4 research outputs found
A pOH Jump Driven by Nî—»N Out-of-Plane Motion in the Photoisomerization of Water-Solvated Triazabutadiene
Utilization
of photoinitiated isomerization reaction has recently
emerged as a very promising platform to modulate the basicity of compounds;
however, theoretical insight into its regulatory mechanism remains
largely unknown and needs to be addressed. For the first time, an
unexpected <i>trans</i>–<i>cis</i> photoisomerization
via the Nî—»N out of plane (NOOP) motion triggered by an in-plane
inversion of N–NN moiety was computationally demonstrated
to regulate the pOH jump of water-solvated triazabutadiene by using
the multiconfigurational perturbation theory together with the calculation
of rate constants of protonation–deprotonation reactions. Kinetic
analyses show that the dramatic pOH change can be attributed to the
reinforced intramolecular hydrogen bonding resulting from water cluster
reorientation and the enhanced coupling between the rotated π
orbital and N lone pair of triazabutadiene in the remarkable <i>trans</i>–<i>cis</i> photoisomerization
Molecular Turnstiles Regulated by Metal Ions
A family of novel molecular turnstiles <b>1</b>–<b>3</b> composed of two stators with pyridyl
binding sites and a
different-sized triptycene rotor was synthesized. The molecular turnstiles
behave in an open state at room temperature in the absence of metal
ions but display significantly different closed states in the presence
of Ag<sup>+</sup> and Pd<sup>2+</sup>. The Ag<sup>+</sup>-mediated
turnstiles <b>1</b>–<b>3Ag</b> exhibited closed
states but unreadable bistability at ambient temperature because the
Ag<sup>+</sup>-mediated macrocyclic framework is not able to restrict
the rotations of the rotors; while temperature was decreased, the
macrocyclic frameworks became stable enough to halt the rotations
of the rotors, eventually leading to the readable closed states for <b>1</b>–<b>3Ag</b>. In contrast, Pd<sup>2+</sup>-mediated
macrocyclic frameworks are stable, giving rise to a detectable closed
state of turnstiles <b>1</b>–<b>3Pd</b> in a wide
range of temperatures. These findings have also been supported by
DFT calculations
Molecular Turnstiles Regulated by Metal Ions
A family of novel molecular turnstiles <b>1</b>–<b>3</b> composed of two stators with pyridyl
binding sites and a
different-sized triptycene rotor was synthesized. The molecular turnstiles
behave in an open state at room temperature in the absence of metal
ions but display significantly different closed states in the presence
of Ag<sup>+</sup> and Pd<sup>2+</sup>. The Ag<sup>+</sup>-mediated
turnstiles <b>1</b>–<b>3Ag</b> exhibited closed
states but unreadable bistability at ambient temperature because the
Ag<sup>+</sup>-mediated macrocyclic framework is not able to restrict
the rotations of the rotors; while temperature was decreased, the
macrocyclic frameworks became stable enough to halt the rotations
of the rotors, eventually leading to the readable closed states for <b>1</b>–<b>3Ag</b>. In contrast, Pd<sup>2+</sup>-mediated
macrocyclic frameworks are stable, giving rise to a detectable closed
state of turnstiles <b>1</b>–<b>3Pd</b> in a wide
range of temperatures. These findings have also been supported by
DFT calculations
Identification of Conserved and Novel microRNAs in Cashmere Goat Skin by Deep Sequencing
<div><p>MicroRNAs (miRNAs) are a class of small RNAs that play significant roles in regulating the expression of the post-transcriptional skin and hair follicle gene. In recent years, extensive studies on these microRNAs have been carried out in mammals such as mice, rats, pigs and cattle. By comparison, the number of microRNAs that have been identified in goats is relatively low; and in particular, the miRNAs associated with the processes of skin and hair follicle development remain largely unknown. In this study, areas of skin where the cashmere grows in anagen were sampled. A total of 10,943,292 reads were obtained using Solexa sequencing, a high-throughput sequencing technology. From 10,644,467 reads, we identified 3,381 distinct reads and after applying the classification statistics we obtained 316 miRNAs. Among them, using conservative identification, we found that 68 miRNAs (55 of these are confirmed to match known sheep and goat miRNAs in miRBase ) are conserved in goat and have been reported in NCBI; the remaining 248 miRNA were conserved in other species but have not been reported in goat. Furthermore, we identified 22 novel miRNAs. Both the known and novel miRNAs were confirmed by a second sequencing using the same method as was used in the first. This study confirmed the authenticity of 316 known miRNAs and the discovery of 22 novel miRNAs in goat. We found that the miRNAs that were co-expressed in goat and sheep were located in the same region of the respective chromosomes and may play an essential role in skin and follicle development. Identificaton of novel miRNAs resulted in significant enrichment of the repertoire of goat miRNAs.</p> </div