Repatha is not a resin; it is a prescription medication known as a PCSK9 inhibitor. Its generic name is evolocumab. Repatha works by helping the liver reduce levels of bad cholesterol (low-density lipoprotein or LDL) in the blood. It is administered via injection and is commonly prescribed for those who are at high risk of cardiovascular disease or who have familial hypercholesterolemia, a genetic condition leading to high cholesterol levels. This significantly differs from resins, which are a class of lipid-lowering medications (e.g., cholestyramine) that work by binding bile acids in the intestine, forcing the body to use excess cholesterol to make more bile acids, thereby lowering the level of cholesterol in the blood.

Medium yarn, also known as worsted, aran, or afghan yarn, is categorized as a "4" on the Craft Yarn Council's Standard Yarn Weight System. It's a popular choice due to its versatility, being suitable for a wide range of knitting and crochet projects including sweaters, blankets, and accessories. Medium yarn works well for both beginners and advanced crafters, offering a balance between fine and bulky yarns. It's thick enough to create warm, durable items, yet fine enough to detail intricate patterns. The recommended needle size for medium yarn is 4.5-5.5 mm (US 7-9), making it an accessible option for various projects.

To dissolve amino acids for chromatography, start by identifying the polarity and solubility properties of the amino acids you're working with, as these will dictate the most suitable solvent. Generally, a neutral, aqueous buffer is effective for most amino acids. For hydrophobic amino acids, a small percentage of organic solvent (such as acetonitrile or methanol) may be added to the aqueous buffer. The pH of the solution is crucial; maintaining a pH around 6-8 can ensure that amino acids are in their zwitterionic form, optimizing their solubility. Gently heating the solution can also improve solubility but be cautious not to degrade sensitive amino acids. Once dissolved, filter the solution to remove undissolved particles and ensure clarity before use in chromatography. Always prepare fresh solutions or store them at appropriate conditions to maintain stability.