The speed of light in a medium is determined by the medium's refractive index. The refractive index (n) is a measure of how much the light slows down compared to its speed in a vacuum. For titanium dioxide (TiO2), the refractive index can vary depending on the crystal structure and the wavelength of light, but it is generally high, around 2.4 to 2.9 for visible light. The speed of light in vacuum (c) is approximately 299,792 kilometers per second. To find the speed of light in titanium dioxide, one uses the formula v = c/n. Assuming an average index of n=2.7 for visible light, the speed of light in TiO2 can be calculated as approximately 111,035 kilometers per second. This high refractive index makes titanium dioxide an excellent material for optical applications, including photonic devices and as a white pigment due to its high reflectivity.

It is estimated that the speed of light in titanium dioxide is about 124.757 miles per second 200.992 kilometers per second. This is about 2.411 times slower than the speed of light in a vacuum.

Basic amino acids, which include lysine, arginine, and histidine, are typified by their side chains which carry a positive charge at physiological pH. This unique property makes them inherently hydrophilic or water-loving. The charged nature of their side chains enables them to form electrostatic interactions and hydrogen bonds with water molecules and other polar substances, rendering them soluble in aqueous environments. In the context of proteins, these basic amino acids are often found on the surface of proteins where they play essential roles in molecular recognition, binding, and catalysis by interacting with other charged molecules including DNA, RNA, and phospholipids. Their hydrophilic nature is crucial for the structural and functional integrity of proteins within the aqueous environment of cells.

Polypropylene (PP) is a thermoplastic polymer widely used in various applications due to its excellent chemical resistance, flexibility, and low density. Understanding the degradation temperature of polypropylene is crucial for its proper use and processing. Polypropylene typically begins to degrade at temperatures around 320 to 340 degrees Celsius (608 to 644 degrees Fahrenheit). However, this threshold can vary depending on factors such as the presence of stabilizers, the specific type of PP (homopolymer, copolymer), and the duration of exposure. In general, prolonged exposure to temperatures above 300°C (572°F) can lead to oxidative degradation, causing chain scission and a reduction in molecular weight. It's important to note that for applications requiring high thermal stability, specially formulated polypropylenes with added stabilizers are available. These modified versions can withstand higher temperatures without significant degradation.