["Facilitate" or "Hinder"： Impact of Spatial Connectivity Networks in the Digital Economy on Carbon Performance].

This study took 254 cities in China from 2011 to 2021 as samples to empirically test how the spatial correlation network characteristics and node centrality of the urban digital economy affect carbon emission performance. The research showed that ① China's urban digital economy showed an obvious network development mode, but from the perspective of network node centrality, there were still significant spatial differences, showing the hierarchical distribution law of "eastern region-central and western region" and "four core urban agglomerations-four non-core urban agglomerations." ② A significant positive correlation was observed between the digital economy spatial correlation network and carbon emission performance.

Expression changes and roles of matrix metalloproteinases in a rat model of traumatic deep vein thrombosis.

Objective: To study the expression changes of matrix metalloproteinases (MMPs) in traumatic deep vein thrombosis (TDVT) in a rat model with the aid of gene chip technology and to explore the roles of MMPs in TDVT.

Methods: Totally 150 Sprague Dawley rats were randomly divided into control group (n equal to 10) and model group (n equal to 140). Rat models of TDVT were established by clamping the femoral vein and fixing the bilateral hind limbs.