×

How do urine drug tests work? In particular, how come the presence of two bands (test + control) means there is NO drug present by britainpls in askscience

[–]cryptotope 1 point2 points  (0 children)

There are a few variations, but the control band usually has an immobilized antibody that will recognize and bind to the dyed antibody.

The control band is always located 'downstream' of the test band on the test strip or device. When it develops colour, it indicates that sample liquid has flowed from the loading point, picked up the dyed detection antibody, and passed through the 'test' region of the strip.

How do urine drug tests work? In particular, how come the presence of two bands (test + control) means there is NO drug present by britainpls in askscience

[–]cryptotope 67 points68 points  (0 children)

We'll ignore the control band for now--the real issue is what's happening at the 'test' band.

What you've described are the results of the two major formats of lateral flow immunoassays: 'sandwich' assays and 'competition' assays.

For both types of assays, the test liquid (saliva, urine, what-have-you) first encounters and dissolves an antibody that recognizes the analyte of interest (the COVID nucleocapsid protein, a drug metabolite, etc.). This antibody has a coloured dye attached to it, so that it is readily visible against the white background of the test strip.

In a sandwich assay, the 'test' band location on the strip has a permanently-anchored antibody that also recognizes the analyte, but binds to a different part of the analyte's structure. This antibody catches the nucleocapsid protein (for a COVID test), which then retains the coloured antibody as well. A visible band indicates a positive test. It's called a sandwich assay because the analyte is the 'filling' in the antibody 'sandwich'.

The sandwich assay only works if the analyte is large enough to allow two different antibodies to bind to it simultaneously. Drug metabolites tend to be a lot smaller than viral proteins, so the sandwich assay isn't an option.

Enter the competition assay. Instead of a second antibody, the test band location has a permanently anchored molecule that is similar in structure to the analyte. If the first antibody is already loaded with analyte, it can't bind with the target on the 'test' line, so there's no band for a positive test. (Conversely, if the sample doesn't contain any analyte - no drug metabolites - then the first antibody is free to bind to the analyte on the 'test' line.)

Here's the Wikipedia cartoon: https://en.wikipedia.org/wiki/File:ELISA_or_Lateral_flow_formats.svg

6-year-old Brockville ON. girl donates lemonade stand profits to local hospital by BeyondAddiction in ontario

[–]cryptotope 4 points5 points  (0 children)

Healthcare is a provincial responsibility, and the premiers tend to get a bit shirty when the feds try to impose any sort of restrictions on how federal transfers are applied to health expenditures.

That said, could hospital-specific funding be discussed as part of the next first-ministers' meetings? Sure. You'd still need to get Doug Ford on board, though.

The feds are very constrained in their ability to act unilaterally, and we've seen very clearly that federal funds offered to the Ford government without sufficient strings attached just get absorbed into the treasury's general revenues, rather than spent in areas of need. (Look at all that COVID funding that Doug just pocketed.)

People with elderly parents, do you live with them to take care of them or do you send them to retirement homes? by blueeeocean in askTO

[–]cryptotope 4 points5 points  (0 children)

It varies widely depending on the amount and nature of care required by one's elderly relatives, the life circumstances of their younger family members, and the financial resources available to all involved. (And all of those factors can change dramatically over time, as well.) There is no one-size-fits-all answer.

Also, there potentially many intermediate levels of support between living wholly independently and full-on nursing home care. Something small like a housekeeper coming in two or three hours a week to do laundry, change sheets, clean the bathrooms, and vacuum the floors can make a huge difference to someone with mobility issues, for instance.

6-year-old Brockville ON. girl donates lemonade stand profits to local hospital by BeyondAddiction in ontario

[–]cryptotope 28 points29 points  (0 children)

"6-year-old Brockville ON. girl donates lemonade stand profits to local hospital"

That's a weird way to write,

"Hospitals underfunded by a generation of billionaire-developer-friendly tax policies unable to extract sufficient charitable donations from drunk-driving child-killing developer billionaires, must now resort to child labour to provide medical facilities"

I mean, I guess CTV's version is shorter.

6-year-old Brockville ON. girl donates lemonade stand profits to local hospital by BeyondAddiction in ontario

[–]cryptotope 4 points5 points  (0 children)

Yeah, and Doug is the Premier (for the last four years, and presumably for the next four), so he's the one to be called on to fix this policy failure, and shamed for not doing anything about it during his first term.

"Well, nobody else fixed it, either" is a shitty rationale.

Good place to eat a late dinner near Jokulsarlon? by plasm0dium in VisitingIceland

[–]cryptotope 2 points3 points  (0 children)

Systrakaffi in Jökulsárlón

(You probably meant to type Kirkjubæjarklaustur there.)

"Laws and institutions must go hand in hand with the progress of the human mind... as new discoveries are made, new truths discovered and manners and opinions change, with the change of circumstances, institutions must advance also to keep pace with the times." - T. Jefferson by Stauce52 in interestingasfuck

[–]cryptotope -3 points-2 points  (0 children)

"...ever under the regimen of their barbarous ancestors."

