No abstract

Spinocerebellar ataxia (SCA) comprises a large group of heterogeneous neurodegenerative disorders inherited in an autosomal dominant fashion. It is characterized by progressive cerebellar ataxia with oculomotor dysfunction, dysarthria, pyramidal signs, extrapyramidal signs, pigmentary retinopathy, peripheral neuropathy, cognitive impairment and other symptoms. It is classified according to the clinical manifestations or genetic nosology. To date, 40 SCAs have been characterized, and include SCA1-40. The pathogenic genes of 28 SCAs were identified. In recent years, with the widespread clinical use of next-generation sequencing, the genes underlying SCAs, and the mutants as well as the affected phenotypes were identified. These advances elucidated the phenotype-genotype relationship in SCAs. We reviewed the recent clinical advances, genetic features and phenotype-genotype correlations involving each SCA and its differentiation. The heterogeneity of the disease and the genetic diagnosis might be attributed to the regional distribution and clinical characteristics. Therefore, recognition of the phenotype-genotype relationship facilitates genetic testing, prognosis and monitoring of symptoms.

A novel nanocomposite of carbon quantum dots (CQDs) and TiO 2 nanotubes was fabricated and its enhanced photocatalytic and photoelectrochemical properties were demonstrated. Carbon quantum dots were obtained by electrochemical-etching graphite electrodes and TiO 2 nanotubes arrays were prepared by anodization methods. Subsequently, CQDs were assembled on the surface of vertically aligned TiO 2 nanotube arrays (CQDs/TiO 2 nanotubes) and the as-prepared samples were characterized by field-emission scanning electron microscopy, X-ray diffraction, UV-vis diffuse reflectance spectroscopy, photoelectrochemical and photocatalytic measurements. XPS measurement shows the presence of carbon species which come from CQDs. A red shift of light absorption edge and more absorption in the visible light region were observed for the resulting samples from the UV-vis diffuse reflectance spectra. An enhanced photocurrent and photopotential were demonstrated for the CQDs sensitized TiO 2 nanotubes under visible light irradiation and the photocurrent density was 2.7 times larger than that of pristine TiO 2 nanotubes. A solar cell was fabricated for further verifying the sensitization of CQDs over TiO 2 nanotubes. Moreover, the photocatalytic activity of CQDs/TiO 2 nanotubes towards the degradation of methylene blue was demonstrated and about 14% enhanced degradation efficiency was obtained with the presence of CQDs. This work developed a simple method to fabricate CQDs and demonstrated the introduction of CQDs to be a new approach for improving the utilization of visible light for TiO 2 nanotube arrays.