Diversity and time delays induce resonance in a modular neuronal network

This paper focuses on the resonance dynamics of a modular neuronal network consisting of several small-world subnetworks. The considered network is composed of delay-coupled FitzHugh-Nagumo (FHN) neurons, whose characteristic parameters present diversity in the form of quenched noise. Our numerical results indicate that when such a network is subjected to an external subthreshold periodic signal, its collective response is optimized for an intermediate level of diversity, namely, a resonant behavior can be induced by an appropriate level of diversity. How the probabilities of intramodule and intermodule connections, as well as the number of subnetworks influence the diversity-induced resonance are also discussed. Further, conclusive evidences demonstrate the nontrivial role of time-delayed coupling on the diversity-induced resonance properties. Especially, multiple resonance is obviously detected when time delays are located at integer multiples of the oscillation period of the signal. Moreover, the phenomenon of fine-tuned delays in inducing multiple resonance remains when diversity is within an intermediate range. Our findings have implications that neural systems may profit from their generic diversity and delayed coupling to optimize the response to external stimulus.

Electron spin resonance study of polycrystalline La(0.75)(Ca(x)Sr(1-x))(0.25)MnO(3) (x = 0, 0.45, 1)

Electron spin resonance (ESR) spectra of polycrystalline La(0.75)(Ca(x)Sr(1-x))(0.25)MnO(3) (x = 0, 0.45, 1) were studied within the temperature range 110 K≤T≤470 K. The temperature dependence of the ESR intensity for the samples is described by a thermally activated model in the paramagnetic regime. It is found that the activation energy in the orthorhombic phase is higher than that in the rhombohedral phase for La(0.75)(Ca(0.45)Sr(0.55))(0.25)MnO(3). It is suggested that a higher energy is required to destroy the correlated polarons due to the fact that correlated polarons only exist in the orthorhombic phase. This proposition is confirmed by the analysis of the ESR linewidth data, which can be well fitted by the model of adiabatic hopping motion of small polarons. In addition, it is found that, at a fixed temperature, the linewidth decreases with increasing Sr doping, which reveals that the structural tolerance factor has a significant effect on the linewidth.

Assessing lead thresholds for phytotoxicity and potential dietary toxicity in selected vegetable crops

Lead tolerance and accumulation in shoots and edible parts varied with crop species and soil type. The critical Pb concentrations at 10% yield reduction were 24.71, 28.25, and 0.567 mg kg(-1) for pakchoi, celery, and hot pepper, respectively under hydroponic conditions, whereas were 13.1, 3.83, 0.734 mg kg(-1) grown in the Inceptisol and 31.7, 30.0, 0.854 mg kg(-1) in the Alluvial soil, respectively. Based on the threshold of human dietary toxicity for Pb, the critical levels of soil available Pb for pakchoi, celery, and hot pepper were 5.07, 8.06, and 0.48 mg kg(-1) for the Inceptisol, and 1.38, 1.47, and 0.162 mg kg(-1) for the Alluvial soil, respectively. Similarly, the total soil Pb thresholds were different from vegetable species and soil types.

[Paeonia Lactiflora injection in treating chronic cor pulmonale with pulmonary hypertension]

The changes of clinical features of blood stasis, hemorheology, arterial blood gas and hemodynamics which was determined by impedance cardiogram and pheopneumogram, hemorheologic examination, blood gaseous analysis and right heart catheterization were observed in 42 patients (male 35, female 7; age 64 +/- 16.5 years), 32 patients with decompensative chronic cor pulmonale (CCP), served as noninvasive methods group (NMG) treated by intravenous injecting 100% Paeonia lactifiora injection 5 ml per day, 10 patients with CCP as well as pulmonary hypertension, which was proved through right heart catheterization were considered as invasive methods group (IMG) treated by pulmonary artery injecting 100% Paeonia lactiflora 5 ml (one-time). After the treatment, the clinical features of blood stasis were improved significantly in NMG (P less than 0.05). Also the results of impedance cardiogram and pheopneumogram (such as: Q-B, B-Y interval and Q-B/B-Y ratio, cardiac output), the hemorheologic parameters (such as: blood viscosity, plasma viscosity, hematocrit and erythrocyte electrophoresis) and oxygen consumption of myocardium were improved significantly in NMG and IMG. In IMG, PAP was reduced by 0.71 +/- 0.27 kPa; PaO2 was promoted significantly in NMG. All of these have statistical significance (P less than 0.05 or 0.01). There are no statistical significance about the change of PaCO2, SaO2, blood pH and Bp (P less than 0.05).