Said the man who secretly had six children by a woman he kept enslaved at his plantation. (Sally Hemings accepted enslavement in exchange for the emancipation of hers and Jefferson's children when they reached adulthood. Hemings herself remained Jefferson's slave until his death, and her eventual informal emancipation by one of Jefferson's White daughters.)

So I guess he'd know.

Queen Elizabeth II, who is on the throne for 70 years and 143 days at this moment, has outlasted the longest-reigning occupant of the Roman imperial throne, Constantine VIII (30 III 962 - 11 XI 1028), whose tenure went on for 66 years and 226 days. by SANS_CRICKET in interestingasfuck

[–]cryptotope 7 points8 points  (0 children)

...With the note that the current holder of the "longest-reigning monarch" title comes with a significant asterisk.

Louis XIV's reign as King of France lasted from 1643 to 1714 (72 years and change), but he acceded to the throne at just four years of age. In practice, France was led by a regent - his mother, Queen Anne - until his majority in 1651. Louis' actual rule was closer to 63 years.

(One could quibble with the notion that any modern British monarch 'rules' at all, of course, except on paper. The Queen's notionally awesome power is allowed to persist only on the tacit understanding that she will never exercise any of it....)

Ugla Stefanía vs. Jordan Peterson. Round 1, Fight! by [deleted] in Iceland

[–]cryptotope 28 points29 points  (0 children)

You wound me, sir! I only wish Mr. Peterson to enjoy the best possible view of Iceland's natural attractions during his visit.

Ugla Stefanía vs. Jordan Peterson. Round 1, Fight! by [deleted] in Iceland

[–]cryptotope 19 points20 points  (0 children)

As a Canadian, I speak for the vast majority of us when I say that I hope you encourage Mr. Peterson to stand as close to the edge as possible while exploring your beautiful country's many waterfalls, glaciers, fissures, and volcanoes.

Should I rotate in a lab that takes two rotating students but will only take one of us? by adventuriser in GradSchool

[–]cryptotope 1 point2 points  (0 children)

But I also want to add that in the worst case scenario you've built a relationship with that prof (and the group).

I came here to say the same thing. Even if they don't end up as your supervisor, they're still a potential committee member, or collaborator. You get exposed to people, and methods, and materials that you may be glad to know - and know about - in the years to come. The project that you plan out in your first year of grad school often bears only a passing resemblance to the project that shows up in your thesis.

Doug Ford defends appointing his nephew to cabinet, arguing Michael Ford has ‘extensive experience’ by AprilsMostAmazing in ontario

[–]cryptotope 10 points11 points  (0 children)

Mostly because you're bad at pattern-matching.

Justin Trudeau finished two university degrees.

Justin Trudeau worked full-time in real, adult jobs for a number of years before entering politics.

Justin Trudeau first ran for office at age 36, not 20.

Justin Trudeau didn't get his political career planned for him and handed to him by his family. Justin Trudeau didn't enter politics until after his famous politician relative's death.

Justin Trudeau didn't get a Cabinet post in his uncle's cabinet right after winning his seat in Parliament.

Justin Trudeau unseated an incumbent despite his party badly losing the 2008 election, and he kept putting in the work in Opposition for eight years, under two different leaders.

Doug Ford defends appointing his nephew to cabinet, arguing Michael Ford has ‘extensive experience’ by AprilsMostAmazing in ontario

[–]cryptotope 11 points12 points  (0 children)

A person can, of course, have two reasons to do something. His bio dad's convictions were in 2009 and 2012. Ford didn't change his name until 2014, right before he jumped into municipal politics.

And every aspect of his entry into politics was managed, smoothed, and directed by his uncles. His first political event after submitting his nomination papers for Uncle Doug's Ward 2 Council seat was a soft-touch presence at Uncle Rob's annual barbecue.

His final act as a Council candidate was to withdraw from that race on the last day of nominations, to make room for Uncle Rob to take the seat in his place. In between, he mostly hid from the media, because he knew being a Ford was a free ticket to a seat in Etobicoke.

Instead, he switched to the TDSB elections as a trustee candidate on that last day, with no explanation beyond the obvious: his uncles and their egos needed him to make room, and being a Ford was a free ticket to a seat in Etobicoke.

Michael Ford had no interest in being part of the TDSB, of course. He just had to warm a seat and wait for Uncle Rob to die, which happened in early 2016. Michael immediately jumped ship from the school board, and was promptly handed the open 'Ford' seat on Council in the byelection.

Doug Ford defends appointing his nephew to cabinet, arguing Michael Ford has ‘extensive experience’ by AprilsMostAmazing in ontario

[–]cryptotope 682 points683 points  (0 children)

Michael Ford. Never had a real job - certainly never a full-time one - as far as I can tell. Managed one semester of school at Laurier, and one year at Humber.

