TedEd: How can we solve the antibiotic resistance crisis?

A TedEd by Gerry Wright

Antibiotics are some of the most important drugs in modern medicine. We commonly use them to fights infectious diseases. But they make many other things possible, from surgery to chemotherapy and organ transplants. But they are becoming less effective. Many bacteria have developed resistance to antibiotics, some having full resistance to every drug available. We've also stopped creating new drugs. The first antibiotic was penicillin, discovered in 1928 by Alexander Fleming. He warned that overuse of these would ruin their miracle. Between the 1940s and 80s, resistant bacteria appeared, which pharmaceutical companies countered with new drugs. This was very successful, as well as profitable. However, many of these were only effective on a few types of bacteria, and antibiotics were being prescribed more and more carefully. As a result, the industry became less profitable. So, antibiotic discovery stopped, while bacteria continued to gain resistance. To combat this, we need to regulate existing antibiotics, create new ones, fight resistance, and find new ways to beat bacteria. The agricultural community uses the most antibiotics, often to treat animals. This gives diseases like salmonella more chances to become resistant. In nature, many new antibiotics can be found. For example, many fungi have bacterial resistance because they need it to survive in their environment. Furthermore, existing antibiotics can be given defense against degrading mechanisms that bacteria use to fight them. This allows antibiotics to stay alive long enough to fight the disease. The biggest factor in this is funding. Since antibiotics are no longer profitable and countries don't support companies that make them, discovery of new ones in inhibited. There are ways to solve this, however. For instance, the UK is testing a strategy where healthcare providers buy antibiotic subscriptions. But whatever we do, we need to make sure antibiotics can continue to be used.

TedEd: Exploring other dimensions

A TedEd by Alex Rosenthal and George Zaidan

We live in a three dimensional world, meaning we have length, width, and height. But what if we were squished flat onto a two dimensional plane? Edwin Abbott wrote a novella called Flatland in 1884 on these premises. It details the experiences of a square that has been exposed to the 3D world. But before we talk about that, what is a dimension? It is a direction, basically a line, that is perpendicular to others. A one-dimensional world is a line, 2D is two perpendicular lines, and we live in a 3D world with a third perpendicular. But what about higher dimensions? Flatland can help us explore these possibilities. In Flatland, the flat objects see a line. Closer objects are brighter than those far away, helping them see depth. This makes them unable to see the third dimension. However, a sphere visits one day, and the way a square sees it amazes him. Then, the square is lifted into the third dimension by the sphere, allowing him to see what no one else has ever seen before. The square wants to see the fourth and higher dimensions, but the sphere can't accept this, which is understandable. It would be very hard for us to imagine a fourth dimension. We can look at it the way the square saw the sphere. 2D cross-sections of a 3D object, replaced by the third and fourth dimensions. Or, we can take a point and extend it in all directions and eventually get a 4D hypercube (see video at 3:42 for better explanation). There could be entire 4D worlds that we can't see because of the way we see things.

TedEd: What would happen if you didn’t drink water?

A TedEd by Mia Nacamulli

Our bodies are made mostly of water. As babies, we are 75% water, which shrinks to between 55 and 60% as we grow older. Water serves to lubricate joins, regulate temperature, and nourish the brain and spinal cord. Many vital organs like the heart, brain, and lungs have high water percentages. What happens if we don't get enough of it? We lose around 3 liters a day due to sweat, urine, and bowel movements. When dehydration occurs, sensory receptor's in the brain's hypothalamus release antidiuretic hormones. In the kidneys, these create aquaporins, which allow blood to retain more water. Dehydration can cause tiredness, bad mood, lower blood pressure, and impair cognitive abilities. The opposite is over-hydration, or hyponatremia. This occurs often in athletes who drink to much. This decreases or stops output of hormones, causing sodium electrolytes to become diluted and cells to swell. In severe cases, the kidneys can't keep up with the diluted urine. This causes water intoxication, leading to headache, vomiting, and in rare cases, death. So how much is healthy? It can vary based on weight and environment, but 2.5-3.7 liters a day is recommended for men, while 2-2.7 liters is good for women. Don't forget, many of your foods also have water in them.

TedEd: Could we cure aging during your lifetime?

Made by Kurzgesagt - In a Nutshell

Many human diseases and injuries are caused by aging. As our lifespans increased, the time we spent outside of good health also increased. Now scientists are turning toward increasing our health span, or the time of our lives we spend disease free. This video explains three potential methods that could slow aging. The first is destroying senescent cells. When our cells replicate, they lose a tiny bit of DNA at the ends. This could be really bad, so we have telomeres at the ends of chromosomes to protect them. As the cells replicate, however, the telomeres wear away until they are gone. At this point, these cells become senescent, kind of like zombies. These cells do not die because they lack the production of proteins that tell them to do so. However, tests on mice showed that we can inject those to kill off senescent cells with minimal damage to healthy cells. The second method involves NAD+. This is an enzyme that tells the body how to take care of itself. However, your body makes less of these as you age. Low amounts of it causes diseases like skin cancer and Alzheimer's. Unfortunately, it can't enter cells as a pill. However, it can enter as a fluid substance that turns into NAD+ inside the cell. Clinical trials on mice proved positive and human trials may begin soon. The final option is stem cells. These create new cells for things like muscles. Like NAD+, we lose these as we grow. These can be more readily injected into areas such as the brain and heart. For more info, visit lifespan.io.