看到「This Human-Powered Paper Centrifuge Is Pure Genius」這個設計真的很巧妙... 全文刊登在 nature biomedical engineering 上：「Hand-powered ultralow-cost paper centrifuge」。
起源來自於小時候的玩具 (我也有印象，但忘記中文叫什麼了...)：
Here, we report an ultralow-cost (20 cents), lightweight (2 g), human-powered paper centrifuge (which we name ‘paperfuge’) designed on the basis of a theoretical model inspired by the fundamental mechanics of an ancient whirligig (or buzzer toy; 3,300 BC).
研究後發現離心速度可以到 125000rpm：
The paperfuge achieves speeds of 125,000 r.p.m. (and equivalent centrifugal forces of 30,000 g), with theoretical limits predicting 1,000,000 r.p.m.
對於無法買昂貴醫療器材的地區，這樣就有簡單但又頗有效的離心機做檢驗...