Supported nanoparticles (NPs) of nonplasmonic transition metals (Pd, Pt, Rh, and Ir) are widely used as thermally activated catalysts for the synthesis of important organic compounds, but little is known about their photocatalytic capabilities. We discovered that irradiation with light can significantly enhance the intrinsic catalytic performance of these metal NPs at ambient temperatures for several types of reactions. These metal NPs strongly absorb the light mainly through interband electronic transitions. The excited electrons interact with the reactant molecules on the particles to accelerate these reactions. The rate of the catalyzed reaction depends on the concentration and energy of the excited electrons, which can be increased by increasing the light intensity or by reducing the irradiation wavelength. The metal NPs can also effectively couple thermal and light energy sources to more efficiently drive chemical transformations.

Bone marrow transplantation offers great promise for treating a number of disease states. However, the widespread application of this approach is dependent upon the development of less toxic methods to establish chimerism and avoid graft-versus-host disease (GVHD). CD8+/TCR− facilitating cells (FCs) have been shown to enhance engraftment of hematopoietic stem cells (HSCs) in allogeneic recipients without causing GVHD. In the present studies, we have identified the main subpopulation of FCs as plasmacytoid precursor dendritic cells (p-preDCs). FCs and p-preDCs share many phenotypic, morphological, and functional features: both produce IFN-α and TNF-α, both are activated by toll-like receptor (TLR)-9 ligand (CpG ODN) stimulation, and both expand and mature after Flt3 ligand (FL) treatment. FL-mobilized FCs, most of which express a preDC phenotype, significantly enhance engraftment of HSCs and induce donor-specific tolerance to skin allografts. However, p-preDCs alone or p-preDCs from the FC population facilitate HSC engraftment less efficiently than total FCs. Moreover, FCs depleted of preDCs completely fail to facilitate HSC engraftment. These results are the first to define a direct functional role for p-preDCs in HSC engraftment, and also suggest that p-preDCs need to be in a certain state of maturation/activation to be fully functional.

Palladium (Pd)-catalyzed cross-coupling reactions are among the most important methods in organic synthesis. We report the discovery of highly efficient and green photocatalytic processes by which cross-coupling reactions, including Sonogashira, Stille, Hiyama, Ullmann, and Buchwald−Hartwig reactions, can be driven with visible light at temperatures slightly above room temperature using alloy nanoparticles of gold and Pd on zirconium oxide, thus achieving high yields. The alloy nanoparticles absorb visible light, and their conduction electrons gain energy, which is available at the surface Pd sites. Results of the density functional theory calculations indicate that transfer of the light excited electrons from the nanoparticle surface to the reactant molecules adsorbed on the nanoparticle surface activates the reactants. When the light intensity was increased, a higher reaction rate was observed, because of the increased population of photoexcited electrons. The irradiation wavelength also has an important impact on the reaction rates. Ultraviolet irradiation can drive some reactions with the chlorobenzene substrate, while visible light irradiation failed to, and substantially improve the yields of the reactions with the bromobenzene substrate. The discovery reveals the possibility of using low-energy and -density sources such as sunlight to drive chemical transformations.

Abstract-We systematically investigated the comparative efficacy of three different cytokine regimens, administered after a reperfused myocardial infarction, in regenerating cardiac tissue and improving left ventricular (LV) function. Wild-type (WT) mice underwent a 30-minute coronary occlusion followed by reperfusion and received vehicle, granulocyte colony-stimulating factor (G-CSF)ϩFlt-3 ligand (FL), G-CSFϩstem cell factor (SCF), or G-CSF alone starting 4 hours after reperfusion. In separate experiments, chimeric mice generated by reconstitution of radioablated WT mice with bone marrow from enhanced green fluorescent protein (EGFP) transgenic mice underwent identical protocols. Mice were euthanized 5 weeks later. Echocardiographically, LV function was improved in G-CSFϩFL-and G-CSFϩSCF-treated but not in G-CSF-treated mice, whereas LV end-diastolic dimensions were smaller in all three groups. Morphometrically, cytokine-treated hearts had smaller LV diameter and volume. Numerous EGFP-positive cardiomyocytes, capillaries, and arterioles were noted in the infarcted region in cytokine-treated chimeric mice treated with G-CSFϩFL or G-CSFϩSCF, but the numbers were much smaller in G-CSF-treated mice. G-CSFϩFL therapy mobilized bone marrow-derived cells exhibiting increased expression of surface antigens (CD62L and CD11a) that facilitate homing. We conclude that postinfarct cytokine therapy with G-CSFϩFL or G-CSFϩSCF limits adverse LV remodeling and improves LV performance by promoting cardiac regeneration and probably also by exerting other beneficial actions unrelated to regeneration, and that G-CSF alone is less effective. , no therapies are currently available to restore dead myocardium. Although mobilization of bone marrow cells (BMCs) by cytokines has been suggested to regenerate cardiac tissue after MI and to produce functional improvement, the reports on the effects of cytokine treatment are conflicting. [1][2][3][4][5][6] Furthermore, previous studies of cytokines have used models of permanent coronary ligation 1-3,5 that do not reflect the fact that most patients with acute MI undergo coronary reperfusion. In addition, these studies have administered cytokines as a pretreatment 1,2 or performed splenectomy 1,2,5 or both, 1,2 neither of which would be clinically feasible. Although various cytokines have been tested, the relative efficacy of different treatments or combinations of treatments has not been elucidated. Finally, the mechanism whereby cytokines improve left ventricular (LV) function and structure after MI remains obscure. It has been proposed that cytokines mobilize BMCs with subsequent homing to the infarcted tissue and transdifferentiation into cardiac lineage, 1-3 but this hypothesis remains unproven. Thus, numerous unresolved issues persist regarding the use of cytokines as a strategy to achieve cardiac repair after MI.Accordingly, in the present study, we examined the effect of three cytokines (granulocyte colony-stimulating factor [G-CSF], stem cell factor [SCF], and Flt-3 ligand [FL]) on ca...