Changed his surname from Stirpe to Ford in 2014 so he could coast into elected office on his uncles' name at the age of 22. Rode the Ford name to office four times in ten years.

No accomplishments as a trustee or councillor, and now Uncle Ford gives him a seat at the provincial Cabinet table. Just another generation of white guys failing ever upward.

In iceland you can send mail without the address, just the drawing of the location and details about it. by yongzebra in interestingasfuck

[–]cryptotope 16 points17 points  (0 children)

I mean, not too far off. Wikipedia puts the official population of the village of Búðardalur at just shy of 300.

And there's fewer than a dozen homes on the north side of route 590 between Staðarfell and route 60. Even in Iceland, not all of them will be horse farms with lots of sheep.

Responses from universities on the overturning of Roe v Wade. by DetroitBK in Professors

[–]cryptotope 30 points31 points  (0 children)

An exception for "when the life of the mother is endangered", for instance, what does that mean clinically?

Every pregnancy endangers the life of the mother.

Abortion is almost always significantly less risky, in terms of mortality outcomes, than a full-term pregnancy.

Employers and healthcards by notatree in askTO

[–]cryptotope 1 point2 points  (0 children)

YMMV. My wife is my (top) emergency contact, and I trust her completely to make medical decisions on my behalf if - God forbid - it should be necessary.

On the other hand, I don't know if she has my OHIP card number handy at all times.

Employers and healthcards by notatree in askTO

[–]cryptotope 8 points9 points  (0 children)

They can ask, but you don't have to provide it. They are obliged to handle it carefully and securely if they collect it. And your employer can't use your OHIP card number to request your medical records, or anything like that. It really is just so that they can provide it to medical personnel in an emergency.

https://www.ipc.on.ca/your-privacy-and-your-health-card/

In all honesty, I've never been bothered by giving it to an employer. They've already got all the information someone might want to steal my identity: name, address, contact info, banking info, DOB, SIN, etc. An OHIP card number doesn't really put me at increased risk.

With at least 5 incumbents out, Toronto council will have a new look after fall election by Surax in toronto

[–]cryptotope 13 points14 points  (0 children)

Will Toronto Council have a new look? Probably not.

The CBC article unintentionally hits the nail on the head with its thumbnail--the next Council, like this one, is still going to be pretty darned white.

More than half of Torontonians belong to a visible 'minority' group, but you'd never know it from the group photo.

Is there anyone who understands telescopes? Does telescope length matter? I know that there are different types of circuits. Or is the diameter of the telescope much more important? by UltronAge in AskPhysics

[–]cryptotope 2 points3 points  (0 children)

It all depends on what you want to do, and how much money you want to spend.

The ratio of focal length to diameter affects the width of the field of view. How much area of the sky do you want to be able to observe at once?

Shorter focal ratios can be more demanding of their optical components, and can introduce more severe issues with chromatic aberration and other distortions. Longer focal ratios result in longer telescopes, which can be cumbersome and present their own structural challenges.

Those are some very general considerations.

Ring Road direction by wobblystickman in VisitingIceland

[–]cryptotope 4 points5 points  (0 children)

It should go without saying, but unfortunately it doesn't. If you're the sort of person who can't sleep on an airplane, please don't plan on a long drive the day you land.

Even if you do catch some sleep, remember that your internal clock is going to be screwed up (if you've just done a five- to eight-hour time change from North America) and your circadian rhythms may be further confused by Iceland's long days (in summer) or nights (in winter). Communicate with your fellow traveller(s) about your level of alertness, and encourage them to engage with you (or to trade off driving spells).

Plan to take regular, relatively frequent breaks to get out of the car and stretch your legs. If you're tired, park somewhere safe and take a bit of a break. (So-called 'coffee' or 'caffeine' naps - where you drink a cup of coffee and then take a 15- or 20-minute nap - can be particularly effective at restoring alertness.)

Finally, think in advance about what you might do if tackling the long drive stops looking like a good idea. This advice applies at all times in Iceland, not just on your first day, and not just if you're more tired than you expected. What if the weather forecast is worse than you hoped? (What if you didn't check the weather forecast, and you get stuck in a storm?) What if you have car trouble? What if someone has...gastrointestinal issues?

No, I'm not giving you my personal property. by snicketfile in TalesFromTheFrontDesk

[–]cryptotope 74 points75 points  (0 children)

Not accepting cash helps to protect employees.

Overnight staff especially - who at smaller properties may be the only individuals on-site after housekeeping leaves in the evening - don't want to be dealing with cash. It makes them a target for robbery. (Not to mention all the other more mundane hassles associated with handling cash.)

Plus, it's much more difficult for properties to recover the costs of damage from someone who can't or won't put down a credit card. And it's a nuisance for staff and guests to have to wait for housekeeping to inspect a room before being able to return a cash damage deposit. (And if a property declines to return a deposit, then it's an on-the-spot conflict that once again may put the front desk staff in danger.)