356 research outputs found
Shape Amphiphiles in 2‑D: Assembly of 1‑D Stripes and Control of Their Surface Density
The morphology of monolayers assembled
from mixtures of a shape-amphiphilic
molecule, {33,19} = 1-((hentriaconta-14,16-diyn-1-yloxy)Âmethyl)-5-((heptadecyloxy)Âmethyl)Âanthracene,
and a symmetric molecule, {19<sub>2</sub>}, at the solution–HOPG
interface depends strongly on the components’ solution concentrations
and sample annealing history. The kinked alkadiyne side chain, {33},
packs optimally only with antiparallel aligned, {33} side chains.
Thus, optimal packing of {33} side chains should assemble “{33}
stripes” consisting of two adjacent {33,19} columns with interdigitated
{33} chains. The aliphatic {19} side chain of {33,19} can pack with
antiparallel aligned {19} side chains from {19<sub>2</sub>} or from
{33,19}. Thus, {33} stripes can incorporate as “guests”
within {19<sub>2</sub>} “host” monolayers. The composition
and morphology of monolayers formed by drop casting solutions of {33,19}
and {19<sub>2</sub>} at 19 °C are dominated by assembly kinetics.
Short {33} strips are immersed haphazardly in monolayers comprised
mostly of {19<sub>2</sub>}. Thermal annealing promotes fuller expression
of {33,19}’s shape amphiphilicity and assembly of thermodynamically
determined monolayers incorporating 1-D {33} stripes within a 2-D
matrix of {19<sub>2</sub>}. Larger solution mole fractions of {19<sub>2</sub>} yield annealed monolayers with nearly constant {33} strip
lengths, decreased {33} strip density, and increased {33} strip spacing
Shape Amphiphiles in 2‑D: Assembly of 1‑D Stripes and Control of Their Surface Density
The morphology of monolayers assembled
from mixtures of a shape-amphiphilic
molecule, {33,19} = 1-((hentriaconta-14,16-diyn-1-yloxy)Âmethyl)-5-((heptadecyloxy)Âmethyl)Âanthracene,
and a symmetric molecule, {19<sub>2</sub>}, at the solution–HOPG
interface depends strongly on the components’ solution concentrations
and sample annealing history. The kinked alkadiyne side chain, {33},
packs optimally only with antiparallel aligned, {33} side chains.
Thus, optimal packing of {33} side chains should assemble “{33}
stripes” consisting of two adjacent {33,19} columns with interdigitated
{33} chains. The aliphatic {19} side chain of {33,19} can pack with
antiparallel aligned {19} side chains from {19<sub>2</sub>} or from
{33,19}. Thus, {33} stripes can incorporate as “guests”
within {19<sub>2</sub>} “host” monolayers. The composition
and morphology of monolayers formed by drop casting solutions of {33,19}
and {19<sub>2</sub>} at 19 °C are dominated by assembly kinetics.
Short {33} strips are immersed haphazardly in monolayers comprised
mostly of {19<sub>2</sub>}. Thermal annealing promotes fuller expression
of {33,19}’s shape amphiphilicity and assembly of thermodynamically
determined monolayers incorporating 1-D {33} stripes within a 2-D
matrix of {19<sub>2</sub>}. Larger solution mole fractions of {19<sub>2</sub>} yield annealed monolayers with nearly constant {33} strip
lengths, decreased {33} strip density, and increased {33} strip spacing
Shape-Directed Patterning and Surface Reaction of Tetra-diacetylene Monolayers: Formation of Linear and Two-Dimensional Grid Polydiacetylene Alternating Copolymers
Side
chains containing two diacetylene units spaced by an odd number
of methylene units exhibit pronounced “bumps” composed
of 0.3 nm steps, in opposite directions, at odd and even side-chain
positions. In densely packed self-assembled monolayers, the bis-diacetylene
bumps stack into each other, similar to the stacking of paper cups.
Bis-diacetylene side chain structure and associated packing constraints
can be tailored by altering the bump width, direction, side-chain
location, and overall side-chain length as a means to direct the identities
and alignments of adjacent molecules within monolayers. Scanning tunneling
microscopy (STM) at the solution–HOPG interface confirms the
high selectivity and fidelity with which bis-diacetylene bump stacking
directs the packing of shape-complementary side chains within one-component
monolayers and within two-component, 1-D self-patterned monolayers.
Drop cast or moderately annealed monolayers of anthracenes bearing
two bis-diacetylene side chains assemble single domains as large as
10<sup>5</sup> nm<sup>2</sup>. Light-induced cross-linking of two-component,
1-D patterned monolayers generates linear polydiacetylene alternating
copolymers (A-B-)<sub><i>x</i></sub> and 2-D grid polydiacetylene
alternating copolymers (A<sub>‑B‑</sub><sup>‑B‑</sup>A<sub>‑B‑</sub><sup>‑B‑</sup>)<sub><i>x</i></sub> that covalently lock in monolayer
structure and patterns
Data_of_Figure_3_4.Number_of_the_offspring_of_pollen_and_pollen-free_foundresses_across_different_species
Number of the offspring of pollen and pollen-free foundresses across different specie
Data_of_Figure_1_2.Number_of_offspring_of_pollen_carried_and_pollen-free_foundresses_according_to_different_foundress_numbers.xls
Number of offspring of pollen carried and pollen-free foundresses according to different foundress number
Data_of_Figure_4.Number_of_the_foundress_and_the_fruit diameter_across_different_species
Number of the foundress and the fruit diameter across different specie
The general two-stage class of policies.
<p>In stage 1, for each resident we choose the number of fingers () to acquire and whether ) or not ( to acquire the irises, based on the BFD and BID scores . We then observe the new similarity scores of the acquired biometrics, where the fingerprint scores are ranked according to the index . We compute the likelihood ratio and accept the resident as genuine if is greater than the upper threshold , reject the resident if is smaller than the lower threshold , and otherwise continue to stage 2, where both irises (if ) and additional fingerprints are acquired. Finally, we compute the likelihood ratio based on the biometrics acquired in stage 2 and then accept or reject the resident using the second-stage threshold .</p
Prevalence (%) of leisure-time physical inactivity in U.S. states, 2008–2013.
<p>Prevalence (%) of leisure-time physical inactivity in U.S. states, 2008–2013.</p
Biosynthesis of 7,8-dihydroxyflavone glycosides via OcUGT1-catalyzed glycosylation and transglycosylation
<p>Herein, a flavonoid glycosyltransferase (GT) OcUGT1 was determined to be able to attack C-8 position of 7,8-dihydroxyflavone (7,8-DHF) via both glycosylation and transglycosylation reactions. OcUGT1-catalyzed glycosylation of 7,8-DHF resulted in the formation of two monoglycosides 7-<i>O</i>-β-D-glucosyl-8-hydroxyflavone (<b>1a</b>), 7-hydroxy-8-<i>O</i>-β-D-glucosylflavone (<b>1b</b>), as well as one diglycoside 7,8-di-<i>O</i>-β-D-glucosylflavone (<b>1c</b>). Under the action of OcUGT1, inter-molecular trans-glycosylations from aryl β-glycosides to 7,8-DHF to form monoglycosides <b>1a</b> and <b>1b</b> were observable.</p
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