The term "priority amino acid" isn't a widely recognized concept in biochemistry or nutrition as each amino acid plays a unique and essential role in the body. However, the term might refer to essential amino acids, which are crucial for human health but cannot be synthesized by the body, thus need to be obtained through diet. These include leucine, isoleucine, valine (branched-chain amino acids important for muscle repair), lysine, methionine, phenylalanine, threonine, tryptophan, and histidine. The prioritization could also be contextual, depending on nutritional needs, health conditions, or specific goals like muscle building, where leucine is often prioritized for its role in muscle protein synthesis. Always, a balanced intake covering all essential amino acids is recommended for optimal health.

Cross-linked polyethylene (PEX) pipe is widely regarded as safe for plumbing applications, offering a durable and flexible solution for water supply systems. It has been rigorously tested and has a good track record for safety and reliability. PEX does not corrode, reducing the risk of leaks and pipe damage. However, some concerns have been raised about the potential for chemicals to leach from PEX into drinking water, especially when exposed to high temperatures. Studies have shown that these levels are generally below established safety standards. Moreover, it's important to ensure that the PEX piping used complies with NSF/ANSI 61 standards, which certify materials for safety in drinking water applications. Overall, with proper installation and compliance with safety standards, PEX is considered a safe option for water piping.

Powder coating is a dry finishing process used to create a durable and protective finish on a wide range of materials, primarily metals. Unlike traditional liquid paint, powder coating uses electrostatically charged particles of pigment and resin, which are sprayed onto a surface. These charged particles adhere until they are melted and fused into a smooth coating in a curing oven. This method offers several advantages including a thicker, more uniform, and durable finish without running or sagging. It's also more environmentally friendly, as it emits fewer volatile organic compounds (VOCs) than liquid paint. Powder coating is widely used in automotive, appliance, and furniture manufacturing, among other industries, due to its durability and high-quality finish.