Multinuclear PFGSTE NMR description of K, Na, Li, and H specific activation energies governing diffusion in alkali nitrite solutions.

While pulsed field gradient stimulated echo nuclear magnetic resonance (PFGSTE NMR) spectroscopy has found widespread use in the quantification of self-diffusivity for many NMR-active nuclei, extending this technique to uncommon nuclei with unfavorable NMR properties remains an active area of research. Potassium-39 (K) is an archetypical NMR nucleus exhibiting an unfavorable gyromagnetic ratio combined with a very low Larmor frequency. Despite these unfavorable properties, this work demonstrates that K PFGSTE NMR experiments are possible in aqueous solutions of concentrated potassium nitrite.

Anionic Effects on Concentrated Aqueous Lithium Ion Dynamics.

The dynamics, orientational anisotropy, diffusivity, viscosity, and density were measured for concentrated lithium salt solutions, including lithium chloride (LiCl), lithium bromide (LiBr), lithium nitrite (LiNO), and lithium nitrate (LiNO), with methyl thiocyanate as an infrared vibrational probe molecule, using two-dimensional infrared spectroscopy (2D IR), nuclear magnetic resonance (NMR) spectroscopy, and viscometry. The 2D IR, NMR, and viscosity results show that LiNO exhibits longer correlation times, lower diffusivity, and nearly 4 times greater viscosity compared to those of the other lithium salt solutions of the same concentration, suggesting that nitrite anions may strongly facilitate structure formation via strengthening water-ion network interactions, directly impacting bulk solution properties at sufficiently high concentrations. Additionally, the LiNO and LiNO solutions show significantly weakened chemical interactions between the lithium cations and the methyl thiocyanate when compared with those of the lithium halide salts.

Laser refrigeration of optically levitated sodium yttrium fluoride nanocrystals.

Solid state laser refrigeration can cool optically levitated nanocrystals in an optical dipole trap, allowing for internal temperature control by mitigating photothermal heating. This work demonstrates cooling of ytterbium-doped cubic sodium yttrium fluoride nanocrystals to 252 K on average with the most effective crystal cooling to 241 K. The amount of cooling increases linearly with the intensity of the cooling laser and is dependent on the pressure of the gas surrounding the nanocrystal.

Lipidic inhibitors of human N-myristoyltransferase.

This study was undertaken in order to identify compounds which inhibit the activity of human myristoyl-CoA:protein N-myristoyltransferase (hNMT). In particular, the structural features of such molecules which contribute to enzyme inhibition were investigated. Two groups of compounds, namely myristic acid and analogs 1-13 and derivatives of myristoyl-CoA 14-19 were evaluated.

Human N-myristoyltransferase amino-terminal domain involved in targeting the enzyme to the ribosomal subcellular fraction.

N-Myristoyltransferase (NMT) catalyzes the cotranslational acylation with myristic acid of the NH2-terminal glycines of a number of cellular and viral proteins. Most of the in vitro NMT activity (60-85%) in isoosmotic cell homogenates of human lymphoblastic leukemia (i.e.