Evaluation of tourism competitiveness and mechanisms of spatial differentiation in Xinjiang, China.

Evaluation of tourism competitiveness is useful for measuring the level of regional tourism development. It is of great importance to understand the advantages and disadvantages of tourism development correctly and formulate corresponding development strategies. To investigate tourism competitiveness, this paper established an evaluation index system, including tourism development competitiveness, tourism resource competitiveness, and tourism-support competitiveness, for 14 prefectures and cities in Xinjiang in China. The characteristics and laws of spatial differentiation were analyzed. Factor analysis was applied to examine the spatial differentiation of regional tourism competitiveness. The results showed an obvious spatial differentiation in tourism competitiveness among the 14 prefectures and cities. In terms of development competitiveness, Yili and Urumqi constituted the spatial center, followed by Changji, Altay, and Ba Prefecture. As the provincial capital, Urumqi has political, economic, cultural, transportation, and geographic advantages, but its competitiveness is not prominent in terms of monopoly and efficiency. In terms of resource competitiveness, Yili is the core attraction, while Urumqi, Kashgar, Altay, and Ba Prefecture are dominant attractions. With respect to supporting competitiveness, Bo Prefecture has high value, followed by Urumqi City and Aksu. Hetian and Ke Prefecture have the lowest values. The comprehensive competitiveness of tourism is centered on Yili. Urumqi and Bo Prefecture are subcenters, and Changji, Altay, Ba Prefecture, Aksu, and Kashgar are characterized as multi-polar competition areas. Using the KMO and Bartlett's sphericity tests, the cumulative contribution variance of the eigenvalues of the eight factors extracted by the maximum variance rotation method was found to be 92.714%. Socio-economic conditions, tourism resources, infrastructure construction, regional cultural influence, ecological environment carrying capacity, tertiary industry development, tourism service level, and living security system are the main driving factors affecting the spatial differentiation of tourism competitiveness in Xinjiang. Analyzing the spatial evolution characteristics and the driving factors of the regional tourism competitiveness in Xinjiang, this paper seeks to promote the optimal allocation of tourism production factors in the macro regional system, and provide theoretical guidance and an empirical basis for the comprehensive and harmonic development of regional tourism.

68Ga-NOTA PET imaging for gastric emptying assessment in mice.

BACKGROUND: Positron emission tomography (PET) has the potential for visualization and quantification of gastric emptying (GE). The traditional Chinese medicine (TCM) has been recognized promising for constipation. This study aimed to establish a PET imaging method for noninvasive GE measurement and to evaluate the efficacy of a TCM on delayed GE caused by constipation using PET imaging. METHODS: [68Ga]Ga-NOTA was synthesized as the tracer and sesame paste with different viscosity were selected as test meals. The dynamic PET scans were performed after [68Ga]Ga-NOTA mixed with test meals were administered to normal mice. Two methods were utilized for the quantification of PET imaging. A constipation mouse model was treated with maren chengqi decoction (MCD), and the established PET imaging scans were performed after the treatment. RESULTS: [68Ga]Ga-NOTA was synthesized within 20 min, and its radiochemical purity was > 95%. PET images showed the dynamic process of GE. %ID/g, volume, and total activity correlated well with each other. Among which, the half of GE time derived from %ID/g for 4 test meals were 3.92 ± 0.87 min, 13.1 ± 1.25 min, 17.8 ± 1.31 min, and 59.7 ± 3.11 min, respectively. Constipation mice treated with MCD showed improved body weight and fecal conditions as well as ameliorated GE measured by [68Ga]Ga-NOTA PET. CONCLUSIONS: A PET imaging method for noninvasive GE measurement was established with stable radiotracer, high image quality, and reliable quantification methods. The efficacy of MCD on delayed GE was demonstrated using PET.