Wikipedia:Reference desk/Archives/Science/2021 September 6

= September 6 =

Covid PCR Test
Once you've taken a sample from your tonsils and nostril for a PCR test, is there a limit on the amount of time available to actually test the sample before the test will no longer give valid results? I submitted a test in the post and just wondered what happens if there are delays along the way. Thanks. 88.111.85.155 (talk) 12:37, 6 September 2021 (UTC)
 * Extended storage of SARS-CoV-2 nasopharyngeal swabs does not negatively impact results of molecular-based testing across three clinical platforms says: "This study demonstrates that nasopharyngeal swab specimens can be stored under refrigeration or even ambient conditions for 21 days without clinically impacting the results of the real-time reverse transcriptase-PCR testing". Alansplodge (talk) 12:54, 6 September 2021 (UTC)
 * BTW, "severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)" is the name of the virus that causes COVID-19 019)-and-the-virus-that-causes-it Naming the coronavirus disease (COVID-19) and the virus that causes it (WHO) Alansplodge (talk) 12:57, 6 September 2021 (UTC)

Why is there no way to INCREASE energy harvest in the gut?
There are many ways to reduce energy harvest from food. There's gastric bypass surgery; there are enzyme inhibitors like orlistat and acarbose, which reduce absorption of calories from fat and starch; there are even drugs like dapagliflozin, which increase excretion of carbohydrate calories in the urine. There's even a stomach pumping machine that literally sucks food out of your stomach just after you've eaten it. There are also nutrients like fiber and calcium, which can bind to fat in the intestine. Why is there nothing that does the opposite? Of course, I'm sure part of the answer is that so many people need to lose weight for health reasons, but what about people with digestive disorders, for example? These people are mainly just told to avoid certain foods, right? Why isn't there a pill you can take that helps you absorb more fats or carbohydrates? What would be some of the possibilities here (besides, say, expensive digestive enzymes)? Of course, I'm sure there's more interest in reducing energy harvest to reduce obesity, but what could you do (in theory) to help the gut absorb more calories? I've read that even in healthy people, fecal energy content varies significantly (typically between 2-10%), so I think there would be some room for improvement even in healthy individuals (e.g., those wanting to gain weight). Clearly, putting any meaningful number of calories in a tiny pill is impossible, but why can't we make weight-gain pills that help the body absorb more calories from food?173.185.94.69 (talk) 15:46, 6 September 2021 (UTC)
 * There's taking antibiotics to kill off gut bacteria and reduce competition, but that's not encouraged. Apparently there's some evidence that antibiotics can cause weight gain, but I'm sure it's debatable how big the impact is. Blythwood (talk) 16:16, 6 September 2021 (UTC)


 * In several million years, evolution has fine-tuned the hominid digestive system for maximal energy harvesting. It is a very complex system, and one should not expect that a simple intervention can substantially increase the yield. --Lambiam 19:52, 6 September 2021 (UTC)
 * There is such thing as digestive enzyme supplementation. Ruslik_ Zero 20:30, 6 September 2021 (UTC)
 * Okay, thank you!173.185.94.69 (talk) 21:31, 6 September 2021 (UTC)