Can e-commerce reduce urban CO2 emissions? Evidence from National E-commerce Demonstration Cities policy in China.

The existing studies ignore the potential impact of e-commerce on CO2 emissions. Based on panel data of 284 cities at the prefecture level and above in China from 2003 to 2019, we regard National E-commerce Demonstration Cities (NEDC) policy as a quasi-natural experiment and empirically examine the impact and mechanism of NEDC policy on urban CO2 emissions by using multi-period difference-in-difference (DID) model and mediating effect model. The results show that, under the premise of satisfying parallel trends, the NEDC policy significantly reduces urban CO2 emissions. Compared with the non-pilot cities, the NEDC policy leads to decreases in urban CO2 emissions by 0.83%. The result still holds after a series of robustness tests, which include placebo test, propensity score matching (PSM) DID estimation, and instrumental variable estimation. The NEDC policy reduces urban CO2 emissions through promoting industrial structure upgrading, green technology innovation, and economic agglomeration. Heterogeneity analysis shows that the reduction effect of NEDC policy on urban CO2 emissions is stronger in non-western cities, larger scale cities, and resource-based cities.

A new anterolateral approach for type C fractures of the distal femur.

To provide an anatomic basis for treating type C distal femoral fractures by a new anterolateral approach. Twenty surgical procedures were performed in 10 adult cadaveric specimens using a new anterolateral approach followed by dissection of all lower limbs. The main anterolateral muscles and ligaments were observed. Vessels and nerves related to the new anterolateral approach were also evaluated. Full exposure of the distal femur was achieved. The iliotibial band was protected, and damage to the quadriceps femoris was reduced. The distance between the common peroneal nerve and the new incision line at the level of the lateral epicondyle of the femur was (χ̄ ± s) 8.19 ± 0.79 cm (range, 7.48-9.57 cm). This new anterolateral approach to the distal femur is safe. Although it induces slight soft tissue damage, its exposure is excellent. Knee rehabilitation can be performed in the early postoperative period.

Morphology and properties of hybrid composites based on polypropylene/polylactic acid blend and bamboo fiber.

The design of new composites based on a polypropylene (PP)/polylactic acid (PLA) matrix and filler bamboo fiber (BF) leads to changes in process ability, morphology, and rheological properties of the raw thermoplastic. We have designed more environmentally friendly composites blended with PLA, filled with bamboo fiber. To refine dispersion of PLA and improve composite toughness, MAH-g-PP was included in the filler-matrix interface to enhance interface strength for PP, PLA and BF. The incorporation of MAH-g-PP into composites brought about beneficial changes in morphology and rheological, related with improved dispersion of PLA and increased bamboo fiber-matrix interactions. The SEM results showed the particle size of the dispersed PLA and BF phase significantly reduced with adding a litter MAH-g-PP. The XRD and DSC results showed that spread and phases in the composites preserved crystallization. The good rheological, morphological and thermal properties obtained when the ratio of PP/PLA/BF/MAH-g-PP was 48.75/13/35/3.25.