108 research outputs found
Regioselective Synthesis of Highly Substituted Imidazoles via the Sequential Reaction of Allenyl Sulfonamides and Amines
A novel
synthesis of imidazoles from electron-withdrawing group-substituted
allenyl sulfonamides with amines was developed. The 4- and 5-functionalized
imidazoles were constructed regioselectively, which depended on the
substituents on the nitrogen atoms
Hydroxyphosphinylation Reaction of 3âCyclopropylideneprop-2-en-1-ones via CâP ÏâBond Cleavage
An
unexpected hydroxyphosphinylation of 3-cyclopropylideneprop-2-en-1-ones
with phosphines has been observed. This method provides a unique regio-
and stereoselective synthesis of highly functionalized 1-dialkylphinyl-3-oxo-(1<i>Z</i>)-alkenyl cyclopropanols with important potentials. The
reaction displays an unusual mechanistic featureîža highly selective
cleavage of CâP Ï bonds in phosphines
Hydroxyphosphinylation Reaction of 3âCyclopropylideneprop-2-en-1-ones via CâP ÏâBond Cleavage
An
unexpected hydroxyphosphinylation of 3-cyclopropylideneprop-2-en-1-ones
with phosphines has been observed. This method provides a unique regio-
and stereoselective synthesis of highly functionalized 1-dialkylphinyl-3-oxo-(1<i>Z</i>)-alkenyl cyclopropanols with important potentials. The
reaction displays an unusual mechanistic featureîža highly selective
cleavage of CâP Ï bonds in phosphines
Rhodamine-actin (red) was injected into embryos expressing a distinct GFP fusion protein (green; specified in left column)
Puncta was scored as colocalized if two puncta moved in unison over a minimum of two consecutive time points (arrowheads). Time points (s) are indicated at the top right of panel. Percentage of colocalization is shown in the right column. (AâF) Live series shows that actin puncta colocalize with Rab7-GFPâlabeled late endosomes (A), Dah-GFPâlabeled vesicles (B), Syt-GFPâlabeled vesicles (C), and Rab5-GFPâlabeled early endosomes (D). Actin puncta did not show considerable colocalization with Grasp65-GFPâlabeled Golgi (E) or Clathrin light chainâGFPâlabeled membrane (F). Insets in C depict single channels for actin (left) and Syt-GFP (right). Error = SEM. Bar, 5 ÎŒm<p><b>Copyright information:</b></p><p>Taken from "Vesicles and actin are targeted to the cleavage furrow via furrow microtubules and the central spindle"</p><p></p><p>The Journal of Cell Biology 2008;181(5):777-790.</p><p>Published online 2 Jun 2008</p><p>PMCID:PMC2396810.</p><p></p
Bright and High-Color-Rendering White Light-Emitting Diode Using Color-Tunable Oxychloride and Oxyfluoride Phosphors
White
lighting converted by tricolor phosphor and near-ultraviolet
light-emitting diode demonstrates great potential in general lighting.
However, a major problem with this approach is the lower luminous
efficiency of the resulting white lighting by the reabsorption among
tricolor phosphors. In this work, we propose a general but effective
method for achieving high-efficacy white light-emitting diodes (WLEDs)
by using two-color phosphors having the same host that can lower energy
loss by reabsorption. Color-tunable Sr<sub>7.95</sub>Si<sub>4</sub>O<sub>12</sub>Cl<sub>8</sub>:0.05Eu<sup>2+</sup> (SSO_Cl:0.05Eu<sup>2+</sup>) phosphors are synthesized by cationic substitution strategy,
and the emission colors can be tuned from blue-greenish to blue/yellow
by Sr â Mg/Ca substitution. The red-shifted emission is attributed
to the increased Eu<sup>2+</sup> d-orbital splitting owing to the
smaller size of Ca<sup>2+</sup>, whereas blue-shifted Eu<sup>2+</sup> emission is unusual in Mg-substitution for Sr<sup>2+</sup>. WLEDs
with luminous efficacies (η<sub>L</sub>) of 28.9â56 lm/W
and CRIs of 79â90.2 are demonstrated using the two-color phosphors.
