The diarylethene derivative, 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene, undergoes a reversible photoisomerization between its ring-open and ring-closed forms in the solid-state and has applications as a photomechanical material. Mechanical properties of macrocrystals, nanowire single crystals, and amorphous films as a function of multiple sequential UV and visible light exposures have been quantified using atomic force microscopy nanoindentation. The isomerization reaction has no effect on the elastic modulus of each solid. But going from the macro- to the nanowire crystal results in a remarkable over 3-fold decrease in the elastic modulus. The macrocrystal and amorphous solids are highly resistant to photomechanical fatigue, while nanowire crystals show clear evidence of photomechanical fatigue attributed to a transition from crystal to amorphous forms. This study provides first experimental evidence of size-dependent photomechanical fatigue in photoreactive molecular crystalline solids and suggests crystal morphology and size must be considered for future photomechanical applications.Vinylogous Darzens and aza-Darzens reactions employing a benzothiophene 1,1-dioxide nucleophile are reported. These new [2 + 1] annulation reactions, which proceed under mild reaction conditions, are γ-selective, affording trans-epoxides selectively and favoring trans-aziridines. The reactions are base-dependent, with KOtBu and Cs2CO3 being optimal for aldehyde and imine annulations, respectively. Comparison of the benzothiophene nucleophile to its acyclic counterpart reveals superior performance in the case of aldehydes, while the outcome varies depending on the sulfonamide imine used.Two novel polycyclic polyprenylated acylphloroglucinols (PPAPs), hyperfols A (1) and B (2), and two known biosynthetically related precursors (3 and 4) were isolated from Hypericum perforatum. Compound 1 possesses an unprecedented 2,3-seco-PPAP with a fused 5/5/9/5 tetracyclic skeleton, and 2 features a 30-norPPAP. Their structures were established by spectroscopic analysis, computer-assisted structure elucidation software, and electronic circular dichroism calculations. Moreover, compounds 1 and 4 exhibit significant cytotoxicity against human erythroleukemia cells by inducing cell apoptosis.The motion of peanut-shaped magnetic microrods (PSMRs) with different magnetic moment (Ms) orientations φM under a nonuniform AC magnetic field has been investigated systematically. When gradually changing φM from 90° (perpendicular to the long axis of the PSMR) to 0°, the motion of the PSMR evolves from rolling to precession, then to tumbling. Systematic investigations on the translational velocity vp versus the magnitude of the applied magnetic field B and the angular velocity ωB show that the overall motion of the PSMRs can be divided into four different zones Brownian motion zone, synchronized zone, asynchronized zone, and oscillation zone. The vp-ωB relationship can be rescaled by a critical frequency ωc, which is determined by Ms, B, and a hydrodynamic term. An intrinsic quality factor qm for the translational motion of a magnetically driven micro-/nanomotor is defined and is found to range from 0.73 to 13.65 T-1 in the literature, while the Fe PSMRs in the current work give the highest qm (= 25.48 T-1). High speed movies reveal that both the tumbling and precession motions of the PSMRs have a discretized nature. At the instances when the magnetic field changes direction, the PSMR performs an instantaneous rotation and the strong hydrodynamic wall effect would impose a driving force to move the PSMR translationally, and about more than 60% of the time, the PSMR neither rotates nor moves translationally. Based on this discretized motion nature, an analytic expression for qm is found to be determined by the shape of the surface walker, the hydrodynamics near a wall, and the magnetic properties of the surface walker. This work can help us to better understand the motion of magnetic surface walkers and gain insight into designing better micro-/nanomotors.A copper-catalyzed sequential cyclization/migration reaction of alkynyl hydrazides for the synthesis of ring-expanded N-N fused pyrazolones was developed. Control experiments indicate that the copper-ligand complex plays an essential role in the reaction. This approach features a broad scope including some functional group tolerance as well as a nucleophilic addition/1,3-migration/formal 1,2-migration sequence. This protocol provides simple manipulation and less waste due to high yield and atom economy. The synthetic utility of N-N fused pyrazolones was also demonstrated by further transformations.Tendon is a highly organized, dense connective tissue that has been demonstrated to have very little turnover.  https://www.selleckchem.com/CDK.html  In spite of the low turnover, tendon can grow in response to loading, which may take place primarily at the periphery. Tendon injuries and recurrence of injuries are common in both humans and animals in sports. It is unclear why some areas of the tendon are more susceptible to such injuries and whether this is due to intrinsic regional differences in extracellular matrix (ECM) production or tissue turnover. This study aimed to compare populations of tenocytes derived from the tendon core and periphery. Tenocytes were isolated from equine superficial digital flexor tendons (SDFTs), and the proliferation capacity was determined. ECM production was characterized by immuno- and histological staining and by liquid chromatography-mass spectrometry-based proteomics. Core and periphery SDFT cultures exhibited comparable proliferation rates and had very similar proteome profiles, but showed biological variation in collagen type I deposition. In conclusion, the intrinsic properties of tenocytes from different regions of the tendon are very similar, and other factors in the tissue may contribute to how specific areas respond to loading or injury.The synthesis of atomically precise clusters is nowadays well established. The study of isolated clusters in the gas phase has also become an approved field of research. Although both approaches examine the same research objects, namely nanoclusters, little is known about to what extent results from gas phase studies can be transferred to colloidal systems and vice versa. In particular, it is not yet sufficiently understood how ligands influence the geometric and electronic structure of clusters from an experimental point of view. By comparing a ligand-stabilized tin nanocluster in solution with an isolated species in the gas phase and considering different geometric arrangements with the same number of tin atoms, the impacts of ligand stabilization, molecular symmetry, and solvatochromism on the optical behavior are thoroughly worked out for the first time.