This product is used for central air conditioning system circulating water detergents.

本品用于中央空调循环水系统除垢剂。

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It also appears to lower levels of ghrelin, the 'hunger hormone', circulating in the digestive system.

同时人体中一种在消化系统循环中被称为“饥饿激素”的物质的水平也有明显的下降。

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Flu vaccines work by introducing a killed version of circulating virus strains, which trains the body's immune system to recognize and attack similar invaders in the future.

流感疫苗通过导入一种杀死的流感病毒变种起作用，来训练身体的免疫系统识别这些变种并在将来遇到类似的入侵者时作出反击。

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The gravity-based system responded as it was designed to, circulating water and steam in a continuous loop to keep the scale-model reactor at a safe temperature automatically.

CNN: Today/Tomorrow - Helping nuclear plants keep their cool

By mimicking the conditions created by melanomas, they showed that in the presence of tumour cells, the immune system sent out IgG4 antibodies, but when faced with healthy cells it functioned as expected with IgG1 circulating.

BBC: Skin cancer 'able to fight off body's immune system'