5 research outputs found
Temporal profile curves for calcium transients during single twitch activation (A) and tetanic stimulation (B).
<p>Each line corresponds to the average of all single fiber measurements that have been included in the statistical analysis. For improving the visibility of group differences, the time interval was adjusted accordingly. The red and black dashed lines indicate the drift of the baseline calcium during the tetanic stimulation. Treatment of fibers with 25 μM FK506 (red line) leads to an elevated inter-peak-baseline level compared to untreated control fibers (black line). </p
Energy utilization in FDB fibers.
<p>The graph shows the estimates for the relative baseline change ± SEM after different treatment conditions (pretreatment/injection). Changes, displayed in %, are statistically valuated by the corresponding p-value. The increased SERCA activity observed after FK506 injection can be incompletely normalized by pretreatment with JTV-519.</p
Photoinduced Brook-Type Rearrangement of Acylcyclopolysilanes
Previously unknown 1,1,4-trisÂ(trimethylsilyl)-4-acyldodecamethylcyclohexasilanes
(Me<sub>3</sub>Si)<sub>2</sub>Si<sub>6</sub>Me<sub>12</sub>(Me<sub>3</sub>Si)ÂCOR (<b>16a</b>, R = <i>tert</i>-butyl; <b>16b</b>, R = 1-adamantyl) have been synthesized by the reaction
of the potassium silanides (Me<sub>3</sub>Si)<sub>2</sub>Si<sub>6</sub>Me<sub>12</sub>(Me<sub>3</sub>Si)K with acid chlorides ClCOR, and
their photochemical rearrangement reactions have been studied. The
molecular structures of <b>16a</b>,<b>b</b> as determined
by single-crystal X-ray diffraction analysis exhibit an unusual twist-boat
conformation of the cyclohexasilane ring. When <b>16a</b>,<b>b</b> were photolyzed with λ >300 nm radiation, they
underwent
Brook type 1,3-Si → O migration reactions to generate the cyclohexasilanes <b>17a</b>,<b>b</b> with exocyclic SiC bonds along
with smaller amounts of the ring-enlarged species <b>19a</b>,<b>b</b> with endocyclic Siî—»C double bonds. While <b>17a</b>,<b>b</b> were stable enough to allow characterization
by NMR and UV absorption spectroscopy, the less stable products <b>19a</b>,<b>b</b> could only be observed in the form of their
methanol adducts
The graph shows the estimates for the AUC (mean±SEM) for the four groups.
<p>Changes, displayed in %, are statistically valuated by the corresponding p-value. n: number of fibers measured per group. Control (n=42), FK506 (n=42), JTV-519 (n=53) and JTV-519 + FK506 (n= 44).</p
Stable Silenolates and Brook-Type Silenes with Exocyclic Structures
The
first silenolates with exocyclic structures [(Me<sub>3</sub>Si)<sub>2</sub>SiÂ(Si<sub>2</sub>Me<sub>4</sub>)<sub>2</sub>SiCÂ(R)ÂO]<sup>−</sup>K<sup>+</sup> (<b>2a</b>: R = 1-adamantyl; <b>2b</b>:
mesityl; <b>2c</b>: <i>o</i>-tolyl) were
synthesized by the reaction of the corresponding acylcyclohexasilanes <b>1a</b>–<b>c</b> with KO<i>t</i>Bu. NMR
spectroscopy and single-crystal X-ray diffraction analysis suggest
that the aryl-substituted silenolates <b>2b</b>,<b>c</b> exhibit increased character of functionalized silenes as compared
to the alkyl-substituted derivative <b>2a</b> due to the different
coordination of the K<sup>+</sup> counterion to the SiCÂ(R)O moiety. <b>2b</b>,<b>c</b>, thus, reacted with ClSi<i>i</i>Pr<sub>3</sub> to give the exocyclic silenes (Me<sub>3</sub>Si)<sub>2</sub>SiÂ(Si<sub>2</sub>Me<sub>4</sub>)<sub>2</sub>Siî—»CÂ(OSi<i>i</i>Pr<sub>3</sub>)ÂR (<b>3b</b>: R = Mes; <b>3c</b>: <i>o</i>-Tol), while <b>2a</b> afforded the Si-silylated
acylcyclohexasilane <b>1d</b>. The thermally remarkably stable
compound <b>3b</b>, which is the first isolated silene with
the sp<sup>2</sup> silicon atom incorporated into a cyclopolysilane
framework, could be fully characterized structurally and spectroscopically