Catalytic Addition of Simple Alkenes to Carbonyl Compounds by Use of Group 10 Metals

Recent advances using nickel complexes in the activation of unactivated monosubstituted olefins for catalytic intermolecular carbon-carbon bond-forming reactions with carbonyl compounds, such as simple aldehydes, isocyanates, and conjugated aldehydes and ketones, are discussed. In these reactions, the olefins function as vinyl- and allylmetal equivalents, providing a new strategy for organic synthesis. Current limitations and the outlook for this new strategy are also discussed.National Institute of General Medical Sciences (U.S.) (GM-063775)National Institute of General Medical Sciences (U.S.) (GM-072566)National Science Foundation (U.S.) (CAREER CHE-0134704)Amgen Inc.Boehringer Ingelheim PharmaceuticalsBristol-Myers Squibb CompanyMerck & Co., Inc.GlaxoSmithKlineJohnson & JohnsonPfizer Inc.Alfred P. Sloan FoundationWyeth ResearchDeshpande Center for Technological InnovationNational Science Foundation (U.S.) (CHE-9809061)National Science Foundation (U.S.) (DBI-9729592)National Institutes of Health (U.S.) (1S10RR13886-01

The Anatomic Course of the First Jejunal Branch of the Superior Mesenteric Vein in Relation to the Superior Mesenteric Artery

Introduction. The purpose of this study is to determine the anatomic course of the first jejunal branch of the superior mesenteric vein (SMV) in relation to the superior mesenteric artery (SMA). Methods. Three hundred consecutive contrast-enhanced computed tomography (CT) scans were reviewed by a surgical oncologist with confirmation of findings by a radiologist. Results. The overall incidence of a first jejunal branch coursing anterior to the SMA was 41%. There was no correlation between patient gender and position of the jejunal branch. In addition, there was no correlation between size of the first jejunal branch and its location in relation to the SMA. The IMV drained into the SMV in 27% of the patients. The IMV drained into the SMV-portal vein confluence in 17% of patients and inserted into the splenic vein in 54%. An anterior coursing first jejunal branch statistically correlated with an IMV that drained into the SMV-portal vein confluence (P = 0.009). Conclusion. The first jejunal branch of the SMV has a highly variable course in relation to the SMA and has a higher incidence of an anterior location in this population than previously reported

Soft Phonon Mode Triggering Fast Ag Diffusion in Superionic Argyrodite Ag8_8GeSe6_6

The structural coexistence of dual rigid and mobile sublattices in superionic Argyrodites yields ultralow lattice thermal conductivity along with decent electrical and ionic conductivities and therefore attracts intense interest for batteries, fuel cells, and thermoelectric applications. However, a comprehensive understanding of their underlying lattice and diffusive dynamics in terms of the interplay between phonons and mobile ions is missing. Herein, inelastic neutron scattering is employed to unravel that phonon softening on heating to T$_c$ ≈ 350 K triggers fast Ag diffusion in the canonical superionic Argyrodite Ag$_8$GeSe$_6$. Ab initio molecular dynamics simulations reproduce the experimental neutron scattering signals and identify the partially ultrafast Ag diffusion with a large diffusion coefficient of 10$^{−4}$ cm$^{−2}$ s$^{−1}$. The study illustrates the microscopic interconnection between soft phonons and mobile ions and provides a paradigm for an intertwined interaction of the lattice and diffusive dynamics in superionic materials

