6 ms·
As usual, what you really want to do is read the paper: http://www.nature.com/articles/s41551-016-0009 http://www.nature.com/articles/s41551-016-0009 This is a
by nneonneo 10y ago
As usual, what you really want to do is read the paper: http://www.nature.com/articles/s41551-016-0009 http://www.nature.com/articles/s41551-016-0009
This is a well-written and very clear paper. It covers several aspects that went unmentioned in the Gizmodo article, and highlights that although building such a device may be trivial, evaluating and studying it is not.
Some highlights: the paper covers how the device was built in detail, including information on the three safety mechanisms used to ensure the operator doesn't get exposed to infected blood (shatterproof plastic capillaries, epoxied sample holders made from drinking straws, and sealing of the capillaries inside two paper discs). It is exclusively made from low-cost materials, but it's more than just a piece of paper, handles and some string (fishing wire).
The paper also covers the physical dynamics of the "paperfuge" in great detail, analyzing its rotational dynamics and building a theoretical model of motion that agrees well with the physical observations (captured with a 6000fps high-speed camera). It also shows that the max RPM varies with disc size, with 125000 RPM for a small disc (5mm diameter). The paper even mentions that this was submitted as a Guiness World Record.
Finally it shows that the paperfuge produces sample separation results on par with electromechanical centrifuges using similar spinning time (1.5min for paperfuge, 2min for centrifuge for plasma separation), and does an analysis of the resulting blood samples.
- HCIdivision17 10y agoThanks a lot for the summary. It's so hard to look at simple things and see how difficult it is to make them a product, and even harder to see the edge cases that prevent it from being used in healthcare. I really like that there's a comparison to commercial centrifuges, since that shows the quality of medical care isn't going down simply to be cheap. Overall it looks like a well thought out design.
- csours 10y agoIf I was using this thing, I would fix one end to a solid endpoint and pull the other end so that I would not be in the line of fire if the thing exploded.
- taneq 10y agoThe video shows them doing exactly this with one end tied to a door handle.
- tbabb 10y agoHoly crap. 125,000RPM for a 5mm disc means the edge is spinning at nearly 9,000mph. On top of that, the g-force would be a = v^2 / r v = 2 * pi * 5mm * 125000/60 s^-1` r = 5mm ...giving 87,000 gees?! I start to wonder if general relativity effects (frame-dragging?) start to become noticeable at that acceleration.
- jessriedel 10y agoThis is an impressively high spin rate. The sub-$1k centrifuges on Amazon look like they about 10,000 RPM, although at least one gets 100,000 RPM. https://www.amazon.com/s/ref=s9_dnav_bw_ct02_s?node=317985011&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=merchandised-search-2&pf_rd_r=2MEEMSYNQJR3WY5B5YXN&pf_rd_t=101&pf_rd_p=47218708-b9f8-48c8-b89e-556a5cc1a394&pf_rd_i=317983011 https://www.amazon.com/s/ref=s9_dnav_bw_ct02_s?node=31798501...
- hguant 10y agoQuick math and google says no: 9,000 MPH = 0.00001342 C Threshold for relativistic effects is .01 C according to this paper: http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/rellim.html http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/rellim.ht... EDIT: Rereading that paper, they're focused at the particle level, which may or may not make this irrelevant. I know anecdotally that GPS satellites have to take relativity into account. Geostationary satellites move at 1.9 miles per seconds, which is 6840 mph - quite a bit lower than our centrifuge. That being said, the precision required for GPS means that very small changes due to relative effects have a rather large impact. In short, where there is motion, there is relativity. Is it enough to measure here? Possibly - sticking a small microcontroller and having it report the time would be interesting. Is it enough to matter? The answer is relative.
- wosos 10y agoYes, putting MC and check it's time after a device-lifetime of use would be quite an interesting experiment.
- andrepd 10y agoI believe in GPS satellites relativistic effects are due in greater part to the difference in gravity between the surface of the earth and the satellite, more so than the special relativity effects.
- hackuser 10y ago> As usual, what you really want to do is read the paper: An aside: If you are not reading Nature you may be missing out on a lot. I would guess the same applies to Science. Only the back half of Nature is actual research papers, which often are indeed very slow going. The other half is science news written clearly - it's fascinating, not a chore at all - and with a level of knowledge and sophistication unmatched elsewhere (AFAIK), and most importantly it will completely change your perspective: There is a world of research and knowledge that you won't even know exists if you read the more 'popular' science press. A little time reading Nature will save you much more time reading less informative publications.
- apathy 10y agoIf you read Nature and science papers, plan on reading the supplementary materials (typically 20-200 pages) where we are forced to put all the real science. And the online methods (a half measure spurred by outrage at the preceding). Wouldn't want to waste words on silly shit like methods, references, discussions, etc in a CNS paper, would we? LIGO doesn't even bother sending papers to Nature or science any more. The editors at both are unbearably pompous.
- sohkamyung 10y agoAgree. Nature News and Comment [1] is where I usually go first for my science news - [1] http://www.nature.com/news/ http://www.nature.com/news/
- baldfat 10y agoAt $199 a year it is extremely expensive. I remember I was paying close to $1,000 a year for the journal my 1,000 student college I work for. Not including JSTOR and other subscriptions for these Journals. The bill 10 years ago was about $70,000 for journal access on computers where I had the print copies in boxes behind the journals or in the storage area collecting dust.
- hackuser 10y agoSo how does someone not connected to a university get access to all this essential knowledge? Subscribing as an individual to JSTOR, etc. is far too expensive (thousands per year, I believe) and complicated. I don't want the administrative burden of my own research library.