长期以来科学家发现，密集的低密度脂小颗粒偷袭进入动脉壁，比蓬松的大颗粒更容易堵塞血管。

Scientists have long known that small, dense LDL particles sneak into the artery wall to build up and narrow blood vessels more easily than larger, fluffier particles.

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城市化进程的不断加剧，在产生巨大经济效益的同时，也带来了城市人口膨胀、建筑密度过大、交通严重堵塞、环境持续恶化等一系列的问题。

Since the intensification of urbanization, it not only brought great economic benefits, but also the population explosion, excessive building density, terrible traffic jam, and other problems.

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