Richard Feynman’s 1959 lecture “There’s plenty of room at the bottom” envisioned atomic pick and place to build complex nanoscale machines. The lecture is often considered the conceptual birth of nanotechnology.
I am sure this is not the first time conductive AFM has been used to achieve nanoscale patterning to build a useful piece of tech, but very cool nonetheless.
Amazing that this can be achieved at such a low cost. The DVD optical pickup is truly a marvel of engineering, incorporating fairly complicated optics into such a small space. The focusing lens additionally has a electromagnetically controlled suspension system for adjusting the focus, so in theory you should be able to achieve z positioning of the microspheres as well. It would be great if the red dvd laser could be filtered out and the microscopic fluctuations of the trapped particle could be imaged with the camera to estimate the trap stiffness.
A similar optical pickup made of optical components from newport or thorlabs would run you a few thousand dollars, whereas these dvd optical pickups can be had for $10-20.
Here is another great paper (and accompanying youtube video) that shows optical trapping, atomic force microscopy, and even imaging with a dvd optical pickup.
what about computational methods? i have always wondered how stacking many short exposures without tracking compares to deconvolution of a single long exposure. it seems that there is software able to do this by taking into account both motion blur and the PSF of the imaging system:
this paper came out a few years ago using super resolution fluorescence and dna origami to track unwinding of dna by single helicase enzymes! its not an easy technique but it is doable with the right equipment (the 2014 Nobel Prize in chemistry was for super resolution microscopy)
One important distinction is to understand that VA ECMO is more often used as mechanical circulatory support in cases of severe heart failure leading to cardiogenic shock. Used alone or in conjunction with other mechanical devices (balloon pumps or impella pumps) it can augment cardiac output to provide sufficient perfusion and oxygenation of your organs and distal extremities.
VV ECMO, on the other hand, is used purely for gas exchange (O2 and CO2) due to respiratory failure. Much of the debate in the critical care community is centered around which circumstances and patients derive the most benefit from initiation of VV ECMO. The best studied use case, is in the setting of acute respiratory distress syndrome, which is defined by very specific criteria (bilateral noncardiogenic pulmonary edema with ratio of arterial oxygenation partial pressure to fraction of inspired oxygen less than 300 mmHg). The EOLIA trial published in NEJM in 2018 looked at early initiation of VV ECMO in patients with severe ARDS [1]. It demonstrated no mortality benefit of ECMO, however many say that the study was not appropriately powered as the assumptions used to design the study were from 2008 when mortality from ARDS was much higher. Re-analysis of the data from the EOLIA trial using bayesian methods suggests that there might actually some benefit to early initiation of ECMO [2]
Hackaday has featured a couple of projects featuring the ps3 optical pickup unit. The author of one of the projects breaks out the 40-pin ribbon cable and is able to drive it with some simple circuitry
Heres a decent open source? stage that i adapted for one of my projects in the past. Resolution is 1 micron laterally. If i remember correctly they address several issues including stepper motor backlash and micro-stepping. Cost can be well below the $1000 they quote depending on the parts you choose, or e.g. if you do only two axis (xy) stage instead of three (xyz)
Was the phosphorescent dye inhaled? What was the physical process responsible for the phase lag? Would love to read more about your device if you ever published your results!
I really enjoy using Julia too but I have also been disappointed with how the updates have played out. Just a few weeks ago I rolled back my installation from v1.2 to the LTS version because of silly errors in the plotting package not allowing me to plot.
Otherwise it really is a pleasure to use, and I have found that the LTS install has zero compatibility issues thus far.
True iodine deficiency is quite rare in the west as many table salts are fortified with iodine. It is extremely uncommon to see people with Goiter in the US. The same goes for thiamine/B1 deficiency which used to cause cardiovascular and neurological disease in alcoholics, but is now very rare becuse many pastas/breads/cereals are fortified with B1.
Building on your comment, I think that while it does help to have high quality cameras and objective lenses, it is always worthwhile to push the limits of how cheap we can go. There have been many nicely done papers in this vein recently, showing for example, how cheapER cameras perform on supperresolution microscopy setups [1]. That paper showed that the setup is able to resolve cellular structures (actin filaments) less than 100 nm apart and measures the standard deviation of localization of single fluorophore emmitters.
Super-resolution implies that you are imaging below the diffraction (Abbe) limit. While the Fourier ring correlation can be used as a surrogate for resolution (it is frequently used in both cryo-em and fluorescent microscopy) you must define the correlation cutoff or else the measurement is meaningless. I do not see any mention of a cutoff used in the linked paper.
I would be more convinced if they actually imaged something smaller than the diffraction limit of their microscope, like the nuclear pore, which was recently proposed as a standard for the field [2]. Nonetheless I am impressed by the image quality given how un-rigid and prone to thermal drift/expansion their microscope probably is.
That is indeed an extreme example, given how matter of factly they teach transposons in molecular bio these days.
When we couldn't get a paper published, my old PI would always joke, "There's always BBRC!", referring to the journal biochemical and biophysical research communications. The impact factor was and still is quite low, and it would make the post docs bristle when he said it.
But I once asked him, why BBRC? and he explained that Aaron Ciechanover and Avram Herschko published their first paper on ubiquitinylation (how proteins get tagged for degradation in the proteasome) in that journal [1,2]. It won them a Nobel prize 26 years later and exploded into a huge field. You just never know sometimes.
"At least with medical school, Peter said, the job prospects are better. New doctors begin making $60,000 and their salary increases by $20,000 a year during residency."
Actually not true. A resident's salary might increase by $20k between the start and end of their training (esp for intensive 7-8 surgical programs), but most programs only increase salary by $3,000 per year. In the following tables, PGY stands for post-graduate year, and extends from residency into fellowship if you choose to do one. Usually the salaries are the same for all residents, regardless of whether you are training to be a neurosurgeon or a psychiatrist.
The cell's ability to mechanically sense it's surroundings is fascinating. There is an old paper from 2006 in Cell that was similar to this study in that it showed onencould direct stem cell differentiation down different lineages purely by growing the cells on different stiffness substrates. Definitely worth a read of you are interested in this topic:
The hypothesis for many prion diseases is that of "seeding" whereby a small number (or maybe even a single) prion protein acts as a template to induce misfolding of other proteins with similar sequence but native folds [1,2]. This causes a chain reaction in the proliferation of the prion protein inside the cell, and then in other cells as prion proteins are transported/secreted to the surrounding tissue.
Zotero has been great. I switched four years ago and never looked back. Plugin support is great- I have drag and drop support in my latex editor and fairly easy citation selection in Lyx
This comes at a very important time, with measles outbreaks occuring around the world from Brooklyn to Japan. It is horrible because it puts at risk the lives of those who are too young to receive the vaccine. I completely agree with Google but I think that the government and/or healthcare workers need to make a bigger effort to teach the public about how vaccines work and how safe they are for the person receiving them.
I am sure this is not the first time conductive AFM has been used to achieve nanoscale patterning to build a useful piece of tech, but very cool nonetheless.
https://web.pa.msu.edu/people/yang/RFeynman_plentySpace.pdf