Random replicators with high-order interactions

We use tools of the equilibrium statistical mechanics of disordered systems to study analytically the statistical properties of an ecosystem composed of N species interacting via random mutual interactions, as well as via deterministic self-interactions of order p>/=2. We show that the main effect of increasing the order of the interactions among the species is to make the system less competitive, in the sense that the fraction of extinct species is greatly reduced. In addition, we find that for p>2 there is a threshold value which gives a lower bound to the concentration of the surviving species, preventing then the existence of rare species and, consequently, increasing the robustness of the ecosystem to external perturbations.     

Catalytic aminomethylation of α,ω-diacetylenes with secondary diamines and aldehydes as an efficient approach to diaza alkatetraynes and tetraaza tetraacetylenic macrocycles

An ef cient synthesis of diazaalkatetraynes and tetraaza macroheterocycles by the Mannich aminomethylation of α,ω-di(tetra)acetylenes with secondary diamines and aldehydes using CuCl as a catalyst was developed.

     

Directed Aminomethylation of Pyrrole,Indole, and Carbazole with <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>-Tetramethylmethanediamine

Catalytic aminomethylation of pyrrole and indole with N,N,N′,N′-tetramethylmethanediamine in the presence of 5 mol % of ZrOCl₂·8H₂O proceeds selectively at the positions 2, 5 of pyrrole and 1, 3 of indole. Carbazole under the same conditions affords 3-formyl-9-aminomethyl derivative. The reaction in the presence of 5 mol % of K₂CO₃ occurs as monoaminomethylation: for pyrrole at the position 2, for indole at the position 3, and for carbazole at the nitrogen atom of the substrate. Water-soluble 1,1′-(1H-pyrrole-2,5-diyl)bis(N,N-dimethylmethanamine) exhibits a fungistatic activity with respect to phytopathogenic fungi Rhizoctonia solani.     

The mechanism of formation and specifics of fragmentation for negative molecular ions of allylsilanes

The processes of formation of negative ions by allylsilane molecules were studied by resonanceelectron-capture mass spectrometry, and photoelectron spectra of these compounds were obtained. It was experimentally found that the overwhelming majority of fragment negative ions are produced in the energy range ～6–10 eV. It was shown that the resonance-electron-capture mass spectrum is almost entirely described by one or two series of intershell resonances due to excitation of an electron successively from several higher occupied orbitals to the lower unoccupied π molecular orbital.     

Maturation of auditory temporal integration and inhibition assessed with event-related potentials (ERPs)

Background

We examined development of auditory temporal integration and inhibition by assessing electrophysiological responses to tone pairs separated by interstimulus intervals (ISIs) of 25, 50, 100, 200, 400, and 800 ms in 28 children aged 7 to 9 years, and 15 adults.

Results

In adults a distinct neural response was elicited to tones presented at ISIs of 25 ms or longer, whereas in children this was only seen in response to tones presented at ISIs above 100 ms. In adults, late N1 amplitude was larger for the second tone of the tone pair when separated by ISIs as short as 100 ms, consistent with the perceptual integration of successive stimuli within the temporal window of integration. In contrast, children showed enhanced negativity only when tone pairs were separated by ISIs of 200 ms. In children, the amplitude of the P1 component was attenuated at ISIs below 200 ms, consistent with a refractory process.

Conclusions

These results indicate that adults integrate sequential auditory information into smaller temporal segments than children. These results suggest that there are marked maturational changes from childhood to adulthood in the perceptual processes underpinning the grouping of incoming auditory sensory information, and that electrophysiological measures provide a sensitive, non-invasive method allowing further examination of these changes.     

Cycloaddition of diazocycloalkanes to [60]fullerene in the presence of Pd-containing complex catalyst

A catalytic method for the selective and efficient synthesis of cycloalkylidenehomofullerenes by cycloaddition of [60]fullerene to diazocycloalkanes generated in situ from the corresponding hydrazones in the presence of a complex catalytic system [Pd(acac)₂-PPh₃-Et₃Al] has been developed.     

Synthesis of fullerene epoxide (C<Subscript>60</Subscript>O) by oxidation of fullerene C<Subscript>60</Subscript> with oxygen catalyzed by Mn(III), Ni(II), and Co(II) acetylacetonates

A procedure has been developed for the synthesis of fullerene monoepoxide C₆₀O via liquid-phase oxidation of fullerene C₆₀ in the presence of accessible catalysts [(Mn(acac)₃, Ni(acac)₂, and Co(acac)₂].     

1H and 13C NMR chemical shift assignments of spiro-cycloalkylidenehomo- and methanofullerenes by the DFT-GIAO method

The (1)H and (13)C NMR chemical shifts of spiro-cycloalkylidene[60]fullerenes were assigned using experimental NMR data and the Density Functional Theory (DFT)-Gauge Independence Of Atomic Orbitals method (GAIO) calculation method in the Perdew Burke Ernzerhof (PBE)/3z approach. The calculated values of the (13)C NMR chemical shifts adequately reproduce the experimental values at this quantum chemistry approach. Similar assignments will be helpful for (13)C NMR spectral analysis of homo- and methano[60]fullerene derivatives for structure elucidation and to determine the influence of fullerene frames on substituents and the influence of substituents on fullerene cores.