S2- Macrobicyclic Ligand

The selective liquid–liquid extraction of various transition metal cations from the aqueous phase to the organic phase was carried out using a 14-membered N₂O₂S₂-macrobicycle. Metal picrates such as Pb²⁺, Co²⁺, Zn²⁺, Ni²⁺,Cu²⁺ and Cd²⁺ were used in this extraction studies. It was found that the ligand showed moderate selectivity towards Pb²⁺ only among the other metals. The extraction constant (log K _ex) was determined to be 13.8 for Pb²⁺ complex.     

Synthesis and reactions of 4H-3,1-benzothiazines

This study is directed towards the synthesis of the pyrrolo[1,2-α]indole skeleton which is the essential ring system of the active antitumor miomycins. To this end a number of fused heterocycles such as benzothiazines, benzoxazines, indoles and quinolines were synthesized. The structures of the new compounds were assigned by ir, ¹H nmr and ms-data.     

Nuclear spin-lattice and nuclear spin-spin relaxation time measurements in EuB6 at low temperatures using the spin-echo technique

Experimental results on the nuclear spin-lattice and nuclear spin-spin relaxation times in the ferromagnetic EuB₆ at temperatures below 4·2 K are presented using the external magnetic field,H _ext, in the range of 0 ⩽H _ext ⩽ 10 kG. Nuclear spin-spin relaxation time computed on the basis of the Suhl-Nakamura process turns out to be 3·2μs, which compares well with the experimental value 11·1μs obtained with the 10 kG magnetic field at 1·7 K. It is found that in the ferromagnetic EuB₆,T ₁ is approximately 5 × 10³ times larger thanT ₂ at 1·7 K with the 10 kG magnetic field. Thus the effect ofT ₁ onT ₂ can be neglected. From the experimental value ofT ₂, the value of the homogeneous line broadening is found to be 14 kHz. The corresponding value obtained from the cw method is 175 kHz. This evidently shows the presence of the inhomogeneous line broadening in the cw NMR.     

Nicotinic acid adsorption thermodynamics study on carboxymethyl cellulose Ce(IV) molybdophosphate composite cation-exchanger

The thermodynamics of nicotinic acid adsorption from aqueous solution on carboxymethyl cellulose Ce(IV) molybdophosphate composite cation exchanger were studied. The composite cation exchanger was synthesized by sol–gel method and thereby characterized using scanning electron microscopy, thermogravimetric analysis, X-ray powder diffraction and fourier transform infra red spectroscopy. The analytical applicability and thermodynamic parameters, such as Freundlich constant, thermodynamic equilibrium constant (K _ο), standard free energy changes (ΔG°), standard enthalpy changes (ΔH°) and standard entropy changes (ΔS°) of this composite cation exchanger have been evaluated. The thermodynamic parameters showed that the adsorption of nicotinic acid onto composite cation exchanger is feasible, spontaneous and exothermic, suggesting their suitability for the potential application of nicotinic acid removal from waste water.     

Regulatory Role of Nano-Curcumin against Tartrazine-Induced Oxidative Stress,Apoptosis-Related Genes Expression,and Genotoxicity in Rats

The present study evaluates the regulatory effect of Nano-Curcumin (Nano-CUR) against tartrazine (TZ)-induced injuries on apoptosis-related gene expression (i.e., p⁵³, CASP-3 and CASP-9), antioxidant status, and DNA damages in bone marrow in treated rats. Male rats were arbitrarily separated into five groups, and each group was comprised of 10 rats each. The 1st group served as control (G1). The 2nd group ingested 7.5 mg TZ/kg. b.w. (body weight). The 3rd group ingested Nano-CUR 1 g/kg b.w. The 4th and 5th groups were respectively administered with (1 g Nano-CUR + 7.5 mg TZ/kg. b.w.) and (2 g Nano-CUR + 7.5 mg TZ/kg. b.w.). At the end of the experiment, blood samples, livers, and kidneys were collected. Livers and kidneys were homogenized and used for the analysis of reduced glutathione, malonaldhyde, total antioxidant capacity, lipid peroxide antioxidant enzyme activities, apoptosis-related gene expression, and genotoxicity by comit test. The ingestion of TZ for 50 days resulted in significant decreases in body, and kidney weights in rats and a relative increase in the liver weight compared to control. In contrast, the ingestion of Nano-CUR with TZ remarkably upgraded the body weight and relative liver weight compared to the normal range in the control. Aditionally, TZ ingestion in rats increased the oxidative stress biomarkers lipid peroxide (LPO) and malonaldehyde (MDA) significantly, whereas it decreased the reduced glutathione (GSH) levels and total antioxidant capacity (TAC). Similarly, the levels of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) significantly deteriorated in response to TZ ingestion. Moreover, the results revealed a remarkable up-regulation in the level of expression for the three examined genes, including p⁵³, CASP-3, and CASP-9 in TZ-ingested rats compared to the control. On the other hand, the comet assay result indicates that the ingestion of TZ induced DNA damage in bone marrow. Notably, the administration of Nano-CUR protected the kidney and liver of TZ-ingested rats as evidenced by a significant elevation in all antioxidant activities of tested enzymes (i.e, SOD, GPx, and CAT), vital recovery in GSH and TAC levels, and a statistical decrease in LPO and MDA compared to TZ-ingested rats. Interestingly, the ingestion of rats with TZ modulates the observed up-regulation in the level of expression for the chosen genes, indicating the interfering role in the signaling transduction process of TZ-mediated poisoning. The results indicate that the administration of Nano-CUR may protect against TZ-induced DNA damage in bone marrow. According to the results, Nano-CUR exerted a potential protective effect against oxidative stress, DNA damage, and the up-regulation of apoptosis-related genes induced by TZ ingested to rats.