By employing a narrow-line Mn<sup>4+</sup> emission deep red oxyfluoride
phosphor, a high CRI (Ra = 90.3, R9 = 94) WLED with η<sub>L</sub> of 39.3 lm/W is obtained. These findings provide a possible way
for developing high CRI WLED by using two-color phosphors
(A) Phalloidin in fixed embryos shows F-actin puncta in cycle 14 interphase cells (arrow)
(B) F-actin puncta localize to the cell equator near furrow MTs (arrowheads) and the central spindle at cytokinesis (arrows). Merged images of F-actin (phalloidin; red) and MTs (α-Tub; green) are shown in the bottom panels. (CâJ) Live series of cycle 14 telophase. Rhodamine-actin, red; Tub-GFP, green. Actin puncta accumulate near the central spindle (D, bracket). Arrowheads in CâF show an individual actin puncta moving alongside an MT bundle at the central spindle. Furrow MTs (G, arrowed bracket) align perpendicular to the cleavage plane. Its midpoint contacts the furrow tip (G, arrowhead). Actin puncta are visible near ends of furrow MTs (I, blue arrowhead) and accumulate at the contact point between the leading furrow edge and furrow MTs (G and I, white arrowheads). Arrow in I shows an actin puncta colocalized with the central spindle. Time points (s) are shown at the top right of each panel. For full video, see Video 2, available at . Bars, 5 ÎŒm.<p><b>Copyright information:</b></p><p>Taken from "Vesicles and actin are targeted to the cleavage furrow via furrow microtubules and the central spindle"</p><p></p><p>The Journal of Cell Biology 2008;181(5):777-790.</p><p>Published online 2 Jun 2008</p><p>PMCID:PMC2396810.</p><p></p
Free vibration analysis of composite cylindrical shells with non-uniform thickness walls
The paper proposes to characterize the free vibration behaviour of non-uniform cylindrical shells using spline approximation under first order shear deformation theory. The system of coupled differential equations in terms of displacement and rotational functions are obtained. These functions are approximated by cubic splines. A generalized eigenvalue problem is obtained and solved numerically for an eigenfrequency parameter and an associated eigenvector which are spline coefficients. Four and two layered cylindrical shells consisting of two different lamination materials and plies comprising of same as well as different materials under two different boundary conditions are analyzed. The effect of length parameter, circumferential node number, material properties, ply orientation, number of lay ups, and coefficients of thickness variations on the frequency parameter is investigated
Interaction of a Hydrophobic-Functionalized PAMAM Dendrimer with Bovine Serum Albumin: Thermodynamic and Structural Changes
The
interaction between a hydrophobic-functionalized PAMAM dendrimer
(PAMAM-NH<sub>2</sub>-C12, 25%, G4) and bovine serum albumin (BSA)
has been investigated by circular dichroism (CD), UVâvis, and
fluorescence spectroscopic methods and molecular modeling. The analysis
of the effects of dendrimer complexation on the stability and conformation
of BSA indicated that the binding process of the hydrophobic-functionalized
dendrimer with BSA induced the relatively large changes in secondary
structure of protein. Thermal denaturation of BSA, when carried out
in the presence of dendrimer, also indicated that this hydrophobic-functionalized
dendrimer acted as a structure destabilizer for BSA. The hydrophobic,
electrostatic, and hydrogen bonding forces played important roles
in the complex formation. The putative binding site of PAMAM-NH<sub>2</sub>-C12 (25%) dendrimer on BSA was near to domain I and domain
II. The effect of hydrophobic modification on the stability and structure
of BSA would find useful information on the cytotoxicity of PAMAM
dendrimer
Polyacrylonitrile Fiber Supported <i>N</i>âHeterocyclic Carbene Ag(I) As Efficient Catalysts for Three-Component Coupling and Intramolecular 1,3-Dipolar Cycloaddition Reactions under Flow Conditions
A series of recoverable and reusable <i>N</i>-heterocyclic carbene silver complexes supported on polyacrylonitrile
fiber were prepared and characterized. Their catalytic performances
in three-component coupling reactions of aldehydes, amines, and alkynes
(A3 coupling) to synthesize propargylamines were evaluated. The catalysts
were also used to prepare fused triazoles in one-pot reactions with
excellent yields and diastereoselectivities. In these reactions, the
substrates underwent A3 coupling followed by intramolecular 1,3-dipolar
cycloaddition. The above reactions were also successfully performed
in a continuous-flow process, and sustainable, modular, and efficient
syntheses of propargylamines and fused triazoles were achieved
Cardiolipin Hydrolysis by iPLA<sub>2</sub>.
<p>A. GC/MS analysis of the free fatty acids released from cardiolipin by hydrolysis with (red) and in the absence of (blue) iPLA<sub>2</sub>. B. The main mass peak released by iPLA<sub>2</sub> at 8.0 min on GC is oleic acid (18â¶1). C. LC/MS analysis of the main fatty acid released from cardiolipin hydrolysis by iPLA<sub>2</sub>.</p
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