I'm finishing my PhD in hyperpolarization (hopefully) soon. In my opinion, hyperpolarization will significantly contribute to early-stage diagnosis. We're designing machines, processes, and chemicals that create novel contrast agents for MRI, enabling the localization of cancer cells and even tracking their metabolism. For example, it's possible to inject hyperpolarized pyruvate and track its conversion to lactate. Essentially, this technique boosts the MRI/NMR signal of the contrast agent by up to 100,000-fold. When the contrast agent undergoes metabolism, it creates a unique signal footprint through chemical shift changes, which can aid in characterizing cancer.
I have a question, if you don't mind. What are the nuclei polarized relative to? The molecules in a liquite rotate a lot and I am curious whether the nuclear spins stay aligned with the electron systems or if they remain fixed in an inertial frame.
There are two semi-connected concepts at play here. Polarization in this context refers to the ratio of neutralizing (i.e. "up" vs "down") spins in a given system. For most nuclei in organic systems like protons, carbons, and nitrogens, this ratio is naturally very small, which is the reason that magnetic resonance approaches like MRI usually have poor signal-to-noise. Hyperpolarization techniques usually involve the transfer of polarization from a source of high ratio, like a free electron, to a relevant target (in the original poster's example, 13C in pyruvate). The polarization in this case is hyperpolarized 13C, which has an "up"-to-"down" spin ratio that is much higher than regular 13C, which makes the signal-to-noise that you get from the pyruvate much higher than it would be otherwise. Tumors love pyruvate so this approach means that tumors will light up like a beacon in your MRI.
The physical rotation/tumbling of molecules in an MRI is also very important, because the strong magnetic field is the thing inducing the "up"-vs-"down" split in the first place, and if the molecular motion is happening at a certain frequency with respect to the external magnetic field there are other interactions that can come into play which can affect the coherence of the nuclear spins (i.e. they can fall out of sync). Thankfully, the rotation of a small molecule like pyruvate is very fast (might higher then the "spin" frequency-a.k.a the Larmor frequenct of 13C at the magnetic field strengths involved in MRI) so the physical tumbling of pyruvate doesn't really come into play when trying to measure its signal. It can be another story for molecules that don't tumble quickly, like the ones that make up tissues, fat, etc.
Great explanation. Indeed, the "rotation/tumbling" is nothing to worry about. One of our biggest challenges is relaxation. The moment we polarize, the clock ticks. Usually, the time scope is around 15-90s. I'm in the field of para-hydrogen and built automated systems which carry out the chemical reactions, polarization transfers and sample cleaning. Many hyperpolarization experiments with para-hydrogen prefer nasty solvents as chloroform or methanol. It is a technical challenge to replace them by water within seconds. One of my favorite topics is Xenon hyperpolarization. It's very elegant, no cleaning required, no wet chemistry, and provides amazing lung scans.
Sounds exciting. Routine periodic medical imaging seems like one of those Star Trek technologies thats in reach but not quite been implemented outside of rich countries in Asia.
Hyperpolarization also allows for cheaper MRI scanners. With hyperpolarization, you achieve polarization (needed for SNR) without the need of big magnets (=expensive). Even in rich countries, MRI scanners reach their physical and technical limits. 3T magnets are already 7-figures and costs of bigger magnets will increase non-linearly. Moreover, with higher fields, side effects increase, too.
As a scientist, I'm so glad that we're forced to publish all our primary/secondary data along with the publication itself. It's stored in a repository which is "locked" when the DOI (digital object identifier) is generated. Overall, the publishing process is tedious and frustrating, but this extra work is crucial and cases like this makes that very clear. However, in most of the recent cases you didn't even need to look at the data as even the publication itself shows the misconduct.
Typically if you think you found a security vulnerability and/or quirk, you contact the company before writing it up and hitting publish[1]. That way the company is not left in a potentially vulnerable state.
I disclosed this personally 4 years ago via hacker one. The larger issue, imo, is that it indexes the content and allows an attacker to craft search terms which reveal the full contents of the document sort of like a blind SQLi. I was told it was working as intended and my report was black-holed on h1 and was told via email that it was "informational" and not a vulnerability.
It's lame to come on here and act like people reporting this are acting in bad faith. I asked for permission to talk about it and was granted it, so I don't see why the author of this post shouldn't be able to do the same considering he doesn't even get into the search indexing aspect. The company is in a vulnerable state due to negligence in addressing the issue, not because it was publicly disclosed.
I think not. It keeps battery cycles low and is likely better than some other behavior. As far as I remember, batteries don't like to go way below 20% and don't like fast charging from 80% upwards. However, to my knowledge, it is wise to drain the battery 1-2 times a year so that the charging controller can calibrate. A way to do that is to type "yes" in your terminal (or 3-4 terminals) and wait, it will make the CPU run at 100%. After your MacBook shut off, leave it for some hours before you charge it again.
Somee MacBook Pro models also incorporate a feature called "Battery Health Management."It can help optimize the charging patterns based on your habits and usage to reduce the wear on the battery over time. It may slightly adjust the charging levels to prevent the battery from staying at maximum charge for prolonged periods (to stop battery aging).
Clearly, he possesses considerable expertise, but it's puzzling why such a skilled individual would falter towards the end, resulting in poor solder joints on the 2.54mm pin headers. This isn't merely a question of aesthetics; these joints are susceptible to failure.
His work is commendable, but I would encourage him to either learn proper soldering techniques or, if he already possesses the skills, to take a moment to use some flux and clean up the joints. It's a simple process that takes just three seconds per joint.
I have it as well and at this point used the same head for 5 months. There's no visible deterioration and I exceed the recommended brushing time by doing 5 instead of 3 minutes.
Why exactly is the head only good for 3 months?
Brushing your teeth for too long can have bad effects on your dental health[1][2]. The heads loose their strength over time and if you replace that with pushing harder, you might also overbrush.
You probably don't brush correctly: you need to apply sufficient pressure on your teeth so the bristles can scrub the enamel well enough. Or else there is no way your head has no visible deterioration after 5 months at 5 min per brushing.
It's not only a matter of aesthetics but bacteria etc. Your brush head collects a sh*tload of food waste (which you don't see with your eyes) and remains a bit wet after usage. Perfect substrate for some living organisms. If you have a microscope, feel free to have a closer look.
We use Kanboard in our institute, but its UI/UX is among the worst I've experienced. It's reliable, but extremely unintuitive, causing people to avoid using it. However, it has potential.
It's kinda strange, I tried to sell my Flipper Zero and was wondering why people name them weirdly. As it turns out, ebay doesn't allow to sell it. If anyone has an idea where I can offer it (Germany, Europe), let me know.
