Methylation variation at an intronic retrotransposon associated with normal versus mantled oil-palm development; loss of methylation is associated with altered splicing and reduced yield.

A solid with unusually rapid ionic motion while its host framework remains ordered.

Zirconia stabilized by addition of yttria. At suitable elevated temperatures, oxygen vacancies allow oxide-ion transport, making the material useful in an oxygen concentration cell. Its oxide-ion transference number must remain sufficiently close to one for a simple ionic Nernst equation interpretation.

SNAP-25 is a SNARE protein that contributes two helices to the neuronal fusion complex, partnering with syntaxin and synaptobrevin. Lipid attachment anchors SNAP-25 to membranes despite its lack of a conventional membrane-spanning helix. Assembly helps couple recognition of a secretory carrier to membrane fusion. Its two helical contributions explain why a four-helix SNARE complex need not contain four separate protein chains. ^[ref]

A v-SNARE is a SNARE protein assigned to a transport vesicle in a specified fusion event. Complementary interaction with a t-SNARE on the target produces a membrane-bridging SNARE complex. Synaptobrevin is a familiar example in neuronal secretion. The label describes which membrane initially carries the component; after membrane fusion, both sets of components occupy the same membrane and must be reorganized for reuse. ^[ref]

A t-SNARE is a SNARE protein or complementary assembly assigned to the target membrane in a particular membrane-transport event. It pairs with a v-SNARE on the incoming carrier to form a fusion-associated SNARE complex. The prefix describes the experimental transport arrangement; it does not imply that a given membrane is always a target in every trafficking pathway. The neuronal target assembly includes syntaxin and SNAP-25. ^[ref]

A SNARE complex is an assembly of complementary SNARE proteins, commonly forming a four-helix bundle. A trans complex bridges opposing membranes and can promote membrane fusion; after fusion, its components occupy the same membrane in a cis complex. ATP-dependent disassembly permits component reuse. This distinction explains why detecting a complex alone does not determine whether it is a fusion intermediate or a product remaining after fusion. ^[ref]

Syntaxin-4 is a membrane-associated SNARE protein involved in fusion at the plasma cell membrane. In regulated GLUT4 delivery, it participates with compatible partners in the fusion machinery that exposes transporters at the cell surface. Its presence identifies a possible component of that machinery; productive fusion also depends on assembly and regulation of the whole SNARE complex. ^[ref]

Carbon-centred substitution in a cyclic sulfonate ester. The incoming nucleophile bonds to the oxygen-bound ring carbon and the resulting product retains the carbon–sulfur bond.

Approach of a nucleophile opposite the leaving-group bond permits bond formation with inversion at the attacked tetrahedral carbon in an SN2 pathway.

A guide RNA associated with Piwi-family proteins. Most characterized animal piRNA pathways use Dicer-independent processing of single-stranded precursors; the approximately 21-nucleotide C. elegans 21U RNAs are distinct from the longer typical fly and mammalian piRNAs.^[ref]

Four equal beads of mass $m$ are connected cyclically by identical springs of stiffness $k$ following arcs of a frictionless circular guide. In signed arc displacements $q_j$, the quadratic Lagrangian is $L=(m/2)\sum {\dot{q}}_j^2-(k/2)\sum (q_{j+1}-q_j{)}^2$. The stiffness is $k$ times the four-cycle graph Laplacian. Its eigenvectors can be chosen as $(1,1,1,1)/2$, $(1,0,-1,0)/\sqrt{2}$, $(0,1,0,-1)/\sqrt{2}$, and $(1,-1,1,-1)/2$, with squared frequencies in the title. Their dot products with $q$ are decoupled normal mode coordinates. The zero mode is a rigid rotation; the two middle modes span a degenerate eigenspace; the highest mode alternates adjacent arc displacements. Changing the guide radius multiplies angular inertia and angular spring energy by the same factor, leaving these frequencies unchanged.

A pair of electrons allocated to cluster bonding. closo, nido and arachno counts distinguish the number of missing vertices relative to a closed parent polyhedron.

The triangular function $f(x)=(1-|x|)$ on $|x|<1$, zero elsewhere, has Fourier transform $\hat{f}(k)=[\sin (k/2)/(k/2){]}^2$ in the angular-frequency convention. Its squared L2 norm is $2/3$. Parseval's identity therefore givesThis proves the displayed value. The removable value at zero is one, and the fourth-power decay bounds the tail. The sinc-squared integral follows similarly from a rectangular function rather than a triangle.