Quantitative evaluation of extrinsic factors influencing electrical excitability in neuronal networks： Voltage Threshold Measurement Method(VTMM)

The electrical excitability of neural networks is influenced by different environmental factors. Effective and simple methods are required to objectively and quantitatively evaluate the influence of such factors, including variations in temperature and pharmaceutical dosage. The aim of this paper was to introduce ‘the voltage threshold measurement method＇, which is a new method using microelectrode arrays that can quantitatively evaluate the influence of different factors on the electrical excitability of neural networks. We sought to verify the feasibility and efficacy of the method by studying the effects of acetylcholine, ethanol, and temperature on hippocampal neuronal networks and hippocampal brain slices. First, we determined the voltage of the stimulation pulse signal that elicited action potentials in the two types of neural networks under normal conditions. Second, we obtained the voltage thresholds for the two types of neural networks under different concentrations of acetylcholine, ethanol, and different temperatures. Finally, we obtained the relationship between voltage threshold and the three influential factors. Our results indicated that the normal voltage thresholds of the hippocampal neuronal network and hippocampal slice preparation were 56 and 31 m V, respectively. The voltage thresholds of the two types of neural networks were inversely proportional to acetylcholine concentration, and had an exponential dependency on ethanol concentration. The curves of the voltage threshold and the temperature of the medium for the two types of neural networks were U-shaped. The hippocampal neuronal network and hippocampal slice preparations lost their excitability when the temperature of the medium decreased below 34 and 33°C or increased above 42 and 43°C, respectively. These results demonstrate that the voltage threshold measurement method is effective and simple for examining the performance/excitability of neuronal networks.

Comparative Investigation on Step-cycle Tensile Behaviors of Two Bimodal Pipe-grade Polyethylene with Different Slow Crack Growth Resistance

In this work,step-cycle tensile behavior of two bimodal polyethylene(PE)materials,a PEI 00 grade pipe material,XS10,and a PEI 00-RC(Resistant Crack)grade pipe material,XSC50,was comparatively investigated.By decomposing the strain into a recoverable part and an unrecoverable part,it was found that the deformation recovery capability of XSC50 during stretching was larger than that of XS10.Structural evolution characterized by in situ synchrotron small angle X-ray scattering indicated that the fragmentation of initial crystals in XSC50 occurred at lower strain than in XS10.Considering that XSC50 had relatively small lamellar thickness and similar crystallinity to XS10,we speculated that the larger deformation recovery capability of XSC50 during stretching probably derived from stronger entangled amorphous region caused by larger density of tie molecules and entanglements,which were usually regarded to have a significant influence on the slow crack growth(SCG)resistance of PE materials.As expected,the experimental result of strain hardening modulus test suggested that the deformation recovery capability during stretching was positively correlated with the SCG resistance for XS10 and XSC50 used in this work.The step-cycle tensile test had the potential to be developed into a supplement for comparison of SCG resistance of PE materials.

Copper-cobalt-nickel oxide nanowire arrays on copper foams as self-standing anode materials for lithium ion batteries

Numerous scientists are in the pursuit of energy storage materials with high energy and high power density by assembly of electrochemically active materials into conductive scaffolds,owing to the emerging need for next-generation energy storage devices.In this architectures,the active materials bonded to the conductive scaffold can provide a robust and free-standing structure,which is crucial to the fabrication of materials with high gravimetric capacity.Thus,hierarchical copper-cobalt-nickel ternary oxide(CuCoNi-oxide) nanowire arrays grown from copper foam were successfully fabricated as freestanding anode materials for lithium ion batteries(LIBs).CuCoNi-oxide nanowire arrays could provide more active sites owing to the hyperbranched structure,leading to a better specific capacity of 1191 mAh/g,cycle performance of 73% retention in comparison to CuO nanowire structure,which exhibited a specific capacity of 1029 mAh/g and capacity retention of 43%,respectively.