Although separation of single-walled carbon nanotubes (SWCNTs) according to their helicity and handedness has been attracting tremendous interest recently, exploration of the left-and right-handed SWCNT enantiomers (defined as "M" and "P") to chiral sensing still remains in the early stage. Here we presented a new electrochemical sensor for chiral discrimination, which for the first time amplified the chiral selection on the electrode surface based on the left-or right-handed semiconducting SWCNT enantiomers with (6,5)-enriched chirality. The enantioselectivity was demonstrated by different peak current response to analyte enantiomers, observed in differential pulse voltammogram (DPV). Chiral distinguishing might be a result of the formation of an efficient chiral nanospace originating from the high purity of single enantiomer of (6,5) SWCNT. The obtained chiral electrodes were also applied to determine the enantiomeric excess (ee) of DOPA. There was a good linear relationship between DPV peak currents and % ee of L-DOPA. This study is the first example showing how the structure of chiral SWCNTs influences electrochemical chiral recognition.

From the two aspects of land quantity and spatial distribution, this article studies the existing problems and ideas for optimizing the supply of medical and health (M&H) land for municipal units to promote an equal supply of urban public services. Method: The existing problems were explored with the help of the kernel density, the spatial gravity model and the buffer zone analysis method, and the key optimization areas of M&H land under the trends of population flow were explored by constructing a suitability evaluation system for the natural, social and ecological elements. Results: The total amount of M&H land in the study area was lower than the standard. The characteristics of land supply that support hospitals and primary medical care are different, which makes it difficult for the population in different regions to obtain services from the two types of medical facilities. The supply of both types of land has room for improvement. Conclusion: The effect of public M&H supply is greatly affected by the factors of land supply, which directly causes the problem of uneven medical services in different regions. The land-use layout should be scientifically planned according to the characteristics of different regions.

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