ABSTRACT
We report experimental evidence for a crossover between a liquidlike state and a gaslike state in fluid methane (CH_{4}). This crossover is observed in all of our experiments, up to a temperature of 397 K, 2.1 times the critical temperature of methane. The crossover has been characterized with both Raman spectroscopy and x-ray diffraction in a number of separate experiments, and confirmed to be reversible. We associate this crossover with the Frenkel line-a recently hypothesized crossover in dynamic properties of fluids extending to arbitrarily high pressure and temperature, dividing the phase diagram into separate regions where the fluid possesses liquidlike and gaslike properties. On the liquidlike side the Raman-active vibration increases in frequency linearly as pressure is increased, as expected due to the repulsive interaction between adjacent molecules. On the gaslike side this competes with the attractive van der Waals potential leading the vibration frequency to decrease as pressure is increased.
ABSTRACT
Infantile Tremor Syndrome is a distinct clinical entity most commonly seen in Indian Subcontinent. Syndrome consists of tremors, mental and developmental retardation, abnormal skin pigmentation and anemia in children between 6 months to 2 years. The etiology is still elusive. Amongst various theories, nutritional theory is the most accepted. So far there are no cases reported of vitamin C deficiency in ITS. In this article, three cases of ITS associated with vitamin C deficiency are reported.
