42820 research outputs found
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Improvement of bovine in vitro fertilization embryo preservation techniques by slow-freezing and non-freezing methods
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Indonesia's Societal Shifts and Disaster Risk Management: Transition and Challenge
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Biomechanical properties of regenerated digital flexor tendon in immature newt following complete transection
Get PDFBackground: Adult newt (9-month-old) has become an emerging research model to study complete regeneration of injured adult tendon. If younger newts exhibit tendon regeneration similar to adult ones, they can be used as an additional experimental model, assuring a high- throughput of experiments using genetic manipulation owing to shorter period of growing. Objective: To examine mechanical properties and tissue structure of tendon in immature Iberian ribbed newt following complete transection. Methods: Digital flexor tendon of the middle finger of the left hindlimb in 4- and 6-month-old Iberian ribbed newt (4mo and 6mo, respectively) was transected. Regenerated tendon was mechanically tested at 6 and 12 weeks postoperatively. Collagen fiber structure was also observed using two-photon microscopy. Results: In both 4mo and 6mo newts, regenerated tendon at 6 weeks exhibited significantly lower tensile strength than corresponding normal tendons and had unorganized collagen structure. At 12 weeks, Regenerated tendon in both groups had the strength comparable to normal controls. Additionally, the collagen structure seemed more organized compared to that at 6 weeks and comparable to controls. These phenomena were essentially similar to those in adult newts. Conclusion: 4mo and 6mo newts can also be used as experimental models of adult tendon regeneration research.First published online March 18, 2025journal articl
Generation of Bis(pentafluorophenyl)boron Enolates from Alkynes and Their Catalyst-Free Alkyne Coupling
No full textCarbon-carbon bond forming reactions are powerful synthetic tools for constructing organic molecular frameworks. In this study, strongly Lewis acidic bis(pentafluorophenyl)boron enolates were generated from alkynes through oxygen transfer from 2,6-dibromopyridine N-oxide using tris(pentafluorophenyl)borane [B(C6F5)3]. Boron enolates were highly reactive owing to the strong Lewis acidity of the boron centers, and thus immediately coupled with alkynes. N-Ethynylphthalimide reacted as an alkyne with 2,6-dibromopyridine N-oxide and B(C6F5)3 to form a semi-stable bis(pentafluorophenyl)boron enolate through the coordination of the carbonyl group to the boron center. This enolate underwent coupling with another alkyne.journal articl
Synthesis of Spirocyclic Phthalans via Ru-Catalyzed [2 + 2 + 2] Cycloaddition of 1,6-Diynes with Ex-Situ Generated Acetylene
No full textSpirocyclic motifs are attracting increasing attention owing to their three-dimensional geometries that endow bioactive molecules with superior physical and biological properties. We developed an efficient method for constructing spirocyclic phthalans via the Ru-catalyzed [2 + 2 + 2] cycloaddition of cycloalkanone-derived 1,6-diynes with acetylene gas ex-situ-generated from calcium carbide and H2O.journal articl
