In this note we report on simple estimates of the properties of metastable solid helium that is at a pressure below the normal melting pressure. We calculate the nucleation rate for formation of the liquid phase and estimate the “spinodal” pressure at which the solid becomes macroscopically unstable.

OBJECTIVE UV-A/Riboflavin cross-linking of corneal collagen fibers (CXL) is a highly promising therapy for corneal melting in humans. A prospective interventional, nonrandomized, controlled study was conducted to compare the stabilizing effect of CXL treatment on melting keratitis in dogs and cats and the complication rate of CXL to those of standardized intensive medical treatment. PROCEDURE...

Thermal denaturations of the type 1 DNA polymerases from Thermus aquaticus (Taq polymerase) and Escherichia coli (Pol 1) have been examined using differential scanning calorimetry and CD spectroscopy. The full-length proteins are single-polypeptide chains comprising a polymerase domain, a proofreading domain (inactive in Taq) and a 5' nuclease domain. Removal of the 5' nuclease domains produces...

BACKGROUND High-resolution DNA melting is a closed-tube method for genotyping and variant scanning that depends on the thermal stability of PCR-generated products. Instruments vary in thermal precision, sample format, melting rates, acquisition, and software. Instrument genotyping accuracy has not been assessed. METHODS Each genotype of the single nucleotide variant (SNV) (c.3405-29A>T) of CP...

Climate is changing worldwide, but Arctic Alaska is warming at a rate almost twice the global average [1]. Changes already observed in Alaskan landscapes include rapidly eroding shorelines, melting ground ice (permafrost), wetland drying, ice wedge degradation, increased shrub growth at high latitudes, and conifer forest decline [2-4]. Sustainable ecological function, community resiliency, and ...

Simulations are reported to investigate solid superheating and liquid supercooling of two-dimensional systems with a Yukawa interparticle potential. Motivated by experiments where a dusty plasma is heated and then cooled suddenly, we track particle motion using a simulation with Langevin dynamics. Hysteresis is observed when the temperature is varied rapidly in a heating and cooling cycle. As i...

Through a flame-melting/rapid-cooling process, metastable forms of solid state compounds can be discovered. We describe here an example where both slow and rapid crystallizations of a stoichiometric "KInSnSe(4)" melt give rise to kinetic forms of KInSnSe(4). These forms (alpha- and beta-) convert to the thermodynamically stable gamma-form upon heating below the melting point.

Classical nucleation theory (CNT) has been extensively employed to interpret crystal nucleation phenomena and postulates the formation of an ordered crystalline nucleus directly from vapor or solution. Here, we provide the first experimental demonstration of a two-step mechanism that facilitates deposition of crystals on solid surfaces from vapor. Crucially, this occurs from saturated vapor wit...

In the absence of juvenile liquid water, condensation of water vapor to ice and subsequent melting of ice are the only means of producing liquid water on the martian surface. However, the evaporation rate is so high that the available heat sources cannot melt pure ice. Liquid water is therefore limited to concentrated solutions of strongly deliquescent salts.

Gene expression is largely regulated during the initiation of RNA polymerase II (PolII) transcription. In this issue, Kouzine et al. show that control of DNA melting is one of the critical rate-limiting steps for productive mRNA elongation. We discuss these findings in the context of other key energetic transitions.