Premature Ventricular Contractions (PVCs) are extra heartbeats that originate in one of the heart's ventricles. They are common and often harmless but can sometimes cause symptoms or indicate underlying heart conditions. Side effects may include palpitations or the sensation of the heart skipping a beat, chest pain, dizziness, and fatigue due to disrupted heart rhythm. For individuals with frequent PVCs or underlying heart issues, there could be an increased risk of developing more serious arrhythmias or cardiomyopathy. It is essential for those experiencing these symptoms frequently or severely to consult a healthcare professional for assessment and possible treatment to manage the condition and mitigate risks. Lifestyle modifications and medications are common management strategies.

The intrinsic viscosity of polypropylene is an essential parameter reflecting its molecular weight and thus, its processing and mechanical properties. Typically measured in dilute solution, it provides insight into the polymer's chain length and branching characteristics. In polypropylene, this attribute influences its melt flow, toughness, and clarity, crucial for applications ranging from packaging to automotive parts. The intrinsic viscosity values can vary depending on the polymerization process and conditions used to produce the polypropylene, with higher values indicating higher molecular weights and, consequently, higher performance in certain applications. Adjusting the polymerization parameters allows manufacturers to tailor the intrinsic viscosity to meet specific needs, balancing processability with mechanical properties.

Yarns that resist pilling are typically tighter spun and made from long-staple fibers such as merino wool, silk, and linen. Synthetic blends can also offer reduced pilling properties due to their resilient nature. Tightly plied yarns, where multiple strands are twisted together, tend to pill less because the structure decreases the surface fibers' exposure to friction, a common cause of pilling. Additionally, yarns treated for strength, such as "superwash" wools, are less prone to pilling. Although no yarn is completely pill-proof, selecting one with these characteristics can significantly minimize the problem. Always consider the project's end use when choosing yarn, as some wear and tear is inevitable in high-friction areas like underarms and sides.