Amorphous-Like Ultralow Thermal Transport in Crystalline Argyrodite Cu7PS6

Due to their amorphous-like ultralow lattice thermal conductivity both below and above the superionic phase transition, crystalline Cu- and Ag-based superionic argyrodites have garnered widespread attention as promising thermoelectric materials. However, despite their intriguing properties, quantifying their lattice thermal conductivities and a comprehensive understanding of the microscopic dynamics that drive these extraordinary properties are still lacking. Here, an integrated experimental and theoretical approach is adopted to reveal the presence of Cu-dominated low-energy optical phonons in the Cu-based argyrodite Cu7PS6. These phonons yield strong acoustic-optical phonon scattering through avoided crossing, enabling ultralow lattice thermal conductivity. The Unified Theory of thermal transport is employed to analyze heat conduction and successfully reproduce the experimental amorphous-like ultralow lattice thermal conductivities, ranging from 0.43 to 0.58 W m−1 K−1, in the temperature range of 100–400 K. The study reveals that the amorphous-like ultralow thermal conductivity of Cu7PS6 stems from a significantly dominant wave-like conduction mechanism. Moreover, the simulations elucidate the wave-like thermal transport mainly results from the contribution of Cu-associated low-energy overlapping optical phonons. This study highlights the crucial role of low-energy and overlapping optical modes in facilitating amorphous-like ultralow thermal transport, providing a thorough understanding of the underlying complex dynamics of argyrodites

Spectroscopy of Covalently Functionalized Graphene

International audienceThe atomically flat surface of graphene provides an opportunity to apply carbon-carbon bond-forming chemical reactions to engineer the electronic properties of graphene circuitry. In particular, covalent functionalization of the surface or the edge of graphene ribbons provides a novel way to introduce patterning that can modulate the energy band gap, affect electron scattering, and direct current flow by producing dielectric regions in a graphene wafer. We discuss the use of Raman spectroscopy and scanning tunneling microscopy to characterize the surface functionalization periodicities and densities that have been produced by the chemical derivatization of epitaxial graphene together with the concomitant changes in the electronic and magnetic properties of the graphene surface laye

The proto‐oncogene function of Mdm2 in bone

Mouse double minute 2 (Mdm2) is a multifaceted oncoprotein that is highly regulated with distinct domains capable of cellular transformation. Loss of Mdm2 is embryonically lethal, making it difficult to study in a mouse model without additional genetic alterations. Global overexpression through increased Mdm2 gene copy number (Mdm2Tg) results in the development of hematopoietic neoplasms and sarcomas in adult animals. In these mice, we found an increase in osteoblastogenesis, differentiation, and a high bone mass phenotype. Since it was difficult to discern the cell lineage that generated this phenotype, we generated osteoblast‐specific Mdm2 overexpressing (Mdm2TgOb) mice in 2 different strains, C57BL/6 and DBA. These mice did not develop malignancies; however, these animals and the MG63 human osteosarcoma cell line with high levels of Mdm2 showed an increase in bone mineralization. Importantly, overexpression of Mdm2 corrected age‐related bone loss in mice, providing a role for the proto‐oncogenic activity of Mdm2 in bone health of adult animals

Switching Virally Suppressed, Treatment-Experienced Patients to a Raltegravir-Containing Regimen Does Not Alter Levels of HIV-1 DNA

Background: Current HIV-1 antiretroviral therapy (ART) greatly reduces virus replication but does not significantly affect the viral reservoir. Raltegravir, a recently introduced integrase inhibitor, could, at least theoretically, reduce residual viremia in patients on ART and affect the viral reservoir size. The aim of this study was to assess whether switching therapy in treatment-experienced patients that were virally suppressed to a raltegravir-containing regimen reduces the size of the viral reservoir, and if such treatment leads to a change in levels of HIV 2-LTR circles in this patient group. Methods: 14 ART experienced individuals with a suppressed viral load (,50 HIV-1 RNA copies/mL plasma) at baseline (for at least 2 months) were switched to a raltegravir-containing regimen. Blood samples were taken at baseline and at $2 timepoints up to 4866 weeks. Levels of total HIV-1 DNA and 2-LTR circles in peripheral blood mononuclear cells (PBMCs) were measured using real-time PCR assays. Results: There was no significant change in HIV-1 total DNA levels over the study duration (p = 0.808), median slope 0.24 (conservative nonparametric 95 % CI: 211.78, 26.23). Low levels of 2-LTR circles were detected in 2 patients. One had 16 copies/10 6 PBMCs at baseline and the other had 34 copies/10 6 PBMCs at week 51. Conclusions: The switch to a raltegravir containing regimen was not associated with a significant change in HIV-1 total DNA levels in this cohort. There were no observed changes in the levels of HIV-1 2-LTR circles associated with raltegravi